add tonemapping shaders

shader/ToneMap/Uncharted2.glsl

@@ -0,0 +1,20 @@
+// Uncharted 2 tone map
+// see: http://filmicworlds.com/blog/filmic-tonemapping-operators/
+vec3 toneMapUncharted2Impl(vec3 color)
+{
+    const float A = 0.15;
+    const float B = 0.50;
+    const float C = 0.10;
+    const float D = 0.20;
+    const float E = 0.02;
+    const float F = 0.30;
+    return ((color*(A*color+C*B)+D*E)/(color*(A*color+B)+D*F))-E/F;
+}
+
+vec3 ToneMapping(vec3 color)
+{
+    const float W = 11.2;
+    color = toneMapUncharted2Impl(color * 2.0);
+    vec3 whiteScale = 1.0 / toneMapUncharted2Impl(vec3(W));
+    return linearTosRGB(color * whiteScale);
+}