86 lines
2.6 KiB
GLSL
86 lines
2.6 KiB
GLSL
// From paper http://graphics.cs.williams.edu/papers/AlchemyHPG11/
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// and improvements here http://graphics.cs.williams.edu/papers/SAOHPG12/
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uniform sampler2D ntex;
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uniform sampler2D dtex;
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uniform sampler2D noise_texture;
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uniform vec4 samplePoints[16];
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#ifdef UBO_DISABLED
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uniform mat4 ViewMatrix;
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uniform mat4 ProjectionMatrix;
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uniform mat4 InverseViewMatrix;
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uniform mat4 InverseProjectionMatrix;
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#else
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layout (std140) uniform MatrixesData
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{
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mat4 ViewMatrix;
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mat4 ProjectionMatrix;
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mat4 InverseViewMatrix;
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mat4 InverseProjectionMatrix;
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mat4 ShadowViewProjMatrixes[4];
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};
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#endif
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in vec2 uv;
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out float AO;
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const float sigma = 1.;
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const float beta = 0.0001;
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const float epsilon = .00001;
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const float radius = .1;
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const float k = 1.;
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#define SAMPLES 16
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const float invSamples = 1. / SAMPLES;
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vec3 DecodeNormal(vec2 n);
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vec4 getPosFromUVDepth(vec3 uvDepth, mat4 InverseProjectionMatrix);
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vec3 rand(vec2 co)
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{
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float noiseX = clamp(fract(sin(dot(co ,vec2(12.9898,78.233))) * 43758.5453),0.0,1.0)*2.0-1.0;
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float noiseY = clamp(fract(sin(dot(co ,vec2(12.9898,78.233)*2.0)) * 43758.5453),0.0,1.0)*2.0-1.0;
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return vec3(noiseX, noiseY, length(texture(noise_texture, co * pow(3.14159265359, 2.)).xyz));
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}
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void main(void)
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{
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vec4 cur = texture(ntex, uv);
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float curdepth = texture(dtex, uv).x;
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vec4 FragPos = getPosFromUVDepth(vec3(uv, curdepth), InverseProjectionMatrix);
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// get the normal of current fragment
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vec3 ddx = dFdx(FragPos.xyz);
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vec3 ddy = dFdy(FragPos.xyz);
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vec3 norm = normalize(cross(ddy, ddx));
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// Workaround for nvidia and skyboxes
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float len = dot(vec3(1.0), abs(cur.xyz));
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if (len < 0.2 || curdepth > 0.9955) discard;
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float randAngle = rand(uv).x;
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vec2 Xaxis = vec2(cos(randAngle), sin(randAngle));
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Xaxis = normalize(Xaxis);
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vec2 Yaxis = vec2(sin(randAngle), -cos(randAngle));
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Yaxis = normalize(Yaxis);
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float bl = 0.0;
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for(int i = 0; i < SAMPLES; ++i) {
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vec2 occluder_uv = samplePoints[i].x * Xaxis + samplePoints[i].y * Yaxis;
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occluder_uv *= samplePoints[i].w * radius;
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occluder_uv += uv;
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if (occluder_uv.x < 0. || occluder_uv.x > 1. || occluder_uv.y < 0. || occluder_uv.y > 1.) continue;
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float occluderFragmentDepth = texture(dtex, occluder_uv).x;
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vec4 OccluderPos = getPosFromUVDepth(vec3(occluder_uv, occluderFragmentDepth), InverseProjectionMatrix);
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vec3 vi = (OccluderPos - FragPos).xyz;
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bl += max(0, dot(vi, norm) - FragPos.z * beta) / (dot(vi, vi) + epsilon);
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}
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AO = max(pow(1.0 - 2. * sigma * bl * invSamples, k), 0.);
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}
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