From df77089d90024f229e4dd27a25a9b97645b614d1 Mon Sep 17 00:00:00 2001
From: yum <yum.food.vr@gmail.com>
Date: Fri, 14 Mar 2025 18:36:01 -0700
Subject: Simplify spherical harmonics

Implement standard SH9 as a learning exercise. Drop poi's fancy SH9
code. Realize that we just want diffuse and lock everything else away
behind a ui-inaccessible #define.
---
 poi.cginc | 61 -------------------------------------------------------------
 1 file changed, 61 deletions(-)

(limited to 'poi.cginc')

diff --git a/poi.cginc b/poi.cginc
index df89bbf..cc12b1a 100644
--- a/poi.cginc
+++ b/poi.cginc
@@ -57,72 +57,11 @@ float3 HSVtoRGB(in float3 HSV)
   return ((RGB - 1) * HSV.y + 1) * HSV.z;
 }
 
-float shEvaluateDiffuseL1Geomerics_local(float L0, float3 L1, float3 n)
-{
-  // average energy
-  float R0 = max(0, L0);
-
-  // avg direction of incoming light
-  float3 R1 = 0.5f * L1;
-
-  // directional brightness
-  float lenR1 = length(R1);
-
-  // linear angle between normal and direction 0-1
-  //float q = 0.5f * (1.0f + dot(R1 / lenR1, n));
-  //float q = dot(R1 / lenR1, n) * 0.5 + 0.5;
-  float q = dot(normalize(R1), n) * 0.5 + 0.5;
-  q = saturate(q); // Thanks to ScruffyRuffles for the bug identity.
-
-  // power for q
-  // lerps from 1 (linear) to 3 (cubic) based on directionality
-  float p = 1.0f + 2.0f * lenR1 / R0;
-
-  // dynamic range constant
-  // should vary between 4 (highly directional) and 0 (ambient)
-  float a = (1.0f - lenR1 / R0) / (1.0f + lenR1 / R0);
-
-  return R0 * (a + (1.0f - a) * (p + 1.0f) * pow(q, p));
-}
-
-half3 BetterSH9(half4 normal)
-{
-  float3 indirect;
-  float3 L0 = float3(unity_SHAr.w, unity_SHAg.w, unity_SHAb.w) + float3(unity_SHBr.z, unity_SHBg.z, unity_SHBb.z) / 3.0;
-  indirect.r = shEvaluateDiffuseL1Geomerics_local(L0.r, unity_SHAr.xyz, normal.xyz);
-  indirect.g = shEvaluateDiffuseL1Geomerics_local(L0.g, unity_SHAg.xyz, normal.xyz);
-  indirect.b = shEvaluateDiffuseL1Geomerics_local(L0.b, unity_SHAb.xyz, normal.xyz);
-  indirect = max(0, indirect);
-  indirect += SHEvalLinearL2(normal);
-  return indirect;
-}
-
 float calculateluminance(float3 color)
 {
   return color.r * 0.299 + color.g * 0.587 + color.b * 0.114;
 }
 
-float3 getPoiLightingDirect(float3 normal) {
-  float3 magic = max(BetterSH9(normalize(unity_SHAr + unity_SHAg + unity_SHAb)), 0);
-  float3 normalLight = _LightColor0.rgb + BetterSH9(float4(0, 0, 0, 1));
-
-  float magiLumi = calculateluminance(magic);
-  float normaLumi = calculateluminance(normalLight);
-  float maginormalumi = magiLumi + normaLumi;
-
-  float magiratio = magiLumi / maginormalumi;
-  float normaRatio = normaLumi / maginormalumi;
-
-  float target = calculateluminance(magic * magiratio + normalLight * normaRatio);
-  float3 properLightColor = magic + normalLight;
-  float properLuminance = calculateluminance(magic + normalLight);
-  return properLightColor * max(0.0001, (target / properLuminance));
-}
-
-float3 getPoiLightingIndirect() {
-  return BetterSH9(float4(0, 0, 0, 1));
-}
-
 bool SceneHasReflections()
 {
   float width, height;
-- 
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