From 5629d437dae33c2cdb283a139f8632fb613c0a43 Mon Sep 17 00:00:00 2001
From: yum <yum.food.vr@gmail.com>
Date: Tue, 8 Apr 2025 19:05:47 -0700
Subject: Fix backface normals, fix depth writing precision issues

---
 2ner.cginc | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

(limited to '2ner.cginc')

diff --git a/2ner.cginc b/2ner.cginc
index d8bc010..065015f 100644
--- a/2ner.cginc
+++ b/2ner.cginc
@@ -156,7 +156,7 @@ v2f vert(appdata v) {
   return o;
 }
 
-float4 frag(v2f i
+float4 frag(v2f i, uint facing : SV_IsFrontFace
 #if defined(_HARNACK_TRACING) || defined(_SHATTER_WAVE) || defined(_VERTEX_DOMAIN_WARPING)
   , out float depth : SV_DepthLessEqual
 #endif
@@ -168,6 +168,8 @@ float4 frag(v2f i
   // Not necessarily normalized after interpolation
   i.normal = normalize(i.normal);
 
+  i.normal *= facing ? 1 : -1;
+
   i.normal = UnityObjectToWorldNormal(i.normal);
   i.tangent = UnityObjectToWorldNormal(i.tangent);
   i.binormal = UnityObjectToWorldNormal(i.binormal);
@@ -178,8 +180,23 @@ float4 frag(v2f i
 
 #if defined(_SHATTER_WAVE) || defined(_VERTEX_DOMAIN_WARPING)
   {
-    float4 clip_pos = mul(UNITY_MATRIX_VP, float4(i.worldPos, 1.0));
-    depth = clip_pos.z / clip_pos.w;
+    [branch]
+    if (
+        false
+#if defined(_SHATTER_WAVE)
+        || any(_Shatter_Wave_Amplitude > 1E-4)
+#endif
+#if defined(_VERTEX_DOMAIN_WARPING)
+        || _Vertex_Domain_Warping_Octaves > 0.1
+#endif
+    ) {
+      float4 clip_pos = UnityObjectToClipPos(i.objPos);
+      depth = clip_pos.z / clip_pos.w;
+    } else {
+      // Perspective division takes place before the fragment shader, so we
+      // don't have to divide again.
+      depth = i.pos.z;
+    }
   }
 #endif
 
-- 
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