#14: Use RHalf/RFloat (not RGBA) texture format for data texture. Use half precision floating point format for TF textures.

Assets/Scripts/TransferFunction/TransferFunction.cs

@@ -18,7 +18,8 @@ namespace UnityVolumeRendering
 
         public TransferFunction()
         {
-            texture = new Texture2D(TEXTURE_WIDTH, TEXTURE_HEIGHT, TextureFormat.RGBAFloat, false);
+            TextureFormat texformat = SystemInfo.SupportsTextureFormat(TextureFormat.RGBAHalf) ? TextureFormat.RGBAHalf : TextureFormat.RGBAFloat;
+            texture = new Texture2D(TEXTURE_WIDTH, TEXTURE_HEIGHT, texformat, false);
             tfCols = new Color[TEXTURE_WIDTH * TEXTURE_HEIGHT];
         }
 

Assets/Scripts/TransferFunction/TransferFunction2D.cs

@@ -24,7 +24,8 @@ namespace UnityVolumeRendering
 
         public TransferFunction2D()
         {
-            texture = new Texture2D(TEXTURE_WIDTH, TEXTURE_HEIGHT, TextureFormat.RGBAFloat, false);
+            TextureFormat texformat = SystemInfo.SupportsTextureFormat(TextureFormat.RGBAHalf) ? TextureFormat.RGBAHalf : TextureFormat.RGBAFloat;
+            texture = new Texture2D(TEXTURE_WIDTH, TEXTURE_HEIGHT, texformat, false);
         }
 
         public void AddBox(float x, float y, float width, float height, Color colour, float alpha)

Assets/Scripts/TransferFunction/TransferFunctionDatabase.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 9805df7fa7b5e1b4cbc7c9c9fb18d2d5
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/VolumeData/VolumeDataset.cs

@@ -10,16 +10,25 @@ namespace UnityVolumeRendering
 
         private int minDataValue = int.MaxValue;
         private int maxDataValue = int.MinValue;
-        private Texture3D texture = null;
+        private Texture3D dataTexture = null;
+        private Texture3D gradientTexture = null;
 
-        public Texture3D GetTexture()
+        public Texture3D GetDataTexture()
         {
-            if (texture == null)
+            if (dataTexture == null)
             {
-                texture = new Texture3D(dimX, dimY, dimZ, TextureFormat.RGBAFloat, false);
-                texture.wrapMode = TextureWrapMode.Clamp;
+                dataTexture = CreateTextureInternal();
             }
-            return texture;
+            return dataTexture;
+        }
+
+        public Texture3D GetGradientTexture()
+        {
+            if (gradientTexture == null)
+            {
+                gradientTexture = CreateGradientTextureInternal();
+            }
+            return gradientTexture;
         }
 
         public int GetMinDataValue()
@@ -48,5 +57,69 @@ namespace UnityVolumeRendering
                 maxDataValue = Math.Max(maxDataValue, val);
             }
         }
+
+        private Texture3D CreateTextureInternal()
+        {
+            TextureFormat texformat = SystemInfo.SupportsTextureFormat(TextureFormat.RHalf) ? TextureFormat.RHalf : TextureFormat.RFloat;
+            Texture3D texture = new Texture3D(dimX, dimY, dimZ, texformat, false);
+            texture.wrapMode = TextureWrapMode.Clamp;
+
+            int minValue = GetMinDataValue();
+            int maxValue = GetMaxDataValue();
+            int maxRange = maxValue - minValue;
+
+            Color[] cols = new Color[data.Length];
+            for (int x = 0; x < dimX; x++)
+            {
+                for (int y = 0; y < dimY; y++)
+                {
+                    for (int z = 0; z < dimZ; z++)
+                    {
+                        int iData = x + y * dimX + z * (dimX * dimY);
+                        cols[iData] = new Color((float)(data[iData] - minValue) / maxRange, 0.0f, 0.0f, 0.0f);
+                    }
+                }
+            }
+            texture.SetPixels(cols);
+            texture.Apply();
+            return texture;
+        }
+
+        private Texture3D CreateGradientTextureInternal()
+        {
+            TextureFormat texformat = SystemInfo.SupportsTextureFormat(TextureFormat.RGBAHalf) ? TextureFormat.RGBAHalf : TextureFormat.RGBAFloat;
+            Texture3D texture = new Texture3D(dimX, dimY, dimZ, texformat, false);
+            texture.wrapMode = TextureWrapMode.Clamp;
+
+            int minValue = GetMinDataValue();
+            int maxValue = GetMaxDataValue();
+            int maxRange = maxValue - minValue;
+
+            Color[] cols = new Color[data.Length];
+            for (int x = 0; x < dimX; x++)
+            {
+                for (int y = 0; y < dimY; y++)
+                {
+                    for (int z = 0; z < dimZ; z++)
+                    {
+                        int iData = x + y * dimX + z * (dimX * dimY);
+
+                        int x1 = data[Math.Min(x + 1, dimX - 1) + y * dimX + z * (dimX * dimY)] - minValue;
+                        int x2 = data[Math.Max(x - 1, 0) + y * dimX + z * (dimX * dimY)] - minValue;
+                        int y1 = data[x + Math.Min(y + 1, dimY - 1) * dimX + z * (dimX * dimY)] - minValue;
+                        int y2 = data[x + Math.Max(y - 1, 0) * dimX + z * (dimX * dimY)] - minValue;
+                        int z1 = data[x + y * dimX + Math.Min(z + 1, dimZ - 1) * (dimX * dimY)] - minValue;
+                        int z2 = data[x + y * dimX + Math.Max(z - 1, 0) * (dimX * dimY)] - minValue;
+
+                        Vector3 grad = new Vector3((x2 - x1) / (float)maxRange, (y2 - y1) / (float)maxRange, (z2 - z1) / (float)maxRange);
+
+                        cols[iData] = new Color(grad.x, grad.y, grad.z, (float)(data[iData] - minValue) / maxRange);
+                    }
+                }
+            }
+            texture.SetPixels(cols);
+            texture.Apply();
+            return texture;
+        }
     }
 }

Assets/Scripts/VolumeObject/VolumeObjectFactory.cs

@@ -14,41 +14,6 @@ namespace UnityVolumeRendering
 
             volObj.dataset = dataset;
 
-            int dimX = dataset.dimX;
-            int dimY = dataset.dimY;
-            int dimZ = dataset.dimZ;
-
-            int minValue = dataset.GetMinDataValue();
-            int maxValue = dataset.GetMaxDataValue();
-            int maxRange = maxValue - minValue;
-
-            Color[] cols = new Color[dataset.data.Length];
-            for (int x = 0; x < dataset.dimX; x++)
-            {
-                for (int y = 0; y < dataset.dimY; y++)
-                {
-                    for (int z = 0; z < dataset.dimZ; z++)
-                    {
-                        int iData = x + y * dimX + z * (dimX * dimY);
-
-                        int x1 = dataset.data[Math.Min(x + 1, dimX - 1) + y * dataset.dimX + z * (dataset.dimX * dataset.dimY)] - minValue;
-                        int x2 = dataset.data[Math.Max(x - 1, 0) + y * dataset.dimX + z * (dataset.dimX * dataset.dimY)] - minValue;
-                        int y1 = dataset.data[x + Math.Min(y + 1, dimY - 1) * dataset.dimX + z * (dataset.dimX * dataset.dimY)] - minValue;
-                        int y2 = dataset.data[x + Math.Max(y - 1, 0) * dataset.dimX + z * (dataset.dimX * dataset.dimY)] - minValue;
-                        int z1 = dataset.data[x + y * dataset.dimX + Math.Min(z + 1, dimZ - 1) * (dataset.dimX * dataset.dimY)] - minValue;
-                        int z2 = dataset.data[x + y * dataset.dimX + Math.Max(z - 1, 0) * (dataset.dimX * dataset.dimY)] - minValue;
-
-                        Vector3 grad = new Vector3((x2 - x1) / (float)maxRange, (y2 - y1) / (float)maxRange, (z2 - z1) / (float)maxRange);
-
-                        cols[iData] = new Color(grad.x, grad.y, grad.z, (float)(dataset.data[iData] - minValue) / maxRange);
-                    }
-                }
-            }
-
-            Texture3D tex = dataset.GetTexture();
-            tex.SetPixels(cols);
-            tex.Apply();
-
             const int noiseDimX = 512;
             const int noiseDimY = 512;
             Texture2D noiseTexture = NoiseTextureGenerator.GenerateNoiseTexture(noiseDimX, noiseDimY);
@@ -62,7 +27,8 @@ namespace UnityVolumeRendering
             TransferFunction2D tf2D = TransferFunctionDatabase.CreateTransferFunction2D();
             volObj.transferFunction2D = tf2D;
 
-            meshRenderer.sharedMaterial.SetTexture("_DataTex", tex);
+            meshRenderer.sharedMaterial.SetTexture("_DataTex", dataset.GetDataTexture());
+            meshRenderer.sharedMaterial.SetTexture("_GradientTex", dataset.GetGradientTexture());
             meshRenderer.sharedMaterial.SetTexture("_NoiseTex", noiseTexture);
             meshRenderer.sharedMaterial.SetTexture("_TFTex", tfTexture);
 

Assets/Scripts/VolumeObject/VolumeRenderedObject.cs

@@ -24,7 +24,7 @@ namespace UnityVolumeRendering
             MeshRenderer sliceMeshRend = sliceRenderingPlane.GetComponent<MeshRenderer>();
             sliceMeshRend.material = new Material(sliceMeshRend.sharedMaterial);
             Material sliceMat = sliceRenderingPlane.GetComponent<MeshRenderer>().sharedMaterial;
-            sliceMat.SetTexture("_DataTex", dataset.GetTexture());
+            sliceMat.SetTexture("_DataTex", dataset.GetDataTexture());
             sliceMat.SetTexture("_TFTex", transferFunction.GetTexture());
             sliceMat.SetMatrix("_parentInverseMat", transform.worldToLocalMatrix);
             sliceMat.SetMatrix("_planeMat", Matrix4x4.TRS(sliceRenderingPlane.transform.position, sliceRenderingPlane.transform.rotation, Vector3.one)); // TODO: allow changing scale

Assets/Shaders/DirectVolumeRenderingShader.shader

@@ -3,6 +3,7 @@
     Properties
     {
         _DataTex ("Data Texture (Generated)", 3D) = "" {}
+        _GradientTex("Gradient Texture (Generated)", 3D) = "" {}
         _NoiseTex("Noise Texture (Generated)", 2D) = "white" {}
         _TFTex("Transfer Function Texture (Generated)", 2D) = "" {}
         _MinVal("Min val", Range(0.0, 1.0)) = 0.0
@@ -53,6 +54,7 @@
             };
 
             sampler3D _DataTex;
+            sampler3D _GradientTex;
             sampler2D _NoiseTex;
             sampler2D _TFTex;
 
@@ -79,13 +81,13 @@
             // Gets the density at the specified position
             float getDensity(float3 pos)
             {
-                return tex3Dlod(_DataTex, float4(pos.x, pos.y, pos.z, 0.0f)).a;
+                return tex3Dlod(_DataTex, float4(pos.x, pos.y, pos.z, 0.0f));
             }
 
             // Gets the gradient at the specified position
             float3 getGradient(float3 pos)
             {
-                return tex3Dlod(_DataTex, float4(pos.x, pos.y, pos.z, 0.0f)).rgb;
+                return tex3Dlod(_GradientTex, float4(pos.x, pos.y, pos.z, 0.0f)).rgb;
             }
 
             // Converts local position to depth value

Assets/Shaders/SliceRenderingShader.shader

@@ -54,7 +54,7 @@ Shader "VolumeRendering/SliceRenderingShader"
             fixed4 frag (v2f i) : SV_Target
             {
                 float3 dataCoord = i.relVert +float3(0.5f, 0.5f, 0.5f);
-                float dataVal = tex3D(_DataTex, dataCoord).a;
+                float dataVal = tex3D(_DataTex, dataCoord);
                 float4 col = tex2D(_TFTex, float2(dataVal, 0.0f));
                 col.a = 1.0f;