public void ScatterPhoton(ShadingState state, Color power) { Color refr = Color.mul(1 - f0, color); Color refl = Color.mul(f0, color); float avgR = refl.getAverage(); float avgT = refr.getAverage(); double rnd = state.getRandom(0, 0, 1); if (rnd < avgR) { state.faceforward(); // don't reflect internally if (state.isBehind()) return; // photon is reflected float cos = state.getCosND(); power.mul(refl).mul(1.0f / avgR); float dn = 2 * cos; Vector3 dir = new Vector3(); dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x; dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y; dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z; state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power); } else if (rnd < avgR + avgT) { state.faceforward(); // photon is refracted float cos = state.getCosND(); float neta = state.isBehind() ? eta : 1.0f / eta; power.mul(refr).mul(1.0f / avgT); float wK = -neta; float arg = 1 - (neta * neta * (1 - (cos * cos))); Vector3 dir = new Vector3(); if (state.isBehind() && absorptionDistance > 0) { // this ray is inside the object and leaving it // compute attenuation that occured along the ray power.mul(Color.mul(-state.getRay().getMax() / absorptionDistance, absorptionColor.copy().opposite()).exp()); } if (arg < 0) { // TIR float dn = 2 * cos; dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x; dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y; dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z; state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power); } else { float nK = (neta * cos) - (float)Math.Sqrt(arg); dir.x = (-wK * state.getRay().dx) + (nK * state.getNormal().x); dir.y = (-wK * state.getRay().dy) + (nK * state.getNormal().y); dir.z = (-wK * state.getRay().dz) + (nK * state.getNormal().z); state.traceRefractionPhoton(new Ray(state.getPoint(), dir), power); } } }
public void ScatterPhoton(ShadingState state, Color power) { Color refr = Color.mul(1 - f0, color); Color refl = Color.mul(f0, color); float avgR = refl.getAverage(); float avgT = refr.getAverage(); double rnd = state.getRandom(0, 0, 1); if (rnd < avgR) { state.faceforward(); // don't reflect internally if (state.isBehind()) { return; } // photon is reflected float cos = state.getCosND(); power.mul(refl).mul(1.0f / avgR); float dn = 2 * cos; Vector3 dir = new Vector3(); dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x; dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y; dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z; state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power); } else if (rnd < avgR + avgT) { state.faceforward(); // photon is refracted float cos = state.getCosND(); float neta = state.isBehind() ? eta : 1.0f / eta; power.mul(refr).mul(1.0f / avgT); float wK = -neta; float arg = 1 - (neta * neta * (1 - (cos * cos))); Vector3 dir = new Vector3(); if (state.isBehind() && absorptionDistance > 0) { // this ray is inside the object and leaving it // compute attenuation that occured along the ray power.mul(Color.mul(-state.getRay().getMax() / absorptionDistance, absorptionColor.copy().opposite()).exp()); } if (arg < 0) { // TIR float dn = 2 * cos; dir.x = (dn * state.getNormal().x) + state.getRay().getDirection().x; dir.y = (dn * state.getNormal().y) + state.getRay().getDirection().y; dir.z = (dn * state.getNormal().z) + state.getRay().getDirection().z; state.traceReflectionPhoton(new Ray(state.getPoint(), dir), power); } else { float nK = (neta * cos) - (float)Math.Sqrt(arg); dir.x = (-wK * state.getRay().dx) + (nK * state.getNormal().x); dir.y = (-wK * state.getRay().dy) + (nK * state.getNormal().y); dir.z = (-wK * state.getRay().dz) + (nK * state.getNormal().z); state.traceRefractionPhoton(new Ray(state.getPoint(), dir), power); } } }