Campbell Barton
9b89de2571
Also use doxy style function reference `#` prefix chars when referencing identifiers.
92 lines
2.7 KiB
GLSL
92 lines
2.7 KiB
GLSL
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#pragma BLENDER_REQUIRE(common_math_geom_lib.glsl)
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#pragma BLENDER_REQUIRE(bsdf_common_lib.glsl)
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#pragma BLENDER_REQUIRE(bsdf_sampling_lib.glsl)
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#pragma BLENDER_REQUIRE(raytrace_lib.glsl)
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#pragma BLENDER_REQUIRE(surface_lib.glsl)
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/* ------------ Refraction ------------ */
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#define BTDF_BIAS 0.85
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uniform sampler2D refractColorBuffer;
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uniform float refractionDepth;
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vec4 screen_space_refraction(vec3 vP, vec3 N, vec3 V, float ior, float roughnessSquared, vec4 rand)
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{
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float alpha = max(0.002, roughnessSquared);
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/* Importance sampling bias */
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rand.x = mix(rand.x, 0.0, BTDF_BIAS);
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vec3 T, B;
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make_orthonormal_basis(N, T, B);
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float pdf;
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/* Microfacet normal */
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vec3 H = sample_ggx(rand.xzw, alpha, V, N, T, B, pdf);
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/* If ray is bad (i.e. going below the plane) regenerate. */
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if (F_eta(ior, dot(H, V)) < 1.0) {
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H = sample_ggx(rand.xzw * vec3(1.0, -1.0, -1.0), alpha, V, N, T, B, pdf);
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}
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vec3 vV = viewCameraVec(vP);
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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 R = refract(-V, H, 1.0 / ior);
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R = transform_direction(ViewMatrix, R);
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Ray ray;
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ray.origin = vP;
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ray.direction = R * 1e16;
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RayTraceParameters params;
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params.thickness = ssrThickness;
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params.jitter = rand.y;
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params.trace_quality = ssrQuality;
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params.roughness = roughnessSquared;
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vec3 hit_pos;
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bool hit = raytrace(ray, params, false, true, hit_pos);
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if (hit && (F_eta(ior, dot(H, V)) < 1.0)) {
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hit_pos = get_view_space_from_depth(hit_pos.xy, hit_pos.z);
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float hit_dist = distance(hit_pos, vP);
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float cone_cos = cone_cosine(roughnessSquared);
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float cone_tan = sqrt(1 - cone_cos * cone_cos) / cone_cos;
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/* Empirical fit for refraction. */
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/* TODO: find a better fit or precompute inside the LUT. */
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cone_tan *= 0.5 * fast_sqrt(f0_from_ior((ior < 1.0) ? 1.0 / ior : ior));
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float cone_footprint = hit_dist * cone_tan;
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/* find the offset in screen space by multiplying a point
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* in camera space at the depth of the point by the projection matrix. */
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float homcoord = ProjectionMatrix[2][3] * hit_pos.z + ProjectionMatrix[3][3];
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/* UV space footprint */
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cone_footprint = BTDF_BIAS * 0.5 * max(ProjectionMatrix[0][0], ProjectionMatrix[1][1]) *
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cone_footprint / homcoord;
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vec2 hit_uvs = project_point(ProjectionMatrix, hit_pos).xy * 0.5 + 0.5;
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/* Texel footprint */
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vec2 texture_size = vec2(textureSize(refractColorBuffer, 0).xy) / hizUvScale.xy;
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float mip = clamp(log2(cone_footprint * max(texture_size.x, texture_size.y)), 0.0, 9.0);
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vec3 spec = textureLod(refractColorBuffer, hit_uvs * hizUvScale.xy, mip).xyz;
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float mask = screen_border_mask(hit_uvs);
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return vec4(spec, mask);
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}
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return vec4(0.0);
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}
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