diff --git a/data/shaders/pbribl/filtercube.vert b/data/shaders/pbribl/filtercube.vert new file mode 100644 index 00000000..1226e28e --- /dev/null +++ b/data/shaders/pbribl/filtercube.vert @@ -0,0 +1,19 @@ +#version 450 + +layout (location = 0) in vec3 inPos; + +layout(push_constant) uniform PushConsts { + layout (offset = 0) mat4 mvp; +} pushConsts; + +layout (location = 0) out vec3 outUVW; + +out gl_PerVertex { + vec4 gl_Position; +}; + +void main() +{ + outUVW = inPos; + gl_Position = pushConsts.mvp * vec4(inPos.xyz, 1.0); +} diff --git a/data/shaders/pbribl/filtercube.vert.spv b/data/shaders/pbribl/filtercube.vert.spv new file mode 100644 index 00000000..d858d61a Binary files /dev/null and b/data/shaders/pbribl/filtercube.vert.spv differ diff --git a/data/shaders/pbribl/prefilterenvmap.frag b/data/shaders/pbribl/prefilterenvmap.frag new file mode 100644 index 00000000..dada35f0 --- /dev/null +++ b/data/shaders/pbribl/prefilterenvmap.frag @@ -0,0 +1,90 @@ +#version 450 + +layout (location = 0) in vec3 inPos; +layout (location = 0) out vec4 outColor; + +layout (binding = 0) uniform samplerCube samplerEnv; + +layout(push_constant) uniform PushConsts { + layout (offset = 64) float roughness; + layout (offset = 68) uint numSamples; +} pushConsts; + +const float PI = 3.1415926536; + +// Based omn http://byteblacksmith.com/improvements-to-the-canonical-one-liner-glsl-rand-for-opengl-es-2-0/ +float random(vec2 co) +{ + float a = 12.9898; + float b = 78.233; + float c = 43758.5453; + float dt= dot(co.xy ,vec2(a,b)); + float sn= mod(dt,3.14); + return fract(sin(sn) * c); +} + +vec2 hammersley2d(uint i, uint N) +{ + // Radical inverse based on http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html + uint bits = (i << 16u) | (i >> 16u); + bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u); + bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u); + bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u); + bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u); + float rdi = float(bits) * 2.3283064365386963e-10; + return vec2(float(i) /float(N), rdi); +} + +// Based on http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_slides.pdf +vec3 importanceSample_GGX(vec2 Xi, float roughness, vec3 normal) +{ + // Maps a 2D point to a hemisphere with spread based on roughness + float alpha = roughness * roughness; + float phi = 2.0 * PI * Xi.x + random(normal.xz) * 0.1; + float cosTheta = sqrt((1.0 - Xi.y) / (1.0 + (alpha*alpha - 1.0) * Xi.y)); + float sinTheta = sqrt(1.0 - cosTheta * cosTheta); + vec3 H = vec3(sinTheta * cos(phi), sinTheta * sin(phi), cosTheta); + + // Tangent space + vec3 up = abs(normal.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0); + vec3 tangentX = normalize(cross(up, normal)); + vec3 tangentY = normalize(cross(normal, tangentX)); + + // Convert to world Space + return normalize(tangentX * H.x + tangentY * H.y + normal * H.z); +} + +// Normal Distribution function +float D_GGX(float dotNH, float roughness) +{ + float alpha = roughness * roughness; + float alpha2 = alpha * alpha; + float denom = dotNH * dotNH * (alpha2 - 1.0) + 1.0; + return (alpha2)/(PI * denom*denom); +} + +vec3 prefilterEnvMap(vec3 R, float roughness) +{ + vec3 N = R; + vec3 V = R; + vec3 color = vec3(0.0); + float totalWeight = 0.0; + for(uint i = 0u; i < pushConsts.numSamples; i++) { + vec2 Xi = hammersley2d(i, pushConsts.numSamples); + vec3 H = importanceSample_GGX(Xi, roughness, N); + vec3 L = 2.0 * dot(V, H) * H - V; + float dotNL = clamp(dot(N, L), 0.0, 1.0); + if(dotNL > 0.0) { + color += texture(samplerEnv, L).rgb * dotNL; + totalWeight += dotNL; + } + } + return (color / totalWeight); +} + + +void main() +{ + vec3 N = normalize(inPos); + outColor = vec4(prefilterEnvMap(N, pushConsts.roughness), 1.0); +} diff --git a/data/shaders/pbribl/prefilterenvmap.frag.spv b/data/shaders/pbribl/prefilterenvmap.frag.spv new file mode 100644 index 00000000..0cdcde25 Binary files /dev/null and b/data/shaders/pbribl/prefilterenvmap.frag.spv differ