You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

240 lines
5.4 KiB
Python

"""
Various transforms used for by the 3D code
"""
import numpy as np
import numpy.linalg as linalg
from matplotlib import cbook
@cbook.deprecated("3.1")
def line2d(p0, p1):
"""
Return 2D equation of line in the form ax+by+c = 0
"""
# x + x1 = 0
x0, y0 = p0[:2]
x1, y1 = p1[:2]
#
if x0 == x1:
a = -1
b = 0
c = x1
elif y0 == y1:
a = 0
b = 1
c = -y1
else:
a = y0 - y1
b = x0 - x1
c = x0*y1 - x1*y0
return a, b, c
@cbook.deprecated("3.1")
def line2d_dist(l, p):
"""
Distance from line to point
line is a tuple of coefficients a, b, c
"""
a, b, c = l
x0, y0 = p
return abs((a*x0 + b*y0 + c) / np.hypot(a, b))
def _line2d_seg_dist(p1, p2, p0):
"""distance(s) from line defined by p1 - p2 to point(s) p0
p0[0] = x(s)
p0[1] = y(s)
intersection point p = p1 + u*(p2-p1)
and intersection point lies within segment if u is between 0 and 1
"""
x21 = p2[0] - p1[0]
y21 = p2[1] - p1[1]
x01 = np.asarray(p0[0]) - p1[0]
y01 = np.asarray(p0[1]) - p1[1]
u = (x01*x21 + y01*y21) / (x21**2 + y21**2)
u = np.clip(u, 0, 1)
d = np.hypot(x01 - u*x21, y01 - u*y21)
return d
@cbook.deprecated("3.1")
def line2d_seg_dist(p1, p2, p0):
"""distance(s) from line defined by p1 - p2 to point(s) p0
p0[0] = x(s)
p0[1] = y(s)
intersection point p = p1 + u*(p2-p1)
and intersection point lies within segment if u is between 0 and 1
"""
return _line2d_seg_dist(p1, p2, p0)
@cbook.deprecated("3.1", alternative="np.linalg.norm")
def mod(v):
"""3d vector length"""
return np.sqrt(v[0]**2+v[1]**2+v[2]**2)
def world_transformation(xmin, xmax,
ymin, ymax,
zmin, zmax):
dx, dy, dz = (xmax-xmin), (ymax-ymin), (zmax-zmin)
return np.array([[1/dx, 0, 0, -xmin/dx],
[0, 1/dy, 0, -ymin/dy],
[0, 0, 1/dz, -zmin/dz],
[0, 0, 0, 1]])
def view_transformation(E, R, V):
n = (E - R)
## new
# n /= np.linalg.norm(n)
# u = np.cross(V, n)
# u /= np.linalg.norm(u)
# v = np.cross(n, u)
# Mr = np.diag([1.] * 4)
# Mt = np.diag([1.] * 4)
# Mr[:3,:3] = u, v, n
# Mt[:3,-1] = -E
## end new
## old
n = n / np.linalg.norm(n)
u = np.cross(V, n)
u = u / np.linalg.norm(u)
v = np.cross(n, u)
Mr = [[u[0], u[1], u[2], 0],
[v[0], v[1], v[2], 0],
[n[0], n[1], n[2], 0],
[0, 0, 0, 1]]
#
Mt = [[1, 0, 0, -E[0]],
[0, 1, 0, -E[1]],
[0, 0, 1, -E[2]],
[0, 0, 0, 1]]
## end old
return np.dot(Mr, Mt)
def persp_transformation(zfront, zback):
a = (zfront+zback)/(zfront-zback)
b = -2*(zfront*zback)/(zfront-zback)
return np.array([[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, a, b],
[0, 0, -1, 0]])
def ortho_transformation(zfront, zback):
# note: w component in the resulting vector will be (zback-zfront), not 1
a = -(zfront + zback)
b = -(zfront - zback)
return np.array([[2, 0, 0, 0],
[0, 2, 0, 0],
[0, 0, -2, 0],
[0, 0, a, b]])
def _proj_transform_vec(vec, M):
vecw = np.dot(M, vec)
w = vecw[3]
# clip here..
txs, tys, tzs = vecw[0]/w, vecw[1]/w, vecw[2]/w
return txs, tys, tzs
@cbook.deprecated("3.1")
def proj_transform_vec(vec, M):
return _proj_transform_vec(vec, M)
def _proj_transform_vec_clip(vec, M):
vecw = np.dot(M, vec)
w = vecw[3]
# clip here.
txs, tys, tzs = vecw[0] / w, vecw[1] / w, vecw[2] / w
tis = (0 <= vecw[0]) & (vecw[0] <= 1) & (0 <= vecw[1]) & (vecw[1] <= 1)
if np.any(tis):
tis = vecw[1] < 1
return txs, tys, tzs, tis
@cbook.deprecated("3.1")
def proj_transform_vec_clip(vec, M):
return _proj_transform_vec_clip(vec, M)
def inv_transform(xs, ys, zs, M):
iM = linalg.inv(M)
vec = _vec_pad_ones(xs, ys, zs)
vecr = np.dot(iM, vec)
try:
vecr = vecr / vecr[3]
except OverflowError:
pass
return vecr[0], vecr[1], vecr[2]
def _vec_pad_ones(xs, ys, zs):
return np.array([xs, ys, zs, np.ones_like(xs)])
@cbook.deprecated("3.1")
def vec_pad_ones(xs, ys, zs):
return _vec_pad_ones(xs, ys, zs)
def proj_transform(xs, ys, zs, M):
"""
Transform the points by the projection matrix
"""
vec = _vec_pad_ones(xs, ys, zs)
return _proj_transform_vec(vec, M)
transform = proj_transform
def proj_transform_clip(xs, ys, zs, M):
"""
Transform the points by the projection matrix
and return the clipping result
returns txs, tys, tzs, tis
"""
vec = _vec_pad_ones(xs, ys, zs)
return _proj_transform_vec_clip(vec, M)
def proj_points(points, M):
return np.column_stack(proj_trans_points(points, M))
def proj_trans_points(points, M):
xs, ys, zs = zip(*points)
return proj_transform(xs, ys, zs, M)
@cbook.deprecated("3.1")
def proj_trans_clip_points(points, M):
xs, ys, zs = zip(*points)
return proj_transform_clip(xs, ys, zs, M)
def rot_x(V, alpha):
cosa, sina = np.cos(alpha), np.sin(alpha)
M1 = np.array([[1, 0, 0, 0],
[0, cosa, -sina, 0],
[0, sina, cosa, 0],
[0, 0, 0, 1]])
return np.dot(M1, V)