optimised water caustics shader and pass

Packages/com.verasl.water-system/Scripts/Rendering/WaterCausticsFeature.cs

 using UnityEngine;
 using UnityEngine.Rendering;
+using UnityEngine.Rendering.Universal;
-    public class WaterCausticsFeature : UnityEngine.Rendering.Universal.ScriptableRendererFeature
+    public class WaterCausticsFeature : ScriptableRendererFeature
     {
         private WaterCausticsPass m_WaterCausticsPass;
         public WaterCausticSettings settings = new WaterCausticSettings();
         {
             m_WaterCausticsPass = new WaterCausticsPass();
             m_WaterCausticsPass.m_WaterCausticMaterial = settings.material;
+            m_WaterCausticsPass.renderPassEvent = RenderPassEvent.AfterRenderingSkybox + 1;
         }
 
         public override void AddRenderPasses(UnityEngine.Rendering.Universal.ScriptableRenderer renderer, ref UnityEngine.Rendering.Universal.RenderingData renderingData)
             }
 
             CommandBuffer cmd = CommandBufferPool.Get(k_RenderWaterCausticsTag);
-            cmd.SetViewProjectionMatrices(Matrix4x4.identity, Matrix4x4.identity);
-            cmd.DrawMesh(UnityEngine.Rendering.Universal.RenderingUtils.fullscreenMesh, Matrix4x4.identity, m_WaterCausticMaterial, 0, 0);
-            cmd.SetViewProjectionMatrices(renderingData.cameraData.camera.worldToCameraMatrix, renderingData.cameraData.camera.projectionMatrix);
-            
+            cmd.DrawMesh(RenderingUtils.fullscreenMesh, Matrix4x4.identity, m_WaterCausticMaterial, 0, 0);
             context.ExecuteCommandBuffer(cmd);
             CommandBufferPool.Release(cmd);
         }

Packages/com.verasl.water-system/Shaders/Caustics.shader

                 return worldPos;
             }
             
+            // Can be done per-vertex
-            {
-            
+            {            
                 //anim
                 float2 uv = rawUV * _Size + float2(_Time.y, _Time.x) * 0.1;
                 return uv + offset * 0.25;
             {
-                Varyings output = (Varyings)0;
-
-                UNITY_SETUP_INSTANCE_ID(input);
-                UNITY_TRANSFER_INSTANCE_ID(input, output);
-                UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);
-            
-                VertexPositionInputs vertexInput = GetVertexPositionInputs(input.positionOS.xyz);
-                output.positionOS = vertexInput.positionCS;
-
-                output.uv = input.uv;
+                Varyings output;
+                output.positionOS = float4(input.positionOS.xyz, 1.0);
+                output.uv = float2(input.uv.x, 1.0 - input.uv.y);
                 return output;
             }