189 lines
7.3 KiB
GLSL
189 lines
7.3 KiB
GLSL
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vec3 tint_from_color(vec3 color)
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{
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float lum = dot(color, vec3(0.3, 0.6, 0.1)); /* luminance approx. */
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return (lum > 0.0) ? color / lum : vec3(1.0); /* normalize lum. to isolate hue+sat */
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}
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float principled_sheen(float NV)
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{
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float f = 1.0 - NV;
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/* Empirical approximation (manual curve fitting). Can be refined. */
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float sheen = f * f * f * 0.077 + f * 0.01 + 0.00026;
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return sheen;
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}
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void node_bsdf_principled(vec4 base_color,
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float subsurface,
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vec3 subsurface_radius,
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vec4 subsurface_color,
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float subsurface_ior,
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float subsurface_anisotropy,
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float metallic,
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float specular,
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float specular_tint,
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float roughness,
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float anisotropic,
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float anisotropic_rotation,
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float sheen,
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float sheen_tint,
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float clearcoat,
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float clearcoat_roughness,
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float ior,
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float transmission,
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float transmission_roughness,
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vec4 emission,
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float emission_strength,
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float alpha,
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vec3 N,
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vec3 CN,
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vec3 T,
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float weight,
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const float do_diffuse,
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const float do_clearcoat,
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const float do_refraction,
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const float do_multiscatter,
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float do_sss,
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out Closure result)
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{
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/* Match cycles. */
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metallic = clamp(metallic, 0.0, 1.0);
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transmission = clamp(transmission, 0.0, 1.0) * (1.0 - metallic);
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float diffuse_weight = (1.0 - transmission) * (1.0 - metallic);
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float specular_weight = (1.0 - transmission);
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float clearcoat_weight = max(clearcoat, 0.0) * 0.25;
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transmission_roughness = 1.0 - (1.0 - roughness) * (1.0 - transmission_roughness);
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specular = max(0.0, specular);
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N = safe_normalize(N);
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CN = safe_normalize(CN);
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vec3 V = cameraVec(g_data.P);
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float NV = dot(N, V);
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float fresnel = (do_multiscatter != 0.0) ? btdf_lut(NV, roughness, ior).y : F_eta(ior, NV);
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float glass_reflection_weight = fresnel * transmission;
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float glass_transmission_weight = (1.0 - fresnel) * transmission;
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vec3 base_color_tint = tint_from_color(base_color.rgb);
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vec2 split_sum = brdf_lut(NV, roughness);
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ClosureTransparency transparency_data;
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transparency_data.weight = weight;
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transparency_data.transmittance = vec3(1.0 - alpha);
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transparency_data.holdout = 0.0;
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weight *= alpha;
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ClosureEmission emission_data;
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emission_data.weight = weight;
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emission_data.emission = emission.rgb * emission_strength;
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/* Diffuse. */
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ClosureDiffuse diffuse_data;
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diffuse_data.weight = diffuse_weight * weight;
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diffuse_data.color = mix(base_color.rgb, subsurface_color.rgb, subsurface);
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/* Sheen Coarse approximation: We reuse the diffuse radiance and just scale it. */
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vec3 sheen_color = mix(vec3(1.0), base_color_tint, sheen_tint);
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diffuse_data.color += sheen * sheen_color * principled_sheen(NV);
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diffuse_data.N = N;
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diffuse_data.sss_radius = subsurface_radius * subsurface;
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diffuse_data.sss_id = uint(do_sss);
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/* NOTE(@fclem): We need to blend the reflection color but also need to avoid applying the
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* weights so we compute the ratio. */
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float reflection_weight = specular_weight + glass_reflection_weight;
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float reflection_weight_inv = safe_rcp(reflection_weight);
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specular_weight *= reflection_weight_inv;
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glass_reflection_weight *= reflection_weight_inv;
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/* Reflection. */
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ClosureReflection reflection_data;
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reflection_data.weight = reflection_weight * weight;
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reflection_data.N = N;
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reflection_data.roughness = roughness;
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if (true) {
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vec3 dielectric_f0_color = mix(vec3(1.0), base_color_tint, specular_tint);
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vec3 metallic_f0_color = base_color.rgb;
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vec3 f0 = mix((0.08 * specular) * dielectric_f0_color, metallic_f0_color, metallic);
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/* Cycles does this blending using the microfacet fresnel factor. However, our fresnel
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* is already baked inside the split sum LUT. We approximate by changing the f90 color
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* directly in a non linear fashion. */
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vec3 f90 = mix(f0, vec3(1.0), fast_sqrt(specular));
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vec3 reflection_brdf = (do_multiscatter != 0.0) ? F_brdf_multi_scatter(f0, f90, split_sum) :
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F_brdf_single_scatter(f0, f90, split_sum);
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reflection_data.color = reflection_brdf * specular_weight;
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}
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if (true) {
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/* Poor approximation since we baked the LUT using a fixed IOR. */
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vec3 f0 = mix(vec3(1.0), base_color.rgb, specular_tint);
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vec3 f90 = vec3(1.0);
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vec3 glass_brdf = (do_multiscatter != 0.0) ? F_brdf_multi_scatter(f0, f90, split_sum) :
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F_brdf_single_scatter(f0, f90, split_sum);
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/* Avoid 3 glossy evaluation. Use the same closure for glass reflection. */
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reflection_data.color += glass_brdf * glass_reflection_weight;
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}
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ClosureReflection clearcoat_data;
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clearcoat_data.weight = clearcoat_weight * weight;
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clearcoat_data.N = CN;
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clearcoat_data.roughness = clearcoat_roughness;
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if (true) {
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float NV = dot(clearcoat_data.N, V);
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vec2 split_sum = brdf_lut(NV, clearcoat_data.roughness);
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vec3 brdf = F_brdf_single_scatter(vec3(0.04), vec3(1.0), split_sum);
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clearcoat_data.color = brdf;
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}
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/* Refraction. */
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ClosureRefraction refraction_data;
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refraction_data.weight = glass_transmission_weight * weight;
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float btdf = (do_multiscatter != 0.0) ? 1.0 : btdf_lut(NV, roughness, ior).x;
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refraction_data.color = base_color.rgb * btdf;
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refraction_data.N = N;
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refraction_data.roughness = do_multiscatter != 0.0 ? roughness :
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max(roughness, transmission_roughness);
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refraction_data.ior = ior;
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/* Ref. #98190: Defines are optimizations for old compilers.
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* Might become unnecessary with EEVEE-Next. */
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if (do_diffuse == 0.0 && do_refraction == 0.0 && do_clearcoat != 0.0) {
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#ifdef PRINCIPLED_CLEARCOAT
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/* Metallic & Clearcoat case. */
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result = closure_eval(reflection_data, clearcoat_data);
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#endif
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}
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else if (do_diffuse == 0.0 && do_refraction == 0.0 && do_clearcoat == 0.0) {
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#ifdef PRINCIPLED_METALLIC
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/* Metallic case. */
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result = closure_eval(reflection_data);
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#endif
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}
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else if (do_diffuse != 0.0 && do_refraction == 0.0 && do_clearcoat == 0.0) {
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#ifdef PRINCIPLED_DIELECTRIC
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/* Dielectric case. */
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result = closure_eval(diffuse_data, reflection_data);
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#endif
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}
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else if (do_diffuse == 0.0 && do_refraction != 0.0 && do_clearcoat == 0.0) {
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#ifdef PRINCIPLED_GLASS
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/* Glass case. */
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result = closure_eval(reflection_data, refraction_data);
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#endif
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}
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else {
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#ifdef PRINCIPLED_ANY
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/* Un-optimized case. */
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result = closure_eval(diffuse_data, reflection_data, clearcoat_data, refraction_data);
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#endif
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}
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Closure emission_cl = closure_eval(emission_data);
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Closure transparency_cl = closure_eval(transparency_data);
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result = closure_add(result, emission_cl);
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result = closure_add(result, transparency_cl);
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}
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