From 6579d30f558908c23889f9e691a5932a49ecdedd Mon Sep 17 00:00:00 2001
From: yum <yum.food.vr@gmail.com>
Date: Sat, 29 Mar 2025 20:23:19 -0700
Subject: Optimize tessellation code - vectorizing and frustrum culling

---
 shatter_wave.cginc | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

(limited to 'shatter_wave.cginc')

diff --git a/shatter_wave.cginc b/shatter_wave.cginc
index 8636df6..f86a6ac 100644
--- a/shatter_wave.cginc
+++ b/shatter_wave.cginc
@@ -15,11 +15,22 @@ void shatterWaveVert(inout float3 objPos, float3 objNormal, float3 objTangent) {
   float3 wave_axis2 = normalize(_Shatter_Wave_Direction2);
   float3 wave_axis3 = normalize(_Shatter_Wave_Direction3);
   float4x3 wave_axes = float4x3(wave_axis0, wave_axis1, wave_axis2, wave_axis3);
-  float4x3 objPos_proj;
-  objPos_proj[0] = dot(objPos, wave_axis0) * normalize(wave_axis0);
-  objPos_proj[1] = dot(objPos, wave_axis1) * normalize(wave_axis1);
-  objPos_proj[2] = dot(objPos, wave_axis2) * normalize(wave_axis2);
-  objPos_proj[3] = dot(objPos, wave_axis3) * normalize(wave_axis3);
+  
+  float4 projDots = mul(wave_axes, objPos);
+  // Equivalent code:
+  // float4 projDots = float4(
+  //   dot(objPos, wave_axis0),
+  //   dot(objPos, wave_axis1),
+  //   dot(objPos, wave_axis2),
+  //   dot(objPos, wave_axis3)
+  // );
+  
+  float4x3 objPos_proj = float4x3(
+    projDots.x * wave_axis0,
+    projDots.y * wave_axis1,
+    projDots.z * wave_axis2,
+    projDots.w * wave_axis3
+  );
 
 #if defined(_SHATTER_WAVE_AUDIOLINK)
   float4 wave_t;
@@ -64,25 +75,23 @@ void shatterWaveVert(inout float3 objPos, float3 objNormal, float3 objTangent) {
 
   float4 wave_center = wave_t;
 
-  // TODO calculate signed distance from wave center
-  float4 distance_signed;
-  for (uint i = 0; i < 4; i++) {
-    float3 dist_to_center = objPos_proj[i] - wave_center[i] * wave_axes[i];
-    distance_signed[i] = dot(dist_to_center, wave_axes[i]);
-  }
+  float4 distance_signed = float4(
+    dot(objPos_proj[0] - wave_center.x * wave_axes[0], wave_axes[0]),
+    dot(objPos_proj[1] - wave_center.y * wave_axes[1], wave_axes[1]),
+    dot(objPos_proj[2] - wave_center.z * wave_axes[2], wave_axes[2]),
+    dot(objPos_proj[3] - wave_center.w * wave_axes[3], wave_axes[3])
+  );
 
 #if defined(_SHATTER_WAVE_ROTATION)
   float4 thetas = clamp(distance_signed * _Shatter_Wave_Rotation_Strength, -1, 1) * TAU;
+  [unroll]
   for (uint i = 0; i < 4; i++) {
     objPos = rotate_vector(objPos, get_quaternion(wave_axes[i], thetas[i]));
   }
 #endif
 
   float4 offset = exp(-abs(distance_signed) * _Shatter_Wave_Power) * _Shatter_Wave_Amplitude;
-  objPos += objNormal * offset[0];
-  objPos += objNormal * offset[1];
-  objPos += objNormal * offset[2];
-  objPos += objNormal * offset[3];
+  objPos += objNormal * (offset.x + offset.y + offset.z + offset.w);
 }
 
 void shatterWaveFrag(inout float3 normal, float3 objPos) {
-- 
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