diff options
Diffstat (limited to 'source/blender/draw/engines/eevee/shaders/ssr_lib.glsl')
-rw-r--r-- | source/blender/draw/engines/eevee/shaders/ssr_lib.glsl | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee/shaders/ssr_lib.glsl b/source/blender/draw/engines/eevee/shaders/ssr_lib.glsl new file mode 100644 index 00000000000..92287d2ecbc --- /dev/null +++ b/source/blender/draw/engines/eevee/shaders/ssr_lib.glsl @@ -0,0 +1,73 @@ +/* ------------ Refraction ------------ */ + +#define BTDF_BIAS 0.85 + +vec4 screen_space_refraction(vec3 viewPosition, vec3 N, vec3 V, float ior, float roughnessSquared, vec3 rand, float ofs) +{ + float a2 = max(5e-6, roughnessSquared * roughnessSquared); + float jitter = fract(rand.x + ofs); + + /* Importance sampling bias */ + rand.x = mix(rand.x, 0.0, BTDF_BIAS); + + vec3 T, B; + float NH; + make_orthonormal_basis(N, T, B); + vec3 H = sample_ggx(rand, a2, N, T, B, NH); /* Microfacet normal */ + float pdf = pdf_ggx_reflect(NH, a2); + + /* If ray is bad (i.e. going below the plane) regenerate. */ + if (F_eta(ior, dot(H, V)) < 1.0) { + H = sample_ggx(rand * vec3(1.0, -1.0, -1.0), a2, N, T, B, NH); /* Microfacet normal */ + pdf = pdf_ggx_reflect(NH, a2); + } + + vec3 vV = viewCameraVec; + float eta = 1.0/ior; + if (dot(H, V) < 0.0) { + H = -H; + eta = ior; + } + + vec3 R = refract(-V, H, 1.0 / ior); + + R = transform_direction(ViewMatrix, R); + + vec3 hit_pos = raycast(-1, viewPosition, R * 1e16, ssrThickness, jitter, ssrQuality, roughnessSquared, false); + + if ((hit_pos.z > 0.0) && (F_eta(ior, dot(H, V)) < 1.0)) { + hit_pos = get_view_space_from_depth(hit_pos.xy, hit_pos.z); + float hit_dist = distance(hit_pos, viewPosition); + + float cone_cos = cone_cosine(roughnessSquared); + float cone_tan = sqrt(1 - cone_cos * cone_cos) / cone_cos; + + /* Empirical fit for refraction. */ + /* TODO find a better fit or precompute inside the LUT. */ + cone_tan *= 0.5 * fast_sqrt(f0_from_ior((ior < 1.0) ? 1.0 / ior : ior)); + + float cone_footprint = hit_dist * cone_tan; + + /* find the offset in screen space by multiplying a point + * in camera space at the depth of the point by the projection matrix. */ + float homcoord = ProjectionMatrix[2][3] * hit_pos.z + ProjectionMatrix[3][3]; + /* UV space footprint */ + cone_footprint = BTDF_BIAS * 0.5 * max(ProjectionMatrix[0][0], ProjectionMatrix[1][1]) * cone_footprint / homcoord; + + vec2 hit_uvs = project_point(ProjectionMatrix, hit_pos).xy * 0.5 + 0.5; + + /* Texel footprint */ + vec2 texture_size = vec2(textureSize(colorBuffer, 0).xy); + float mip = clamp(log2(cone_footprint * max(texture_size.x, texture_size.y)), 0.0, 9.0); + + /* Correct UVs for mipmaping mis-alignment */ + hit_uvs *= mip_ratio_interp(mip); + + vec3 spec = textureLod(colorBuffer, hit_uvs, mip).xyz; + float mask = screen_border_mask(hit_uvs); + + return vec4(spec, mask); + } + + return vec4(0.0); +} |