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glups/geometry.py
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geometry.py
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from numpy import *
def RotateAround(angle,axis,point,ObsM):
'''
this should be C
'''
# this work with OpenGL
#Q = ones(16,float)
#glLoadIdentity();
#glTranslated(point[0],point[1],point[2]);
#glRotated(angle,axis[0],axis[1],axis[2]);
#glTranslated(-point[0],-point[1],-point[2]);
##Q = glGetDoublev(GL_MODELVIEW_MATRIX);
#glMultMatrixd(ObsM);
#ObsM = glGetDoublev(GL_MODELVIEW_MATRIX);
#return ravel(ObsM)
angle = angle*pi/180
point = concatenate((point,array([0])))
M = ObsM
M.shape = (4,4)
# center point
M = M-point
# construction of the rotation matrix
norm = sqrt(axis[0]**2 + axis[1]**2 + axis[2]**2)
if norm == 0:
return x
sn = sin(-angle/2.)
e0 = cos(-angle/2.)
e1 = axis[0]*sn/norm
e2 = axis[1]*sn/norm
e3 = axis[2]*sn/norm
a = zeros((4,4),float)
a[0,0] = e0**2 + e1**2 - e2**2 - e3**2
a[1,0] = 2.*(e1*e2 + e0*e3)
a[2,0] = 2.*(e1*e3 - e0*e2)
a[3,0] = 0.
a[0,1] = 2.*(e1*e2 - e0*e3)
a[1,1] = e0**2 - e1**2 + e2**2 - e3**2
a[2,1] = 2.*(e2*e3 + e0*e1)
a[3,1] = 0.
a[0,2] = 2.*(e1*e3 + e0*e2)
a[1,2] = 2.*(e2*e3 - e0*e1)
a[2,2] = e0**2 - e1**2 - e2**2 + e3**2
a[3,2] = 0.
a[0,3] = 0.
a[1,3] = 0.
a[2,3] = 0.
a[3,3] = 1.
a = a.astype(float)
# multiply x and v
M = dot(M,a)
# decenter point
M = M+point
return ravel(M)
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