[2884] | 1 | #include "../shaderenv.h"
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| 2 |
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[2881] | 3 | ////////////////////
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| 4 | // Screen Spaced Ambient Occlusion shader
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| 5 | // based on shader of Alexander Kusternig
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| 6 |
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| 7 |
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[3006] | 8 | #define USE_EYE_SPACE_DEPTH 1
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[3001] | 9 |
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| 10 |
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[2881] | 11 | struct fragment
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| 12 | {
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[2889] | 13 | float2 texCoord: TEXCOORD0;
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| 14 | float3 view: TEXCOORD1;
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[2881] | 15 | };
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| 16 |
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| 17 |
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| 18 | struct pixel
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| 19 | {
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| 20 | float4 illum_col: COLOR0;
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| 21 | };
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| 22 |
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| 23 |
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[2990] | 24 | inline float2 myreflect(float2 pt, float2 n)
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[2881] | 25 | {
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| 26 | // distance to plane
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| 27 | float d = dot(n, pt);
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| 28 | // reflect around plane
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| 29 | float2 rpt = pt - d * 2.0f * n;
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[2886] | 30 |
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[2881] | 31 | return rpt;
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| 32 | }
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| 33 |
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| 34 |
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[2990] | 35 | inline float3 Interpol(float2 w, float3 bl, float3 br, float3 tl, float3 tr)
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[2986] | 36 | {
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[2991] | 37 | float3 x1 = lerp(bl, tl, w.y);
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| 38 | float3 x2 = lerp(br, tr, w.y);
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| 39 | float3 v = lerp(x1, x2, w.x);
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[2987] | 40 |
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| 41 | return v;
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| 42 | }
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| 43 |
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[2988] | 44 |
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[2992] | 45 | // reconstruct world space position
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[3017] | 46 | inline float3 ReconstructSamplePos(uniform sampler2D colors,
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| 47 | float2 texcoord,
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| 48 | float3 bl, float3 br, float3 tl, float3 tr)
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[2988] | 49 | {
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[3019] | 50 | //const float eyeSpaceDepth = tex2Dlod(colors, float4(texcoord, 0, 0)).w;
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| 51 | const float eyeSpaceDepth = tex2D(colors, texcoord).w;
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[3017] | 52 | float3 viewVec = Interpol(texcoord, bl, br, tl, tr);
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| 53 | float3 samplePos = -viewVec * eyeSpaceDepth;
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| 54 |
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[2999] | 55 | return samplePos;
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[2988] | 56 | }
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| 57 |
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| 58 |
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[2881] | 59 | /** The ssao shader returning the an intensity value between 0 and 1
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| 60 | */
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[2904] | 61 | float2 ssao(fragment IN,
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[2985] | 62 | uniform sampler2D colors,
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[2881] | 63 | uniform sampler2D noiseTexture,
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| 64 | uniform float2 samples[NUM_SAMPLES],
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| 65 | uniform float3 currentNormal,
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[3006] | 66 | uniform float3 centerPosition,
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[2985] | 67 | uniform float scaleFactor,
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[2986] | 68 | uniform float3 bl,
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| 69 | uniform float3 br,
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| 70 | uniform float3 tl,
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[3017] | 71 | uniform float3 tr,
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| 72 | uniform float3 viewDir
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[2881] | 73 | )
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| 74 | {
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| 75 | // Check in a circular area around the current position.
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| 76 | // Shoot vectors to the positions there, and check the angle to these positions.
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| 77 | // Summing up these angles gives an estimation of the occlusion at the current position.
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| 78 |
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| 79 | float total_ao = 0.0;
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[2904] | 80 | float numSamples = 0;
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[2881] | 81 |
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[2986] | 82 |
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[2881] | 83 | for (int i = 0; i < NUM_SAMPLES; ++ i)
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| 84 | {
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[2892] | 85 | const float2 offset = samples[i];
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[2881] | 86 |
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[2903] | 87 | #if 1
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[2881] | 88 | ////////////////////
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[2903] | 89 | // add random noise: reflect around random normal vector (warning: slow!)
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[2985] | 90 |
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[3017] | 91 | float2 mynoise = tex2D(noiseTexture, IN.texCoord).xy;
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[2892] | 92 | const float2 offsetTransformed = myreflect(offset, mynoise);
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[2903] | 93 | #else
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| 94 | const float2 offsetTransformed = offset;
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| 95 | #endif
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[2881] | 96 | // weight with projected coordinate to reach similar kernel size for near and far
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[3019] | 97 | const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor;
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[2881] | 98 |
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[3019] | 99 | //if ((texcoord.x <= 1.0f) && (texcoord.x >= 0.0f) && (texcoord.y <= 1.0f) && (texcoord.y >= 0.0f)) ++ numSamples;
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[2904] | 100 |
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[3017] | 101 | const float3 samplePos = ReconstructSamplePos(colors, texcoord, bl, br, tl, tr);
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[2989] | 102 |
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[2881] | 103 |
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[3017] | 104 | ////////////////
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| 105 | //-- compute contribution of sample using the direction and angle
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[2881] | 106 |
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[3017] | 107 | float3 dirSample = samplePos - centerPosition;
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[3019] | 108 | const float magSample = length(dirSample);
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| 109 | // normalize
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| 110 | dirSample /= magSample;
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[2999] | 111 |
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[2885] | 112 | // angle between current normal and direction to sample controls AO intensity.
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[3019] | 113 | const float cosAngle = max(dot(dirSample, currentNormal), 0.0f);
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[2881] | 114 |
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[2979] | 115 | // the distance_scale offset is used to avoid singularity that occurs at global illumination when
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| 116 | // the distance to a sample approaches zero
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[3019] | 117 | const float intensity = SAMPLE_INTENSITY / (DISTANCE_SCALE + magSample * magSample);
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[2881] | 118 |
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[3017] | 119 | #if 1
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[2885] | 120 | // if surface normal perpenticular to view dir, approx. half of the samples will not count
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| 121 | // => compensate for this (on the other hand, projected sampling area could be larger!)
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[3017] | 122 | const float viewCorrection = 1.0f + VIEW_CORRECTION_SCALE * dot(viewDir, currentNormal);
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| 123 | total_ao += cosAngle * intensity * viewCorrection;
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| 124 | #else
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| 125 | total_ao += cosAngle * intensity;
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[2911] | 126 | #endif
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[2881] | 127 | }
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| 128 |
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[2904] | 129 | return float2(max(0.0f, 1.0f - total_ao), numSamples);
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[2881] | 130 | }
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| 131 |
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[3017] | 132 | #pragma position_invariant main
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[2881] | 133 |
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| 134 | /** The mrt shader for screen space ambient occlusion
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| 135 | */
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| 136 | pixel main(fragment IN,
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| 137 | uniform sampler2D colors,
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| 138 | uniform sampler2D normals,
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| 139 | uniform sampler2D noiseTexture,
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| 140 | uniform float2 samples[NUM_SAMPLES],
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| 141 | uniform sampler2D oldTex,
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| 142 | const uniform float4x4 oldModelViewProj,
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[3004] | 143 | const uniform float4x4 modelViewProj,
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[2985] | 144 | uniform float temporalCoherence,
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[2986] | 145 | uniform float3 eyePos,
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| 146 | uniform float3 bl,
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| 147 | uniform float3 br,
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| 148 | uniform float3 tl,
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[2997] | 149 | uniform float3 tr
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[2881] | 150 | )
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| 151 | {
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| 152 | pixel OUT;
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| 153 |
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[3006] | 154 | float4 norm = tex2Dlod(normals, float4(IN.texCoord, 0 ,0));
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[3017] | 155 | const float3 normal = normalize(norm.xyz);
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[2975] | 156 |
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[2993] | 157 | /// reconstruct position from the eye space depth
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[3001] | 158 | float3 viewDir = IN.view;
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[3006] | 159 | const float eyeDepth = tex2Dlod(colors, float4(IN.texCoord, 0, 0)).w;
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[3014] | 160 | const float3 eyeSpacePos = -viewDir * eyeDepth;
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[3017] | 161 | const float3 centerPosition = eyePos + eyeSpacePos;
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[3014] | 162 |
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[3017] | 163 | float4 realPos = float4(centerPosition, 1.0f);
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[3001] | 164 |
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[3016] | 165 |
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[3017] | 166 | ////////////////
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| 167 | //-- calculcate the current projected depth for next frame
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| 168 |
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| 169 | float4 currentPos = mul(modelViewProj, realPos);
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| 170 |
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| 171 | const float w = SAMPLE_RADIUS / currentPos.w;
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| 172 | currentPos /= currentPos.w;
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| 173 |
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| 174 | const float currentDepth = currentPos.z * 1e-3f;
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[2993] | 175 |
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[3017] | 176 | const float2 ao = ssao(IN, colors, noiseTexture, samples, normal, eyeSpacePos, w, bl, br, tl, tr, normalize(viewDir));
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[3005] | 177 |
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[3000] | 178 |
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[3005] | 179 | /////////////////
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| 180 | //-- compute temporally smoothing
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| 181 |
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| 182 |
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[3017] | 183 | // reproject new frame into old one
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[3004] | 184 |
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| 185 | // calculate projected depth
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| 186 | float4 projPos = mul(oldModelViewProj, realPos);
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[3005] | 187 | projPos /= projPos.w;
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[2881] | 188 |
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[2996] | 189 | // the current depth projected into the old frame
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[3017] | 190 | const float projDepth = projPos.z * 1e-3f;
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[2881] | 191 |
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[2995] | 192 | // fit from unit cube into 0 .. 1
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[3017] | 193 | const float2 tex = projPos.xy * 0.5f + 0.5f;
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[2995] | 194 |
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[3006] | 195 | // retrieve the sample from the last frame
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[2881] | 196 | float4 oldCol = tex2D(oldTex, tex);
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| 197 |
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[3017] | 198 | const float oldDepth = oldCol.z;
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| 199 | //const float depthDif = 1.0f - projDepth / oldDepth;
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| 200 | const float depthDif = projDepth - oldDepth;
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[3006] | 201 |
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| 202 |
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[3000] | 203 | //const float oldNumSamples = oldCol.y;
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[3017] | 204 | const float oldWeight = clamp(oldCol.y, 0, temporalCoherence);
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[2881] | 205 |
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[2897] | 206 | float newWeight;
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[2881] | 207 |
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[2993] | 208 | // the number of valid samples in this frame
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[2999] | 209 | //const float newNumSamples = ao.y;
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[2982] | 210 |
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[2904] | 211 | if (//(temporalCoherence > 0) &&
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[2897] | 212 | (tex.x >= 0.0f) && (tex.x < 1.0f) &&
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[2881] | 213 | (tex.y >= 0.0f) && (tex.y < 1.0f) &&
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[3009] | 214 | (abs(depthDif) < MIN_DEPTH_DIFF)
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[2991] | 215 | // if visibility changed in the surrounding area we have to recompute
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[2999] | 216 | //&& (oldNumSamples > 0.8f * newNumSamples)
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[2904] | 217 | )
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[2881] | 218 | {
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[2904] | 219 | // increase the weight for convergence
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| 220 | newWeight = oldWeight + 1.0f;
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[3017] | 221 | OUT.illum_col.x = (ao.x + oldCol.x * oldWeight) / newWeight;
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[2904] | 222 | //if (!(oldNumSamples > ao.y - 1.5f)) newWeight = 0;
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[2881] | 223 | }
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| 224 | else
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[2982] | 225 | {
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[3017] | 226 | OUT.illum_col.x = ao.x;
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[2897] | 227 | newWeight = 0;
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[2881] | 228 | }
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| 229 |
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[3017] | 230 | //OUT.illum_col.y=depthDif;
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| 231 | OUT.illum_col.y = newWeight;
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| 232 | OUT.illum_col.z = currentDepth;
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[2880] | 233 |
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[2881] | 234 | return OUT;
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| 235 | }
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[2880] | 236 |
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[2881] | 237 |
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[3017] | 238 | float Filter(float2 texCoord,
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| 239 | uniform sampler2D ssaoTex,
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| 240 | uniform float2 filterOffs[NUM_DOWNSAMPLES],
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| 241 | uniform float filterWeights[NUM_DOWNSAMPLES]
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| 242 | )
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| 243 | {
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| 244 | float average = .0f;
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| 245 | float w = .0f;
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| 246 |
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| 247 | for (int i = 0; i < NUM_DOWNSAMPLES; ++ i)
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| 248 | {
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| 249 | average += filterWeights[i] * tex2Dlod(ssaoTex, float4(texCoord + filterOffs[i], 0, 0)).x;
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| 250 | w += filterWeights[i];
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| 251 | }
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| 252 |
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| 253 | average *= 1.0f / (float)w;
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| 254 |
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| 255 | return average;
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| 256 | }
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| 257 |
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| 258 |
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[2880] | 259 | pixel combine(fragment IN,
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| 260 | uniform sampler2D colors,
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[3017] | 261 | uniform sampler2D ssaoTex,
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| 262 | uniform float2 filterOffs[NUM_DOWNSAMPLES],
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| 263 | uniform float filterWeights[NUM_DOWNSAMPLES]
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| 264 | )
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[2880] | 265 | {
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| 266 | pixel OUT;
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| 267 |
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[3006] | 268 | float4 col = tex2Dlod(colors, float4(IN.texCoord, 0, 0));
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[3017] | 269 | float3 ao = tex2Dlod(ssaoTex, float4(IN.texCoord, 0, 0));
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[2880] | 270 |
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[3017] | 271 | if (ao.y < 2000.0f)
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| 272 | ao.x = Filter(IN.texCoord, ssaoTex, filterOffs, filterWeights);
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| 273 |
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[3016] | 274 | OUT.illum_col = col * ao.x;
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[3017] | 275 | //OUT.illum_col.xyz = float3(ao.x,1-ao.y*1e-2f, 0);
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[2975] | 276 | OUT.illum_col.w = col.w;
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[2880] | 277 |
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| 278 | return OUT;
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[3000] | 279 | }
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