added PBRNetral Tonemapping

shader/ToneMap/PBRNetral.glsl

@@ -0,0 +1,19 @@
+vec3 ToneMapping(vec3 color)
+{
+    const float startCompression = 0.8 - 0.04;
+    const float desaturation = 0.15;
+
+    float x = min(color.r, min(color.g, color.b));
+    float offset = x < 0.08 ? x - 6.25 * x * x : 0.04;
+    color -= offset;
+
+    float peak = max(color.r, max(color.g, color.b));
+    if (peak < startCompression) return color;
+
+    const float d = 1. - startCompression;
+    float newPeak = 1. - d * d / (peak + d - startCompression);
+    color *= newPeak / peak;
+
+    float g = 1. - 1. / (desaturation * (peak - newPeak) + 1.);
+    return mix(color, newPeak * vec3(1, 1, 1), g);
+}