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import vec3,mat2
def identity():
return ((1.0, 0.0, 0.0),
(0.0, 1.0, 0.0),
(0.0, 0.0, 1.0))
def fromscale(scale):
x,y,z= scale
x,y,z= float(x),float(y),float(z)
return (( x, 0.0, 0.0),
(0.0, y, 0.0),
(0.0, 0.0, z))
def fromscaleN(n):
return fromscale((n,n,n))
def mul(a,b):
b_trans= zip(* b)
return tuple([transmulvec3(b_trans, a_r) for a_r in a])
# multiple vector v by a transposed matrix
def transmulvec3(m_trans,v):
return tuple([vec3.dot(v, m_c) for m_c in m_trans])
def mulvec3(m,v):
return transmulvec3(zip(* m), v)
def mulN(m,N):
return tuple([vec3.mulN(v,N) for v in m])
def det(m):
((m00,m01,m02),
(m10,m11,m12),
(m20,m21,m22))= m
a= m00 * mat2.det( ((m11, m12), (m21, m22)) );
b= m10 * mat2.det( ((m01, m02), (m21, m22)) );
c= m20 * mat2.det( ((m01, m02), (m11, m12)) );
return a-b+c
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