Solid Angle of a Triangle

Finds the solid angle of a triangle in 3D space

function omega=Solid_Angle_Triangle(p,va,vb,vc)

Input:

p is (1*3) coordinate vector for the origin point.

va is (1*3) coordinate vector for the first vertex of the triangle.

vb is (1*3) coordinate vector for the second vertex of the triangle.

vc is (1*3) coordinate vector for the third vertex of the triangle.

Output:

omega: solid angle.