public Color getIrradiance(ShadingState state, Color diffuseReflectance) {
OrthoNormalBasis onb = state.getBasis();
Vector3 w = new Vector3();
Color result = Color.black();
for (int i = 0; i < samples; i++) {
float xi = (float) state.getRandom(i, 0, samples);
float xj = (float) state.getRandom(i, 1, samples);
float phi = (float) (2 * Math.PI * xi);
float cosPhi = (float) Math.cos(phi);
float sinPhi = (float) Math.sin(phi);
float sinTheta = (float) Math.sqrt(xj);
float cosTheta = (float) Math.sqrt(1.0f - xj);
w.x = cosPhi * sinTheta;
w.y = sinPhi * sinTheta;
w.z = cosTheta;
onb.transform(w);
Ray r = new Ray(state.getPoint(), w);
r.setMax(maxDist);
result.add(Color.blend(bright, dark, state.traceShadow(r)));
}
return result.mul((float) Math.PI / samples);
}
