Hmm, makes sense. I calculate the angle as a dot product of the view and light vectors:

Code:vec4 wPos = mWorld*gl_Vertex; //world matrix * "in" vertex position vec3 lPos = vec3(0.0, 10000.0, 5000.0); vec3 V = normalize(wPos.xyz - eyePosition); vec3 L = normalize(lPos - eyePosition); float theta = dot(L, V);