//////////////////////////////////////////////////////////////////////
// LibFile: distributors.scad
//   Functions and modules to distribute children or copies of children.
//   To use, add the following lines to the beginning of your file:
//   ```
//   include <BOSL2/std.scad>
//   ```
//////////////////////////////////////////////////////////////////////


//////////////////////////////////////////////////////////////////////
// Section: Translational Distributors
//////////////////////////////////////////////////////////////////////


// Module: move_copies()
//
// Description:
//   Translates copies of all children to each given translation offset.
//
// Usage:
//   move_copies(a) ...
//
// Arguments:
//   a = Array of XYZ offset vectors. Default `[[0,0,0]]`
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   #sphere(r=10);
//   move_copies([[-25,-25,0], [25,-25,0], [0,0,50], [0,25,0]]) sphere(r=10);
module move_copies(a=[[0,0,0]])
{
	assert(is_list(a));
	for ($idx = idx(a)) {
		$pos = a[$idx];
		assert(is_vector($pos));
		translate($pos) children();
	}
}


// Module: line_of()
//
// Description:
//   Evenly distributes `n` copies of all children along a line.
//   Copies every child at each position.
//
// Usage:
//   line_of(l, [n], [p1]) ...
//   line_of(l, spacing, [p1]) ...
//   line_of(spacing, [n], [p1]) ...
//   line_of(p1, p2, [n]) ...
//   line_of(p1, p2, spacing) ...
//
// Arguments:
//   p1 = Starting point of line.
//   p2 = Ending point of line.
//   l = Length to spread copies over.
//   spacing = A 3D vector indicating which direction and distance to place each subsequent copy at.
//   n = Number of copies to distribute along the line. (Default: 2)
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example(FlatSpin):
//   line_of([0,0,0], [5,5,20], n=6) cube(size=[3,2,1],center=true);
// Examples:
//   line_of(l=40, n=6) cube(size=[3,2,1],center=true);
//   line_of(l=[15,30], n=6) cube(size=[3,2,1],center=true);
//   line_of(l=40, spacing=10) cube(size=[3,2,1],center=true);
//   line_of(spacing=[5,5,0], n=5) cube(size=[3,2,1],center=true);
// Example:
//   line_of(l=20, n=3) {
//       cube(size=[1,3,1],center=true);
//       cube(size=[3,1,1],center=true);
//   }
module line_of(p1, p2, spacing, l, n)
{
	ll = (
		!is_undef(l)? scalar_vec3(l, 0) :
		(!is_undef(spacing) && !is_undef(n))? (n * scalar_vec3(spacing, 0)) :
		(!is_undef(p1) && !is_undef(p2))? point3d(p2-p1) :
		undef
	);
	cnt = (
		!is_undef(n)? n :
		(!is_undef(spacing) && !is_undef(ll))? floor(norm(ll) / norm(scalar_vec3(spacing, 0)) + 1.000001) :
		2
	);
	spc = (
		is_undef(spacing)? (ll/(cnt-1)) :
		is_num(spacing) && !is_undef(ll)? (ll/(cnt-1)) :
		scalar_vec3(spacing, 0)
	);
	assert(!is_undef(cnt), "Need two of `spacing`, 'l', 'n', or `p1`/`p2` arguments in `line_of()`.");
	spos = !is_undef(p1)? point3d(p1) : -(cnt-1)/2 * spc;
	for (i=[0:1:cnt-1]) {
		pos = i * spc + spos;
		$pos = pos;
		$idx = i;
		translate(pos) children();
	}
}


// Module: xcopies()
//
// Description:
//   Spreads out `n` copies of the children along a line on the X axis.
//
// Usage:
//   xcopies(spacing, [n], [sp]) ...
//   xcopies(l, [n], [sp]) ...
//
// Arguments:
//   spacing = spacing between copies. (Default: 1.0)
//   n = Number of copies to spread out. (Default: 2)
//   l = Length to spread copies over.
//   sp = If given, copies will be spread on a line to the right of starting position `sp`.  If not given, copies will be spread along a line that is centered at [0,0,0].
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Examples:
//   xcopies(20) sphere(3);
//   xcopies(20, n=3) sphere(3);
//   xcopies(spacing=15, l=50) sphere(3);
//   xcopies(n=4, l=30, sp=[0,10,0]) sphere(3);
// Example:
//   xcopies(10, n=3) {
//       cube(size=[1,3,1],center=true);
//       cube(size=[3,1,1],center=true);
//   }
module xcopies(spacing, n, l, sp)
{
	line_of(l=l*RIGHT, spacing=spacing*RIGHT, n=n, p1=sp) children();
}


// Module: ycopies()
//
// Description:
//   Spreads out `n` copies of the children along a line on the Y axis.
//
// Usage:
//   ycopies(spacing, [n], [sp]) ...
//   ycopies(l, [n], [sp]) ...
//
// Arguments:
//   spacing = spacing between copies. (Default: 1.0)
//   n = Number of copies to spread out. (Default: 2)
//   l = Length to spread copies over.
//   sp = If given, copies will be spread on a line back from starting position `sp`.  If not given, copies will be spread along a line that is centered at [0,0,0].
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Examples:
//   ycopies(20) sphere(3);
//   ycopies(20, n=3) sphere(3);
//   ycopies(spacing=15, l=50) sphere(3);
//   ycopies(n=4, l=30, sp=[10,0,0]) sphere(3);
// Example:
//   ycopies(10, n=3) {
//       cube(size=[1,3,1],center=true);
//       cube(size=[3,1,1],center=true);
//   }
module ycopies(spacing, n, l, sp)
{
	line_of(l=l*BACK, spacing=spacing*BACK, n=n, p1=sp) children();
}


// Module: zcopies()
//
// Description:
//   Spreads out `n` copies of the children along a line on the Z axis.
//
// Usage:
//   zcopies(spacing, [n], [sp]) ...
//   zcopies(l, [n], [sp]) ...
//
// Arguments:
//   spacing = spacing between copies. (Default: 1.0)
//   n = Number of copies to spread out. (Default: 2)
//   l = Length to spread copies over.
//   sp = If given, copies will be spread on a line up from starting position `sp`.  If not given, copies will be spread along a line that is centered at [0,0,0].
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Examples:
//   zcopies(20) sphere(3);
//   zcopies(20, n=3) sphere(3);
//   zcopies(spacing=15, l=50) sphere(3);
//   zcopies(n=4, l=30, sp=[10,0,0]) sphere(3);
// Example:
//   zcopies(10, n=3) {
//       cube(size=[1,3,1],center=true);
//       cube(size=[3,1,1],center=true);
//   }
module zcopies(spacing, n, l, sp)
{
	line_of(l=l*UP, spacing=spacing*UP, n=n, p1=sp) children();
}



// Module: distribute()
//
// Description:
//   Spreads out each individual child along the direction `dir`.
//   Every child is placed at a different position, in order.
//   This is useful for laying out groups of disparate objects
//   where you only really care about the spacing between them.
//
// Usage:
//   distribute(spacing, dir, [sizes]) ...
//   distribute(l, dir, [sizes]) ...
//
// Arguments:
//   spacing = Spacing to add between each child. (Default: 10.0)
//   sizes = Array containing how much space each child will need.
//   dir = Vector direction to distribute copies along.
//   l = Length to distribute copies along.
//
// Side Effect:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   distribute(sizes=[100, 30, 50], dir=UP) {
//       sphere(r=50);
//       cube([10,20,30], center=true);
//       cylinder(d=30, h=50, center=true);
//   }
module distribute(spacing=undef, sizes=undef, dir=RIGHT, l=undef)
{
	gaps = ($children < 2)? [0] :
		!is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
		[for (i=[0:1:$children-2]) 0];
	spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
	gaps2 = [for (gap = gaps) gap+spc];
	spos = dir * -sum(gaps2)/2;
	for (i=[0:1:$children-1]) {
		totspc = sum(concat([0], slice(gaps2, 0, i)));
		$pos = spos + totspc * dir;
		$idx = i;
		translate($pos) children(i);
	}
}


// Module: xdistribute()
//
// Description:
//   Spreads out each individual child along the X axis.
//   Every child is placed at a different position, in order.
//   This is useful for laying out groups of disparate objects
//   where you only really care about the spacing between them.
//
// Usage:
//   xdistribute(spacing, [sizes]) ...
//   xdistribute(l, [sizes]) ...
//
// Arguments:
//   spacing = spacing between each child. (Default: 10.0)
//   sizes = Array containing how much space each child will need.
//   l = Length to distribute copies along.
//
// Side Effect:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   xdistribute(sizes=[100, 10, 30], spacing=40) {
//       sphere(r=50);
//       cube([10,20,30], center=true);
//       cylinder(d=30, h=50, center=true);
//   }
module xdistribute(spacing=10, sizes=undef, l=undef)
{
	dir = RIGHT;
	gaps = ($children < 2)? [0] :
		!is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
		[for (i=[0:1:$children-2]) 0];
	spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
	gaps2 = [for (gap = gaps) gap+spc];
	spos = dir * -sum(gaps2)/2;
	for (i=[0:1:$children-1]) {
		totspc = sum(concat([0], slice(gaps2, 0, i)));
		$pos = spos + totspc * dir;
		$idx = i;
		translate($pos) children(i);
	}
}


// Module: ydistribute()
//
// Description:
//   Spreads out each individual child along the Y axis.
//   Every child is placed at a different position, in order.
//   This is useful for laying out groups of disparate objects
//   where you only really care about the spacing between them.
//
// Usage:
//   ydistribute(spacing, [sizes])
//   ydistribute(l, [sizes])
//
// Arguments:
//   spacing = spacing between each child. (Default: 10.0)
//   sizes = Array containing how much space each child will need.
//   l = Length to distribute copies along.
//
// Side Effect:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   ydistribute(sizes=[30, 20, 100], spacing=40) {
//       cylinder(d=30, h=50, center=true);
//       cube([10,20,30], center=true);
//       sphere(r=50);
//   }
module ydistribute(spacing=10, sizes=undef, l=undef)
{
	dir = BACK;
	gaps = ($children < 2)? [0] :
		!is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
		[for (i=[0:1:$children-2]) 0];
	spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
	gaps2 = [for (gap = gaps) gap+spc];
	spos = dir * -sum(gaps2)/2;
	for (i=[0:1:$children-1]) {
		totspc = sum(concat([0], slice(gaps2, 0, i)));
		$pos = spos + totspc * dir;
		$idx = i;
		translate($pos) children(i);
	}
}


// Module: zdistribute()
//
// Description:
//   Spreads out each individual child along the Z axis.
//   Every child is placed at a different position, in order.
//   This is useful for laying out groups of disparate objects
//   where you only really care about the spacing between them.
//
// Usage:
//   zdistribute(spacing, [sizes])
//   zdistribute(l, [sizes])
//
// Arguments:
//   spacing = spacing between each child. (Default: 10.0)
//   sizes = Array containing how much space each child will need.
//   l = Length to distribute copies along.
//
// Side Effect:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   zdistribute(sizes=[30, 20, 100], spacing=40) {
//       cylinder(d=30, h=50, center=true);
//       cube([10,20,30], center=true);
//       sphere(r=50);
//   }
module zdistribute(spacing=10, sizes=undef, l=undef)
{
	dir = UP;
	gaps = ($children < 2)? [0] :
		!is_undef(sizes)? [for (i=[0:1:$children-2]) sizes[i]/2 + sizes[i+1]/2] :
		[for (i=[0:1:$children-2]) 0];
	spc = !is_undef(l)? ((l - sum(gaps)) / ($children-1)) : default(spacing, 10);
	gaps2 = [for (gap = gaps) gap+spc];
	spos = dir * -sum(gaps2)/2;
	for (i=[0:1:$children-1]) {
		totspc = sum(concat([0], slice(gaps2, 0, i)));
		$pos = spos + totspc * dir;
		$idx = i;
		translate($pos) children(i);
	}
}



// Module: grid2d()
//
// Description:
//   Makes a square or hexagonal grid of copies of children.
//
// Usage:
//   grid2d(spacing, size, [stagger], [scale], [inside]) ...
//   grid2d(n, size, [stagger], [scale], [inside]) ...
//   grid2d(spacing, n, [stagger], [scale], [inside]) ...
//   grid2d(spacing, inside, [stagger], [scale]) ...
//   grid2d(n, inside, [stagger], [scale]) ...
//
// Arguments:
//   size = The [X,Y] size to spread the copies over.
//   spacing = Distance between copies in [X,Y] or scalar distance.
//   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)
//   stagger = If true, make a staggered (hexagonal) grid.  If false, make square grid.  If `"alt"`, makes alternate staggered pattern.  Default: false
//   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.
//
// Side Effects:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$col` is set to the integer column number for each child.
//   `$row` is set to the integer row number for each child.
//
// Examples:
//   grid2d(size=50, spacing=10) cylinder(d=10, h=1);
//   grid2d(size=50, spacing=[10,15]) cylinder(d=10, h=1);
//   grid2d(spacing=10, n=[13,7], stagger=true) cylinder(d=6, h=5);
//   grid2d(spacing=10, n=[13,7], stagger="alt") cylinder(d=6, h=5);
//   grid2d(size=50, n=11, stagger=true) cylinder(d=5, h=1);
//
// Example:
//   poly = [[-25,-25], [25,25], [-25,25], [25,-25]];
//   grid2d(spacing=5, stagger=true, inside=poly)
//      zrot(180/6) cylinder(d=5, h=1, $fn=6);
//   %polygon(poly);
//
// Example: Using `$row` and `$col`
//   grid2d(spacing=8, n=8)
//       color(($row+$col)%2?"black":"red")
//           cube([8,8,0.01], center=false);
//
// Example:
//   // Makes a grid of hexagon pillars whose tops are all
//   // angled to reflect light at [0,0,50], if they were shiny.
//   hexregion = circle(r=50.01,$fn=6);
//   grid2d(spacing=10, stagger=true, inside=hexregion) union() {
//       // Note: The union() is needed or else $pos will be
//       //   inexplicably unreadable.
//       ref_v = (unit([0,0,50]-point3d($pos)) + UP)/2;
//       half_of(v=-ref_v, cp=[0,0,5])
//           zrot(180/6)
//               cylinder(h=20, d=10/cos(180/6)+0.01, $fn=6);
//   }
module grid2d(spacing, n, size, stagger=false, inside=undef)
{
	assert(in_list(stagger, [false, true, "alt"]));
	bounds = is_undef(inside)? undef :
		is_path(inside)? pointlist_bounds(inside) :
		assert(is_region(inside))
		pointlist_bounds(flatten(inside));
	size = is_num(size)? [size, size] :
		is_vector(size)? assert(len(size)==2) size :
		bounds!=undef? [
			for (i=[0:1]) 2*max(abs(bounds[0][i]),bounds[1][i])
		] : undef;
	spacing = is_num(spacing)? (
			stagger!=false? polar_to_xy(spacing,60) :
			[spacing,spacing]
		) :
		is_vector(spacing)? assert(len(spacing)==2) spacing :
		size!=undef? (
			is_num(n)? vdiv(size,(n-1)*[1,1]) :
			is_vector(n)? assert(len(n)==2) vdiv(size,n-[1,1]) :
			vdiv(size,(stagger==false? [1,1] : [2,2]))
		) :
		undef;
	n = is_num(n)? [n,n] :
		is_vector(n)? assert(len(n)==2) n :
		size!=undef && spacing!=undef? vfloor(vdiv(size,spacing))+[1,1] :
		[2,2];
	offset = vmul(spacing, n-[1,1])/2;
	if (stagger == false) {
		for (row = [0:1:n.y-1]) {
			for (col = [0:1:n.x-1]) {
				pos = vmul([col,row],spacing) - offset;
				if (
					is_undef(inside) ||
					(is_path(inside) && point_in_polygon(pos, inside)>=0) ||
					(is_region(inside) && point_in_region(pos, inside)>=0)
				) {
					$col = col;
					$row = row;
					$pos = pos;
					translate(pos) children();
				}
			}
		}
	} else {
		// stagger == true or stagger == "alt"
		staggermod = (stagger == "alt")? 1 : 0;
		cols1 = ceil(n.x/2);
		cols2 = n.x - cols1;
		for (row = [0:1:n.y-1]) {
			rowcols = ((row%2) == staggermod)? cols1 : cols2;
			if (rowcols > 0) {
				for (col = [0:1:rowcols-1]) {
					rowdx = (row%2 != staggermod)? spacing.x : 0;
					pos = vmul([2*col,row],spacing) + [rowdx,0] - offset;
					if (
						is_undef(inside) ||
						(is_path(inside) && point_in_polygon(pos, inside)>=0) ||
						(is_region(inside) && point_in_region(pos, inside)>=0)
					) {
						$col = col * 2 + ((row%2!=staggermod)? 1 : 0);
						$row = row;
						$pos = pos;
						translate(pos) children();
					}
				}
			}
		}
	}
}



// Module: grid3d()
//
// Description:
//   Makes a 3D grid of duplicate children.
//
// Usage:
//   grid3d(n, spacing) ...
//   grid3d(n=[Xn,Yn,Zn], spacing=[dX,dY,dZ]) ...
//   grid3d([xa], [ya], [za]) ...
//
// Arguments:
//   xa = array or range of X-axis values to offset by. (Default: [0])
//   ya = array or range of Y-axis values to offset by. (Default: [0])
//   za = array or range of Z-axis values to offset by. (Default: [0])
//   n = Optional number of copies to have per axis.
//   spacing = spacing of copies per axis. Use with `n`.
//
// Side Effect:
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the [Xidx,Yidx,Zidx] index values of each child copy, when using `count` and `n`.
//
// Examples(FlatSpin):
//   grid3d(xa=[0:25:50],ya=[0,40],za=[-20:40:20]) sphere(r=5);
//   grid3d(n=[3, 4, 2], spacing=[60, 50, 40]) sphere(r=10);
// Examples:
//   grid3d(ya=[-60:40:60],za=[0,70]) sphere(r=10);
//   grid3d(n=3, spacing=30) sphere(r=10);
//   grid3d(n=[3, 1, 2], spacing=30) sphere(r=10);
//   grid3d(n=[3, 4], spacing=[80, 60]) sphere(r=10);
// Examples:
//   grid3d(n=[10, 10, 10], spacing=50) color($idx/9) cube(50, center=true);
module grid3d(xa=[0], ya=[0], za=[0], n=undef, spacing=undef)
{
	n = scalar_vec3(n, 1);
	spacing = scalar_vec3(spacing, undef);
	if (!is_undef(n) && !is_undef(spacing)) {
		for (xi = [0:1:n.x-1]) {
			for (yi = [0:1:n.y-1]) {
				for (zi = [0:1:n.z-1]) {
					$idx = [xi,yi,zi];
					$pos = vmul(spacing, $idx - (n-[1,1,1])/2);
					translate($pos) children();
				}
			}
		}
	} else {
		for (xoff = xa, yoff = ya, zoff = za) {
			$pos = [xoff, yoff, zoff];
			translate($pos) children();
		}
	}
}



//////////////////////////////////////////////////////////////////////
// Section: Rotational Distributors
//////////////////////////////////////////////////////////////////////


// Module: rot_copies()
//
// Description:
//   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.
//   Given a list of scalar angles in `rots`, rotates copies of the children to each of those angles around the axis of rotation.
//   If given a vector `v`, that becomes the axis of rotation.  Default axis of rotation is UP.
//   If given a count `n`, makes that many copies, rotated evenly around the axis.
//   If given an offset `delta`, translates each child by that amount before rotating them into place.  This makes rings.
//   If given a centerpoint `cp`, centers the ring around that centerpoint.
//   If `subrot` is true, each child will be rotated in place to keep the same size towards the center.
//   The first (unrotated) copy will be placed at the relative starting angle `sa`.
//
// Usage:
//   rot_copies(rots, [cp], [sa], [delta], [subrot]) ...
//   rot_copies(rots, v, [cp], [sa], [delta], [subrot]) ...
//   rot_copies(n, [v], [cp], [sa], [delta], [subrot]) ...
//
// Arguments:
//   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`.
//   v = If given, this is the vector of the axis to rotate around.
//   cp = Centerpoint to rotate around.  Default: `[0,0,0]`
//   n = Optional number of evenly distributed copies, rotated around the axis.
//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise.  Default: 0
//   delta = [X,Y,Z] amount to move away from cp before rotating.  Makes rings of copies.  Default: `[0,0,0]`
//   subrot = If false, don't sub-rotate children as they are copied around the ring.  Only makes sense when used with `delta`.  Default: `true`
//
// Side Effects:
//   `$ang` is set to the rotation angle (or XYZ rotation triplet) of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index value of each child copy.
//   `$axis` is set to the axis to rotate around, if `rots` was given as a list of angles instead of a list of [X,Y,Z] rotation angles.
//
// Example:
//   #cylinder(h=20, r1=5, r2=0);
//   rot_copies([[45,0,0],[0,45,90],[90,-45,270]]) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   rot_copies([45, 90, 135], v=DOWN+BACK)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   rot_copies(n=6, v=DOWN+BACK)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   rot_copies(n=6, v=DOWN+BACK, delta=[10,0,0])
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   rot_copies(n=6, v=UP+FWD, delta=[10,0,0], sa=45)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   rot_copies(n=6, v=DOWN+BACK, delta=[20,0,0], subrot=false)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
module rot_copies(rots=[], v=undef, cp=[0,0,0], n=undef, sa=0, offset=0, delta=[0,0,0], subrot=true)
{
	sang = sa + offset;
	angs = !is_undef(n)?
		(n<=0? [] : [for (i=[0:1:n-1]) i/n*360+sang]) :
		rots==[]? [] :
		assert(!is_string(rots), "Argument rots must be an angle, a list of angles, or a range of angles.")
		assert(!is_undef(rots[0]), "Argument rots must be an angle, a list of angles, or a range of angles.")
		[for (a=rots) a];
	for ($idx = idx(angs)) {
		$ang = angs[$idx];
		$axis = v;
		translate(cp) {
			rotate(a=$ang, v=v) {
				translate(delta) {
					rot(a=(subrot? sang : $ang), v=v, reverse=true) {
						translate(-cp) {
							children();
						}
					}
				}
			}
		}
	}
}


// Module: xrot_copies()
//
// Usage:
//   xrot_copies(rots, [r], [cp], [sa], [subrot]) ...
//   xrot_copies(n, [r], [cp], [sa], [subrot]) ...
//
// Description:
//   Given an array of angles, rotates copies of the children to each of those angles around the X axis.
//   If given a count `n`, makes that many copies, rotated evenly around the X axis.
//   If given an offset radius `r`, distributes children around a ring of that radius.
//   If given a centerpoint `cp`, centers the ring around that centerpoint.
//   If `subrot` is true, each child will be rotated in place to keep the same size towards the center.
//   The first (unrotated) copy will be placed at the relative starting angle `sa`.
//
// Arguments:
//   rots = Optional array of rotation angles, in degrees, to make copies at.
//   cp = Centerpoint to rotate around.
//   n = Optional number of evenly distributed copies to be rotated around the ring.
//   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.
//   r = Radius to move children back, away from cp, before rotating.  Makes rings of copies.
//   subrot = If false, don't sub-rotate children as they are copied around the ring.
//
// Side Effects:
//   `$idx` is set to the index value of each child copy.
//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
//   `$axis` is set to the axis vector rotated around.
//
// Example:
//   xrot_copies([180, 270, 315])
//       cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   xrot_copies(n=6)
//       cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   xrot_copies(n=6, r=10)
//       xrot(-90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   xrot_copies(n=6, r=10, sa=45)
//       xrot(-90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   xrot_copies(n=6, r=20, subrot=false)
//       xrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
//   color("red",0.333) xrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
module xrot_copies(rots=[], cp=[0,0,0], n=undef, sa=0, r=0, subrot=true)
{
	rot_copies(rots=rots, v=RIGHT, cp=cp, n=n, sa=sa, delta=[0, r, 0], subrot=subrot) children();
}


// Module: yrot_copies()
//
// Usage:
//   yrot_copies(rots, [r], [cp], [sa], [subrot]) ...
//   yrot_copies(n, [r], [cp], [sa], [subrot]) ...
//
// Description:
//   Given an array of angles, rotates copies of the children to each of those angles around the Y axis.
//   If given a count `n`, makes that many copies, rotated evenly around the Y axis.
//   If given an offset radius `r`, distributes children around a ring of that radius.
//   If given a centerpoint `cp`, centers the ring around that centerpoint.
//   If `subrot` is true, each child will be rotated in place to keep the same size towards the center.
//   The first (unrotated) copy will be placed at the relative starting angle `sa`.
//
// Arguments:
//   rots = Optional array of rotation angles, in degrees, to make copies at.
//   cp = Centerpoint to rotate around.
//   n = Optional number of evenly distributed copies to be rotated around the ring.
//   sa = Starting angle, in degrees.  For use with `n`.  Angle is in degrees counter-clockwise from X-, when facing the origin from Y+.
//   r = Radius to move children left, away from cp, before rotating.  Makes rings of copies.
//   subrot = If false, don't sub-rotate children as they are copied around the ring.
//
// Side Effects:
//   `$idx` is set to the index value of each child copy.
//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
//   `$axis` is set to the axis vector rotated around.
//
// Example:
//   yrot_copies([180, 270, 315])
//       cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   yrot_copies(n=6)
//       cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   yrot_copies(n=6, r=10)
//       yrot(-90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   yrot_copies(n=6, r=10, sa=45)
//       yrot(-90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   yrot_copies(n=6, r=20, subrot=false)
//       yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
module yrot_copies(rots=[], cp=[0,0,0], n=undef, sa=0, r=0, subrot=true)
{
	rot_copies(rots=rots, v=BACK, cp=cp, n=n, sa=sa, delta=[-r, 0, 0], subrot=subrot) children();
}


// Module: zrot_copies()
//
// Usage:
//   zrot_copies(rots, [r], [cp], [sa], [subrot]) ...
//   zrot_copies(n, [r], [cp], [sa], [subrot]) ...
//
// Description:
//   Given an array of angles, rotates copies of the children to each of those angles around the Z axis.
//   If given a count `n`, makes that many copies, rotated evenly around the Z axis.
//   If given an offset radius `r`, distributes children around a ring of that radius.
//   If given a centerpoint `cp`, centers the ring around that centerpoint.
//   If `subrot` is true, each child will be rotated in place to keep the same size towards the center.
//   The first (unrotated) copy will be placed at the relative starting angle `sa`.
//
// Arguments:
//   rots = Optional array of rotation angles, in degrees, to make copies at.
//   cp = Centerpoint to rotate around.  Default: [0,0,0]
//   n = Optional number of evenly distributed copies to be rotated around the ring.
//   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
//   r = Radius to move children right, away from cp, before rotating.  Makes rings of copies.  Default: 0
//   subrot = If false, don't sub-rotate children as they are copied around the ring.  Default: true
//
// Side Effects:
//   `$idx` is set to the index value of each child copy.
//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
//   `$axis` is set to the axis vector rotated around.
//
// Example:
//   zrot_copies([180, 270, 315])
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   zrot_copies(n=6)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   zrot_copies(n=6, r=10)
//       yrot(90) cylinder(h=20, r1=5, r2=0);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0);
//
// Example:
//   zrot_copies(n=6, r=20, sa=45)
//       yrot(90) cylinder(h=20, r1=5, r2=0, center=true);
//   color("red",0.333) yrot(90) cylinder(h=20, r1=5, r2=0, center=true);
//
// Example:
//   zrot_copies(n=6, r=20, subrot=false)
//       yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
//   color("red",0.333) yrot(-90) cylinder(h=20, r1=5, r2=0, center=true);
module zrot_copies(rots=[], cp=[0,0,0], n=undef, sa=0, r=0, subrot=true)
{
	rot_copies(rots=rots, v=UP, cp=cp, n=n, sa=sa, delta=[r, 0, 0], subrot=subrot) children();
}


// Module: arc_of()
//
// Description:
//   Evenly distributes n duplicate children around an ovoid arc on the XY plane.
//
// Usage:
//   arc_of(r|d, n, [sa], [ea], [rot]
//   arc_of(rx|dx, ry|dy, n, [sa], [ea], [rot]
//
// Arguments:
//   n = number of copies to distribute around the circle. (Default: 6)
//   r = radius of circle (Default: 1)
//   rx = radius of ellipse on X axis. Used instead of r.
//   ry = radius of ellipse on Y axis. Used instead of r.
//   d = diameter of circle. (Default: 2)
//   dx = diameter of ellipse on X axis. Used instead of d.
//   dy = diameter of ellipse on Y axis. Used instead of d.
//   rot = whether to rotate the copied children.  (Default: false)
//   sa = starting angle. (Default: 0.0)
//   ea = ending angle. Will distribute copies CCW from sa to ea. (Default: 360.0)
//
// Side Effects:
//   `$ang` is set to the rotation angle of each child copy, and can be used to modify each child individually.
//   `$pos` is set to the relative centerpoint of each child copy, and can be used to modify each child individually.
//   `$idx` is set to the index value of each child copy.
//
// Example:
//   #cube(size=[10,3,3],center=true);
//   arc_of(d=40, n=5) cube(size=[10,3,3],center=true);
//
// Example:
//   #cube(size=[10,3,3],center=true);
//   arc_of(d=40, n=5, sa=45, ea=225) cube(size=[10,3,3],center=true);
//
// Example:
//   #cube(size=[10,3,3],center=true);
//   arc_of(r=15, n=8, rot=false) cube(size=[10,3,3],center=true);
//
// Example:
//   #cube(size=[10,3,3],center=true);
//   arc_of(rx=20, ry=10, n=8) cube(size=[10,3,3],center=true);
module arc_of(
	n=6,
	r=undef, rx=undef, ry=undef,
	d=undef, dx=undef, dy=undef,
	sa=0, ea=360,
	rot=true
) {
	rx = get_radius(r1=rx, r=r, d1=dx, d=d, dflt=1);
	ry = get_radius(r1=ry, r=r, d1=dy, d=d, dflt=1);
	sa = posmod(sa, 360);
	ea = posmod(ea, 360);
	n = (abs(ea-sa)<0.01)?(n+1):n;
	delt = (((ea<=sa)?360.0:0)+ea-sa)/(n-1);
	for ($idx = [0:1:n-1]) {
		$ang = sa + ($idx * delt);
		$pos =[rx*cos($ang), ry*sin($ang), 0];
		translate($pos) {
			zrot(rot? atan2(ry*sin($ang), rx*cos($ang)) : 0) {
				children();
			}
		}
	}
}



// Module: ovoid_spread()
//
// Description:
//   Spreads children semi-evenly over the surface of a sphere.
//
// Usage:
//   ovoid_spread(r|d, n, [cone_ang], [scale], [perp]) ...
//
// Arguments:
//   r = Radius of the sphere to distribute over
//   d = Diameter of the sphere to distribute over
//   n = How many copies to evenly spread over the surface.
//   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
//   scale = The [X,Y,Z] scaling factors to reshape the sphere being covered.
//   perp = If true, rotate children to be perpendicular to the sphere surface.  Default: true
//
// Side Effects:
//   `$pos` is set to the relative post-scaled centerpoint of each child copy, and can be used to modify each child individually.
//   `$theta` is set to the theta angle of the child from the center of the sphere.
//   `$phi` is set to the pre-scaled phi angle of the child from the center of the sphere.
//   `$rad` is set to the pre-scaled radial distance of the child from the center of the sphere.
//   `$idx` is set to the index number of each child being copied.
//
// Example:
//   ovoid_spread(n=250, d=100, cone_ang=45, scale=[3,3,1])
//       cylinder(d=10, h=10, center=false);
//
// Example:
//   ovoid_spread(n=500, d=100, cone_ang=180)
//       color(unit(point3d(vabs($pos))))
//           cylinder(d=8, h=10, center=false);
module ovoid_spread(r=undef, d=undef, n=100, cone_ang=90, scale=[1,1,1], perp=true)
{
	r = get_radius(r=r, d=d, dflt=50);
	cnt = ceil(n / (cone_ang/180));

	// Calculate an array of [theta,phi] angles for `n` number of
	// points, almost evenly spaced across the surface of a sphere.
	// This approximation is based on the golden spiral method.
	theta_phis = [for (x=[0:1:n-1]) [180*(1+sqrt(5))*(x+0.5)%360, acos(1-2*(x+0.5)/cnt)]];

	for ($idx = idx(theta_phis)) {
		tp = theta_phis[$idx];
		xyz = spherical_to_xyz(r, tp[0], tp[1]);
		$pos = vmul(xyz,scale);
		$theta = tp[0];
		$phi = tp[1];
		$rad = r;
		translate($pos) {
			if (perp) {
				rot(from=UP, to=xyz) children();
			} else {
				children();
			}
		}
	}
}



//////////////////////////////////////////////////////////////////////
// Section: Reflectional Distributors
//////////////////////////////////////////////////////////////////////


// Module: mirror_copy()
//
// Description:
//   Makes a copy of the children, mirrored across the given plane.
//
// Usage:
//   mirror_copy(v, [cp], [offset]) ...
//
// Arguments:
//   v = The normal vector of the plane to mirror across.
//   offset = distance to offset away from the plane.
//   cp = A point that lies on the mirroring plane.
//
// Side Effects:
//   `$orig` is true for the original instance of children.  False for the copy.
//   `$idx` is set to the index value of each copy.
//
// Example:
//   mirror_copy([1,-1,0]) zrot(-45) yrot(90) cylinder(d1=10, d2=0, h=20);
//   color("blue",0.25) zrot(-45) cube([0.01,15,15], center=true);
//
// Example:
//   mirror_copy([1,1,0], offset=5) rot(a=90,v=[-1,1,0]) cylinder(d1=10, d2=0, h=20);
//   color("blue",0.25) zrot(45) cube([0.01,15,15], center=true);
//
// Example:
//   mirror_copy(UP+BACK, cp=[0,-5,-5]) rot(from=UP, to=BACK+UP) cylinder(d1=10, d2=0, h=20);
//   color("blue",0.25) translate([0,-5,-5]) rot(from=UP, to=BACK+UP) cube([15,15,0.01], center=true);
module mirror_copy(v=[0,0,1], offset=0, cp)
{
	cp = is_vector(v,4)? plane_normal(v) * v[3] :
		is_vector(cp)? cp :
		is_num(cp)? cp*unit(v) :
		[0,0,0];
	nv = is_vector(v,4)? plane_normal(v) : unit(v);
	off = nv*offset;
	if (cp == [0,0,0]) {
		translate(off) {
			$orig = true;
			$idx = 0;
			children();
		}
		mirror(nv) translate(off) {
			$orig = false;
			$idx = 1;
			children();
		}
	} else {
		translate(off) children();
		translate(cp) mirror(nv) translate(-cp) translate(off) children();
	}
}


// Module: xflip_copy()
//
// Description:
//   Makes a copy of the children, mirrored across the X axis.
//
// Usage:
//   xflip_copy([x], [offset]) ...
//
// Arguments:
//   offset = Distance to offset children right, before copying.
//   x = The X coordinate of the mirroring plane.  Default: 0
//
// Side Effects:
//   `$orig` is true for the original instance of children.  False for the copy.
//   `$idx` is set to the index value of each copy.
//
// Example:
//   xflip_copy() yrot(90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([0.01,15,15], center=true);
//
// Example:
//   xflip_copy(offset=5) yrot(90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([0.01,15,15], center=true);
//
// Example:
//   xflip_copy(x=-5) yrot(90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) left(5) cube([0.01,15,15], center=true);
module xflip_copy(offset=0, x=0)
{
	mirror_copy(v=[1,0,0], offset=offset, cp=[x,0,0]) children();
}


// Module: yflip_copy()
//
// Description:
//   Makes a copy of the children, mirrored across the Y axis.
//
// Usage:
//   yflip_copy([y], [offset]) ...
//
// Arguments:
//   offset = Distance to offset children back, before copying.
//   y = The Y coordinate of the mirroring plane.  Default: 0
//
// Side Effects:
//   `$orig` is true for the original instance of children.  False for the copy.
//   `$idx` is set to the index value of each copy.
//
// Example:
//   yflip_copy() xrot(-90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([15,0.01,15], center=true);
//
// Example:
//   yflip_copy(offset=5) xrot(-90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([15,0.01,15], center=true);
//
// Example:
//   yflip_copy(y=-5) xrot(-90) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) fwd(5) cube([15,0.01,15], center=true);
module yflip_copy(offset=0, y=0)
{
	mirror_copy(v=[0,1,0], offset=offset, cp=[0,y,0]) children();
}


// Module: zflip_copy()
//
// Description:
//   Makes a copy of the children, mirrored across the Z axis.
//
// Usage:
//   zflip_copy([z], [offset]) ...
//
// Arguments:
//   offset = Distance to offset children up, before copying.
//   z = The Z coordinate of the mirroring plane.  Default: 0
//
// Side Effects:
//   `$orig` is true for the original instance of children.  False for the copy.
//   `$idx` is set to the index value of each copy.
//
// Example:
//   zflip_copy() cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([15,15,0.01], center=true);
//
// Example:
//   zflip_copy(offset=5) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) cube([15,15,0.01], center=true);
//
// Example:
//   zflip_copy(z=-5) cylinder(h=20, r1=4, r2=0);
//   color("blue",0.25) down(5) cube([15,15,0.01], center=true);
module zflip_copy(offset=0, z=0)
{
	mirror_copy(v=[0,0,1], offset=offset, cp=[0,0,z]) children();
}



// vim: noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap