1 | #include "../shaderenv.h"
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2 |
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3 |
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4 | ////////////////////
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5 | // Screen Spaced Ambient Occlusion shader
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6 | // based on shader of Alexander Kusternig
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7 |
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8 |
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9 | #define USE_EYESPACE_DEPTH 1
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10 |
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11 |
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12 | struct fragment
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13 | {
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14 | float2 texCoord: TEXCOORD0;
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15 | float3 view: TEXCOORD1;
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16 | };
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17 |
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18 |
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19 | struct pixel
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20 | {
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21 | float4 illum_col: COLOR0;
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22 | };
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23 |
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24 |
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25 | inline float occlusionPower(float radius, float dist)
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26 | {
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27 | return 6.283185307179586476925286766559f * (1.0f - cos(asin(radius / dist)));
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28 | }
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29 |
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30 |
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31 | inline float SqrLen(float3 v)
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32 | {
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33 | return v.x * v.x + v.y * v.y + v.z * v.z;
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34 | }
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35 |
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36 |
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37 | inline float2 myreflect(float2 pt, float2 n)
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38 | {
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39 | // distance to plane
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40 | float d = dot(n, pt);
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41 | // reflect around plane
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42 | float2 rpt = pt - d * 2.0f * n;
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43 |
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44 | return rpt;
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45 | }
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46 |
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47 |
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48 | inline float3 Interpol(float2 w, float3 bl, float3 br, float3 tl, float3 tr)
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49 | {
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50 | float3 x1 = lerp(bl, tl, w.y);
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51 | float3 x2 = lerp(br, tr, w.y);
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52 | float3 v = lerp(x1, x2, w.x);
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53 |
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54 | return v;
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55 | }
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56 |
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57 |
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58 | // reconstruct world space position
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59 | inline float3 ReconstructSamplePos(float eyeSpaceDepth,
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60 | float2 texcoord,
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61 | float3 bl, float3 br, float3 tl, float3 tr)
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62 | {
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63 | float3 viewVec = Interpol(texcoord, bl, br, tl, tr);
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64 | float3 samplePos = -viewVec * eyeSpaceDepth;
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65 |
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66 | return samplePos;
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67 | }
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68 |
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69 |
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70 |
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71 | /** This shader computes the reprojection and stores
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72 | the ssao value of the old pixel as well as the
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73 | weight of the pixel in the new frame.
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74 | */
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75 | inline float2 temporalSmoothing(float4 worldPos,
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76 | float eyeSpaceDepth,
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77 | float2 texcoord0,
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78 | float3 oldEyePos,
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79 | sampler2D oldTex,
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80 | float4x4 oldModelViewProj,
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81 | sampler2D colors,
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82 | float3 projPos,
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83 | float invW,
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84 | float3 oldbl,
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85 | float3 oldbr,
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86 | float3 oldtl,
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87 | float3 oldtr,
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88 | float3 diffVec
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89 | )
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90 | {
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91 | // compute position from old frame for dynamic objects + translational portion
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92 | const float3 translatedPos = diffVec - oldEyePos + worldPos.xyz;
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93 |
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94 |
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95 | /////////////////
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96 | //-- reproject into old frame and calculate texture position of sample in old frame
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97 |
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98 | // note: the old model view matrix only holds the view orientation part
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99 | float4 backProjPos = mul(oldModelViewProj, float4(translatedPos, 1.0f));
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100 | backProjPos /= backProjPos.w;
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101 |
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102 | // fit from unit cube into 0 .. 1
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103 | const float2 oldTexCoords = backProjPos.xy * 0.5f + 0.5f;
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104 | // retrieve the sample from the last frame
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105 | const float4 oldPixel = tex2Dlod(oldTex, float4(oldTexCoords, .0f, .0f));
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106 |
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107 | // the ssao value in the old frame
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108 | const float ssao = oldPixel.x;
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109 |
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110 | #if USE_EYESPACE_DEPTH
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111 |
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112 | // calculate eye space position of sample in old frame
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113 | const float oldEyeSpaceDepth = oldPixel.w;
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114 |
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115 | // vector from eye pos to old sample
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116 | const float3 viewVec = Interpol(oldTexCoords, oldbl, oldbr, oldtl, oldtr);
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117 | const float invLen = 1.0f / length(viewVec);
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118 | const float projectedEyeSpaceDepth = invLen * length(translatedPos);
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119 | //const float projectedEyeSpaceDepth = length(translatedPos);
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120 |
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121 | const float depthDif = abs(1.0f - oldEyeSpaceDepth / projectedEyeSpaceDepth);
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122 |
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123 | #else
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124 |
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125 | // calculate eye space position of sample in old frame
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126 | const float oldDepth = oldPixel.w;
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127 | // the depth projected into the old frame
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128 | const float projectedDepth = projPos.z;
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129 | // calculate depth difference
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130 | const float depthDif = abs(projectedDepth - oldDepth);
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131 |
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132 | #endif
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133 |
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134 | const float xOffs = 1.0f / 1024.0f;
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135 | const float yOffs = 1.0f / 768.0f;
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136 | const float eps = 1e-6f;
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137 |
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138 | // the weight of the old value
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139 | float w;
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140 |
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141 | //////////////
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142 | //-- reuse old value only if it was still valid in the old frame
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143 |
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144 | if (1
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145 | && (oldTexCoords.x + eps >= xOffs) && (oldTexCoords.x <= 1.0f - xOffs + eps)
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146 | && (oldTexCoords.y + eps >= yOffs) && (oldTexCoords.y <= 1.0f - yOffs + eps)
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147 | && (depthDif <= MIN_DEPTH_DIFF)
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148 | )
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149 | {
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150 | // pixel valid => retrieve the convergence weight
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151 | w = oldPixel.y;
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152 | }
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153 | else
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154 | {
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155 | w = 0.0f;
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156 | }
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157 |
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158 | return float2(ssao, w);
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159 | }
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160 |
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161 |
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162 | /** The ssao shader returning the an intensity value between 0 and 1
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163 | This version of the ssao shader uses the dotproduct between pixel and
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164 | sample normal as weight.
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165 | */
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166 | float3 ssao2(fragment IN,
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167 | sampler2D colors,
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168 | sampler2D noiseTex,
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169 | float2 samples[NUM_SAMPLES],
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170 | float3 normal,
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171 | float3 centerPosition,
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172 | float scaleFactor,
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173 | float3 bl,
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174 | float3 br,
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175 | float3 tl,
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176 | float3 tr,
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177 | float3 viewDir,
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178 | sampler2D normalTex
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179 | )
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180 | {
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181 | float total_ao = .0f;
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182 | float numSamples = .0f;
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183 | float validSamples = .0f;
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184 |
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185 | for (int i = 0; i < NUM_SAMPLES; ++ i)
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186 | {
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187 | const float2 offset = samples[i];
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188 |
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189 | #if 1
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190 | ////////////////////
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191 | //-- add random noise: reflect around random normal vector (rather slow!)
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192 |
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193 | const float2 mynoise = tex2Dlod(noiseTex, float4(IN.texCoord * 4.0f, 0, 0)).xy;
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194 | const float2 offsetTransformed = myreflect(offset, mynoise);
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195 | #else
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196 | const float2 offsetTransformed = offset;
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197 | #endif
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198 | // weight with projected coordinate to reach similar kernel size for near and far
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199 | //const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor + jitter;
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200 | const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor;
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201 |
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202 | //if ((texcoord.x <= 1.0f) && (texcoord.x >= 0.0f) && (texcoord.y <= 1.0f) && (texcoord.y >= 0.0f)) ++ numSamples;
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203 | float4 sampleColor = tex2Dlod(colors, float4(texcoord, 0, 0));
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204 |
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205 | const float3 samplePos = ReconstructSamplePos(sampleColor.w, texcoord, bl, br, tl, tr);
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206 | // the normal of the current sample
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207 | const float3 sampleNormal = tex2Dlod(normalTex, float4(texcoord, 0, 0)).xyz;
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208 |
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209 |
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210 | ////////////////
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211 | //-- compute contribution of sample using the direction and angle
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212 |
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213 | float3 dirSample = samplePos - centerPosition;
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214 |
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215 | const float sqrLen = max(SqrLen(dirSample), 1e-2f);
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216 | const float lengthToSample = sqrt(sqrLen);
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217 | //const float lengthToSample = max(length(dirSample), 1e-6f);
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218 |
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219 | dirSample /= lengthToSample; // normalize
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220 |
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221 | // angle between current normal and direction to sample controls AO intensity.
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222 | float cosAngle = .5f + dot(sampleNormal, -normal) * 0.5f;
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223 | // use binary decision to cull samples that are behind current shading point
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224 | cosAngle *= step(0.0f, dot(dirSample, normal));
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225 |
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226 | const float aoContrib = SAMPLE_INTENSITY / sqrLen;
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227 | //const float aoContrib = (1.0f > lengthToSample) ? occlusionPower(9e-2f, DISTANCE_SCALE + lengthToSample): .0f;
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228 |
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229 | #if 1
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230 | // if surface normal perpenticular to view dir, approx. half of the samples will not count
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231 | // => compensate for this (on the other hand, projected sampling area could be larger!)
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232 |
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233 | const float viewCorrection = 1.0f + VIEW_CORRECTION_SCALE * max(dot(viewDir, normal), 0.0f);
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234 | total_ao += cosAngle * aoContrib * viewCorrection;
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235 | #else
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236 | total_ao += cosAngle * aoContrib;
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237 | #endif
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238 | // check if the samples have been valid in the last frame
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239 | validSamples += (1.0f - step(1.0f, lengthToSample)) * sampleColor.x;
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240 |
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241 | ++ numSamples;
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242 | }
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243 |
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244 | total_ao /= numSamples;
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245 |
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246 | return float3(max(0.0f, 1.0f - total_ao), validSamples, numSamples);
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247 | }
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248 |
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249 |
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250 | /** The ssao shader returning the an intensity value between 0 and 1.
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251 | This version of the ssao shader uses the dotproduct between
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252 | pixel-to-sample direction and sample normal as weight.
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253 |
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254 | The algorithm works like the following:
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255 | 1) Check in a circular area around the current position.
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256 | 2) Shoot vectors to the positions there, and check the angle to these positions.
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257 | 3) Summing up these angles gives an estimation of the occlusion at the current position.
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258 | */
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259 | float3 ssao(fragment IN,
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260 | sampler2D colors,
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261 | sampler2D noiseTex,
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262 | float2 samples[NUM_SAMPLES],
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263 | float3 normal,
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264 | float3 centerPosition,
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265 | float scaleFactor,
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266 | float3 bl,
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267 | float3 br,
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268 | float3 tl,
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269 | float3 tr,
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270 | float3 viewDir,
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271 | float newWeight,
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272 | bool isMovingObject
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273 | )
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274 | {
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275 | float total_ao = .0f;
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276 | float validSamples = .0f;
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277 | float numSamples = .0f;
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278 |
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279 | for (int i = 0; i < NUM_SAMPLES; ++ i)
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280 | {
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281 | const float2 offset = samples[i];
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282 |
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283 | #if 1
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284 | ////////////////////
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285 | //-- add random noise: reflect around random normal vector
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286 | //-- (slows down the computation for some reason!)
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287 |
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288 | float2 mynoise = tex2Dlod(noiseTex, float4(IN.texCoord * 4.0f, 0, 0)).xy;
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289 | const float2 offsetTransformed = myreflect(offset, mynoise);
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290 | #else
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291 | const float2 offsetTransformed = offset;
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292 | #endif
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293 | // weight with projected coordinate to reach similar kernel size for near and far
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294 | const float2 texcoord = IN.texCoord.xy + offsetTransformed * scaleFactor;
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295 |
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296 | const float4 sampleColor = tex2Dlod(colors, float4(texcoord, .0f, .0f));
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297 | const float3 samplePos = ReconstructSamplePos(sampleColor.w, texcoord, bl, br, tl, tr);
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298 |
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299 |
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300 | ////////////////
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301 | //-- compute contribution of sample using the direction and angle
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302 |
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303 | float3 dirSample = samplePos - centerPosition;
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304 |
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305 | const float sqrLen = max(SqrLen(dirSample), 1e-2f);
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306 | const float lengthToSample = sqrt(sqrLen);
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307 |
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308 | dirSample /= lengthToSample; // normalize
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309 |
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310 | // angle between current normal and direction to sample controls AO intensity.
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311 | const float cosAngle = max(dot(dirSample, normal), .0f);
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312 | const float aoContrib = SAMPLE_INTENSITY / sqrLen;
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313 | //const float aoContrib = (1.0f > lengthToSample) ? occlusionPower(9e-2f, DISTANCE_SCALE + lengthToSample): .0f;
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314 |
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315 | #if 1
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316 | // if surface normal perpenticular to view dir, approx. half of the samples will not count
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317 | // => compensate for this (on the other hand, projected sampling area could be larger!)
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318 |
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319 | const float viewCorrection = 1.0f + VIEW_CORRECTION_SCALE * max(dot(viewDir, normal), 0.0f);
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320 | total_ao += cosAngle * aoContrib * viewCorrection;
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321 | #else
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322 | total_ao += cosAngle * aoContrib;
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323 | #endif
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324 |
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325 | ++ numSamples;
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326 |
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327 | // check if the samples have been valid in the last frame
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328 | // only mark sample as invalid if taking it into account can have influence the ssao:
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329 | // hence we also check if the sample or the same sample in the previous frame
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330 | // had any chance to be near the current sample
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331 | const float changeFactor = sampleColor.y;
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332 | const float pixelValid = sampleColor.x;
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333 |
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334 | // hack: cedistance measure can fail in some cases => choose something different
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335 | const float tooFarAway = step(0.5f, lengthToSample - changeFactor);
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336 | validSamples = max(validSamples, (1.0f - tooFarAway) * pixelValid);
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337 | //validSamples += sampleColor.x;
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338 |
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339 | //if ((validSamples < 1.0f) && (newWeight > 200) && (numSamples >= 8)) break;
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340 | if ((validSamples < 1.0f) && (numSamples >= 8) && !isMovingObject
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341 | || (newWeight > NUM_SAMPLES * 5) && (numSamples >= 8) && isMovingObject
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342 | )
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343 | {
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344 | break;
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345 | }
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346 | }
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347 |
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348 | total_ao /= numSamples;
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349 |
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350 | //return float3(max(0.0f, 1.0f - total_ao), validSamples, numSamples);
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351 | return float3(total_ao, validSamples, numSamples);
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352 | }
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353 |
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354 |
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355 |
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356 | /** The mrt shader for screen space ambient occlusion
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357 | */
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358 | pixel main(fragment IN,
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359 | uniform sampler2D colors,
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360 | uniform sampler2D normals,
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361 | uniform sampler2D noiseTex,
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362 | uniform float2 samples[NUM_SAMPLES],
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363 | uniform sampler2D oldTex,
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364 | uniform float4x4 modelViewProj,
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365 | uniform float4x4 oldModelViewProj,
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366 | uniform float temporalCoherence,
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367 | uniform float3 bl,
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368 | uniform float3 br,
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369 | uniform float3 tl,
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370 | uniform float3 tr,
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371 | uniform float3 oldEyePos,
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372 | uniform float3 oldbl,
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373 | uniform float3 oldbr,
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374 | uniform float3 oldtl,
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375 | uniform float3 oldtr,
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376 | uniform sampler2D attribsTex
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377 | )
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378 | {
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379 | pixel OUT;
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380 |
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381 | //const float3 normal = normalize(tex2Dlod(normals, float4(IN.texCoord, 0 ,0)).xyz);
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382 | const float3 normal = tex2Dlod(normals, float4(IN.texCoord, 0 ,0)).xyz;
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383 |
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384 | // reconstruct position from the eye space depth
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385 | const float3 viewDir = IN.view;
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386 | const float eyeSpaceDepth = tex2Dlod(colors, float4(IN.texCoord, 0, 0)).w;
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387 | const float4 eyeSpacePos = float4(-viewDir * eyeSpaceDepth, 1.0f);
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388 |
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389 | float3 diffVec = tex2Dlod(attribsTex, float4(IN.texCoord, 0, 0)).xyz;
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390 |
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391 |
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392 | ////////////////
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393 | //-- calculcate the current projected posiion (also used for next frame)
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394 |
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395 | float4 projPos = mul(modelViewProj, eyeSpacePos);
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396 | const float invw = 1.0f / projPos.w;
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397 | projPos *= invw;
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398 | float scaleFactor = SAMPLE_RADIUS * invw;
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399 |
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400 | const float sqrMoveSpeed = SqrLen(diffVec);
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401 | const bool isMovingObject = (sqrMoveSpeed > DYNAMIC_OBJECTS_THRESHOLD);
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402 |
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403 |
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404 | /////////////////
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405 | //-- compute temporal reprojection
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406 |
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407 | float2 temporalVals = temporalSmoothing(eyeSpacePos, eyeSpaceDepth, IN.texCoord, oldEyePos,
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408 | oldTex, oldModelViewProj,
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409 | colors,
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410 | projPos.xyz,
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411 | invw,
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412 | oldbl, oldbr, oldtl, oldtr,
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413 | diffVec
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414 | );
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415 |
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416 | const float oldSsao = temporalVals.x;
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417 | float oldWeight = temporalVals.y;
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418 |
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419 | float3 ao;
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420 |
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421 | // cull background note: this should be done with the stencil buffer
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422 | if (eyeSpaceDepth < 1e10f)
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423 | {
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424 | ao = ssao(IN, colors, noiseTex, samples, normal, eyeSpacePos.xyz, scaleFactor, bl, br, tl, tr, normalize(viewDir), oldWeight, isMovingObject);
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425 | //ao = ssao2(IN, colors, noiseTex, samples, normal, eyeSpacePos.xyz, scaleFactor, bl, br, tl, tr, normalize(viewDir), normals);
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426 | }
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427 | else
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428 | {
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429 | ao = float3(1.0f, 1.0f, 1.0f);
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430 | }
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431 |
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432 | // equals the number of sampled shot in this pass
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433 | const float newWeight = ao.z;
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434 |
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435 | // check if we have to reset pixel because one of the sample points was invalid
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436 | if (!isMovingObject)
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437 | //if (sqrMoveSpeed <= DYNAMIC_OBJECTS_THRESHOLD)
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438 | {
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439 | if (ao.y > 4.0f)
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440 | oldWeight = 0;
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441 | else if (ao.y > 1.0f)
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442 | oldWeight = min(oldWeight, 4.0f * newWeight);
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443 | }
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444 |
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445 | const float combinedWeight = clamp(newWeight + oldWeight, .0f, temporalCoherence);
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446 |
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447 |
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448 | // blend between old and new samples (and avoid division by zero)
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449 | OUT.illum_col.x = (ao.x * newWeight + oldSsao * oldWeight) / max(1e-6f, newWeight + oldWeight);
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450 | OUT.illum_col.z = SqrLen(diffVec);
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451 | OUT.illum_col.y = combinedWeight;
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452 | OUT.illum_col.w = eyeSpaceDepth;
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453 |
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454 | return OUT;
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455 | }
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