1//////////////////////////////////////////////////////////////////////
   2// LibFile: distributors.scad
   3//   Functions and modules to distribute children or copies of children onto
   4//   a line, a grid, or an arbitrary path.  The $idx mechanism means that
   5//   the "copies" of children can vary.  Also includes shortcuts for mirroring.  
   6// Includes:
   7//   include <BOSL2/std.scad>
   8// FileGroup: Basic Modeling
   9// FileSummary: Copy or distribute objects onto a line, grid, or path.  Mirror shortcuts. 
  10// FileFootnotes: STD=Included in std.scad
  11//////////////////////////////////////////////////////////////////////
  12
  13// Section: Adaptive Children Using `$` Variables
  14//   The distributor methods create multiple copies of their children and place them in various ways.  While many models 
  15//   require multiple identical copies of an object, this framework is more powerful than
  16//   might be immediately obvious because of `$` variables.  The distributors set `$` variables that the children can use to change their
  17//   behavior from one child to the next within a single distributor invocation.  This means the copies need not be identical.  
  18//   The {{xcopies()}} module sets `$idx` to the index number of the copy, and in the examples below we use `$idx`, but the various
  19//   distributors offer a variety of `$` variables that you can use in your children.  Check the "Side Effects" section for each module
  20//   to learn what variables that module provides.
  21//   .
  22//   Two gotchas may lead to models that don't behave as expected.  While `if` statements work to control modules, you cannot
  23//   use them to make variable assignments in your child object.  If you write a statement like 
  24//   ```
  25//   if (condition) { c="red";}
  26//   else {c="green";}
  27//   ```
  28//   then the `c` variable is set only in the scope of the `if` and `else` clauses and is not available later on when you actually
  29//   try to use it.  Instead you must use the ternary operator and write:
  30//   ```
  31//   c = condition ? "red" : "green";
  32//   ```
  33//   The second complication is
  34//   that in OpenSCAD version 2021.01 and earlier, assignments in children were executed before their parent.  This means 
  35//   that `$` variables like `$idx` are not available in assignments because the parent hasn't run to set them, so if you use them
  36//   you will get a warning about an unknown variable.
  37//   Two workarounds exist, neither of which are needed in newer versions of OpenSCAD.  The workarounds solve the problem because
  38//   **modules** execute after their parent, so the `$` variables **are** available in modules.  You can put your assignments
  39//   in a `let()` module, or you can wrap your child in a `union()`.  Both methods appear below.
  40// Figure(2D,NoScales): This example shows how we can use `$idx` to produce **different** geometry at each index.
  41//   xcopies(n=10, spacing=10)
  42//     text(str($idx));
  43// Continues:
  44//   ```
  45//   xcopies(n=10, spacing=10)
  46//     text(str($idx));
  47//   ```
  48// Figure(2D,NoScales): Here the children are sometimes squares and sometimes circles as determined by the conditional `if` module. This use of `if` is OK because no variables are assigned.  
  49//   xcopies(n=4, spacing=10)
  50//     if($idx%2==0) circle(r=3,$fn=16);
  51//     else rect(6);
  52// Continues:
  53//   ```
  54//   xcopies(n=4, spacing=10)
  55//     if($idx%2==0) circle(r=3,$fn=16);
  56//     else rect(6);
  57//   ```
  58// Figure(2D,NoScales): Suppose we would like to color odd and even index copies differently.  In this example we compute the color for a given child from `$idx` using the ternary operator.  The `let()` module is a module that sets variables and makes them available to its children.  Note that multiple assignments in `let()` are separated by commas, not semicolons.  
  59//   xcopies(n=6, spacing=10){
  60//       let(c = $idx % 2 == 0 ? "red" : "green")
  61//           color(c) rect(6);
  62//   }
  63// Continues:
  64//   ```
  65//   xcopies(n=6, spacing=10){
  66//       let(c = $idx % 2 == 0 ? "red" : "green")
  67//           color(c) rect(6);
  68//   }
  69//   ```
  70// Figure(2D,NoScales):  This example shows how you can change the position of children adaptively.  If you want to avoid repeating your code for each case, this requires storing a transformation matrix in a variable and then applying it using `multmatrix()`.  We wrap our code in `union()` to ensure that it works in OpenSCAD 2021.01.  
  71//   xcopies(n=5,spacing=10)
  72//     union()
  73//     {
  74//       shiftback = $idx%2==0 ? back(10) : IDENT;
  75//       spin = zrot(180*$idx/4);
  76//       multmatrix(shiftback*spin) stroke([[-4,0],[4,0]],endcap2="arrow2",width=3/4, color="red");
  77//     }
  78// Continues:
  79//   ```
  80//   xcopies(n=5,spacing=10)
  81//     union()
  82//     {
  83//       shiftback = $idx%2==0 ? back(10) : IDENT;
  84//       spin = zrot(180*$idx/4);
  85//       multmatrix(shiftback*spin) stroke([[-4,0],[4,0]],endcap2="arrow2",width=3/4,color="red");
  86//     }
  87//   ```
  88
  89
  90//////////////////////////////////////////////////////////////////////
  91// Section: Translating copies of all the children
  92//////////////////////////////////////////////////////////////////////
  93
  94// Function&Module: move_copies()
  95// Synopsis: Translates copies of all children.
  96// SynTags: MatList, Trans
  97// Topics: Transformations, Distributors, Translation, Copiers
  98// See Also: xcopies(), ycopies(), zcopies(), line_copies(), grid_copies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
  99//
 100// Usage:
 101//   move_copies(a) CHILDREN;
 102// Usage: As a function to translate points, VNF, or Bezier patches
 103//   copies = move_copies(a, p=);
 104// Usage: Get Translation Matrices
 105//   mats = move_copies(a);
 106// Description:
 107//   When called as a module, translates copies of all children to each given translation offset.
 108//   When called as a function, with no `p=` argument, returns a list of transformation matrices, one for each copy.
 109//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 110//
 111// Arguments:
 112//   a = Array of XYZ offset vectors. Default `[[0,0,0]]`
 113//   ---
 114//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 115//
 116// Side Effects:
 117//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 118//   `$idx` is set to the index number of each child being copied.
 119//
 120//
 121// Example:
 122//   #sphere(r=10);
 123//   move_copies([[-25,-25,0], [25,-25,0], [0,0,50], [0,25,0]]) sphere(r=10);
 124module move_copies(a=[[0,0,0]])
 125{
 126    req_children($children);
 127    assert(is_list(a));
 128    for ($idx = idx(a)) {
 129        $pos = a[$idx];
 130        assert(is_vector($pos),"move_copies offsets should be a 2d or 3d vector.");
 131        translate($pos) children();
 132    }
 133}
 134
 135function move_copies(a=[[0,0,0]],p=_NO_ARG) =
 136    assert(is_list(a))
 137    let(
 138        mats = [
 139            for (pos = a)
 140            assert(is_vector(pos),"move_copies offsets should be a 2d or 3d vector.")
 141            translate(pos)
 142        ]
 143    )
 144    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 145
 146
 147// Function&Module: xcopies()
 148// Synopsis: Places copies of children along the X axis. 
 149// SynTags: MatList, Trans
 150// Topics: Transformations, Distributors, Translation, Copiers
 151// See Also: move_copies(), ycopies(), zcopies(), line_copies(), grid_copies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
 152//
 153// Usage:
 154//   xcopies(spacing, [n], [sp=]) CHILDREN;
 155//   xcopies(l=, [n=], [sp=]) CHILDREN;
 156//   xcopies(LIST) CHILDREN;
 157// Usage: As a function to translate points, VNF, or Bezier patches
 158//   copies = xcopies(spacing, [n], [sp=], p=);
 159//   copies = xcopies(l=, [n=], [sp=], p=);
 160//   copies = xcopies(LIST, p=);
 161// Usage: Get Translation Matrices
 162//   mats = xcopies(spacing, [n], [sp=]);
 163//   mats = xcopies(l=, [n=], [sp=]);
 164//   mats = xcopies(LIST);
 165// Description:
 166//   When called as a module, places `n` copies of the children along a line on the X axis.
 167//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 168//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 169//
 170// Arguments:
 171//   spacing = Given a scalar, specifies a uniform spacing between copies. Given a list of scalars, each one gives a specific position along the line. (Default: 1.0)
 172//   n = Number of copies to place. (Default: 2)
 173//   ---
 174//   l = If given, the length to place copies over.
 175//   sp = If given as a point, copies will be placed on a line to the right of starting position `sp`.  If given as a scalar, copies will be placed on a line segment to the right of starting position `[sp,0,0]`.  If not given, copies will be placed along a line segment that is centered at [0,0,0].
 176//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 177//
 178// Side Effects:
 179//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 180//   `$idx` is set to the index number of each child being copied.
 181//
 182// Examples:
 183//   xcopies(20) sphere(3);
 184//   xcopies(20, n=3) sphere(3);
 185//   xcopies(spacing=15, l=50) sphere(3);
 186//   xcopies(n=4, l=30, sp=[0,10,0]) sphere(3);
 187// Example:
 188//   xcopies(10, n=3) {
 189//       cube(size=[1,3,1],center=true);
 190//       cube(size=[3,1,1],center=true);
 191//   }
 192// Example:
 193//   xcopies([1,2,3,5,7]) sphere(d=1);
 194module xcopies(spacing, n, l, sp)
 195{
 196    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 197    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 198    req_children($children);
 199    dir = RIGHT;
 200    sp = is_finite(sp)? (sp*dir) : sp;
 201    if (is_vector(spacing)) {
 202        translate(default(sp,[0,0,0])) {
 203            for (i = idx(spacing)) {
 204                $idx = i;
 205                $pos = spacing[i]*dir;
 206                translate($pos) children();
 207            }
 208        }
 209    } else {
 210        line_copies(
 211            l=u_mul(l,dir),
 212            spacing=u_mul(spacing,dir),
 213            n=n, p1=sp
 214        ) children();
 215    }
 216}
 217
 218
 219function xcopies(spacing, n, l, sp, p=_NO_ARG) =
 220    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 221    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 222    let(
 223        dir = RIGHT,
 224        sp = is_finite(sp)? (sp*dir) : sp,
 225        mats = is_vector(spacing)
 226          ? let(sp = default(sp,[0,0,0])) [for (n = spacing) translate(sp + n*dir)]
 227          : line_copies(l=u_mul(l,dir), spacing=u_mul(spacing,dir), n=n, p1=sp)
 228    )
 229    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 230
 231
 232// Function&Module: ycopies()
 233// Synopsis: Places copies of children along the Y axis. 
 234// SynTags: MatList, Trans
 235// Topics: Transformations, Distributors, Translation, Copiers
 236// See Also: move_copies(), xcopies(), zcopies(), line_copies(), grid_copies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
 237//
 238// Usage:
 239//   ycopies(spacing, [n], [sp=]) CHILDREN;
 240//   ycopies(l=, [n=], [sp=]) CHILDREN;
 241//   ycopies(LIST) CHILDREN;
 242// Usage: As a function to translate points, VNF, or Bezier patches
 243//   copies = ycopies(spacing, [n], [sp=], p=);
 244//   copies = ycopies(l=, [n=], [sp=], p=);
 245//   copies = ycopies(LIST, p=);
 246// Usage: Get Translation Matrices
 247//   mats = ycopies(spacing, [n], [sp=]);
 248//   mats = ycopies(l=, [n=], [sp=]);
 249//   mats = ycopies(LIST);
 250// Description:
 251//   When called as a module, places `n` copies of the children along a line on the Y axis.
 252//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 253//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 254//
 255// Arguments:
 256//   spacing = Given a scalar, specifies a uniform spacing between copies. Given a list of scalars, each one gives a specific position along the line. (Default: 1.0)
 257//   n = Number of copies to place on the line. (Default: 2)
 258//   ---
 259//   l = If given, the length to place copies over.
 260//   sp = If given as a point, copies will be place on a line back from starting position `sp`.  If given as a scalar, copies will be placed on a line back from starting position `[0,sp,0]`.  If not given, copies will be placed along a line that is centered at [0,0,0].
 261//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 262//
 263// Side Effects:
 264//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 265//   `$idx` is set to the index number of each child being copied.
 266//
 267// Examples:
 268//   ycopies(20) sphere(3);
 269//   ycopies(20, n=3) sphere(3);
 270//   ycopies(spacing=15, l=50) sphere(3);
 271//   ycopies(n=4, l=30, sp=[10,0,0]) sphere(3);
 272// Example:
 273//   ycopies(10, n=3) {
 274//       cube(size=[1,3,1],center=true);
 275//       cube(size=[3,1,1],center=true);
 276//   }
 277// Example:
 278//   ycopies([1,2,3,5,7]) sphere(d=1);
 279module ycopies(spacing, n, l, sp)
 280{
 281    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 282    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 283    req_children($children);  
 284    dir = BACK;
 285    sp = is_finite(sp)? (sp*dir) : sp;
 286    if (is_vector(spacing)) {
 287        translate(default(sp,[0,0,0])) {
 288            for (i = idx(spacing)) {
 289                $idx = i;
 290                $pos = spacing[i]*dir;
 291                translate($pos) children();
 292            }
 293        }
 294    } else {
 295        line_copies(
 296            l=u_mul(l,dir),
 297            spacing=u_mul(spacing,dir),
 298            n=n, p1=sp
 299        ) children();
 300    }
 301}
 302
 303
 304function ycopies(spacing, n, l, sp, p=_NO_ARG) =
 305    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 306    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 307    let(
 308        dir = BACK,
 309        sp = is_finite(sp)? (sp*dir) : sp,
 310        mats = is_vector(spacing)
 311          ? let(sp = default(sp,[0,0,0])) [for (n = spacing) translate(sp + n*dir)]
 312          : line_copies(l=u_mul(l,dir), spacing=u_mul(spacing,dir), n=n, p1=sp)
 313    )
 314    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 315
 316
 317// Function&Module: zcopies()
 318// Synopsis: Places copies of children along the Z axis. 
 319// SynTags: MatList, Trans
 320// Topics: Transformations, Distributors, Translation, Copiers
 321// See Also: move_copies(), xcopies(), ycopies(), line_copies(), grid_copies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
 322//
 323// Usage:
 324//   zcopies(spacing, [n], [sp=]) CHILDREN;
 325//   zcopies(l=, [n=], [sp=]) CHILDREN;
 326//   zcopies(LIST) CHILDREN;
 327// Usage: As a function to translate points, VNF, or Bezier patches
 328//   copies = zcopies(spacing, [n], [sp=], p=);
 329//   copies = zcopies(l=, [n=], [sp=], p=);
 330//   copies = zcopies(LIST, p=);
 331// Usage: Get Translation Matrices
 332//   mats = zcopies(spacing, [n], [sp=]);
 333//   mats = zcopies(l=, [n=], [sp=]);
 334//   mats = zcopies(LIST);
 335// Description:
 336//   When called as a module, places `n` copies of the children along a line on the Z axis.
 337//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 338//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 339//
 340// Arguments:
 341//   spacing = Given a scalar, specifies a uniform spacing between copies. Given a list of scalars, each one gives a specific position along the line. (Default: 1.0)
 342//   n = Number of copies to place. (Default: 2)
 343//   ---
 344//   l = If given, the length to place copies over.
 345//   sp = If given as a point, copies will be placed on a line up from starting position `sp`.  If given as a scalar, copies will be placed on a line up from starting position `[0,0,sp]`.  If not given, copies will be placed on a line that is centered at [0,0,0].
 346//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 347//
 348// Side Effects:
 349//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 350//   `$idx` is set to the index number of each child being copied.
 351//
 352// Examples:
 353//   zcopies(20) sphere(3);
 354//   zcopies(20, n=3) sphere(3);
 355//   zcopies(spacing=15, l=50) sphere(3);
 356//   zcopies(n=4, l=30, sp=[10,0,0]) sphere(3);
 357// Example:
 358//   zcopies(10, n=3) {
 359//       cube(size=[1,3,1],center=true);
 360//       cube(size=[3,1,1],center=true);
 361//   }
 362// Example: Cubic sphere packing
 363//   s = 20;
 364//   s2 = s * sin(45);
 365//   zcopies(s2,n=8)
 366//       grid_copies([s2,s2],n=8,stagger=($idx%2)? true : "alt")
 367//          sphere(d=s);
 368// Example: Hexagonal sphere packing
 369//   s = 20;
 370//   xyr = adj_ang_to_hyp(s/2,30);
 371//   h = hyp_adj_to_opp(s,xyr);
 372//   zcopies(h,n=8)
 373//       back(($idx%2)*xyr*cos(60))
 374//           grid_copies(s,n=[12,7],stagger=($idx%2)? "alt" : true)
 375//               sphere(d=s);
 376// Example:
 377//   zcopies([1,2,3,5,7]) sphere(d=1);
 378module zcopies(spacing, n, l, sp)
 379{
 380    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 381    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 382    req_children($children);  
 383    dir = UP;
 384    sp = is_finite(sp)? (sp*dir) : sp;
 385    if (is_vector(spacing)) {
 386        translate(default(sp,[0,0,0])) {
 387            for (i = idx(spacing)) {
 388                $idx = i;
 389                $pos = spacing[i]*dir;
 390                translate($pos) children();
 391            }
 392        }
 393    } else {
 394        line_copies(
 395            l=u_mul(l,dir),
 396            spacing=u_mul(spacing,dir),
 397            n=n, p1=sp
 398        ) children();
 399    }
 400}
 401
 402
 403function zcopies(spacing, n, l, sp, p=_NO_ARG) =
 404    assert(is_undef(n) || num_defined([l,spacing])==1, "When n is given must give exactly one of spacing or l")
 405    assert(is_def(n) || num_defined([l,spacing])>=1, "When n is not given must give at least one of spacing or l")  
 406    let(
 407        dir = UP,
 408        sp = is_finite(sp)? (sp*dir) : sp,
 409        mats = is_vector(spacing)
 410          ? let(sp = default(sp,[0,0,0])) [for (n = spacing) translate(sp + n*dir)]
 411          : line_copies(l=u_mul(l,dir), spacing=u_mul(spacing,dir), n=n, p1=sp)
 412    )
 413    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 414
 415
 416
 417// Function&Module: line_copies()
 418// Synopsis: Places copies of children along an arbitrary line. 
 419// SynTags: MatList, Trans
 420// Topics: Transformations, Distributors, Translation, Copiers
 421// See Also: move_copies(), xcopies(), ycopies(), zcopies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
 422//
 423// Usage: Place `n` copies at a given spacing along the line
 424//   line_copies(spacing, [n], [p1=]) CHILDREN;
 425// Usage: Place as many copies as will fit at a given spacing
 426//   line_copies(spacing, [l=], [p1=]) CHILDREN;
 427// Usage: Place `n` copies along the length of the line
 428//   line_copies([n=], [l=], [p1=]) CHILDREN;
 429// Usage: Place `n` copies along the line from `p1` to `p2`
 430//   line_copies([n=], [p1=], [p2=]) CHILDREN;
 431// Usage: Place copies at the given spacing, centered along the line from `p1` to `p2`
 432//   line_copies([spacing], [p1=], [p2=]) CHILDREN;
 433// Usage: As a function to translate points, VNF, or Bezier patches
 434//   copies = line_copies([spacing], [n], [p1=], p=);
 435//   copies = line_copies([spacing], [l=], [p1=], p=);
 436//   copies = line_copies([n=], [l=], [p1=], p=);
 437//   copies = line_copies([n=], [p1=], [p2=], p=);
 438//   copies = line_copies([spacing], [p1=], [p2=], p=);
 439// Usage: Get Translation Matrices
 440//   mats = line_copies([spacing], [n], [p1=]);
 441//   mats = line_copies([spacing], [l=], [p1=]);
 442//   mats = line_copies([n=], [l=], [p1=]);
 443//   mats = line_copies([n=], [p1=], [p2=]);
 444//   mats = line_copies([spacing], [p1=], [p2=]);
 445// Description:
 446//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 447//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 448//   When called as a module, copies `children()` at one or more evenly spaced positions along a line.
 449//   By default, the line will be centered at the origin, unless the starting point `p1` is given.
 450//   The line will be pointed towards `RIGHT` (X+) unless otherwise given as a vector in `l`,
 451//   `spacing`, or `p1`/`p2`.  The psotion of the copies is specified in one of several ways:
 452//   .
 453//   If You Know...                   | Then Use Something Like...
 454//   -------------------------------- | --------------------------------
 455//   Spacing distance, Count          | `line_copies(spacing=10, n=5) ...` or `line_copies(10, n=5) ...`
 456//   Spacing vector, Count            | `line_copies(spacing=[10,5], n=5) ...` or `line_copies([10,5], n=5) ...`
 457//   Spacing distance, Line length    | `line_copies(spacing=10, l=50) ...` or `line_copies(10, l=50) ...`
 458//   Spacing distance, Line vector    | `line_copies(spacing=10, l=[50,30]) ...` or `line_copies(10, l=[50,30]) ...`
 459//   Spacing vector, Line length      | `line_copies(spacing=[10,5], l=50) ...` or `line_copies([10,5], l=50) ...`
 460//   Line length, Count               | `line_copies(l=50, n=5) ...`
 461//   Line vector, Count               | `line_copies(l=[50,40], n=5) ...`
 462//   Line endpoints, Count            | `line_copies(p1=[10,10], p2=[60,-10], n=5) ...`
 463//   Line endpoints, Spacing distance | `line_copies(p1=[10,10], p2=[60,-10], spacing=10) ...`
 464//
 465// Arguments:
 466//   spacing = Either the scalar spacing distance along the X+ direction, or the vector giving both the direction and spacing distance between each set of copies.
 467//   n = Number of copies to distribute along the line. (Default: 2)
 468//   ---
 469//   l = Either the scalar length of the line, or a vector giving both the direction and length of the line.
 470//   p1 = If given, specifies the starting point of the line.
 471//   p2 = If given with `p1`, specifies the ending point of line, and indirectly calculates the line length.
 472//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 473//
 474// Side Effects:
 475//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 476//   `$idx` is set to the index number of each child being copied.
 477//
 478// Examples:
 479//   line_copies(10) sphere(d=1.5);
 480//   line_copies(10, n=5) sphere(d=3);
 481//   line_copies([10,5], n=5) sphere(d=3);
 482//   line_copies(spacing=10, n=6) sphere(d=3);
 483//   line_copies(spacing=[10,5], n=6) sphere(d=3);
 484//   line_copies(spacing=10, l=50) sphere(d=3);
 485//   line_copies(spacing=10, l=[50,30]) sphere(d=3);
 486//   line_copies(spacing=[10,5], l=50) sphere(d=3);
 487//   line_copies(l=50, n=4) sphere(d=3);
 488//   line_copies(l=[50,-30], n=4) sphere(d=3);
 489// Example(FlatSpin,VPD=133):
 490//   line_copies(p1=[0,0,0], p2=[5,5,20], n=6) cuboid([3,2,1]);
 491// Example(FlatSpin,VPD=133):
 492//   line_copies(p1=[0,0,0], p2=[5,5,20], spacing=6) cuboid([3,2,1]);
 493// Example: All children are copied to each position
 494//   line_copies(l=20, n=3) {
 495//       cube(size=[1,3,1],center=true);
 496//       cube(size=[3,1,1],center=true);
 497//   }
 498// Example(2D): The functional form of line_copies() returns a list of transform matrices.
 499//   mats = line_copies([10,5],n=5);
 500//   for (m = mats) multmatrix(m)  circle(d=3);
 501// Example(2D): The functional form of line_copies() returns a list of points if given a point.
 502//   pts = line_copies([10,5],n=5,p=[0,0,0]);
 503//   move_copies(pts) circle(d=3);
 504
 505module line_of(spacing, n, l, p1, p2) {
 506    deprecate("line_copies");
 507    line_copies(spacing, n, l, p1, p2) children();
 508}
 509
 510module line_copies(spacing, n, l, p1, p2)
 511{
 512    req_children($children);
 513    pts = line_copies(spacing=spacing, n=n, l=l, p1=p1, p2=p2, p=[0,0,0]);
 514    for (i=idx(pts)) {
 515        $idx = i;
 516        $pos = pts[i];
 517        translate($pos) children();
 518    }
 519}
 520
 521function line_copies(spacing, n, l, p1, p2, p=_NO_ARG) =
 522    assert(is_undef(spacing) || is_finite(spacing) || is_vector(spacing))
 523    assert(is_undef(n) || is_finite(n))
 524    assert(is_undef(l) || is_finite(l) || is_vector(l))
 525    assert(is_undef(p1) || is_vector(p1))
 526    assert(is_undef(p2) || is_vector(p2))
 527    assert(is_undef(p2) || is_def(p1), "If p2 is given must also give p1")
 528    assert(is_undef(p2) || is_undef(l), "Cannot give both p2 and l")
 529    assert(is_undef(n) || num_defined([l,spacing,p2])==1,"If n is given then must give exactly one of 'l', 'spacing', or the 'p1'/'p2' pair")
 530    assert(is_def(n) || num_defined([l,spacing,p2])>=1,"If n is given then must give at least one of 'l', 'spacing', or the 'p1'/'p2' pair")    
 531    let(
 532        ll = is_def(l)? scalar_vec3(l, 0)
 533           : is_def(spacing) && is_def(n)? (n-1) * scalar_vec3(spacing, 0)
 534           : is_def(p1) && is_def(p2)? point3d(p2-p1)
 535           : undef,
 536        cnt = is_def(n)? n
 537            : is_def(spacing) && is_def(ll) ? floor(norm(ll) / norm(scalar_vec3(spacing, 0)) + 1.000001)
 538            : 2,
 539        spc = cnt<=1? [0,0,0]
 540            : is_undef(spacing) && is_def(ll)? ll/(cnt-1) 
 541            : is_num(spacing) && is_def(ll)? (ll/(cnt-1)) 
 542            : scalar_vec3(spacing, 0)
 543    )
 544    assert(!is_undef(cnt), "Need two of `spacing`, 'l', 'n', or `p1`/`p2` arguments in `line_copies()`.")
 545    let( spos = !is_undef(p1)? point3d(p1) : -(cnt-1)/2 * spc )
 546    [for (i=[0:1:cnt-1]) translate(i * spc + spos, p=p)];
 547
 548
 549
 550// Function&Module: grid_copies()
 551// Synopsis: Places copies of children in an [X,Y] grid. 
 552// SynTags: MatList, Trans
 553// Topics: Transformations, Distributors, Translation, Copiers
 554// See Also: move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies()
 555//
 556// Usage:
 557//   grid_copies(spacing, size=, [stagger=], [scale=], [inside=]) CHILDREN;
 558//   grid_copies(n=, size=, [stagger=], [scale=], [inside=]) CHILDREN;
 559//   grid_copies(spacing, [n], [stagger=], [scale=], [inside=]) CHILDREN;
 560//   grid_copies(n=, inside=, [stagger], [scale]) CHILDREN;
 561// Usage: As a function to translate points, VNF, or Bezier patches
 562//   copies = grid_copies(spacing, size=, [stagger=], [scale=], [inside=], p=);
 563//   copies = grid_copies(n=, size=, [stagger=], [scale=], [inside=], p=);
 564//   copies = grid_copies(spacing, [n], [stagger=], [scale=], [inside=], p=);
 565//   copies = grid_copies(n=, inside=, [stagger], [scale], p=);
 566// Usage: Get Translation Matrices
 567//   mats = grid_copies(spacing, size=, [stagger=], [scale=], [inside=]);
 568//   mats = grid_copies(n=, size=, [stagger=], [scale=], [inside=]);
 569//   mats = grid_copies(spacing, [n], [stagger=], [scale=], [inside=]);
 570//   mats = grid_copies(n=, inside=, [stagger], [scale]);
 571// Description:
 572//   When called as a module, makes a square or hexagonal grid of copies of children, with an optional masking polygon or region.
 573//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 574//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 575//
 576// Arguments:
 577//   spacing = Distance between copies in [X,Y] or scalar distance.
 578//   n = How many columns and rows of copies to make.  Can be given as `[COLS,ROWS]`, or just as a scalar that specifies both.  If staggered, count both staggered and unstaggered columns and rows.  Default: 2 (3 if staggered)
 579//   size = The [X,Y] size to spread the copies over.
 580//   ---
 581//   stagger = If true, make a staggered (hexagonal) grid.  If false, make square grid.  If `"alt"`, makes alternate staggered pattern.  Default: false
 582//   inside = If given a list of polygon points, or a region, only creates copies whose center would be inside the polygon or region.  Polygon can be concave and/or self crossing.
 583//   nonzero = If inside is set to a polygon with self-crossings then use the nonzero method for deciding if points are in the polygon.  Default: false
 584//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 585//
 586// Side Effects:
 587//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
 588//   `$col` is set to the integer column number for each child.
 589//   `$row` is set to the integer row number for each child.
 590//
 591// Examples:
 592//   grid_copies(size=50, spacing=10) cylinder(d=10, h=1);
 593//   grid_copies(size=50, spacing=[10,15]) cylinder(d=10, h=1);
 594//   grid_copies(spacing=10, n=[13,7], stagger=true) cylinder(d=6, h=5);
 595//   grid_copies(spacing=10, n=[13,7], stagger="alt") cylinder(d=6, h=5);
 596//   grid_copies(size=50, n=11, stagger=true) cylinder(d=5, h=1);
 597//
 598// Example:
 599//   poly = [[-25,-25], [25,25], [-25,25], [25,-25]];
 600//   grid_copies(spacing=5, stagger=true, inside=poly)
 601//      zrot(180/6) cylinder(d=5, h=1, $fn=6);
 602//   %polygon(poly);
 603//
 604// Example: Using `$row` and `$col`
 605//   grid_copies(spacing=8, n=8)
 606//       color(($row+$col)%2?"black":"red")
 607//           cube([8,8,0.01], center=false);
 608//
 609// Example: Makes a grid of hexagon pillars whose tops are all angled to reflect light at [0,0,50], if they were shiny.
 610//   hexregion = circle(r=50.01,$fn=6);
 611//   grid_copies(spacing=10, stagger=true, inside=hexregion)
 612//     union() {   // Needed for OpenSCAD 2021.01 as noted above
 613//       ref_v = (unit([0,0,50]-point3d($pos)) + UP)/2;
 614//       half_of(v=-ref_v, cp=[0,0,5])
 615//           zrot(180/6)
 616//               cylinder(h=20, d=10/cos(180/6)+0.01, $fn=6);
 617//     }
 618
 619module grid2d(spacing, n, size, stagger=false, inside=undef, nonzero)
 620{
 621   deprecate("grid_copies");
 622   grid_copies(spacing, n, size, stagger, inside, nonzero) children();
 623}   
 624
 625module grid_copies(spacing, n, size, stagger=false, inside=undef, nonzero)
 626{
 627    req_children($children);    
 628    dummy = assert(in_list(stagger, [false, true, "alt"]));
 629    bounds = is_undef(inside)? undef :
 630        is_path(inside)? pointlist_bounds(inside) :
 631        assert(is_region(inside))
 632        pointlist_bounds(flatten(inside));
 633    nonzero = is_path(inside) ? default(nonzero,false)
 634            : assert(is_undef(nonzero), "nonzero only allowed if inside is a polygon")
 635              false;
 636    size = is_num(size)? [size, size] :
 637        is_vector(size)? assert(len(size)==2) size :
 638        bounds!=undef? [
 639            for (i=[0:1]) 2*max(abs(bounds[0][i]),bounds[1][i])
 640        ] : undef;
 641    spacing = is_num(spacing)? (
 642            stagger!=false? polar_to_xy(spacing,60) :
 643            [spacing,spacing]
 644        ) :
 645        is_vector(spacing)? assert(len(spacing)==2) spacing :
 646        size!=undef? (
 647            is_num(n)? v_div(size,(n-1)*[1,1]) :
 648            is_vector(n)? assert(len(n)==2) v_div(size,n-[1,1]) :
 649            v_div(size,(stagger==false? [1,1] : [2,2]))
 650        ) :
 651        undef;
 652    n = is_num(n)? [n,n] :
 653        is_vector(n)? assert(len(n)==2) n :
 654        size!=undef && spacing!=undef? v_floor(v_div(size,spacing))+[1,1] :
 655        [2,2];
 656    offset = v_mul(spacing, n-[1,1])/2;
 657    if (stagger == false) {
 658        for (row = [0:1:n.y-1]) {
 659            for (col = [0:1:n.x-1]) {
 660                pos = v_mul([col,row],spacing) - offset;
 661                if (
 662                    is_undef(inside) ||
 663                    (is_path(inside) && point_in_polygon(pos, inside, nonzero=nonzero)>=0) ||
 664                    (is_region(inside) && point_in_region(pos, inside)>=0)
 665                ) {
 666                    $col = col;
 667                    $row = row;
 668                    $pos = pos;
 669                    translate(pos) children();
 670                }
 671            }
 672        }
 673    } else {
 674        // stagger == true or stagger == "alt"
 675        staggermod = (stagger == "alt")? 1 : 0;
 676        cols1 = ceil(n.x/2);
 677        cols2 = n.x - cols1;
 678        for (row = [0:1:n.y-1]) {
 679            rowcols = ((row%2) == staggermod)? cols1 : cols2;
 680            if (rowcols > 0) {
 681                for (col = [0:1:rowcols-1]) {
 682                    rowdx = (row%2 != staggermod)? spacing.x : 0;
 683                    pos = v_mul([2*col,row],spacing) + [rowdx,0] - offset;
 684                    if (
 685                        is_undef(inside) ||
 686                        (is_path(inside) && point_in_polygon(pos, inside, nonzero=nonzero)>=0) ||
 687                        (is_region(inside) && point_in_region(pos, inside)>=0)
 688                    ) {
 689                        $col = col * 2 + ((row%2!=staggermod)? 1 : 0);
 690                        $row = row;
 691                        $pos = pos;
 692                        translate(pos) children();
 693                    }
 694                }
 695            }
 696        }
 697    }
 698}
 699
 700
 701function grid_copies(spacing, n, size, stagger=false, inside=undef, nonzero, p=_NO_ARG) =
 702    let(
 703        dummy = assert(in_list(stagger, [false, true, "alt"])),
 704        bounds = is_undef(inside)? undef :
 705            is_path(inside)? pointlist_bounds(inside) :
 706            assert(is_region(inside))
 707            pointlist_bounds(flatten(inside)),
 708        nonzero = is_path(inside) ? default(nonzero,false)
 709                : assert(is_undef(nonzero), "nonzero only allowed if inside is a polygon")
 710                  false,
 711        size = is_num(size)? [size, size] :
 712            is_vector(size)? assert(len(size)==2) size :
 713            bounds!=undef? [
 714                for (i=[0:1]) 2*max(abs(bounds[0][i]),bounds[1][i])
 715            ] : undef,
 716        spacing = is_num(spacing)? (
 717                stagger!=false? polar_to_xy(spacing,60) :
 718                [spacing,spacing]
 719            ) :
 720            is_vector(spacing)? assert(len(spacing)==2) spacing :
 721            size!=undef? (
 722                is_num(n)? v_div(size,(n-1)*[1,1]) :
 723                is_vector(n)? assert(len(n)==2) v_div(size,n-[1,1]) :
 724                v_div(size,(stagger==false? [1,1] : [2,2]))
 725            ) :
 726            undef,
 727        n = is_num(n)? [n,n] :
 728            is_vector(n)? assert(len(n)==2) n :
 729            size!=undef && spacing!=undef? v_floor(v_div(size,spacing))+[1,1] :
 730            [2,2],
 731        offset = v_mul(spacing, n-[1,1])/2,
 732        mats = stagger == false
 733          ? [
 734                for (row = [0:1:n.y-1], col = [0:1:n.x-1])
 735                let( pos = v_mul([col,row],spacing) - offset )
 736                if (
 737                    is_undef(inside) ||
 738                    (is_path(inside) && point_in_polygon(pos, inside, nonzero=nonzero)>=0) ||
 739                    (is_region(inside) && point_in_region(pos, inside)>=0)
 740                )
 741                translate(pos)
 742            ]
 743          : // stagger == true or stagger == "alt"
 744            let(
 745                staggermod = (stagger == "alt")? 1 : 0,
 746                cols1 = ceil(n.x/2),
 747                cols2 = n.x - cols1
 748            )
 749            [
 750                for (row = [0:1:n.y-1])
 751                let( rowcols = ((row%2) == staggermod)? cols1 : cols2 )
 752                if (rowcols > 0)
 753                for (col = [0:1:rowcols-1])
 754                let(
 755                    rowdx = (row%2 != staggermod)? spacing.x : 0,
 756                    pos = v_mul([2*col,row],spacing) + [rowdx,0] - offset
 757                )
 758                if (
 759                    is_undef(inside) ||
 760                    (is_path(inside) && point_in_polygon(pos, inside, nonzero=nonzero)>=0) ||
 761                    (is_region(inside) && point_in_region(pos, inside)>=0)
 762                )
 763                translate(pos)
 764            ]
 765    )
 766    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 767
 768
 769//////////////////////////////////////////////////////////////////////
 770// Section: Rotating copies of all children
 771//////////////////////////////////////////////////////////////////////
 772
 773// Function&Module: rot_copies()
 774// Synopsis: Rotates copies of children.
 775// SynTags: MatList, Trans
 776// Topics: Transformations, Distributors, Rotation, Copiers
 777// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
 778//
 779// Usage:
 780//   rot_copies(rots, [cp=], [sa=], [delta=], [subrot=]) CHILDREN;
 781//   rot_copies(rots, v, [cp=], [sa=], [delta=], [subrot=]) CHILDREN;
 782//   rot_copies(n=, [v=], [cp=], [sa=], [delta=], [subrot=]) CHILDREN;
 783// Usage: As a function to translate points, VNF, or Bezier patches
 784//   copies = rot_copies(rots, [cp=], [sa=], [delta=], [subrot=], p=);
 785//   copies = rot_copies(rots, v, [cp=], [sa=], [delta=], [subrot=], p=);
 786//   copies = rot_copies(n=, [v=], [cp=], [sa=], [delta=], [subrot=], p=);
 787// Usage: Get Translation Matrices
 788//   mats = rot_copies(rots, [cp=], [sa=], [delta=], [subrot=]);
 789//   mats = rot_copies(rots, v, [cp=], [sa=], [delta=], [subrot=]);
 790//   mats = rot_copies(n=, [v=], [cp=], [sa=], [delta=], [subrot=]);
 791// Description:
 792//   When called as a module:
 793//   - Given a list of [X,Y,Z] rotation angles in `rots`, rotates copies of the children to each of those angles, regardless of axis of rotation.
 794//   - Given a list of scalar angles in `rots`, rotates copies of the children to each of those angles around the axis of rotation.
 795//   - If given a vector `v`, that becomes the axis of rotation.  Default axis of rotation is UP.
 796//   - If given a count `n`, makes that many copies, rotated evenly around the axis.
 797//   - If given an offset `delta`, translates each child by that amount before rotating them into place.  This makes rings.
 798//   - If given a centerpoint `cp`, centers the ring around that centerpoint.
 799//   - If `subrot` is true, each child will be rotated in place to keep the same size towards the center when making rings.
 800//   - The first (unrotated) copy will be placed at the relative starting angle `sa`.
 801//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 802//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 803//
 804// Arguments:
 805//   rots = A list of [X,Y,Z] rotation angles in degrees.  If `v` is given, this will be a list of scalar angles in degrees to rotate around `v`.
 806//   v = If given, this is the vector of the axis to rotate around.
 807//   cp = Centerpoint to rotate around.  Default: `[0,0,0]`
 808//   ---
 809//   n = Optional number of evenly distributed copies, rotated around the axis.
 810//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise.  Default: 0
 811//   delta = [X,Y,Z] amount to move away from cp before rotating.  Makes rings of copies.  Default: `[0,0,0]`
 812//   subrot = If false, don't sub-rotate children as they are copied around the ring.  Only makes sense when used with `delta`.  Default: `true`
 813//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 814//
 815// Side Effects:
 816//   `$ang` is set to the rotation angle (or XYZ rotation triplet) of each child copy, and can be used to modify each child individually.
 817//   `$idx` is set to the index value of each child copy.
 818//   `$axis` is set to the axis to rotate around, if `rots` was given as a list of angles instead of a list of [X,Y,Z] rotation angles.
 819//
 820//
 821// Example:
 822//   #cylinder(h=20, r1=5, r2=0);
 823//   rot_copies([[45,0,0],[0,45,90],[90,-45,270]]) cylinder(h=20, r1=5, r2=0);
 824//
 825// Example:
 826//   rot_copies([45, 90, 135], v=DOWN+BACK)
 827//       yrot(90) cylinder(h=20, r1=5, r2=0);
 828//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
 829//
 830// Example:
 831//   rot_copies(n=6, v=DOWN+BACK)
 832//       yrot(90) cylinder(h=20, r1=5, r2=0);
 833//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
 834//
 835// Example:
 836//   rot_copies(n=6, v=DOWN+BACK, delta=[10,0,0])
 837//       yrot(90) cylinder(h=20, r1=5, r2=0);
 838//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
 839//
 840// Example:
 841//   rot_copies(n=6, v=UP+FWD, delta=[10,0,0], sa=45)
 842//       yrot(90) cylinder(h=20, r1=5, r2=0);
 843//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
 844//
 845// Example:
 846//   rot_copies(n=6, v=DOWN+BACK, delta=[20,0,0], subrot=false)
 847//       yrot(90) cylinder(h=20, r1=5, r2=0);
 848//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
 849module rot_copies(rots=[], v, cp=[0,0,0], n, sa=0, offset=0, delta=[0,0,0], subrot=true)
 850{
 851    req_children($children);  
 852    sang = sa + offset;
 853    angs = !is_undef(n)?
 854        (n<=0? [] : [for (i=[0:1:n-1]) i/n*360+sang]) :
 855        rots==[]? [] :
 856        assert(!is_string(rots), "Argument rots must be an angle, a list of angles, or a range of angles.")
 857        assert(!is_undef(rots[0]), "Argument rots must be an angle, a list of angles, or a range of angles.")
 858        [for (a=rots) a];
 859    for ($idx = idx(angs)) {
 860        $ang = angs[$idx];
 861        $axis = v;
 862        translate(cp) {
 863            rotate(a=$ang, v=v) {
 864                translate(delta) {
 865                    rot(a=(subrot? sang : $ang), v=v, reverse=true) {
 866                        translate(-cp) {
 867                            children();
 868                        }
 869                    }
 870                }
 871            }
 872        }
 873    }
 874}
 875
 876
 877function rot_copies(rots=[], v, cp=[0,0,0], n, sa=0, offset=0, delta=[0,0,0], subrot=true, p=_NO_ARG) =
 878    let(
 879        sang = sa + offset,
 880        angs = !is_undef(n)?
 881            (n<=0? [] : [for (i=[0:1:n-1]) i/n*360+sang]) :
 882            rots==[]? [] :
 883            assert(!is_string(rots), "Argument rots must be an angle, a list of angles, or a range of angles.")
 884            assert(!is_undef(rots[0]), "Argument rots must be an angle, a list of angles, or a range of angles.")
 885            [for (a=rots) a],
 886        mats = [
 887            for (ang = angs)
 888            translate(cp) *
 889                rot(a=ang, v=v) *
 890                translate(delta) *
 891                rot(a=(subrot? sang : ang), v=v, reverse=true) *
 892                translate(-cp)
 893        ]
 894    )
 895    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
 896
 897
 898// Function&Module: xrot_copies()
 899// Synopsis: Rotates copies of children around the X axis.
 900// SynTags: MatList, Trans
 901// Topics: Transformations, Distributors, Rotation, Copiers
 902// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
 903//
 904// Usage:
 905//   xrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]) CHILDREN;
 906//   xrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]) CHILDREN;
 907// Usage: As a function to translate points, VNF, or Bezier patches
 908//   copies = xrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=], p=);
 909//   copies = xrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=], p=);
 910// Usage: Get Translation Matrices
 911//   mats = xrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]);
 912//   mats = xrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]);
 913// Description:
 914//   When called as a module:
 915//   - Given an array of angles, rotates copies of the children to each of those angles around the X axis.
 916//   - If given a count `n`, makes that many copies, rotated evenly around the X axis.
 917//   - If given a radius `r` (or diameter `d`), distributes children around a ring of that size around the X axis.
 918//   - If given a centerpoint `cp`, centers the rotation around that centerpoint.
 919//   - If `subrot` is true, each child will be rotated in place to keep the same size towards the center when making rings.
 920//   - The first (unrotated) copy will be placed at the relative starting angle `sa`.
 921//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
 922//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
 923//
 924// Arguments:
 925//   rots = Optional array of rotation angles, in degrees, to make copies at.
 926//   cp = Centerpoint to rotate around.
 927//   ---
 928//   n = Optional number of evenly distributed copies to be rotated around the ring.
 929//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise from Y+, when facing the origin from X+.  First unrotated copy is placed at that angle.
 930//   r = If given, makes a ring of child copies around the X axis, at the given radius.  Default: 0
 931//   d = If given, makes a ring of child copies around the X axis, at the given diameter.
 932//   subrot = If false, don't sub-rotate children as they are copied around the ring.
 933//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
 934//
 935// Side Effects:
 936//   `$idx` is set to the index value of each child copy.
 937//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
 938//   `$axis` is set to the axis vector rotated around.
 939//
 940//
 941// Example:
 942//   xrot_copies([180, 270, 315])
 943//       cylinder(h=20, r1=5, r2=0);
 944//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
 945//
 946// Example:
 947//   xrot_copies(n=6)
 948//       cylinder(h=20, r1=5, r2=0);
 949//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
 950//
 951// Example:
 952//   xrot_copies(n=6, r=10)
 953//       xrot(-90) cylinder(h=20, r1=5, r2=0);
 954//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0);
 955//
 956// Example:
 957//   xrot_copies(n=6, r=10, sa=45)
 958//       xrot(-90) cylinder(h=20, r1=5, r2=0);
 959//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0);
 960//
 961// Example:
 962//   xrot_copies(n=6, r=20, subrot=false)
 963//       xrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
 964//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
 965module xrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true)
 966{
 967    req_children($children);  
 968    r = get_radius(r=r, d=d, dflt=0);
 969    rot_copies(rots=rots, v=RIGHT, cp=cp, n=n, sa=sa, delta=[0, r, 0], subrot=subrot) children();
 970}
 971
 972
 973function xrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true, p=_NO_ARG) =
 974    let( r = get_radius(r=r, d=d, dflt=0) )
 975    rot_copies(rots=rots, v=RIGHT, cp=cp, n=n, sa=sa, delta=[0, r, 0], subrot=subrot, p=p);
 976
 977
 978// Function&Module: yrot_copies()
 979// Synopsis: Rotates copies of children around the Y axis.
 980// SynTags: MatList, Trans
 981// Topics: Transformations, Distributors, Rotation, Copiers
 982// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
 983//
 984// Usage:
 985//   yrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]) CHILDREN;
 986//   yrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]) CHILDREN;
 987// Usage: As a function to translate points, VNF, or Bezier patches
 988//   copies = yrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=], p=);
 989//   copies = yrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=], p=);
 990// Usage: Get Translation Matrices
 991//   mats = yrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]);
 992//   mats = yrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]);
 993// Description:
 994//   When called as a module:
 995//   - Given an array of angles, rotates copies of the children to each of those angles around the Y axis.
 996//   - If given a count `n`, makes that many copies, rotated evenly around the Y axis.
 997//   - If given a radius `r` (or diameter `d`), distributes children around a ring of that size around the Y axis.
 998//   - If given a centerpoint `cp`, centers the rotation around that centerpoint.
 999//   - If `subrot` is true, each child will be rotated in place to keep the same size towards the center when making rings.
1000//   - The first (unrotated) copy will be placed at the relative starting angle `sa`.
1001//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1002//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1003//
1004// Arguments:
1005//   rots = Optional array of rotation angles, in degrees, to make copies at.
1006//   cp = Centerpoint to rotate around.
1007//   ---
1008//   n = Optional number of evenly distributed copies to be rotated around the ring.
1009//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise from X-, when facing the origin from Y+.
1010//   r = If given, makes a ring of child copies around the Y axis, at the given radius.  Default: 0
1011//   d = If given, makes a ring of child copies around the Y axis, at the given diameter.
1012//   subrot = If false, don't sub-rotate children as they are copied around the ring.
1013//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1014//
1015// Side Effects:
1016//   `$idx` is set to the index value of each child copy.
1017//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
1018//   `$axis` is set to the axis vector rotated around.
1019//
1020//
1021// Example:
1022//   yrot_copies([180, 270, 315])
1023//       cylinder(h=20, r1=5, r2=0);
1024//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
1025//
1026// Example:
1027//   yrot_copies(n=6)
1028//       cylinder(h=20, r1=5, r2=0);
1029//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
1030//
1031// Example:
1032//   yrot_copies(n=6, r=10)
1033//       yrot(-90) cylinder(h=20, r1=5, r2=0);
1034//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0);
1035//
1036// Example:
1037//   yrot_copies(n=6, r=10, sa=45)
1038//       yrot(-90) cylinder(h=20, r1=5, r2=0);
1039//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0);
1040//
1041// Example:
1042//   yrot_copies(n=6, r=20, subrot=false)
1043//       yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
1044//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
1045module yrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true)
1046{
1047    req_children($children);
1048    r = get_radius(r=r, d=d, dflt=0);
1049    rot_copies(rots=rots, v=BACK, cp=cp, n=n, sa=sa, delta=[-r, 0, 0], subrot=subrot) children();
1050}
1051
1052
1053function yrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true, p=_NO_ARG) =
1054    let( r = get_radius(r=r, d=d, dflt=0) )
1055    rot_copies(rots=rots, v=BACK, cp=cp, n=n, sa=sa, delta=[-r, 0, 0], subrot=subrot, p=p);
1056
1057
1058// Function&Module: zrot_copies()
1059// Synopsis: Rotates copies of children around the Z axis.
1060// SynTags: MatList, Trans
1061// Topics: Transformations, Distributors, Rotation, Copiers
1062// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), sphere_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1063//
1064// Usage:
1065//   zrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]) CHILDREN;
1066//   zrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]) CHILDREN;
1067// Usage: As a function to translate points, VNF, or Bezier patches
1068//   copies = zrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=], p=);
1069//   copies = zrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=], p=);
1070// Usage: Get Translation Matrices
1071//   mats = zrot_copies(rots, [cp], [r=|d=], [sa=], [subrot=]);
1072//   mats = zrot_copies(n=, [cp=], [r=|d=], [sa=], [subrot=]);
1073//
1074// Description:
1075//   When called as a module:
1076//   - Given an array of angles, rotates copies of the children to each of those angles around the Z axis.
1077//   - If given a count `n`, makes that many copies, rotated evenly around the Z axis.
1078//   - If given a radius `r` (or diameter `d`), distributes children around a ring of that size around the Z axis.
1079//   - If given a centerpoint `cp`, centers the rotation around that centerpoint.
1080//   - If `subrot` is true, each child will be rotated in place to keep the same size towards the center when making rings.
1081//   - The first (unrotated) copy will be placed at the relative starting angle `sa`.
1082//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1083//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1084//
1085// Arguments:
1086//   rots = Optional array of rotation angles, in degrees, to make copies at.
1087//   cp = Centerpoint to rotate around.  Default: [0,0,0]
1088//   ---
1089//   n = Optional number of evenly distributed copies to be rotated around the ring.
1090//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise from X+, when facing the origin from Z+.  Default: 0
1091//   r = If given, makes a ring of child copies around the Z axis, at the given radius.  Default: 0
1092//   d = If given, makes a ring of child copies around the Z axis, at the given diameter.
1093//   subrot = If false, don't sub-rotate children as they are copied around the ring.  Default: true
1094//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1095//
1096// Side Effects:
1097//   `$idx` is set to the index value of each child copy.
1098//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
1099//   `$axis` is set to the axis vector rotated around.
1100//
1101//
1102// Example:
1103//   zrot_copies([180, 270, 315])
1104//       yrot(90) cylinder(h=20, r1=5, r2=0);
1105//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
1106//
1107// Example:
1108//   zrot_copies(n=6)
1109//       yrot(90) cylinder(h=20, r1=5, r2=0);
1110//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
1111//
1112// Example:
1113//   zrot_copies(n=6, r=10)
1114//       yrot(90) cylinder(h=20, r1=5, r2=0);
1115//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
1116//
1117// Example:
1118//   zrot_copies(n=6, r=20, sa=45)
1119//       yrot(90) cylinder(h=20, r1=5, r2=0, center=true);
1120//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0, center=true);
1121//
1122// Example:
1123//   zrot_copies(n=6, r=20, subrot=false)
1124//       yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
1125//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
1126module zrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true)
1127{
1128    r = get_radius(r=r, d=d, dflt=0);
1129    rot_copies(rots=rots, v=UP, cp=cp, n=n, sa=sa, delta=[r, 0, 0], subrot=subrot) children();
1130}
1131
1132
1133function zrot_copies(rots=[], cp=[0,0,0], n, sa=0, r, d, subrot=true, p=_NO_ARG) =
1134    let( r = get_radius(r=r, d=d, dflt=0) )
1135    rot_copies(rots=rots, v=UP, cp=cp, n=n, sa=sa, delta=[r, 0, 0], subrot=subrot, p=p);
1136
1137
1138// Function&Module: arc_copies()
1139// Synopsis: Distributes duplicates of children along an arc.
1140// SynTags: MatList, Trans
1141// Topics: Transformations, Distributors, Rotation, Copiers
1142// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), sphere_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1143//
1144// Usage:
1145//   arc_copies(n, r|d=, [sa=], [ea=], [rot=]) CHILDREN;
1146//   arc_copies(n, rx=|dx=, ry=|dy=, [sa=], [ea=], [rot=]) CHILDREN;
1147// Usage: As a function to translate points, VNF, or Bezier patches
1148//   copies = arc_copies(n, r|d=, [sa=], [ea=], [rot=], p=);
1149//   copies = arc_copies(n, rx=|dx=, ry=|dy=, [sa=], [ea=], [rot=], p=);
1150// Usage: Get Translation Matrices
1151//   mats = arc_copies(n, r|d=, [sa=], [ea=], [rot=]);
1152//   mats = arc_copies(n, rx=|dx=, ry=|dy=, [sa=], [ea=], [rot=]);
1153//
1154//
1155// Description:
1156//   When called as a module, evenly distributes n duplicate children around an ovoid arc on the XY plane.
1157//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1158//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1159//
1160// Arguments:
1161//   n = number of copies to distribute around the circle. (Default: 6)
1162//   r = radius of circle (Default: 1)
1163//   ---
1164//   rx = radius of ellipse on X axis. Used instead of r.
1165//   ry = radius of ellipse on Y axis. Used instead of r.
1166//   d = diameter of circle. (Default: 2)
1167//   dx = diameter of ellipse on X axis. Used instead of d.
1168//   dy = diameter of ellipse on Y axis. Used instead of d.
1169//   rot = whether to rotate the copied children.  (Default: true)
1170//   sa = starting angle. (Default: 0.0)
1171//   ea = ending angle. Will distribute copies CCW from sa to ea. (Default: 360.0)
1172//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1173//
1174// Side Effects:
1175//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
1176//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
1177//   `$idx` is set to the index value of each child copy.
1178//
1179//
1180// Example:
1181//   #cube(size=[10,3,3],center=true);
1182//   arc_copies(d=40, n=5) cube(size=[10,3,3],center=true);
1183//
1184// Example:
1185//   #cube(size=[10,3,3],center=true);
1186//   arc_copies(d=40, n=5, sa=45, ea=225) cube(size=[10,3,3],center=true);
1187//
1188// Example:
1189//   #cube(size=[10,3,3],center=true);
1190//   arc_copies(r=15, n=8, rot=false) cube(size=[10,3,3],center=true);
1191//
1192// Example:
1193//   #cube(size=[10,3,3],center=true);
1194//   arc_copies(rx=20, ry=10, n=8) cube(size=[10,3,3],center=true);
1195// Example(2D): Using `$idx` to alternate shapes
1196//   arc_copies(r=50, n=19, sa=0, ea=180)
1197//       if ($idx % 2 == 0) rect(6);
1198//       else circle(d=6);
1199
1200module arc_of(n=6,r,rx,ry,d,dx,dy,sa=0,ea=360,rot=true){
1201    deprecate("arc_copies");
1202    arc_copies(n,r,rx,ry,d,dx,dy,sa,ea,rot) children();
1203}    
1204
1205
1206module arc_copies(
1207    n=6,
1208    r=undef,
1209    rx=undef, ry=undef,
1210    d=undef, dx=undef, dy=undef,
1211    sa=0, ea=360,
1212    rot=true
1213) {
1214    req_children($children);  
1215    rx = get_radius(r1=rx, r=r, d1=dx, d=d, dflt=1);
1216    ry = get_radius(r1=ry, r=r, d1=dy, d=d, dflt=1);
1217    sa = posmod(sa, 360);
1218    ea = posmod(ea, 360);
1219    n = (abs(ea-sa)<0.01)?(n+1):n;
1220    delt = (((ea<=sa)?360.0:0)+ea-sa)/(n-1);
1221    for ($idx = [0:1:n-1]) {
1222        $ang = sa + ($idx * delt);
1223        $pos =[rx*cos($ang), ry*sin($ang), 0];
1224        translate($pos) {
1225            zrot(rot? atan2(ry*sin($ang), rx*cos($ang)) : 0) {
1226                children();
1227            }
1228        }
1229    }
1230}
1231
1232
1233function arc_copies(
1234    n=6,
1235    r=undef,
1236    rx=undef, ry=undef,
1237    d=undef, dx=undef, dy=undef,
1238    sa=0, ea=360,
1239    rot=true,
1240    p=_NO_ARG
1241) =
1242    let(
1243        rx = get_radius(r1=rx, r=r, d1=dx, d=d, dflt=1),
1244        ry = get_radius(r1=ry, r=r, d1=dy, d=d, dflt=1),
1245        sa = posmod(sa, 360),
1246        ea = posmod(ea, 360),
1247        n = (abs(ea-sa)<0.01)?(n+1):n,
1248        delt = (((ea<=sa)?360.0:0)+ea-sa)/(n-1),
1249        mats = [
1250            for (i = [0:1:n-1])
1251            let(
1252                ang = sa + (i * delt),
1253                pos =[rx*cos(ang), ry*sin(ang), 0],
1254                ang2 = rot? atan2(ry*sin(ang), rx*cos(ang)) : 0
1255            )
1256            translate(pos) * zrot(ang2)
1257        ]
1258    )
1259    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
1260
1261
1262
1263// Function&Module: sphere_copies()
1264// Synopsis: Distributes copies of children over the surface of a sphere. 
1265// SynTags: MatList, Trans
1266// Topics: Transformations, Distributors, Rotation, Copiers
1267// See Also: rot_copies(), xrot_copies(), yrot_copies(), zrot_copies(), arc_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1268//
1269// Usage:
1270//   sphere_copies(n, r|d=, [cone_ang=], [scale=], [perp=]) CHILDREN;
1271// Usage: As a function to translate points, VNF, or Bezier patches
1272//   copies = sphere_copies(n, r|d=, [cone_ang=], [scale=], [perp=], p=);
1273// Usage: Get Translation Matrices
1274//   mats = sphere_copies(n, r|d=, [cone_ang=], [scale=], [perp=]);
1275//
1276// Description:
1277//   When called as a module, spreads children semi-evenly over the surface of a sphere or ellipsoid.
1278//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1279//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1280//
1281// Arguments:
1282//   n = How many copies to evenly spread over the surface.
1283//   r = Radius of the sphere to distribute over
1284//   ---
1285//   d = Diameter of the sphere to distribute over
1286//   cone_ang = Angle of the cone, in degrees, to limit how much of the sphere gets covered.  For full sphere coverage, use 180.  Measured pre-scaling.  Default: 180
1287//   scale = The [X,Y,Z] scaling factors to reshape the sphere being covered.
1288//   perp = If true, rotate children to be perpendicular to the sphere surface.  Default: true
1289//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1290//
1291// Side Effects:
1292//   `$pos` is set to the relative post-scaled centerpoint of each child copy, and can be used to modify each child individually.
1293//   `$theta` is set to the theta angle of the child from the center of the sphere.
1294//   `$phi` is set to the pre-scaled phi angle of the child from the center of the sphere.
1295//   `$rad` is set to the pre-scaled radial distance of the child from the center of the sphere.
1296//   `$idx` is set to the index number of each child being copied.
1297//
1298//
1299// Example:
1300//   sphere_copies(n=250, d=100, cone_ang=45, scale=[3,3,1])
1301//       cylinder(d=10, h=10, center=false);
1302//
1303// Example:
1304//   sphere_copies(n=500, d=100, cone_ang=180)
1305//       color(unit(point3d(v_abs($pos))))
1306//           cylinder(d=8, h=10, center=false);
1307
1308module ovoid_spread(n=100, r=undef, d=undef, cone_ang=90, scale=[1,1,1], perp=true)
1309{
1310  deprecate("sphere_copies");
1311  sphere_copies(n,r,d,cone_ang,scale,perp) children();
1312}  
1313
1314
1315module sphere_copies(n=100, r=undef, d=undef, cone_ang=90, scale=[1,1,1], perp=true)
1316{
1317    req_children($children);  
1318    r = get_radius(r=r, d=d, dflt=50);
1319    cnt = ceil(n / (cone_ang/180));
1320
1321    // Calculate an array of [theta,phi] angles for `n` number of
1322    // points, almost evenly spaced across the surface of a sphere.
1323    // This approximation is based on the golden spiral method.
1324    theta_phis = [for (x=[0:1:n-1]) [180*(1+sqrt(5))*(x+0.5)%360, acos(1-2*(x+0.5)/cnt)]];
1325
1326    for ($idx = idx(theta_phis)) {
1327        tp = theta_phis[$idx];
1328        xyz = spherical_to_xyz(r, tp[0], tp[1]);
1329        $pos = v_mul(xyz,point3d(scale,1));
1330        $theta = tp[0];
1331        $phi = tp[1];
1332        $rad = r;
1333        translate($pos) {
1334            if (perp) {
1335                rot(from=UP, to=xyz) children();
1336            } else {
1337                children();
1338            }
1339        }
1340    }
1341}
1342
1343
1344function sphere_copies(n=100, r=undef, d=undef, cone_ang=90, scale=[1,1,1], perp=true, p=_NO_ARG) =
1345    let(
1346        r = get_radius(r=r, d=d, dflt=50),
1347        cnt = ceil(n / (cone_ang/180)),
1348
1349        // Calculate an array of [theta,phi] angles for `n` number of
1350        // points, almost evenly spaced across the surface of a sphere.
1351        // This approximation is based on the golden spiral method.
1352        theta_phis = [for (x=[0:1:n-1]) [180*(1+sqrt(5))*(x+0.5)%360, acos(1-2*(x+0.5)/cnt)]],
1353
1354        mats = [
1355            for (tp = theta_phis)
1356            let(
1357                xyz = spherical_to_xyz(r, tp[0], tp[1]),
1358                pos = v_mul(xyz,point3d(scale,1))
1359            )
1360            translate(pos) *
1361            (perp? rot(from=UP, to=xyz) : ident(4))
1362        ]
1363    )
1364    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
1365
1366
1367
1368// Section: Placing copies of all children on a path
1369
1370
1371// Function&Module: path_copies()
1372// Synopsis: Uniformly distributes copies of children along a path.
1373// SynTags: MatList, Trans
1374// Topics: Transformations, Distributors, Copiers
1375// See Also: line_copies(), move_copies(), xcopies(), ycopies(), zcopies(), grid_copies(), xflip_copy(), yflip_copy(), zflip_copy(), mirror_copy()
1376//
1377// Usage: Uniformly distribute copies 
1378//   path_copies(path, [n], [spacing], [sp], [rotate_children], [closed=]) CHILDREN;
1379// Usage: Place copies at specified locations
1380//   path_copies(path, dist=, [rotate_children=], [closed=]) CHILDREN;
1381// Usage: As a function to translate points, VNF, or Bezier patches
1382//   copies = path_copies(path, [n], [spacing], [sp], [rotate_children], [closed=], p=);
1383//   copies = path_copies(path, dist=, [rotate_children=], [closed=], p=);
1384// Usage: Get Translation Matrices
1385//   mats = path_copies(path, [n], [spacing], [sp], [rotate_children], [closed=]);
1386//   mats = path_copies(path, dist=, [rotate_children=], [closed=]);
1387//
1388// Description:
1389//   When called as a module:
1390//   - Place copies all of the children at points along the path based on path length.  You can specify `dist` as
1391//   - a scalar or distance list and the children will be placed at the specified distances from the start of the path.  Otherwise the children are
1392//   - placed at uniformly spaced points along the path.  If you specify `n` but not `spacing` then `n` copies will be placed
1393//   - with one at path[0] if `closed` is true, or spanning the entire path from start to end if `closed` is false.
1394//   - If you specify `spacing` but not `n` then copies will spread out starting from one set at path[0] for `closed=true` or at the path center for open paths.
1395//   - If you specify `sp` then the copies will start at distance `sp` from the start of the path.  
1396//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1397//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1398//
1399// Arguments:
1400//   path = path or 1-region where children are placed
1401//   n = number of copies
1402//   spacing = space between copies
1403//   sp = if given, copies will start distance sp from the path start and spread beyond that point
1404//   rotate_children = if true, rotate children to line up with curve normal.  Default: true
1405//   ---
1406//   dist = Specify a list of distances to determine placement of children.  
1407//   closed = If true treat path as a closed curve.  Default: false
1408//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1409//
1410// Side Effects:
1411//   `$pos` is set to the center of each copy
1412//   `$idx` is set to the index number of each copy.  In the case of closed paths the first copy is at `path[0]` unless you give `sp`.
1413//   `$dir` is set to the direction vector of the path at the point where the copy is placed.
1414//   `$normal` is set to the direction of the normal vector to the path direction that is coplanar with the path at this point
1415//
1416//
1417// Example(2D):
1418//   spiral = [for(theta=[0:360*8]) theta * [cos(theta), sin(theta)]]/100;
1419//   stroke(spiral,width=.25);
1420//   color("red") path_copies(spiral, n=100) circle(r=1);
1421// Example(2D):
1422//   circle = regular_ngon(n=64, or=10);
1423//   stroke(circle,width=1,closed=true);
1424//   color("green") path_copies(circle, n=7, closed=true) circle(r=1+$idx/3);
1425// Example(2D):
1426//   heptagon = regular_ngon(n=7, or=10);
1427//   stroke(heptagon, width=1, closed=true);
1428//   color("purple") path_copies(heptagon, n=9, closed=true) rect([0.5,3],anchor=FRONT);
1429// Example(2D): Direction at the corners is the average of the two adjacent edges
1430//   heptagon = regular_ngon(n=7, or=10);
1431//   stroke(heptagon, width=1, closed=true);
1432//   color("purple") path_copies(heptagon, n=7, closed=true) rect([0.5,3],anchor=FRONT);
1433// Example(2D):  Don't rotate the children
1434//   heptagon = regular_ngon(n=7, or=10);
1435//   stroke(heptagon, width=1, closed=true);
1436//   color("red") path_copies(heptagon, n=9, closed=true, rotate_children=false) rect([0.5,3],anchor=FRONT);
1437// Example(2D): Open path, specify `n`
1438//   sinwav = [for(theta=[0:360]) 5*[theta/180, sin(theta)]];
1439//   stroke(sinwav,width=.1);
1440//   color("red") path_copies(sinwav, n=5) rect([.2,1.5],anchor=FRONT);
1441// Example(2D): Open path, specify `n` and `spacing`
1442//   sinwav = [for(theta=[0:360]) 5*[theta/180, sin(theta)]];
1443//   stroke(sinwav,width=.1);
1444//   color("red") path_copies(sinwav, n=5, spacing=1) rect([.2,1.5],anchor=FRONT);
1445// Example(2D): Closed path, specify `n` and `spacing`, copies centered around circle[0]
1446//   circle = regular_ngon(n=64,or=10);
1447//   stroke(circle,width=.1,closed=true);
1448//   color("red") path_copies(circle, n=10, spacing=1, closed=true) rect([.2,1.5],anchor=FRONT);
1449// Example(2D): Open path, specify `spacing`
1450//   sinwav = [for(theta=[0:360]) 5*[theta/180, sin(theta)]];
1451//   stroke(sinwav,width=.1);
1452//   color("red") path_copies(sinwav, spacing=5) rect([.2,1.5],anchor=FRONT);
1453// Example(2D): Open path, specify `sp`
1454//   sinwav = [for(theta=[0:360]) 5*[theta/180, sin(theta)]];
1455//   stroke(sinwav,width=.1);
1456//   color("red") path_copies(sinwav, n=5, sp=18) rect([.2,1.5],anchor=FRONT);
1457// Example(2D): Open path, specify `dist`
1458//   sinwav = [for(theta=[0:360]) 5*[theta/180, sin(theta)]];
1459//   stroke(sinwav,width=.1);
1460//   color("red") path_copies(sinwav, dist=[1,4,9,16]) rect([.2,1.5],anchor=FRONT);
1461// Example(2D):
1462//   wedge = arc(angle=[0,100], r=10, $fn=64);
1463//   difference(){
1464//     polygon(concat([[0,0]],wedge));
1465//     path_copies(wedge,n=5,spacing=3) fwd(.1) rect([1,4],anchor=FRONT);
1466//   }
1467// Example(Spin,VPD=115): 3d example, with children rotated into the plane of the path
1468//   tilted_circle = lift_plane([[0,0,0], [5,0,5], [0,2,3]],regular_ngon(n=64, or=12));
1469//   path_sweep(regular_ngon(n=16,or=.1),tilted_circle);
1470//   path_copies(tilted_circle, n=15,closed=true) {
1471//      color("blue") cyl(h=3,r=.2, anchor=BOTTOM);      // z-aligned cylinder
1472//      color("red") xcyl(h=10,r=.2, anchor=FRONT+LEFT); // x-aligned cylinder
1473//   }
1474// Example(Spin,VPD=115): 3d example, with rotate_children set to false
1475//   tilted_circle = lift_plane([[0,0,0], [5,0,5], [0,2,3]], regular_ngon(n=64, or=12));
1476//   path_sweep(regular_ngon(n=16,or=.1),tilted_circle);
1477//   path_copies(tilted_circle, n=25,rotate_children=false,closed=true) {
1478//      color("blue") cyl(h=3,r=.2, anchor=BOTTOM);       // z-aligned cylinder
1479//      color("red") xcyl(h=10,r=.2, anchor=FRONT+LEFT);  // x-aligned cylinder
1480//   }
1481
1482module path_spread(path, n, spacing, sp=undef, rotate_children=true, dist, closed){
1483  deprecate("path_copes");
1484  path_copies(path,n,spacing,sp,dist,rotate_children,dist, closed) children();
1485}  
1486
1487
1488module path_copies(path, n, spacing, sp=undef, dist, rotate_children=true, dist, closed)
1489{
1490    req_children($children);  
1491    is_1reg = is_1region(path);
1492    path = is_1reg ? path[0] : path;
1493    closed = default(closed, is_1reg);
1494    length = path_length(path,closed);
1495    distind = is_def(dist) ? sortidx(dist) : undef;
1496    distances =
1497        is_def(dist) ? assert(is_undef(n) && is_undef(spacing) && is_undef(sp), "Can't use n, spacing or undef with dist")
1498                       select(dist,distind)
1499      : is_def(sp)? (   // Start point given
1500            is_def(n) && is_def(spacing)? count(n,sp,spacing) :
1501            is_def(n)? lerpn(sp, length, n) :
1502            list([sp:spacing:length])
1503        )
1504      : is_def(n) && is_undef(spacing)? lerpn(0,length,n,!closed) // N alone given
1505      : (      // No start point and spacing is given, N maybe given
1506        let(
1507            n = is_def(n)? n : floor(length/spacing)+(closed?0:1),
1508            ptlist = count(n,0,spacing),
1509            listcenter = mean(ptlist)
1510        ) closed?
1511            sort([for(entry=ptlist) posmod(entry-listcenter,length)]) :
1512            [for(entry=ptlist) entry + length/2-listcenter ]
1513    );
1514    distOK = min(distances)>=0 && max(distances)<=length;
1515    dummy = assert(distOK,"Cannot fit all of the copies");
1516    cutlist = path_cut_points(path, distances, closed, direction=true);
1517    planar = len(path[0])==2;
1518    for(i=[0:1:len(cutlist)-1]) {
1519        $pos = cutlist[i][0];
1520        $idx = is_def(dist) ? distind[i] : i;
1521        $dir = rotate_children ? (planar?[1,0]:[1,0,0]) : cutlist[i][2];
1522        $normal = rotate_children? (planar?[0,1]:[0,0,1]) : cutlist[i][3];
1523        translate($pos) {
1524            if (rotate_children) {
1525                if(planar) {
1526                    rot(from=[0,1],to=cutlist[i][3]) children();
1527                } else {
1528                    frame_map(x=cutlist[i][2], z=cutlist[i][3])
1529                        children();
1530                }
1531            } else {
1532                children();
1533            }
1534        }
1535    }
1536}
1537
1538
1539function path_copies(path, n, spacing, sp=undef, dist, rotate_children=true, dist, closed, p=_NO_ARG) =
1540    let(
1541        is_1reg = is_1region(path),
1542        path = is_1reg ? path[0] : path,
1543        closed = default(closed, is_1reg),
1544        length = path_length(path,closed),
1545        distind = is_def(dist) ? sortidx(dist) : undef,
1546        distances =
1547            is_def(dist) ? assert(is_undef(n) && is_undef(spacing) && is_undef(sp), "Can't use n, spacing or undef with dist")
1548                           select(dist,distind)
1549          : is_def(sp)? (   // Start point given
1550                is_def(n) && is_def(spacing)? count(n,sp,spacing) :
1551                is_def(n)? lerpn(sp, length, n) :
1552                list([sp:spacing:length])
1553            )
1554          : is_def(n) && is_undef(spacing)? lerpn(0,length,n,!closed) // N alone given
1555          : (      // No start point and spacing is given, N maybe given
1556            let(
1557                n = is_def(n)? n : floor(length/spacing)+(closed?0:1),
1558                ptlist = count(n,0,spacing),
1559                listcenter = mean(ptlist)
1560            ) closed?
1561                sort([for(entry=ptlist) posmod(entry-listcenter,length)]) :
1562                [for(entry=ptlist) entry + length/2-listcenter ]
1563          ),
1564        distOK = min(distances)>=0 && max(distances)<=length,
1565        dummy = assert(distOK,"Cannot fit all of the copies"),
1566        cutlist = path_cut_points(path, distances, closed, direction=true),
1567        planar = len(path[0])==2,
1568        mats = [
1569            for(i=[0:1:len(cutlist)-1])
1570            translate(cutlist[i][0]) * (
1571                !rotate_children? ident(4) :
1572                planar? rot(from=[0,1],to=cutlist[i][3]) :
1573                frame_map(x=cutlist[i][2], z=cutlist[i][3])
1574            )
1575        ]
1576    )
1577    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
1578
1579
1580
1581//////////////////////////////////////////////////////////////////////
1582// Section: Making a copy of all children with reflection
1583//////////////////////////////////////////////////////////////////////
1584
1585// Function&Module: xflip_copy()
1586// Synopsis: Makes a copy of children mirrored across the X axis.
1587// SynTags: MatList, Trans
1588// Topics: Transformations, Distributors, Translation, Copiers
1589// See Also: yflip_copy(), zflip_copy(), mirror_copy(), path_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1590//
1591// Usage:
1592//   xflip_copy([offset], [x]) CHILDREN;
1593// Usage: As a function to translate points, VNF, or Bezier patches
1594//   copies = xflip_copy([offset], [x], p=);
1595// Usage: Get Translation Matrices
1596//   mats = xflip_copy([offset], [x]);
1597//
1598// Description:
1599//   When called as a module, makes a copy of the children, mirrored across the X axis.
1600//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1601//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1602//
1603// Arguments:
1604//   offset = Distance to offset children right, before copying.
1605//   x = The X coordinate of the mirroring plane.  Default: 0
1606//   ---
1607//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1608//
1609// Side Effects:
1610//   `$orig` is true for the original instance of children.  False for the copy.
1611//   `$idx` is set to the index value of each copy.
1612//
1613//
1614// Example:
1615//   xflip_copy() yrot(90) cylinder(h=20, r1=4, r2=0);
1616//   color("blue",0.25) cube([0.01,15,15], center=true);
1617//
1618// Example:
1619//   xflip_copy(offset=5) yrot(90) cylinder(h=20, r1=4, r2=0);
1620//   color("blue",0.25) cube([0.01,15,15], center=true);
1621//
1622// Example:
1623//   xflip_copy(x=-5) yrot(90) cylinder(h=20, r1=4, r2=0);
1624//   color("blue",0.25) left(5) cube([0.01,15,15], center=true);
1625module xflip_copy(offset=0, x=0)
1626{
1627    req_children($children);  
1628    mirror_copy(v=[1,0,0], offset=offset, cp=[x,0,0]) children();
1629}
1630
1631
1632function xflip_copy(offset=0, x=0, p=_NO_ARG) =
1633    mirror_copy(v=[1,0,0], offset=offset, cp=[x,0,0], p=p);
1634
1635
1636// Function&Module: yflip_copy()
1637// Synopsis: Makes a copy of children mirrored across the Y axis.
1638// SynTags: MatList, Trans
1639// Topics: Transformations, Distributors, Translation, Copiers
1640// See Also: xflip_copy(), zflip_copy(), mirror_copy(), path_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1641//
1642// Usage:
1643//   yflip_copy([offset], [y]) CHILDREN;
1644// Usage: As a function to translate points, VNF, or Bezier patches
1645//   copies = yflip_copy([offset], [y], p=);
1646// Usage: Get Translation Matrices
1647//   mats = yflip_copy([offset], [y]);
1648//
1649// Description:
1650//   When called as a module, makes a copy of the children, mirrored across the Y axis.
1651//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1652//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1653//
1654// Arguments:
1655//   offset = Distance to offset children back, before copying.
1656//   y = The Y coordinate of the mirroring plane.  Default: 0
1657//   ---
1658//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1659//
1660// Side Effects:
1661//   `$orig` is true for the original instance of children.  False for the copy.
1662//   `$idx` is set to the index value of each copy.
1663//
1664//
1665// Example:
1666//   yflip_copy() xrot(-90) cylinder(h=20, r1=4, r2=0);
1667//   color("blue",0.25) cube([15,0.01,15], center=true);
1668//
1669// Example:
1670//   yflip_copy(offset=5) xrot(-90) cylinder(h=20, r1=4, r2=0);
1671//   color("blue",0.25) cube([15,0.01,15], center=true);
1672//
1673// Example:
1674//   yflip_copy(y=-5) xrot(-90) cylinder(h=20, r1=4, r2=0);
1675//   color("blue",0.25) fwd(5) cube([15,0.01,15], center=true);
1676module yflip_copy(offset=0, y=0)
1677{
1678    req_children($children);
1679    mirror_copy(v=[0,1,0], offset=offset, cp=[0,y,0]) children();
1680}
1681
1682
1683function yflip_copy(offset=0, y=0, p=_NO_ARG) =
1684    mirror_copy(v=[0,1,0], offset=offset, cp=[0,y,0], p=p);
1685
1686
1687// Function&Module: zflip_copy()
1688// Synopsis: Makes a copy of children mirrored across the Z axis.
1689// SynTags: MatList, Trans
1690// Topics: Transformations, Distributors, Translation, Copiers
1691// See Also: xflip_copy(), yflip_copy(), mirror_copy(), path_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1692//
1693// Usage:
1694//   zflip_copy([offset], [z]) CHILDREN;
1695// Usage: As a function to translate points, VNF, or Bezier patches
1696//   copies = zflip_copy([offset], [z], p=);
1697// Usage: Get Translation Matrices
1698//   mats = zflip_copy([offset], [z]);
1699//
1700// Description:
1701//   When called as a module, makes a copy of the children, mirrored across the Z axis.
1702//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1703//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1704//
1705// Arguments:
1706//   offset = Distance to offset children up, before copying.
1707//   z = The Z coordinate of the mirroring plane.  Default: 0
1708//   ---
1709//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1710//
1711// Side Effects:
1712//   `$orig` is true for the original instance of children.  False for the copy.
1713//   `$idx` is set to the index value of each copy.
1714//
1715//
1716// Example:
1717//   zflip_copy() cylinder(h=20, r1=4, r2=0);
1718//   color("blue",0.25) cube([15,15,0.01], center=true);
1719//
1720// Example:
1721//   zflip_copy(offset=5) cylinder(h=20, r1=4, r2=0);
1722//   color("blue",0.25) cube([15,15,0.01], center=true);
1723//
1724// Example:
1725//   zflip_copy(z=-5) cylinder(h=20, r1=4, r2=0);
1726//   color("blue",0.25) down(5) cube([15,15,0.01], center=true);
1727module zflip_copy(offset=0, z=0)
1728{
1729    req_children($children);  
1730    mirror_copy(v=[0,0,1], offset=offset, cp=[0,0,z]) children();
1731}
1732
1733
1734function zflip_copy(offset=0, z=0, p=_NO_ARG) =
1735    mirror_copy(v=[0,0,1], offset=offset, cp=[0,0,z], p=p);
1736
1737
1738// Function&Module: mirror_copy()
1739// Synopsis: Makes a copy of children mirrored across a given plane.
1740// SynTags: MatList, Trans
1741// Topics: Transformations, Distributors, Translation, Copiers
1742// See Also: xflip_copy(), yflip_copy(), zflip_copy(), path_copies(), move_copies(), xcopies(), ycopies(), zcopies(), line_copies(), grid_copies() 
1743//
1744// Usage:
1745//   mirror_copy(v, [cp], [offset]) CHILDREN;
1746// Usage: As a function to translate points, VNF, or Bezier patches
1747//   copies = mirror_copy(v, [cp], [offset], p=);
1748// Usage: Get Translation Matrices
1749//   mats = mirror_copy(v, [cp], [offset]);
1750//
1751// Description:
1752//   When called as a module, makes a copy of the children, mirrored across the given plane.
1753//   When called as a function, *without* a `p=` argument, returns a list of transformation matrices, one for each copy.
1754//   When called as a function, *with* a `p=` argument, returns a list of transformed copies of `p=`.
1755//
1756// Arguments:
1757//   v = The normal vector of the plane to mirror across.
1758//   offset = distance to offset away from the plane.
1759//   cp = A point that lies on the mirroring plane.
1760//   ---
1761//   p = Either a point, pointlist, VNF or Bezier patch to be translated when used as a function.
1762//
1763// Side Effects:
1764//   `$orig` is true for the original instance of children.  False for the copy.
1765//   `$idx` is set to the index value of each copy.
1766//
1767//
1768// Example:
1769//   mirror_copy([1,-1,0]) zrot(-45) yrot(90) cylinder(d1=10, d2=0, h=20);
1770//   color("blue",0.25) zrot(-45) cube([0.01,15,15], center=true);
1771//
1772// Example:
1773//   mirror_copy([1,1,0], offset=5) rot(a=90,v=[-1,1,0]) cylinder(d1=10, d2=0, h=20);
1774//   color("blue",0.25) zrot(45) cube([0.01,15,15], center=true);
1775//
1776// Example:
1777//   mirror_copy(UP+BACK, cp=[0,-5,-5]) rot(from=UP, to=BACK+UP) cylinder(d1=10, d2=0, h=20);
1778//   color("blue",0.25) translate([0,-5,-5]) rot(from=UP, to=BACK+UP) cube([15,15,0.01], center=true);
1779module mirror_copy(v=[0,0,1], offset=0, cp)
1780{
1781    req_children($children);  
1782    cp = is_vector(v,4)? plane_normal(v) * v[3] :
1783        is_vector(cp)? cp :
1784        is_num(cp)? cp*unit(v) :
1785        [0,0,0];
1786    nv = is_vector(v,4)? plane_normal(v) : unit(v);
1787    off = nv*offset;
1788    if (cp == [0,0,0]) {
1789        translate(off) {
1790            $orig = true;
1791            $idx = 0;
1792            children();
1793        }
1794        mirror(nv) translate(off) {
1795            $orig = false;
1796            $idx = 1;
1797            children();
1798        }
1799    } else {
1800        translate(off) children();
1801        translate(cp) mirror(nv) translate(-cp) translate(off) children();
1802    }
1803}
1804
1805
1806function mirror_copy(v=[0,0,1], offset=0, cp, p=_NO_ARG) =
1807    let(
1808        cp = is_vector(v,4)? plane_normal(v) * v[3] :
1809            is_vector(cp)? cp :
1810            is_num(cp)? cp*unit(v) :
1811            [0,0,0],
1812        nv = is_vector(v,4)? plane_normal(v) : unit(v),
1813        off = nv*offset,
1814        mats = [
1815            translate(off),
1816            translate(cp) *
1817                mirror(nv) *
1818                translate(-cp) *
1819                translate(off)
1820        ]
1821    )
1822    p==_NO_ARG? mats : [for (m = mats) apply(m, p)];
1823
1824
1825
1826////////////////////
1827// Section: Distributing children individually along a line
1828///////////////////
1829// Module: xdistribute()
1830// Synopsis: Distributes each child, individually, out along the X axis.
1831// SynTags: Trans
1832// See Also: xdistribute(), ydistribute(), zdistribute(), distribute()
1833//
1834// Usage:
1835//   xdistribute(spacing, [sizes]) CHILDREN;
1836//   xdistribute(l=, [sizes=]) CHILDREN;
1837//
1838//
1839// Description:
1840//   Spreads out the children individually along the X axis. 
1841//   Every child is placed at a different position, in order.
1842//   This is useful for laying out groups of disparate objects
1843//   where you only really care about the spacing between them.
1844//
1845// Arguments:
1846//   spacing = spacing between each child. (Default: 10.0)
1847//   sizes = Array containing how much space each child will need.
1848//   l = Length to distribute copies along.
1849//
1850// Side Effects:
1851//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
1852//   `$idx` is set to the index number of each child being copied.
1853//
1854// Example:
1855//   xdistribute(sizes=[100, 10, 30], spacing=40) {
1856//       sphere(r=50);
1857//       cube([10,20,30], center=true);
1858//       cylinder(d=30, h=50, center=true);
1859//   }
1860module xdistribute(spacing=10, sizes=undef, l=undef)
1861{
1862    req_children($children);  
1863    dir = RIGHT;
1864    gaps = ($children < 2)? [0] :
1865        !is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
1866        [for (i=[0:1:$children-2]) 0];
1867    spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
1868    gaps2 = [for (gap = gaps) gap+spc];
1869    spos = dir * -sum(gaps2)/2;
1870    spacings = cumsum([0, each gaps2]);
1871    for (i=[0:1:$children-1]) {
1872        $pos = spos + spacings[i] * dir;
1873        $idx = i;
1874        translate($pos) children(i);
1875    }
1876}
1877
1878
1879// Module: ydistribute()
1880// Synopsis: Distributes each child, individually, out along the Y axis.
1881// SynTags: Trans
1882// See Also: xdistribute(), ydistribute(), zdistribute(), distribute()
1883//
1884// Usage:
1885//   ydistribute(spacing, [sizes]) CHILDREN;
1886//   ydistribute(l=, [sizes=]) CHILDREN;
1887//
1888// Description:
1889//   Spreads out the children individually along the Y axis. 
1890//   Every child is placed at a different position, in order.
1891//   This is useful for laying out groups of disparate objects
1892//   where you only really care about the spacing between them.
1893//
1894// Arguments:
1895//   spacing = spacing between each child. (Default: 10.0)
1896//   sizes = Array containing how much space each child will need.
1897//   l = Length to distribute copies along.
1898//
1899// Side Effects:
1900//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
1901//   `$idx` is set to the index number of each child being copied.
1902//
1903// Example:
1904//   ydistribute(sizes=[30, 20, 100], spacing=40) {
1905//       cylinder(d=30, h=50, center=true);
1906//       cube([10,20,30], center=true);
1907//       sphere(r=50);
1908//   }
1909module ydistribute(spacing=10, sizes=undef, l=undef)
1910{
1911    req_children($children);  
1912    dir = BACK;
1913    gaps = ($children < 2)? [0] :
1914        !is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
1915        [for (i=[0:1:$children-2]) 0];
1916    spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
1917    gaps2 = [for (gap = gaps) gap+spc];
1918    spos = dir * -sum(gaps2)/2;
1919    spacings = cumsum([0, each gaps2]);
1920    for (i=[0:1:$children-1]) {
1921        $pos = spos + spacings[i] * dir;
1922        $idx = i;
1923        translate($pos) children(i);
1924    }
1925}
1926
1927
1928// Module: zdistribute()
1929// Synopsis: Distributes each child, individually, out along the Z axis.
1930// SynTags: Trans
1931// See Also: xdistribute(), ydistribute(), zdistribute(), distribute()
1932//
1933// Usage:
1934//   zdistribute(spacing, [sizes]) CHILDREN;
1935//   zdistribute(l=, [sizes=]) CHILDREN;
1936//
1937// Description:
1938//   Spreads out each individual child along the Z axis.
1939//   Every child is placed at a different position, in order.
1940//   This is useful for laying out groups of disparate objects
1941//   where you only really care about the spacing between them.
1942//
1943// Arguments:
1944//   spacing = spacing between each child. (Default: 10.0)
1945//   sizes = Array containing how much space each child will need.
1946//   l = Length to distribute copies along.
1947//
1948// Side Effects:
1949//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
1950//   `$idx` is set to the index number of each child being copied.
1951//
1952// Example:
1953//   zdistribute(sizes=[30, 20, 100], spacing=40) {
1954//       cylinder(d=30, h=50, center=true);
1955//       cube([10,20,30], center=true);
1956//       sphere(r=50);
1957//   }
1958module zdistribute(spacing=10, sizes=undef, l=undef)
1959{
1960    req_children($children);  
1961    dir = UP;
1962    gaps = ($children < 2)? [0] :
1963        !is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
1964        [for (i=[0:1:$children-2]) 0];
1965    spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
1966    gaps2 = [for (gap = gaps) gap+spc];
1967    spos = dir * -sum(gaps2)/2;
1968    spacings = cumsum([0, each gaps2]);
1969    for (i=[0:1:$children-1]) {
1970        $pos = spos + spacings[i] * dir;
1971        $idx = i;
1972        translate($pos) children(i);
1973    }
1974}
1975
1976
1977
1978// Module: distribute()
1979// Synopsis: Distributes each child, individually, out along an arbitrary line.
1980// SynTags: Trans
1981// See Also: xdistribute(), ydistribute(), zdistribute(), distribute()
1982//
1983// Usage:
1984//   distribute(spacing, sizes, dir) CHILDREN;
1985//   distribute(l=, [sizes=], [dir=]) CHILDREN;
1986//
1987// Description:
1988//   Spreads out the children individually along the direction `dir`.
1989//   Every child is placed at a different position, in order.
1990//   This is useful for laying out groups of disparate objects
1991//   where you only really care about the spacing between them.
1992//
1993// Arguments:
1994//   spacing = Spacing to add between each child. (Default: 10.0)
1995//   sizes = Array containing how much space each child will need.
1996//   dir = Vector direction to distribute copies along.  Default: RIGHT
1997//   l = Length to distribute copies along.
1998//
1999// Side Effects:
2000//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
2001//   `$idx` is set to the index number of each child being copied.
2002//
2003// Example:
2004//   distribute(sizes=[100, 30, 50], dir=UP) {
2005//       sphere(r=50);
2006//       cube([10,20,30], center=true);
2007//       cylinder(d=30, h=50, center=true);
2008//   }
2009module distribute(spacing=undef, sizes=undef, dir=RIGHT, l=undef)
2010{
2011    req_children($children);  
2012    gaps = ($children < 2)? [0] :
2013        !is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
2014        [for (i=[0:1:$children-2]) 0];
2015    spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
2016    gaps2 = [for (gap = gaps) gap+spc];
2017    spos = dir * -sum(gaps2)/2;
2018    spacings = cumsum([0, each gaps2]);
2019    for (i=[0:1:$children-1]) {
2020        $pos = spos + spacings[i] * dir;
2021        $idx = i;
2022        translate($pos) children(i);
2023    }
2024}
2025
2026
2027
2028// vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap