Reflection, scattering, and refraction

raygen caustics

			vec3 o_reflect = hitPos + rayPayload.normal * 0.01;
			vec3 d_reflect = reflect(d, rayPayload.normal);

			vec3 temp_o = o_reflect;
			vec3 temp_d = d_reflect;

			if(rayPayload.reflector < 1.0) // if less than fully reflective, do scattering
			{
				vec3 o_scatter = hitPos + rayPayload.normal * 0.01;
				vec3 d_scatter = cosWeightedRandomHemisphereDirection(rayPayload.normal, prng_state);

				temp_o = mix(temp_o, o_scatter, 1.0 - rayPayload.reflector);
				temp_d = mix(temp_d, d_scatter, 1.0 - rayPayload.reflector);
			}

			if(rayPayload.opacity < 1.0) // if partially transparent, do refraction
			{
				vec3 o_transparent = vec3(0.0);
				vec3 d_transparent = vec3(0.0);

				// Incoming
				if(dot(d, rayPayload.normal) <= 0.0)
				{
					o_transparent = hitPos.xyz - rayPayload.normal * 0.01f;
					d_transparent = refract(d, rayPayload.normal, eta);
				}
				else // Outgoing
				{
					vec3 temp_dir = refract(d, -rayPayload.normal, 1.0 / eta);

					if(temp_dir != vec3(0.0))
					{
						o_transparent = hitPos.xyz + rayPayload.normal * 0.01f;
						d_transparent = temp_dir;
					}
					else
					{
						o_transparent = hitPos.xyz - rayPayload.normal * 0.01f;
						d_transparent = reflect(d, -rayPayload.normal);
					}
				}

				temp_o = mix(temp_o, o_transparent, 1.0 - rayPayload.opacity);
				temp_d = mix(temp_d, d_transparent, 1.0 - rayPayload.opacity);
			}
			
			o = temp_o;
			d = temp_d;