BOSL2/affine.scad
2020-06-19 23:00:40 -07:00

470 lines
16 KiB
OpenSCAD

//////////////////////////////////////////////////////////////////////
// LibFile: affine.scad
// Matrix math and affine transformation matrices.
// To use, add the following lines to the beginning of your file:
// ```
// use <BOSL2/std.scad>
// ```
//////////////////////////////////////////////////////////////////////
// Section: Matrix Manipulation
// Function: ident()
// Description: Create an `n` by `n` identity matrix.
// Arguments:
// n = The size of the identity matrix square, `n` by `n`.
function ident(n) = [for (i = [0:1:n-1]) [for (j = [0:1:n-1]) (i==j)?1:0]];
// Function: affine2d_to_3d()
// Description: Takes a 3x3 affine2d matrix and returns its 4x4 affine3d equivalent.
function affine2d_to_3d(m) = concat(
[for (r = [0:2])
concat(
[for (c = [0:2]) m[r][c]],
[0]
)
],
[[0, 0, 0, 1]]
);
// Section: Affine2d 3x3 Transformation Matrices
// Function: affine2d_identity()
// Description: Create a 3x3 affine2d identity matrix.
function affine2d_identity() = ident(3);
// Function: affine2d_translate()
// Description:
// Returns the 3x3 affine2d matrix to perform a 2D translation.
// Arguments:
// v = 2D Offset to translate by. [X,Y]
function affine2d_translate(v) = [
[1, 0, v.x],
[0, 1, v.y],
[0 ,0, 1]
];
// Function: affine2d_scale()
// Description:
// Returns the 3x3 affine2d matrix to perform a 2D scaling transformation.
// Arguments:
// v = 2D vector of scaling factors. [X,Y]
function affine2d_scale(v) = [
[v.x, 0, 0],
[ 0, v.y, 0],
[ 0, 0, 1]
];
// Function: affine2d_zrot()
// Description:
// Returns the 3x3 affine2d matrix to perform a rotation of a 2D vector around the Z axis.
// Arguments:
// ang = Number of degrees to rotate.
function affine2d_zrot(ang) = [
[cos(ang), -sin(ang), 0],
[sin(ang), cos(ang), 0],
[ 0, 0, 1]
];
// Function: affine2d_mirror()
// Usage:
// mat = affine2d_mirror(v);
// Description:
// Returns the 3x3 affine2d matrix to perform a reflection of a 2D vector across the line given by its normal vector.
// Arguments:
// v = The normal vector of the line to reflect across.
function affine2d_mirror(v) =
let(v=unit(point2d(v)), a=v.x, b=v.y)
[
[1-2*a*a, 0-2*a*b, 0],
[0-2*a*b, 1-2*b*b, 0],
[ 0, 0, 1]
];
// Function: affine2d_skew()
// Usage:
// affine2d_skew(xa, ya)
// Description:
// Returns the 3x3 affine2d matrix to skew a 2D vector along the XY plane.
// Arguments:
// xa = Skew angle, in degrees, in the direction of the X axis.
// ya = Skew angle, in degrees, in the direction of the Y axis.
function affine2d_skew(xa, ya) = [
[1, tan(xa), 0],
[tan(ya), 1, 0],
[0, 0, 1]
];
// Function: affine2d_chain()
// Usage:
// affine2d_chain(affines)
// Description:
// Returns a 3x3 affine2d transformation matrix which results from applying each matrix in `affines` in order.
// Arguments:
// affines = A list of 3x3 affine2d matrices.
function affine2d_chain(affines, _m=undef, _i=0) =
(_i>=len(affines))? (is_undef(_m)? ident(3) : _m) :
affine2d_chain(affines, _m=(is_undef(_m)? affines[_i] : affines[_i] * _m), _i=_i+1);
// Section: Affine3d 4x4 Transformation Matrices
// Function: affine3d_identity()
// Description: Create a 4x4 affine3d identity matrix.
function affine3d_identity() = ident(4);
// Function: affine3d_translate()
// Description:
// Returns the 4x4 affine3d matrix to perform a 3D translation.
// Arguments:
// v = 3D offset to translate by. [X,Y,Z]
function affine3d_translate(v) = [
[1, 0, 0, v.x],
[0, 1, 0, v.y],
[0, 0, 1, v.z],
[0 ,0, 0, 1]
];
// Function: affine3d_scale()
// Description:
// Returns the 4x4 affine3d matrix to perform a 3D scaling transformation.
// Arguments:
// v = 3D vector of scaling factors. [X,Y,Z]
function affine3d_scale(v) = [
[v.x, 0, 0, 0],
[ 0, v.y, 0, 0],
[ 0, 0, v.z, 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_xrot()
// Description:
// Returns the 4x4 affine3d matrix to perform a rotation of a 3D vector around the X axis.
// Arguments:
// ang = number of degrees to rotate.
function affine3d_xrot(ang) = [
[1, 0, 0, 0],
[0, cos(ang), -sin(ang), 0],
[0, sin(ang), cos(ang), 0],
[0, 0, 0, 1]
];
// Function: affine3d_yrot()
// Description:
// Returns the 4x4 affine3d matrix to perform a rotation of a 3D vector around the Y axis.
// Arguments:
// ang = Number of degrees to rotate.
function affine3d_yrot(ang) = [
[ cos(ang), 0, sin(ang), 0],
[ 0, 1, 0, 0],
[-sin(ang), 0, cos(ang), 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_zrot()
// Usage:
// affine3d_zrot(ang)
// Description:
// Returns the 4x4 affine3d matrix to perform a rotation of a 3D vector around the Z axis.
// Arguments:
// ang = number of degrees to rotate.
function affine3d_zrot(ang) = [
[cos(ang), -sin(ang), 0, 0],
[sin(ang), cos(ang), 0, 0],
[ 0, 0, 1, 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_rot_by_axis()
// Usage:
// affine3d_rot_by_axis(u, ang);
// Description:
// Returns the 4x4 affine3d matrix to perform a rotation of a 3D vector around an axis.
// Arguments:
// u = 3D axis vector to rotate around.
// ang = number of degrees to rotate.
function affine3d_rot_by_axis(u, ang) =
approx(ang,0)? affine3d_identity() :
let(
u = unit(u),
c = cos(ang),
c2 = 1-c,
s = sin(ang)
) [
[u.x*u.x*c2+c , u.x*u.y*c2-u.z*s, u.x*u.z*c2+u.y*s, 0],
[u.y*u.x*c2+u.z*s, u.y*u.y*c2+c , u.y*u.z*c2-u.x*s, 0],
[u.z*u.x*c2-u.y*s, u.z*u.y*c2+u.x*s, u.z*u.z*c2+c , 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_rot_from_to()
// Usage:
// affine3d_rot_from_to(from, to);
// Description:
// Returns the 4x4 affine3d matrix to perform a rotation of a 3D vector from one vector direction to another.
// Arguments:
// from = 3D axis vector to rotate from.
// to = 3D axis vector to rotate to.
function affine3d_rot_from_to(from, to) =
let(
from = unit(point3d(from)),
to = unit(point3d(to))
) approx(from,to)? affine3d_identity() :
let(
u = vector_axis(from,to),
ang = vector_angle(from,to),
c = cos(ang),
c2 = 1-c,
s = sin(ang)
) [
[u.x*u.x*c2+c , u.x*u.y*c2-u.z*s, u.x*u.z*c2+u.y*s, 0],
[u.y*u.x*c2+u.z*s, u.y*u.y*c2+c , u.y*u.z*c2-u.x*s, 0],
[u.z*u.x*c2-u.y*s, u.z*u.y*c2+u.x*s, u.z*u.z*c2+c , 0],
[ 0, 0, 0, 1]
];
// Function: affine_frame_map()
// Usage:
// map = affine_frame_map(x=v1,y=v2);
// map = affine_frame_map(x=v1,z=v2);
// map = affine_frame_map(y=v1,y=v2);
// map = affine_frame_map(v1,v2,v3);
// Description:
// Returns a transformation that maps one coordinate frame to another. You must specify two or three of `x`, `y`, and `z`. The specified
// axes are mapped to the vectors you supplied. If you give two inputs, the third vector is mapped to the appropriate normal to maintain a right hand coordinate system.
// If the vectors you give are orthogonal the result will be a rotation and the `reverse` parameter will supply the inverse map, which enables you
// to map two arbitrary coordinate systems to each other by using the canonical coordinate system as an intermediary. You cannot use the `reverse` option
// with non-orthogonal inputs.
// Arguments:
// x = Destination vector for x axis
// y = Destination vector for y axis
// z = Destination vector for z axis
// reverse = reverse direction of the map for orthogonal inputs. Default: false
// Examples:
// T = affine_frame_map(x=[1,1,0], y=[-1,1,0]); // This map is just a rotation around the z axis
// T = affine_frame_map(x=[1,0,0], y=[1,1,0]); // This map is not a rotation because x and y aren't orthogonal
// // The next map sends [1,1,0] to [0,1,1] and [-1,1,0] to [0,-1,1]
// T = affine_frame_map(x=[0,1,1], y=[0,-1,1]) * affine_frame_map(x=[1,1,0], y=[-1,1,0],reverse=true);
function affine_frame_map(x,y,z, reverse=false) =
assert(num_defined([x,y,z])>=2, "Must define at least two inputs")
let(
xvalid = is_undef(x) || (is_vector(x) && len(x)==3),
yvalid = is_undef(y) || (is_vector(y) && len(y)==3),
zvalid = is_undef(z) || (is_vector(z) && len(z)==3)
)
assert(xvalid,"Input x must be a length 3 vector")
assert(yvalid,"Input y must be a length 3 vector")
assert(zvalid,"Input z must be a length 3 vector")
let(
x = is_undef(x)? undef : unit(x),
y = is_undef(y)? undef : unit(y),
z = is_undef(z)? undef : unit(z),
map = is_undef(x)? [cross(y,z), y, z] :
is_undef(y)? [x, cross(z,x), z] :
is_undef(z)? [x, y, cross(x,y)] :
[x, y, z]
)
reverse? (
let(
ocheck = (
approx(map[0]*map[1],0) &&
approx(map[0]*map[2],0) &&
approx(map[1]*map[2],0)
)
)
assert(ocheck, "Inputs must be orthogonal when reverse==true")
affine2d_to_3d(map)
) : affine2d_to_3d(transpose(map));
// Function: affine3d_mirror()
// Usage:
// mat = affine3d_mirror(v);
// Description:
// Returns the 4x4 affine3d matrix to perform a reflection of a 3D vector across the plane given by its normal vector.
// Arguments:
// v = The normal vector of the plane to reflect across.
function affine3d_mirror(v) =
let(
v=unit(point3d(v)),
a=v.x, b=v.y, c=v.z
) [
[1-2*a*a, -2*a*b, -2*a*c, 0],
[ -2*b*a, 1-2*b*b, -2*b*c, 0],
[ -2*c*a, -2*c*b, 1-2*c*c, 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_skew()
// Usage:
// mat = affine3d_skew([sxy], [sxz], [syx], [syz], [szx], [szy]);
// Description:
// Returns the 4x4 affine3d matrix to perform a skew transformation.
// Arguments:
// sxy = Skew factor multiplier for skewing along the X axis as you get farther from the Y axis. Default: 0
// sxz = Skew factor multiplier for skewing along the X axis as you get farther from the Z axis. Default: 0
// syx = Skew factor multiplier for skewing along the Y axis as you get farther from the X axis. Default: 0
// syz = Skew factor multiplier for skewing along the Y axis as you get farther from the Z axis. Default: 0
// szx = Skew factor multiplier for skewing along the Z axis as you get farther from the X axis. Default: 0
// szy = Skew factor multiplier for skewing along the Z axis as you get farther from the Y axis. Default: 0
function affine3d_skew(sxy=0, sxz=0, syx=0, syz=0, szx=0, szy=0) = [
[ 1, sxy, sxz, 0],
[syx, 1, syz, 0],
[szx, szy, 1, 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_skew_xy()
// Usage:
// affine3d_skew_xy(xa, ya)
// Description:
// Returns the 4x4 affine3d matrix to perform a skew transformation along the XY plane.
// Arguments:
// xa = Skew angle, in degrees, in the direction of the X axis.
// ya = Skew angle, in degrees, in the direction of the Y axis.
function affine3d_skew_xy(xa, ya) = [
[1, 0, tan(xa), 0],
[0, 1, tan(ya), 0],
[0, 0, 1, 0],
[0, 0, 0, 1]
];
// Function: affine3d_skew_xz()
// Usage:
// affine3d_skew_xz(xa, za)
// Description:
// Returns the 4x4 affine3d matrix to perform a skew transformation along the XZ plane.
// Arguments:
// xa = Skew angle, in degrees, in the direction of the X axis.
// za = Skew angle, in degrees, in the direction of the Z axis.
function affine3d_skew_xz(xa, za) = [
[1, tan(xa), 0, 0],
[0, 1, 0, 0],
[0, tan(za), 1, 0],
[0, 0, 0, 1]
];
// Function: affine3d_skew_yz()
// Usage:
// affine3d_skew_yz(ya, za)
// Description:
// Returns the 4x4 affine3d matrix to perform a skew transformation along the YZ plane.
// Arguments:
// ya = Skew angle, in degrees, in the direction of the Y axis.
// za = Skew angle, in degrees, in the direction of the Z axis.
function affine3d_skew_yz(ya, za) = [
[ 1, 0, 0, 0],
[tan(ya), 1, 0, 0],
[tan(za), 0, 1, 0],
[ 0, 0, 0, 1]
];
// Function: affine3d_chain()
// Usage:
// affine3d_chain(affines)
// Description:
// Returns a 4x4 affine3d transformation matrix which results from applying each matrix in `affines` in order.
// Arguments:
// affines = A list of 4x4 affine3d matrices.
function affine3d_chain(affines, _m=undef, _i=0) =
(_i>=len(affines))? (is_undef(_m)? ident(4) : _m) :
affine3d_chain(affines, _m=(is_undef(_m)? affines[_i] : affines[_i] * _m), _i=_i+1);
// Function: apply()
// Usage: apply(transform, points)
// Description:
// Applies the specified transformation matrix to a point list (or single point). Both inputs can be 2d or 3d, and it is also allowed
// to supply 3d transformations with 2d data as long as the the only action on the z coordinate is a simple scaling.
// Examples:
// transformed = apply(xrot(45), path3d(circle(r=3))); // Rotates 3d circle data around x axis
// transformed = apply(rot(45), circle(r=3)); // Rotates 2d circle data by 45 deg
// transformed = apply(rot(45)*right(4)*scale(3), circle(r=3)); // Scales, translates and rotates 2d circle data
function apply(transform,points) =
points==[] ? [] :
is_vector(points) ? apply(transform, [points])[0] :
let(
tdim = len(transform[0])-1,
datadim = len(points[0])
)
tdim == 3 && datadim == 3 ? [for(p=points) point3d(transform*concat(p,[1]))] :
tdim == 2 && datadim == 2 ? [for(p=points) point2d(transform*concat(p,[1]))] :
tdim == 3 && datadim == 2 ?
assert(is_2d_transform(transform),str("Transforms is 3d but points are 2d"))
[for(p=points) point2d(transform*concat(p,[0,1]))] :
assert(false,str("Unsupported combination: transform with dimension ",tdim,", data of dimension ",datadim));
// Function: apply_list()
// Usage: apply_list(points, transform_list)
// Description:
// Transforms the specified point list (or single point) using a list of transformation matrices. Transformations on
// the list are applied in the order they appear in the list (as in right multiplication of matrices). Both inputs can be
// 2d or 3d, and it is also allowed to supply 3d transformations with 2d data as long as the the only action on the z coordinate
// is a simple scaling. All transformations on `transform_list` must have the same dimension: you cannot mix 2d and 3d transformations
// even when acting on 2d data.
// Examples:
// transformed = apply_list(path3d(circle(r=3)),[xrot(45)]); // Rotates 3d circle data around x axis
// transformed = apply_list(circle(r=3), [scale(3), right(4), rot(45)]); // Scales, then translates, and then rotates 2d circle data
function apply_list(points,transform_list) =
transform_list == []? points :
is_vector(points) ? apply_list([points],transform_list)[0] :
let(
tdims = array_dim(transform_list),
datadim = len(points[0])
)
assert(len(tdims)==3 || tdims[1]!=tdims[2], "Invalid transformation list")
let( tdim = tdims[1]-1 )
tdim==2 && datadim == 2 ? apply(affine2d_chain(transform_list), points) :
tdim==3 && datadim == 3 ? apply(affine3d_chain(transform_list), points) :
tdim==3 && datadim == 2 ?
let(
badlist = [for(i=idx(transform_list)) if (!is_2d_transform(transform_list[i])) i]
)
assert(badlist==[],str("Transforms with indices ",badlist," are 3d but points are 2d"))
apply(affine3d_chain(transform_list), points) :
assert(false,str("Unsupported combination: transform with dimension ",tdim,", data of dimension ",datadim));
// Function: is_2d_transform()
// Usage:
// is_2d_transform(t)
// Description:
// Checks if the input is a 3d transform that does not act on the z coordinate, except
// possibly for a simple scaling of z. Note that an input which is only a zscale returns false.
function is_2d_transform(t) = // z-parameters are zero, except we allow t[2][2]!=1 so scale() works
t[2][0]==0 && t[2][1]==0 && t[2][3]==0 && t[0][2] == 0 && t[1][2]==0 &&
(t[2][2]==1 || !(t[0][0]==1 && t[0][1]==0 && t[1][0]==0 && t[1][1]==1)); // But rule out zscale()
// vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap