BOSL2/coords.scad
2020-09-09 09:57:13 +01:00

359 lines
14 KiB
OpenSCAD

//////////////////////////////////////////////////////////////////////
// LibFile: coords.scad
// Coordinate transformations and coordinate system conversions.
// To use, add the following lines to the beginning of your file:
// ```
// use <BOSL2/std.scad>
// ```
//////////////////////////////////////////////////////////////////////
// Section: Coordinate Manipulation
// Function: point2d()
// Description:
// Returns a 2D vector/point from a 2D or 3D vector.
// If given a 3D point, removes the Z coordinate.
// Arguments:
// p = The coordinates to force into a 2D vector/point.
// fill = Value to fill missing values in vector with.
function point2d(p, fill=0) = [for (i=[0:1]) (p[i]==undef)? fill : p[i]];
// Function: path2d()
// Description:
// Returns a list of 2D vectors/points from a list of 2D, 3D or higher
// dimensional vectors/points. Removes the extra coordinates from
// higher dimensional points. The input must be a path, where
// every vector has the same length.
// Arguments:
// points = A list of 2D or 3D points/vectors.
function path2d(points) =
assert(is_path(points,dim=undef,fast=true),"Input to path2d is not a path")
let (result = points * concat(ident(2), repeat([0,0], len(points[0])-2)))
assert(is_def(result), "Invalid input to path2d")
result;
// Function: point3d()
// Description:
// Returns a 3D vector/point from a 2D or 3D vector.
// Arguments:
// p = The coordinates to force into a 3D vector/point.
// fill = Value to fill missing values in vector with.
function point3d(p, fill=0) = [for (i=[0:2]) (p[i]==undef)? fill : p[i]];
// Function: path3d()
// Description:
// Returns a list of 3D vectors/points from a list of 2D or higher dimensional vectors/points
// by removing extra coordinates or adding the z coordinate.
// Arguments:
// points = A list of 2D, 3D or higher dimensional points/vectors.
// fill = Value to fill missing values in vectors with (in the 2D case)
function path3d(points, fill=0) =
assert(is_num(fill))
assert(is_path(points, dim=undef, fast=true), "Input to path3d is not a path")
let (
change = len(points[0])-3,
M = change < 0? [[1,0,0],[0,1,0]] :
concat(ident(3), repeat([0,0,0],change)),
result = points*M
)
assert(is_def(result), "Input to path3d is invalid")
fill == 0 || change>=0 ? result : result + repeat([0,0,fill], len(result));
// Function: point4d()
// Description:
// Returns a 4D vector/point from a 2D or 3D vector.
// Arguments:
// p = The coordinates to force into a 4D vector/point.
// fill = Value to fill missing values in vector with.
function point4d(p, fill=0) = [for (i=[0:3]) (p[i]==undef)? fill : p[i]];
// Function: path4d()
// Description:
// Returns a list of 4D vectors/points from a list of 2D or 3D vectors/points.
// Arguments:
// points = A list of 2D or 3D points/vectors.
// fill = Value to fill missing values in vectors with.
function path4d(points, fill=0) =
assert(is_num(fill) || is_vector(fill))
assert(is_path(points, dim=undef, fast=true), "Input to path4d is not a path")
let (
change = len(points[0])-4,
M = change < 0 ? select(ident(4), 0, len(points[0])-1) :
concat(ident(4), repeat([0,0,0,0],change)),
result = points*M
)
assert(is_def(result), "Input to path4d is invalid")
fill == 0 || change >= 0 ? result :
let(
addition = is_list(fill) ? concat(0*points[0],fill) :
concat(0*points[0],repeat(fill,-change))
)
assert(len(addition) == 4, "Fill is the wrong length")
result + repeat(addition, len(result));
// Section: Coordinate Systems
// Function: polar_to_xy()
// Usage:
// polar_to_xy(r, theta);
// polar_to_xy([r, theta]);
// Description:
// Convert polar coordinates to 2D cartesian coordinates.
// Returns [X,Y] cartesian coordinates.
// Arguments:
// r = distance from the origin.
// theta = angle in degrees, counter-clockwise of X+.
// Examples:
// xy = polar_to_xy(20,45); // Returns: ~[14.1421365, 14.1421365]
// xy = polar_to_xy(40,30); // Returns: ~[34.6410162, 15]
// xy = polar_to_xy([40,30]); // Returns: ~[34.6410162, 15]
function polar_to_xy(r,theta=undef) = let(
rad = theta==undef? r[0] : r,
t = theta==undef? r[1] : theta
) rad*[cos(t), sin(t)];
// Function: xy_to_polar()
// Usage:
// xy_to_polar(x,y);
// xy_to_polar([X,Y]);
// Description:
// Convert 2D cartesian coordinates to polar coordinates.
// Returns [radius, theta] where theta is the angle counter-clockwise of X+.
// Arguments:
// x = X coordinate.
// y = Y coordinate.
// Examples:
// plr = xy_to_polar(20,30);
// plr = xy_to_polar([40,60]);
function xy_to_polar(x,y=undef) = let(
xx = y==undef? x[0] : x,
yy = y==undef? x[1] : y
) [norm([xx,yy]), atan2(yy,xx)];
// Function: project_plane()
// Usage: With the plane defined by 3 Points
// xyz = project_plane(point, a, b, c);
// Usage: With the plane defined by Pointlist
// xyz = project_plane(point, POINTLIST);
// Usage: With the plane defined by Plane Definition [A,B,C,D] Where Ax+By+Cz=D
// xyz = project_plane(point, PLANE);
// Description:
// Converts the given 3D points from global coordinates to the 2D planar coordinates of the closest
// points on the plane. This coordinate system can be useful in taking a set of nearly coplanar
// points, and converting them to a pure XY set of coordinates for manipulation, before converting
// them back to the original 3D plane. The parameter `point` may be a single point or a list of points
// The plane may be given in one of three ways:
// - by three points, `a`, `b`, and `c`, the planar coordinate system will have `[0,0]` at point `a`, and the Y+ axis will be towards point `b`.
// - by a list of points passed by `a`, finds three reasonably spaced non-collinear points in the list and uses them as points `a`, `b`, and `c` as above.
// - by a plane definition `[A,B,C,D]` passed by `a` where `Ax+By+Cz=D`, the closest point on that plane to the global origin at `[0,0,0]` will be the planar coordinate origin `[0,0]`.
// Arguments:
// point = The 3D point, or list of 3D points to project into the plane's 2D coordinate system.
// a = A 3D point that the plane passes through or a list of points or a plane definition vector.
// b = A 3D point that the plane passes through. Used to define the plane.
// c = A 3D point that the plane passes through. Used to define the plane.
// Example:
// pt = [5,-5,5];
// a=[0,0,0]; b=[10,-10,0]; c=[10,0,10];
// xy = project_plane(pt, a, b, c);
// xy2 = project_plane(pt, [a,b,c]);
function project_plane(point, a, b, c) =
is_undef(b) && is_undef(c) && is_list(a)? let(
mat = is_vector(a,4)? plane_transform(a) :
assert(is_path(a) && len(a)>=3)
plane_transform(plane_from_points(a)),
pts = is_vector(point)? point2d(apply(mat,point)) :
is_path(point)? path2d(apply(mat,point)) :
is_region(point)? [for (x=point) path2d(apply(mat,x))] :
assert(false, "point must be a 3D point, path, or region.")
) pts :
assert(is_vector(a))
assert(is_vector(b))
assert(is_vector(c))
assert(is_vector(point)||is_path(point))
let(
u = unit(b-a),
v = unit(c-a),
n = unit(cross(u,v)),
w = unit(cross(n,u)),
relpoint = apply(move(-a),point)
) relpoint * transpose([w,u]);
// Function: lift_plane()
// Usage: With 3 Points
// xyz = lift_plane(point, a, b, c);
// Usage: With Pointlist
// xyz = lift_plane(point, POINTLIST);
// Usage: With Plane Definition [A,B,C,D] Where Ax+By+Cz=D
// xyz = lift_plane(point, PLANE);
// Description:
// Converts the given 2D point from planar coordinates to the global 3D coordinates of the point on the plane.
// Can be called one of three ways:
// - Given three points, `a`, `b`, and `c`, the planar coordinate system will have `[0,0]` at point `a`, and the Y+ axis will be towards point `b`.
// - Given a list of points, finds three non-collinear points in the list and uses them as points `a`, `b`, and `c` as above.
// - Given a plane definition `[A,B,C,D]` where `Ax+By+Cz=D`, the closest point on that plane to the global origin at `[0,0,0]` will be the planar coordinate origin `[0,0]`.
// Arguments:
// point = The 2D point, or list of 2D points in the plane's coordinate system to get the 3D position of.
// a = A 3D point that the plane passes through. Used to define the plane.
// b = A 3D point that the plane passes through. Used to define the plane.
// c = A 3D point that the plane passes through. Used to define the plane.
function lift_plane(point, a, b, c) =
is_undef(b) && is_undef(c) && is_list(a)? let(
mat = is_vector(a,4)? plane_transform(a) :
assert(is_path(a) && len(a)>=3)
plane_transform(plane_from_points(a)),
imat = matrix_inverse(mat),
pts = is_vector(point)? apply(imat,point3d(point)) :
is_path(point)? apply(imat,path3d(point)) :
is_region(point)? [for (x=point) apply(imat,path3d(x))] :
assert(false, "point must be a 2D point, path, or region.")
) pts :
assert(is_vector(a))
assert(is_vector(b))
assert(is_vector(c))
assert(is_vector(point)||is_path(point))
let(
u = unit(b-a),
v = unit(c-a),
n = unit(cross(u,v)),
w = unit(cross(n,u)),
remapped = point*[w,u]
) apply(move(a),remapped);
// Function: cylindrical_to_xyz()
// Usage:
// cylindrical_to_xyz(r, theta, z)
// cylindrical_to_xyz([r, theta, z])
// Description:
// Convert cylindrical coordinates to 3D cartesian coordinates. Returns [X,Y,Z] cartesian coordinates.
// Arguments:
// r = distance from the Z axis.
// theta = angle in degrees, counter-clockwise of X+ on the XY plane.
// z = Height above XY plane.
// Examples:
// xyz = cylindrical_to_xyz(20,30,40);
// xyz = cylindrical_to_xyz([40,60,50]);
function cylindrical_to_xyz(r,theta=undef,z=undef) = let(
rad = theta==undef? r[0] : r,
t = theta==undef? r[1] : theta,
zed = theta==undef? r[2] : z
) [rad*cos(t), rad*sin(t), zed];
// Function: xyz_to_cylindrical()
// Usage:
// xyz_to_cylindrical(x,y,z)
// xyz_to_cylindrical([X,Y,Z])
// Description:
// Convert 3D cartesian coordinates to cylindrical coordinates.
// Returns [radius,theta,Z]. Theta is the angle counter-clockwise
// of X+ on the XY plane. Z is height above the XY plane.
// Arguments:
// x = X coordinate.
// y = Y coordinate.
// z = Z coordinate.
// Examples:
// cyl = xyz_to_cylindrical(20,30,40);
// cyl = xyz_to_cylindrical([40,50,70]);
function xyz_to_cylindrical(x,y=undef,z=undef) = let(
p = is_num(x)? [x, default(y,0), default(z,0)] : point3d(x)
) [norm([p.x,p.y]), atan2(p.y,p.x), p.z];
// Function: spherical_to_xyz()
// Usage:
// spherical_to_xyz(r, theta, phi);
// spherical_to_xyz([r, theta, phi]);
// Description:
// Convert spherical coordinates to 3D cartesian coordinates.
// Returns [X,Y,Z] cartesian coordinates.
// Arguments:
// r = distance from origin.
// theta = angle in degrees, counter-clockwise of X+ on the XY plane.
// phi = angle in degrees from the vertical Z+ axis.
// Examples:
// xyz = spherical_to_xyz(20,30,40);
// xyz = spherical_to_xyz([40,60,50]);
function spherical_to_xyz(r,theta=undef,phi=undef) = let(
rad = theta==undef? r[0] : r,
t = theta==undef? r[1] : theta,
p = theta==undef? r[2] : phi
) rad*[sin(p)*cos(t), sin(p)*sin(t), cos(p)];
// Function: xyz_to_spherical()
// Usage:
// xyz_to_spherical(x,y,z)
// xyz_to_spherical([X,Y,Z])
// Description:
// Convert 3D cartesian coordinates to spherical coordinates.
// Returns [r,theta,phi], where phi is the angle from the Z+ pole,
// and theta is degrees counter-clockwise of X+ on the XY plane.
// Arguments:
// x = X coordinate.
// y = Y coordinate.
// z = Z coordinate.
// Examples:
// sph = xyz_to_spherical(20,30,40);
// sph = xyz_to_spherical([40,50,70]);
function xyz_to_spherical(x,y=undef,z=undef) = let(
p = is_num(x)? [x, default(y,0), default(z,0)] : point3d(x)
) [norm(p), atan2(p.y,p.x), atan2(norm([p.x,p.y]),p.z)];
// Function: altaz_to_xyz()
// Usage:
// altaz_to_xyz(alt, az, r);
// altaz_to_xyz([alt, az, r]);
// Description:
// Convert altitude/azimuth/range coordinates to 3D cartesian coordinates.
// Returns [X,Y,Z] cartesian coordinates.
// Arguments:
// alt = altitude angle in degrees above the XY plane.
// az = azimuth angle in degrees clockwise of Y+ on the XY plane.
// r = distance from origin.
// Examples:
// xyz = altaz_to_xyz(20,30,40);
// xyz = altaz_to_xyz([40,60,50]);
function altaz_to_xyz(alt,az=undef,r=undef) = let(
p = az==undef? alt[0] : alt,
t = 90 - (az==undef? alt[1] : az),
rad = az==undef? alt[2] : r
) rad*[cos(p)*cos(t), cos(p)*sin(t), sin(p)];
// Function: xyz_to_altaz()
// Usage:
// xyz_to_altaz(x,y,z);
// xyz_to_altaz([X,Y,Z]);
// Description:
// Convert 3D cartesian coordinates to altitude/azimuth/range coordinates.
// Returns [altitude,azimuth,range], where altitude is angle above the
// XY plane, azimuth is degrees clockwise of Y+ on the XY plane, and
// range is the distance from the origin.
// Arguments:
// x = X coordinate.
// y = Y coordinate.
// z = Z coordinate.
// Examples:
// aa = xyz_to_altaz(20,30,40);
// aa = xyz_to_altaz([40,50,70]);
function xyz_to_altaz(x,y=undef,z=undef) = let(
p = is_num(x)? [x, default(y,0), default(z,0)] : point3d(x)
) [atan2(p.z,norm([p.x,p.y])), atan2(p.x,p.y), norm(p)];
// vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap