90 lines
2.1 KiB
GLSL
90 lines
2.1 KiB
GLSL
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#pragma BLENDER_REQUIRE(bsdf_common_lib.glsl)
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uniform sampler1D texHammersley;
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vec3 tangent_to_world(vec3 vector, vec3 N, vec3 T, vec3 B)
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{
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return T * vector.x + B * vector.y + N * vector.z;
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}
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#ifdef HAMMERSLEY_SIZE
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vec3 hammersley_3d(float i, float invsamplenbr)
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{
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vec3 Xi; /* Theta, cos(Phi), sin(Phi) */
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Xi.x = i * invsamplenbr;
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Xi.yz = texelFetch(texHammersley, int(i), 0).rg;
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return Xi;
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}
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#endif
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/* -------------- BSDFS -------------- */
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float pdf_ggx_reflect(float NH, float a2)
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{
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return NH * a2 / D_ggx_opti(NH, a2);
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}
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float pdf_hemisphere()
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{
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return 0.5 * M_1_PI;
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}
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vec3 sample_ggx(vec3 rand, float a2)
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{
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/* Theta is the cone angle. */
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float z = sqrt((1.0 - rand.x) / (1.0 + a2 * rand.x - rand.x)); /* cos theta */
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float r = sqrt(max(0.0, 1.0f - z * z)); /* sin theta */
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float x = r * rand.y;
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float y = r * rand.z;
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/* Microfacet Normal */
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return vec3(x, y, z);
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}
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vec3 sample_ggx(vec3 rand, float a2, vec3 N, vec3 T, vec3 B, out float NH)
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{
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vec3 Ht = sample_ggx(rand, a2);
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NH = Ht.z;
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return tangent_to_world(Ht, N, T, B);
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}
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#ifdef HAMMERSLEY_SIZE
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vec3 sample_ggx(float nsample, float inv_sample_count, float a2, vec3 N, vec3 T, vec3 B)
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{
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vec3 Xi = hammersley_3d(nsample, inv_sample_count);
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vec3 Ht = sample_ggx(Xi, a2);
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return tangent_to_world(Ht, N, T, B);
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}
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vec3 sample_hemisphere(float nsample, float inv_sample_count, vec3 N, vec3 T, vec3 B)
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{
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vec3 Xi = hammersley_3d(nsample, inv_sample_count);
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float z = Xi.x; /* cos theta */
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float r = sqrt(max(0.0, 1.0f - z * z)); /* sin theta */
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float x = r * Xi.y;
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float y = r * Xi.z;
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vec3 Ht = vec3(x, y, z);
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return tangent_to_world(Ht, N, T, B);
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}
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vec3 sample_cone(float nsample, float inv_sample_count, float angle, vec3 N, vec3 T, vec3 B)
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{
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vec3 Xi = hammersley_3d(nsample, inv_sample_count);
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float z = cos(angle * Xi.x); /* cos theta */
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float r = sqrt(max(0.0, 1.0f - z * z)); /* sin theta */
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float x = r * Xi.y;
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float y = r * Xi.z;
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vec3 Ht = vec3(x, y, z);
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return tangent_to_world(Ht, N, T, B);
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}
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#endif
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