material

material.hpp

	class MicrocylinderClothMaterial : public IMaterial {
	public:
		glm::dvec3 tangentu;
		glm::dvec3 tangentv;

		glm::dvec3 bxdf(const glm::dvec3 &wo, const glm::dvec3 &wi) const override {
			if (glm::dot(Ng, wi) < 0.0 || glm::dot(Ng, wo) < 0.0) {
				return glm::dvec3(0.0);
			}

#define A_LINEN_PLAIN 0
#define B_SILK_CREPE_DE_CHINE 1
#define C_POLYESTER_SATIN_CHARMEUSE 0
#define D_POLYESTER_SATIN_CHARMEUSE_BACK 0
#define E_SILK_SHOT 0
#define F_VELVET 0

#if A_LINEN_PLAIN
			// a
			double alpha_0 = 0.33;
			double alpha_1 = 0.33;
			auto params_0 = a_both();
			auto params_1 = a_both();
			static std::vector<double> tangent_offsets_u = { -25, 25 };
			static std::vector<double> tangent_offsets_v = { -25, 25 };
#endif

#if B_SILK_CREPE_DE_CHINE
			// b Silk Crepe de Chine 
			double alpha_0 = 0.75;
			double alpha_1 = 0.25;
			auto params_0 = b_flat();
			auto params_1 = b_twisted();

			// Flat
			static std::vector<double> tangent_offsets_u = {
				-35,
				-35,
				35,
				35
			};
			// Twisted
			static std::vector<double> tangent_offsets_v = { 0.0 };
#endif

#if C_POLYESTER_SATIN_CHARMEUSE
			// c Polyester Satin Charmeuse

			double alpha_0 = 0.9;
			double alpha_1 = 0.1;
			auto params_0 = c_flat();
			auto params_1 = c_twisted();

			// Flat, 
			static std::vector<double> tangent_offsets_u = {
				-32,
				-32,
				-18,
				0,
				0,
				18,
				32,
				32,
			};

			// Twisted
			static std::vector<double> tangent_offsets_v = { 0.0 };
#endif

#if D_POLYESTER_SATIN_CHARMEUSE_BACK
			// Polyester Satin Charmeuse backside
			double alpha_0 = 0.67;
			double alpha_1 = 0.33;
			auto params_0 = c_flat();
			auto params_1 = c_twisted();

			// Flat, 
			static std::vector<double> tangent_offsets_u = {
				-30,
				-30,
				30,
				30,
				-5,
				-5,
				5,
				5,
			};
			// Twisted
			static std::vector<double> tangent_offsets_v = { 0.0 };
#endif

#if E_SILK_SHOT
			// Silk Shot
			double alpha_0 = 0.86;
			double alpha_1 = 0.14;
			auto params_0 = e_dir1();
			auto params_1 = e_dir2();

			// Dir1
			static std::vector<double> tangent_offsets_u = {
				-25,
				-25,
				25,
				25,
			};
			// Dir2
			static std::vector<double> tangent_offsets_v = { 0.0 };
#endif

#if F_VELVET
			// Silk Shot
			double alpha_0 = 0.5;
			double alpha_1 = 0.5;
			auto params_0 = f_velvet();
			auto params_1 = f_velvet();

			//// Dir1
			static std::vector<double> tangent_offsets_u = {
				-90,
				-50,
			};
			// Dir2
			static std::vector<double> tangent_offsets_v = { 
				-90,
				-55,
				55,
				90
			};
#endif

			double cosThetaI;
			glm::dvec3 fs = brdf_x_cosTheta(tangentu, tangentv, Ng, wi, wo, alpha_0, alpha_1, tangent_offsets_u, tangent_offsets_v, params_0, params_1, &cosThetaI);

			return fs / cosThetaI;
		}

		glm::dvec3 sample(PeseudoRandom *random, const glm::dvec3 &wo) const override {
			return UniformHemisphereSampler::sample(random, Ng);
		}
		double pdf(const glm::dvec3 &wo, const glm::dvec3 &sampled_wi) const override {
			return UniformHemisphereSampler::pdf(sampled_wi, Ng);
		}
	};