1 | #include "../shaderenv.h"
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2 |
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3 |
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4 | struct frag
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5 | {
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6 | // normalized screen position
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7 | float2 texCoord: TEXCOORD0;
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8 |
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9 | float2 lt: TEXCOORD1; // left top
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10 | float2 rb: TEXCOORD2; // right bottom
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11 | float2 rt: TEXCOORD3; // right top
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12 | float2 lb: TEXCOORD4; // left bottom
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13 | };
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14 |
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15 |
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16 | struct pixel
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17 | {
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18 | float4 col: COLOR0;
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19 | };
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20 |
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21 |
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22 |
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23 | float4 DownSample(frag IN,
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24 | uniform sampler2D colors,
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25 | uniform float2 downSampleOffs[NUM_DOWNSAMPLES]): COLOR
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26 | {
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27 | // let bilinear filtering do its work
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28 | return tex2Dlod(colors, float4(IN.texCoord, 0, 0));
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29 | /*
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30 | float4 average = .0f;
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31 |
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32 | for (int i = 0; i < NUM_DOWNSAMPLES; ++ i)
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33 | {
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34 | average += tex2Dlod(colors, float4(IN.texCoord + downSampleOffs[i], 0, 0));
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35 | }
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36 |
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37 | average *= 1.0f / (float)NUM_DOWNSAMPLES;
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38 |
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39 | return average;*/
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40 | }
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41 |
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42 |
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43 | /** Does the first downsampling step and on the same time calculates the
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44 | intensity.
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45 | */
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46 | float4 GreyScaleDownSample(frag IN,
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47 | uniform sampler2D colors,
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48 | uniform float2 downSampleOffs[4]
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49 | ): COLOR
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50 | {
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51 |
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52 | // Compute the average of the 4 necessary samples
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53 | float average = .0f;
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54 | float maximum = .0f;
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55 |
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56 | // the rgb weights
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57 | const float3 w = float3(0.299f, 0.587f, 0.114f);
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58 | //float3 w = float3(0.2125f, 0.7154f, 0.0721f);
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59 |
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60 | float4 color;
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61 |
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62 | for (int i = 0; i < 4; ++ i)
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63 | {
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64 | color = tex2D(colors, downSampleOffs[i]);
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65 | const float intensity = dot(cols[i].rgb, w);
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66 |
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67 | maximum = max(maximum, intensity);
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68 | average += log(1e-5f + intensity);
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69 | }
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70 |
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71 | average *= 0.25f;
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72 |
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73 | // Output the luminance to the render target
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74 | return float4(average, maximum, 0.0f, 1.0f);
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75 | }
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76 |
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77 |
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78 | /** Used for downsampling the tone map parameters (average loglum, maximum)
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79 | to the next lower level. This has to be applied until there is only
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80 | a 1x1 texture which holds the required numbers.
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81 | */
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82 | float4 DownSampleForToneMapping(frag IN,
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83 | uniform sampler2D colors,
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84 | uniform float2 downSampleOffs[4]): COLOR
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85 | {
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86 | float average = .0f;
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87 | float maximum = .0f;
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88 |
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89 | float4 color;
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90 |
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91 | for (int i = 0; i < 4; ++ i)
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92 | {
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93 | color = tex2D(colors, downSampleOffs[i]);
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94 |
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95 | maximum = max(maximum, color.y);
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96 | average += color.x;
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97 | }
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98 |
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99 | average *= 1.0f / (float)NUM_DOWNSAMPLES;
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100 |
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101 | return float4(average, maximum, 0.0f, 1.0f);
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102 | }
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103 |
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104 |
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105 |
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106 | pixel ToneMap(frag IN,
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107 | uniform sampler2D colors,
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108 | uniform float imageKey,
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109 | uniform float whiteLum,
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110 | uniform float middleGrey)
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111 | {
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112 | pixel OUT;
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113 |
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114 | float4 color = tex2D(colors, IN.texCoord);
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115 |
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116 | const float pixLum = 0.2125f * color.x + 0.7154f * color.y + 0.0721f * color.z;
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117 |
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118 | // obtain new image key from highest mipmap level
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119 | float logLumScaled = tex2Dlod(colors, float4(.5f, .5f, 0, MAX_LOD_LEVEL)).w;
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120 | float logLum = logLumScaled * LOGLUM_RANGE + MINLOGLUM;
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121 |
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122 | float newImageKey = max(exp(logLum), 1e-6f);
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123 |
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124 | // adjust to middle gray
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125 | const float lum = middleGrey * pixLum / newImageKey;
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126 | // map to range and calc burnout
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127 | const float scaleLum = lum * (1.0f + lum / whiteLum * whiteLum) / (1.0f + lum);
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128 |
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129 | OUT.col = color * scaleLum / pixLum;
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130 | OUT.col.w = color.w;
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131 |
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132 | return OUT;
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133 | }
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134 |
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135 |
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136 | pixel CalcAvgLogLum(frag IN, uniform sampler2D colors)
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137 | {
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138 | ////////////
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139 | //-- write out logaritmic luminance for tone mapping
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140 |
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141 | pixel OUT;
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142 |
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143 | const float4 color = tex2Dlod(colors, float4(IN.texCoord.xy, 0, 0));
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144 | OUT.col = color;
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145 |
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146 | // the old loglum is stored in the hightest mipmap-level
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147 | float oldLogLum = tex2Dlod(colors, float4(IN.texCoord.xy, 0, MAX_LOD_LEVEL)).w;
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148 |
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149 | // the intensity weights
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150 | const float3 w = float3(0.299f, 0.587f, 0.114f);
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151 |
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152 | float lum = dot(color.rgb, w);
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153 | float logLum = log(1e-5f + lum);
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154 |
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155 | float logLumOffset = MINLOGLUM * INV_LOGLUM_RANGE;
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156 | float logLumScaled = logLum * INV_LOGLUM_RANGE - logLumOffset;
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157 |
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158 | const float expFactor = 0.1f;
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159 | // exponential smoothing of tone mapping over time
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160 | if (oldLogLum > 1e-5f) // check if loglum from last frame too small (=> tm too bright)
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161 | OUT.col.w = lerp(oldLogLum, logLumScaled, expFactor);
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162 | else
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163 | OUT.col.w = logLumScaled;
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164 |
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165 | return OUT;
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166 | }
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