Thomas Dinges
6b8bb26c45
Required by Metal backend for efficient shader compilation. EEVEE material resource binding permutations now controlled via CreateInfo and selected based on material options. Other existing CreateInfo's also modified to ensure explicitness for depth-writing mode. Other missing bindings also addressed to ensure full compliance with the Metal backend. Authored by Apple: Michael Parkin-White Ref T96261 Reviewed By: fclem Differential Revision: https://developer.blender.org/D16243
85 lines
2.4 KiB
GLSL
85 lines
2.4 KiB
GLSL
#pragma BLENDER_REQUIRE(common_utiltex_lib.glsl)
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#pragma BLENDER_REQUIRE(bsdf_sampling_lib.glsl)
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void main()
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{
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float x = floor(gl_FragCoord.x) / (LUT_SIZE - 1.0);
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float y = floor(gl_FragCoord.y) / (LUT_SIZE - 1.0);
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float ior = clamp(sqrt(x), 0.05, 0.999);
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/* ior is sin of critical angle. */
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float critical_cos = sqrt(1.0 - saturate(ior * ior));
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y = y * 2.0 - 1.0;
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/* Maximize texture usage on both sides of the critical angle. */
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y *= (y > 0.0) ? (1.0 - critical_cos) : critical_cos;
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/* Center LUT around critical angle to avoid strange interpolation issues when the critical
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* angle is changing. */
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y += critical_cos;
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float NV = clamp(y, 1e-4, 0.9999);
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float a = z_factor * z_factor;
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float a2 = clamp(a * a, 1e-8, 0.9999);
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vec3 V = vec3(sqrt(1.0 - NV * NV), 0.0, NV);
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/* Integrating BTDF */
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float btdf_accum = 0.0;
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float fresnel_accum = 0.0;
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for (float j = 0.0; j < sampleCount; j++) {
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for (float i = 0.0; i < sampleCount; i++) {
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vec3 Xi = (vec3(i, j, 0.0) + 0.5) / sampleCount;
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Xi.yz = vec2(cos(Xi.y * M_2PI), sin(Xi.y * M_2PI));
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/* Microfacet normal. */
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vec3 H = sample_ggx(Xi, a2, V);
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float VH = dot(V, H);
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/* Check if there is total internal reflections. */
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float fresnel = F_eta(ior, VH);
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fresnel_accum += fresnel;
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float eta = 1.0 / ior;
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if (dot(H, V) < 0.0) {
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H = -H;
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eta = ior;
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}
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vec3 L = refract(-V, H, eta);
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float NL = -L.z;
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if ((NL > 0.0) && (fresnel < 0.999)) {
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float LH = dot(L, H);
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/* Balancing the adjustments made in G1_Smith. */
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float G1_l = NL * 2.0 / G1_Smith_GGX_opti(NL, a2);
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/* btdf = abs(VH*LH) * (ior*ior) * D * G(V) * G(L) / (Ht2 * NV)
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* pdf = (VH * abs(LH)) * (ior*ior) * D * G(V) / (Ht2 * NV) */
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float btdf = G1_l * abs(VH * LH) / (VH * abs(LH));
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btdf_accum += btdf;
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}
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}
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}
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btdf_accum /= sampleCount * sampleCount;
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fresnel_accum /= sampleCount * sampleCount;
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if (z_factor == 0.0) {
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/* Perfect mirror. Increased precision because the roughness is clamped. */
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fresnel_accum = F_eta(ior, NV);
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}
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if (x == 0.0) {
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/* Special case. */
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fresnel_accum = 1.0;
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btdf_accum = 0.0;
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}
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/* There is place to put multi-scatter result (which is a little bit different still)
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* and / or lobe fitting for better sampling of. */
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FragColor = vec4(btdf_accum, fresnel_accum, 0.0, 1.0);
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}
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