feature: more proper color correction

src/shaders/post.frag

@@ -7,6 +7,7 @@ const float BARREL_OFFSET = 0.05;
 const float BARREL_AMP = 0.05;
 const float HUGE = 9E16;
 const float PI = 3.14159265;
+const vec3 LUMA = vec3( 0.2126, 0.7152, 0.0722 );
 
 #define saturate(i) clamp(i,0.,1.)
 #define linearstep(a,b,x) saturate(((x)-(a))/((b)-(a)))
@@ -42,6 +43,46 @@ vec3 barrel( float amp, vec2 uv ) {
   return texture( sampler0, vec2( p.x, p.y ) ).xyz;
 }
 
+vec3 aces( vec3 rgb ) {
+  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 saturate( ( rgb * ( a * rgb + b ) ) / ( rgb * ( c * rgb + d ) + e ) );
+}
+
+vec3 liftGammaGain( vec3 rgb ) {
+  const vec4 lift = vec4( -0.07, 0.02, 0.03, 0.01 );
+  const vec4 gamma = vec4( 0.0, -0.02, 0.07, 0.02 );
+  const vec4 gain = vec4( 1.20, 0.95, 0.92, 1.0 );
+
+  // const vec4 lift = vec4( 0.02, -0.01, 0.09, 0.0 );
+  // const vec4 gamma = vec4( -0.05, 0.02, -0.08, 0.0 );
+  // const vec4 gain = vec4( 1.06, 0.96, 1.10, 1.0 );
+
+  vec4 liftt = 1.0 - pow( 1.0 - lift, log2( gain + 1.0 ) );
+
+  vec4 gammat = gamma.rgba - vec4( 0.0, 0.0, 0.0, dot( LUMA, gamma.rgb ) );
+  vec4 gammatTemp = 1.0 + 4.0 * abs( gammat );
+  gammat = mix( gammatTemp, 1.0 / gammatTemp, step( 0.0, gammat ) );
+
+  vec3 col = rgb;
+  float luma = dot( LUMA, col );
+
+  col = pow( col, gammat.rgb );
+  col *= pow( gain.rgb, gammat.rgb );
+  col = max( mix( 2.0 * liftt.rgb, vec3( 1.0 ), col ), 0.0 );
+
+  luma = pow( luma, gammat.a );
+  luma *= pow( gain.a, gammat.a );
+  luma = max( mix( 2.0 * liftt.a, 1.0, luma ), 0.0 );
+
+  col += luma - dot( LUMA, col );
+
+  return saturate( col );
+}
+
 void main() {
   vec2 uv = vUv;
   vec2 p = ( uv * resolution * 2.0 - resolution ) / resolution.y;
@@ -66,10 +107,9 @@ void main() {
   prng( seed );
   prng( seed );
   col += ( pow( prng( seed ), 2.2 ) - 0.25 ) * 0.002;
+  col = aces( saturate( col ) );
   col = pow( saturate( col ), vec3( 0.4545 ) );
-  col.x = linearstep( 0.0, 1.2, col.x + 0.2 * uv.y );
-  col.z = linearstep( -0.1, 1.0, col.z );
-  col = colorMap( col );
+  col = liftGammaGain( col );
 
   fragColor = vec4( col, 1.0 );
 }