def scale(cls, x, y, z, dtype=FLOAT) -> 'Transform':
m = np.eye(4, 4, dtype=dtype)
m_inv = np.eye(4, 4, dtype=dtype)
m[0][0] = x
m[1][1] = y
m[2][2] = z
m_inv[0][0] = 1. / x
m_inv[1][1] = 1. / y
m_inv[2][2] = 1. / z
return cls(m, m_inv, dtype)
def translate(cls, delta: 'geo.Vector', dtype=FLOAT) -> 'Transform':
m = np.eye(4, 4, dtype=dtype)
m_inv = np.eye(4, 4, dtype=dtype)
m[0][3] = delta.x
m[1][3] = delta.y
m[2][3] = delta.z
m_inv[0][3] = -delta.x
m_inv[1][3] = -delta.y
m_inv[2][3] = -delta.z
return cls(m, m_inv, dtype)
def look_at(cls,
pos: 'geo.Point',
look: 'geo.Point',
up: 'geo.Vector',
dtype=FLOAT) -> 'Transform':
"""
look_at
Look-at transformation, from camera
to world
"""
w2c = np.eye(4, 4, dtype=dtype)
c2w = np.eye(4, 4, dtype=dtype)
zc = geo.normalize(look - pos)
xc = geo.normalize(geo.normalize(up).cross(zc))
yc = zc.cross(xc) # orthogonality
# c2w translation
c2w[0][3] = pos.x
c2w[1][3] = pos.y
c2w[2][3] = pos.z
# c2w rotation
c2w[0][0] = xc.x
c2w[0][1] = xc.y
c2w[0][2] = xc.z
c2w[1][0] = yc.x
c2w[1][1] = yc.y
c2w[1][2] = yc.z
c2w[2][0] = zc.x
c2w[2][1] = zc.y
c2w[2][2] = zc.z
# w2c rotation
# in effect as camera extrinsic
w2c[0][0] = xc.x
w2c[0][1] = yc.x
w2c[0][2] = zc.x
w2c[1][0] = xc.y
w2c[1][1] = yc.y
w2c[1][2] = zc.y
w2c[2][0] = xc.z
w2c[2][1] = yc.z
w2c[2][2] = zc.z
# w2c translation
w2c[0][3] = -(pos.x * xc.x + pos.y * yc.x + pos.z * zc.x)
w2c[1][3] = -(pos.x * xc.y + pos.y * yc.y + pos.z * zc.y)
w2c[2][3] = -(pos.x * xc.z + pos.y * yc.z + pos.z * zc.z)
return cls(c2w, w2c, dtype)
def __init__(self, m=None, m_inv=None, dtype=FLOAT):
if m is None:
self.__m = np.eye(4, 4, dtype=dtype)
self.__m_inv = np.eye(4, 4, dtype=dtype)
elif m is not None and m_inv is not None:
self.__m = m.copy()
self.__m_inv = m_inv.copy()
else:
if not np.shape(m) == (4, 4):
raise TypeError('Transform matrix must be 4x4')
self.__m = m.copy()
self.__m_inv = np.linalg.inv(m)
self.__m.flags.writeable = False
self.__m_inv.flags.writeable = False
def rotate_z(cls, angle, dtype=FLOAT) -> 'Transform':
m = np.eye(4, 4, dtype=dtype)
sin_t = np.sin(np.deg2rad(angle))
cos_t = np.cos(np.deg2rad(angle))
m[0][0] = cos_t
m[0][1] = -sin_t
m[1][0] = sin_t
m[1][1] = cos_t
return cls(m, m.T, dtype)
def perspective(cls, fov: FLOAT, n: FLOAT, f: FLOAT, dtype=FLOAT):
# projective along z
m = np.eye(4, dtype=dtype)
m[2, 2] = f / (f - n)
m[2, 3] = -f * n / (f - n)
m[3, 2] = 1.
m[3, 3] = 0.
# scale to viewing volume
tan_inv = 1. / np.tan(np.deg2rad(fov) / 2.)
return cls.scale(tan_inv, tan_inv, 1.) * cls(m)
def rotate(cls, angle, axis: 'geo.Vector', dtype=FLOAT) -> 'Transform':
a = geo.normalize(axis)
s = np.sin(np.deg2rad(angle))
c = np.cos(np.deg2rad(angle))
m = np.eye(4, 4, dtype=dtype)
m[0][0] = a.x * a.x + (1. - a.x * a.x) * c
m[0][1] = a.x * a.y * (1. - c) - a.z * s
m[0][2] = a.x * a.z * (1. - c) + a.y * s
m[1][0] = a.x * a.y * (1. - c) + a.z * s
m[1][1] = a.y * a.y + (1. - a.y * a.y) * c
m[1][2] = a.y * a.z * (1. - c) - a.x * s
m[2][0] = a.x * a.z * (1. - c) - a.y * s
m[2][1] = a.y * a.z * (1. - c) + a.x * s
m[2][2] = a.z * a.z + (1. - a.z * a.z) * c
return cls(m, m.T, dtype)
def is_identity(self) -> bool:
return np.array_equal(self.m, np.eye(4, 4))
