initial commit-moved from vulkan_guide

shaders/tonemap.frag

@@ -0,0 +1,49 @@
+#version 450
+
+layout(location=0) in vec2 inUV;
+layout(location=0) out vec4 outColor;
+
+layout(set=0, binding=0) uniform sampler2D uHdr;
+
+layout(push_constant) uniform Push
+{
+    float exposure;
+    int   mode;
+} pc;
+
+vec3 reinhard(vec3 x)
+{
+    return x / (1.0 + x);
+}
+
+// Narkowicz ACES approximation
+vec3 aces_tonemap(vec3 x)
+{
+    // https://64.github.io/tonemapping/
+    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 clamp((x*(a*x+b))/(x*(c*x+d)+e), 0.0, 1.0);
+}
+
+void main()
+{
+    vec3 hdr = texture(uHdr, inUV).rgb;
+
+    // Simple exposure
+    float exposure = max(pc.exposure, 0.0001);
+    vec3 mapped = hdr * exposure;
+
+    if (pc.mode == 1)
+        mapped = aces_tonemap(mapped);
+    else
+        mapped = reinhard(mapped);
+
+    const float gamma = 2.2;
+    mapped = pow(mapped, vec3(1.0 / gamma));
+
+    outColor = vec4(mapped, 1.0);
+}
+