feat: #86 add some tone mapping function

Assets/BuiltIn/Shader/PostProcessing/GLSL/LibToneMapping.glsl

@@ -1,15 +1,77 @@
 #define TONE_MAPPING
+//#define ACES
+//#define FILMIC
+//#define UNCHARDTED2
+//#define UNREAL
 
 const float gamma = 2.2;
 const float invGamma = 1.0/2.2;
 
+#if defined(ACES)
+// Narkowicz 2015, "ACES Filmic Tone Mapping Curve"
+vec3 aces(vec3 x) {
+  const float a = 2.51;
+  const float b = 0.03;
+  const float c = 2.43;
+  const float d = 0.59;
+  const float e = 0.14;
+  return (x * (a * x + b)) / (x * (c * x + d) + e);
+}
+#endif
+
+#if defined(FILMIC)
+// Filmic Tonemapping Operators http://filmicworlds.com/blog/filmic-tonemapping-operators/
+vec3 filmic(vec3 x) {
+	vec3 X = max(vec3(0.0, 0.0, 0.0), x - 0.004);
+	vec3 result = (X * (6.2 * X + 0.5)) / (X * (6.2 * X + 1.7) + 0.06);
+	return result;
+}
+#endif
+
+#if defined(UNCHARDTED2)
+vec3 uncharted2Tonemap(vec3 x) {
+  float A = 0.15;
+  float B = 0.50;
+  float C = 0.10;
+  float D = 0.20;
+  float E = 0.02;
+  float F = 0.30;
+  float W = 11.2;
+  return ((x * (A * x + C * B) + D * E) / (x * (A * x + B) + D * F)) - E / F;
+}
+
+vec3 uncharted2(vec3 color) {
+  const float W = 11.2;
+  float exposureBias = 2.0;
+  vec3 curr = uncharted2Tonemap(exposureBias * color);
+  vec3 whiteScale = 1.0 / uncharted2Tonemap(vec3(W));
+  return curr * whiteScale;
+}
+#endif
+
+#if defined(UNREAL)
+vec3 unreal(vec3 x) {
+  return x / (x + 0.155) * 1.019;
+}
+#endif
+
 vec3 sRGB(vec3 color)
 {
 	return pow(color, vec3(gamma));
 }
 
 vec3 linearRGB(vec3 color)
 {
+#if defined(ACES)
+	return pow(aces(color), vec3(invGamma));
+#elif defined(FILMIC)
+	return filmic(color);
+#elif defined(UNCHARDTED2)
+	return pow(uncharted2(color), vec3(invGamma));
+#elif defined(UNREAL)
+	return unreal(color);
+#else
 	return pow(color, vec3(invGamma));
+#endif
 }
 

Assets/BuiltIn/Shader/PostProcessing/HLSL/LibToneMapping.hlsl

@@ -1,15 +1,77 @@
 #define TONE_MAPPING
+//#define ACES
+//#define FILMIC
+//#define UNCHARDTED2
+//#define UNREAL
 
 static const float gamma = 2.2;
 static const float invGamma = 1.0/2.2;
 
+#if defined(ACES)
+// Narkowicz 2015, "ACES Filmic Tone Mapping Curve"
+float3 aces(float3 x) {
+  const float a = 2.51;
+  const float b = 0.03;
+  const float c = 2.43;
+  const float d = 0.59;
+  const float e = 0.14;
+  return (x * (a * x + b)) / (x * (c * x + d) + e);
+}
+#endif
+
+#if defined(FILMIC)
+// Filmic Tonemapping Operators http://filmicworlds.com/blog/filmic-tonemapping-operators/
+float3 filmic(float3 x) {
+	float3 X = max(float3(0.0, 0.0, 0.0), x - 0.004);
+	float3 result = (X * (6.2 * X + 0.5)) / (X * (6.2 * X + 1.7) + 0.06);
+	return result;
+}
+#endif
+
+#if defined(UNCHARDTED2)
+float3 uncharted2Tonemap(float3 x) {
+  float A = 0.15;
+  float B = 0.50;
+  float C = 0.10;
+  float D = 0.20;
+  float E = 0.02;
+  float F = 0.30;
+  float W = 11.2;
+  return ((x * (A * x + C * B) + D * E) / (x * (A * x + B) + D * F)) - E / F;
+}
+
+float3 uncharted2(float3 color) {
+  const float W = 11.2;
+  float exposureBias = 2.0;
+  float3 curr = uncharted2Tonemap(exposureBias * color);
+  float3 whiteScale = 1.0 / uncharted2Tonemap(float3(W, W, W));
+  return curr * whiteScale;
+}
+#endif
+
+#if defined(UNREAL)
+float3 unreal(float3 x) {
+  return x / (x + 0.155) * 1.019;
+}
+#endif
+
 float3 sRGB(float3 color)
 {
 	return pow(color, gamma);
 }
 
 float3 linearRGB(float3 color)
 {
+#if defined(ACES)
+	return pow(aces(color), invGamma);
+#elif defined(FILMIC)	
+	return filmic(color);
+#elif defined(UNCHARDTED2)
+	return pow(uncharted2(color), invGamma);
+#elif defined(UNREAL)
+	return unreal(color);
+#else	
 	return pow(color, invGamma);
+#endif
 }