Update documentation and TODO list

Assets/vfx-graph-gs/Scripts/SplatImporter.cs

@@ -70,9 +70,6 @@ namespace SplatVfx.Editor
             opacity, scale_0, scale_1, scale_2, rot_0, rot_1, rot_2, rot_3
         }
 
-        /***********************************************************************
-        - TODO: Add support for more data types
-        ***********************************************************************/
         private static readonly Dictionary<TypeEnum, int> TypeToByteLengths = 
             new()
         {
@@ -92,10 +89,6 @@ namespace SplatVfx.Editor
             { "int8", TypeEnum.Int8 }
         };
 
-        /***********************************************************************
-        - TODO: Add endianness
-        - TODO: Add float size
-        ***********************************************************************/
         private struct HeaderData
         {
             public uint NumElements;
@@ -234,14 +227,14 @@ namespace SplatVfx.Editor
                 );
             int chunkSize = elementsPerChunk * headerData.BytesPerElement;
 
-            Debug.Log($"Elements per chunk: {elementsPerChunk}");
+            // Debug.Log($"Elements per chunk: {elementsPerChunk}");
-            Debug.Log($"Chunk size: {chunkSize}");
+            // Debug.Log($"Chunk size: {chunkSize}");
 
             using var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
             fileStream.Seek(endHeaderPosition, SeekOrigin.Begin);
 
             int totalBytes = (int)fileStream.Length - endHeaderPosition;
-            Debug.Log($"Total bytes: {totalBytes}");
+            // Debug.Log($"Total bytes: {totalBytes}");
 
             var splatDataNative = new SplatDataNative(elementsPerChunk);
             var chunkBuffer = new NativeArray<byte>(chunkSize, Allocator.Persistent);
@@ -280,10 +273,10 @@ namespace SplatVfx.Editor
                 }
 
                 totalElemsRead += numElemsRead;
-                Debug.Log($"Current Elements Read: {totalElemsRead}");
+                // Debug.Log($"Current Elements Read: {totalElemsRead}");
             }
 
-            Debug.Log($"First position Vector3: {splatData.PositionArray[0]}");
+            // Debug.Log($"First position Vector3: {splatData.PositionArray[0]}");
 
             headerData.Dispose();
             splatDataNative.Dispose();
@@ -354,55 +347,5 @@ namespace SplatVfx.Editor
                 }
             }
         }
-
-        // struct ReadData
-        // {
-        //     public float px, py, pz;
-        //     public float sx, sy, sz;
-        //     public byte r, g, b, a;
-        //     public byte rw, rx, ry, rz;
-        // }
-
-        // (Vector3[] position, Vector3[] axis, Color[] color)
-        //     LoadDataArrays(string path)
-        // {
-        //     var bytes = (Span<byte>)File.ReadAllBytes(path);
-        //     var count = bytes.Length / 32;
-
-        //     var source = MemoryMarshal.Cast<byte, ReadData>(bytes);
-
-        //     var position = new Vector3[count];
-        //     var axis = new Vector3[count * 3];
-        //     var color = new Color[count];
-
-        //     for (var i = 0; i < count; i++)
-        //         ParseReadData(source[i],
-        //                       out position[i],
-        //                       out axis[i * 3],
-        //                       out axis[i * 3 + 1],
-        //                       out axis[i * 3 + 2],
-        //                       out color[i]);
-
-        //     return (position, axis, color);
-        // }
-
-        // [BurstCompile]
-        // void ParseReadData(in ReadData src,
-        //                    out Vector3 position,
-        //                    out Vector3 axis1,
-        //                    out Vector3 axis2,
-        //                    out Vector3 axis3,
-        //                    out Color color)
-        // {
-        //     var rv = (math.float4(src.rx, src.ry, src.rz, src.rw) - 128) / 128;
-        //     var q = math.quaternion(-rv.x, -rv.y, rv.z, rv.w);
-        //     position = math.float3(src.px, src.py, -src.pz);
-        //     axis1 = math.mul(q, math.float3(src.sx, 0, 0));
-        //     axis2 = math.mul(q, math.float3(0, src.sy, 0));
-        //     axis3 = math.mul(q, math.float3(0, 0, src.sz));
-        //     color = (Vector4)math.float4(src.r, src.g, src.b, src.a) / 255;
-        // }
-
     }
-
 }

Assets/vfx-graph-gs/VFXGraphHLSL/CalculateSH.hlsl

@@ -1,3 +1,7 @@
+/// Index: The splat's index
+/// Degrees: The degrees of spherical harmonics to calculate
+/// DirClr: A 4x4 matrix with the first row containing a vector from the splat position to the camera, and the second row containing its base color
+/// SHBuffer: The spherical harmonics buffer from a SplatData object
 float3 CalculateSHColor(uint Index, uint Degrees, float4x4 DirClr, StructuredBuffer<float> SHBuffer) {
 	const float SH_C0 = 0.28209479177387814f;
 	const float SH_C1 = 0.4886025119029199f;
@@ -31,10 +35,9 @@ float3 CalculateSHColor(uint Index, uint Degrees, float4x4 DirClr, StructuredBuf
 	// }
 	for (int i = 1; i < 16; i++)
 	{
-		// Access R, G, B values from their separate blocks
+		sh[i].x = SHBuffer[Index * 45 + (i - 1)];
-		sh[i].x = SHBuffer[Index * 45 + (i - 1)];           // R values (indices 0-44)
+		sh[i].y = SHBuffer[Index * 45 + 15 + (i - 1)]; 
-		sh[i].y = SHBuffer[Index * 45 + 15 + (i - 1)];      // G values (indices 45-89)  
+		sh[i].z = SHBuffer[Index * 45 + 30 + (i - 1)];
-		sh[i].z = SHBuffer[Index * 45 + 30 + (i - 1)];      // B values (indices 90-134)
 	}
 
     if (Degrees > 0)
@@ -73,6 +76,8 @@ float3 CalculateSHColor(uint Index, uint Degrees, float4x4 DirClr, StructuredBuf
 }
 
 /*
+> Reference taken from the original Gaussian splatting paper code
+
 	// The implementation is loosely based on code for 
 	// "Differentiable Point-Based Radiance Fields for 
 	// Efficient View Synthesis" by Zhang et al. (2022)

Assets/vfx-graph-gs/VFXGraphHLSL/GetMajorAxes.hlsl

@@ -1,8 +1,10 @@
+/// Hidden
 float CrossProduct(float2 A, float2 B)
 {
     return A.x * B.y - A.y * B.x;
 }
 
+/// Hidden
 float SweepArea(float2 A, float2 B)
 {
     return abs(CrossProduct(A, B));

TODO.md

@@ -0,0 +1,12 @@
+# TODO
+
+- [ ] Rewrite SH Array to use interleaved RGB rather than contiguous data per 
+      channel
+- [ ] Switch to using ByteAddressBuffers instead of loops in CalculateSH.hlsl
+- [ ] Optimize CalculateAxes.hlsl
+- [ ] Allow splat data buffers to be accessible by other VFX Graphs
+- [ ] Add exception reporting and handling for incomplete splat data
+- [ ] Add support for other PLY data types and endianness
+- [ ] Add support for ASCII PLY data
+- [ ] Fix the header parsing logic in SplatImporter.cs
+- [ ] Add more thorough checks in SplatDataBinder.cs