remove per grass seed. Now append ID instead of posWS float3

TwoDTools · Jul 28, 2020 · a7f7074 · a7f7074
1 parent e7a1e1d
commit a7f7074
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Showing 2 changed files with 20 additions and 19 deletions.
diff --git a/...obileGrassInstancedIndirectDemo/InstancedIndirectGrass/Core/InstancedIndirectGrass.shader b/...obileGrassInstancedIndirectDemo/InstancedIndirectGrass/Core/InstancedIndirectGrass.shader
@@ -108,7 +108,8 @@
 
                 half _RandomNormal;
 
-                StructuredBuffer<float4> _TransformBuffer;
+                StructuredBuffer<float3> _AllInstancesTransformBuffer;
+                StructuredBuffer<uint> _VisibleInstanceOnlyTransformIDBuffer;
             CBUFFER_END
 
             sampler2D _GrassBendingRT;
@@ -140,13 +141,9 @@
             {
                 Varyings OUT;
 
-                //bufferData.xyz    is posWS inside ComputeBuffer
-                //bufferData.w      is scaleWS inside ComputeBuffer
-                float4 bufferData = _TransformBuffer[instanceID];
-                float3 perGrassPivotPosWS = bufferData.xyz;//we transform to posWS in C# now
-                float seed01 = bufferData.w;
-                float seedNegative1ToPositive1 = seed01 * 2 - 1;
-                float perGrassHeight = lerp(2,5,seed01) * _GrassHeight;
+                float3 perGrassPivotPosWS = _AllInstancesTransformBuffer[_VisibleInstanceOnlyTransformIDBuffer[instanceID]];//we pre-transform to posWS in C# now
+
+                float perGrassHeight = lerp(2,5,(sin(perGrassPivotPosWS.x*23.4643 + perGrassPivotPosWS.z) * 0.45 + 0.55)) * _GrassHeight;
 
                 //get "is grass stepped" data(bending) from RT
                 float2 grassBendingUV = ((perGrassPivotPosWS.xz - _PivotPosWS.xz) / _BoundSize) * 0.5 + 0.5;//claculate where is this grass inside bound (can optimize to 2 MAD)
@@ -159,7 +156,7 @@
                 float3 cameraTransformForwardWS = -UNITY_MATRIX_V[2].xyz;//UNITY_MATRIX_V[2].xyz == -1 * world space camera Forward unit vector
 
                 //Expand Billboard (billboard Left+right)
-                float3 positionOS = IN.positionOS.x * cameraTransformRightWS * _GrassWidth;
+                float3 positionOS = IN.positionOS.x * cameraTransformRightWS * _GrassWidth * (sin(perGrassPivotPosWS.x*95.4643 + perGrassPivotPosWS.z) * 0.45 + 0.55);//random width from posXZ, min 0.1
 
                 //Expand Billboard (billboard Up)
                 positionOS += IN.positionOS.y * cameraTransformUpWS;         
@@ -206,7 +203,7 @@
 #else
                 mainLight = GetMainLight();
 #endif
-                half3 randomAddToN = (_RandomNormal* seedNegative1ToPositive1 + wind * -0.25) * cameraTransformRightWS;//random normal per grass 
+                half3 randomAddToN = (_RandomNormal* sin(perGrassPivotPosWS.x * 82.32523 + perGrassPivotPosWS.z) + wind * -0.25) * cameraTransformRightWS;//random normal per grass 
                 //default grass's normal is pointing 100% upward in world space, it is an important but simple grass normal trick
                 //-apply random to normal else lighting is too uniform
                 //-apply cameraTransformForwardWS to normal because grass is billboard

diff --git a/...eGrassInstancedIndirectDemo/InstancedIndirectGrass/Core/InstancedIndirectGrassRenderer.cs b/...eGrassInstancedIndirectDemo/InstancedIndirectGrass/Core/InstancedIndirectGrassRenderer.cs
@@ -41,7 +41,7 @@ void LateUpdate()
         cullingComputeShader.SetMatrix("_VPMatrix", vp);
         cullingComputeShader.SetFloat("_MaxDrawDistance", drawDistance);
         cullingComputeShader.SetBuffer(0, "_AllInstancesTransformBuffer", allInstanceTransformBuffer);
-        cullingComputeShader.SetBuffer(0, "_VisibleInstanceOnlyTransformBuffer", visibleInstanceOnlyTransformBuffer);
+        cullingComputeShader.SetBuffer(0, "_VisibleInstanceOnlyTransformIDBuffer", visibleInstanceOnlyTransformBuffer);
         cullingComputeShader.Dispatch(0, Mathf.CeilToInt(instanceCount/1024), 1, 1);
         ComputeBuffer.CopyCount(visibleInstanceOnlyTransformBuffer, argsBuffer, 4);
 
@@ -122,37 +122,41 @@ void UpdateAllInstanceTransformBufferIfNeeded()
         ///////////////////////////
         if (allInstanceTransformBuffer != null)
             allInstanceTransformBuffer.Release();
-        allInstanceTransformBuffer = new ComputeBuffer(instanceCount, sizeof(float)*4); //float4 per grass
+        allInstanceTransformBuffer = new ComputeBuffer(instanceCount, sizeof(float)*3); //float3 posWS only, per grass
 
         if (visibleInstanceOnlyTransformBuffer != null)
             visibleInstanceOnlyTransformBuffer.Release();
-        visibleInstanceOnlyTransformBuffer = new ComputeBuffer(instanceCount, sizeof(float) * 4, ComputeBufferType.Append);
+        visibleInstanceOnlyTransformBuffer = new ComputeBuffer(instanceCount, sizeof(uint), ComputeBufferType.Append); //uint only, per visible grass
 
         //keep grass visual the same
         UnityEngine.Random.InitState(123);
 
         //spawn grass inside gizmo cube 
-        Vector4[] positions = new Vector4[instanceCount];
+        Vector3[] positions = new Vector3[instanceCount];
         for (int i = 0; i < instanceCount; i++)
         {
             Vector3 pos = Vector3.zero;
 
-            //local pos (can define any local pos here, random is just an example)
+            //can define any posWS in this section, random is just an example
+            //TODO: allow API call to set posWS
+            //===================================================
+            //local pos
             pos.x = UnityEngine.Random.Range(-1f, 1f);
+            pos.y = 0;
             pos.z = UnityEngine.Random.Range(-1f, 1f);
 
             //transform to posWS in C#
             pos.x *= transform.lossyScale.x;
             pos.z *= transform.lossyScale.z;
             pos += transform.position;
+            //===================================================
 
-            float seed = UnityEngine.Random.Range(0f, 1f);
-
-            positions[i] = new Vector4(pos.x,pos.y,pos.z, seed);
+            positions[i] = new Vector3(pos.x,pos.y,pos.z);
         }
 
         allInstanceTransformBuffer.SetData(positions);
-        instanceMaterial.SetBuffer("_TransformBuffer", visibleInstanceOnlyTransformBuffer);
+        instanceMaterial.SetBuffer("_AllInstancesTransformBuffer", allInstanceTransformBuffer);
+        instanceMaterial.SetBuffer("_VisibleInstanceOnlyTransformIDBuffer", visibleInstanceOnlyTransformBuffer);
 
         ///////////////////////////
         // Indirect args buffer