Refactor tonemapping curves into their own headers

Also add iq's "almost identity" curve.

1 files changed, 3 insertions, 41 deletions

diff --git a/fog.cginc b/fog.cginc
index 8fbe7de..3a0f5e9 100644
--- a/fog.cginc
+++ b/fog.cginc
@@ -9,6 +9,7 @@
 #include "oklab.cginc"
 #include "pbr.cginc"
 #include "poi.cginc"
+#include "tone.cginc"
 
 #ifndef __FOG_INC
 #define __FOG_INC
@@ -209,45 +210,6 @@ float fog00_map_dr(
 }
 #endif
 
-// https://knarkowicz.wordpress.com/2016/01/06/aces-filmic-tone-mapping-curve/
-// cc0
-float3 AcesFilmic(float3 x) {
-  float a = 2.51f;
-  float b = 0.03f;
-  float c = 2.43f;
-  float d = 0.59f;
-  float e = 0.14f;
-  return saturate((x*(a*x+b))/(x*(c*x+d)+e));
-}
-
-// Clamp x to [0, k].
-// Assumes that x is already on [0, 1].
-float3 SmoothClamp(float3 x, float k) {
-  // Derivation of `b` from `k`:
-  //  f(x, b) = b * x / (x + b)
-  //  We want f(1, b) = k.
-  //  In other words, we want the max value the function can take on [0, 1] to
-  //  be k.
-  //   k = f(1, b)
-  //     = b / (1 + b)
-  //   b = k * (1 + b)
-  //     = k + kb
-  //   1 = k/b + k
-  //   1 - k = k/b
-  //   1/(1-k) = b/k
-  //   b = k/(1-k)
-  float e = 1E-4;
-  k = min(1-e, k);
-  float b = k/(1-k);
-  return b * x / (x + b);
-}
-float SmoothClamp(float x, float k) {
-  float e = 1E-4;
-  k = min(1-e, k);
-  float b = k/(1-k);
-  return b * x / (x + b);
-}
-
 Fog00PBR getFog00(v2f i, ToonerData tdata) {
   float3 cam_pos = _WorldSpaceCameraPos;
   float3 obj_pos = i.worldPos;
@@ -415,11 +377,11 @@ Fog00PBR getFog00(v2f i, ToonerData tdata) {
   //pbr.albedo.rgb += ign(tdata.screen_uv_round) * .00390625;
 
   // Remap onto [0, 1]
-  pbr.albedo.rgb = AcesFilmic(pbr.albedo.rgb);
+  pbr.albedo.rgb = aces_filmic(pbr.albedo.rgb);
   // Clamp so max brightness is comfortable. Do it in perceptually uniform
   // space to avoid affecting saturation.
   pbr.albedo.rgb = LRGBtoOKLAB(pbr.albedo.rgb);
-  pbr.albedo.x = SmoothClamp(pbr.albedo.x, _Gimmick_Fog_00_Max_Brightness);
+  pbr.albedo.x = smooth_clamp(pbr.albedo.x, _Gimmick_Fog_00_Max_Brightness);
   pbr.albedo.rgb = OKLABtoLRGB(pbr.albedo.rgb);
 
   float4 clip_pos = mul(UNITY_MATRIX_VP, float4(ro, 1.0));