Make procedural shader fast

Assets/Scripts/ProceduralShader.cs

@@ -54,74 +54,67 @@ public class ProceduralShader : MonoBehaviour
     public void SetColors(Mesh mesh, Texture2D heightMap, int subdivisions, int numVerts)
     {
         //Color32[] colors = new Color32[numVerts];
-        System.DateTime before = System.DateTime.Now;
+        System.Diagnostics.Stopwatch stopwatch = new System.Diagnostics.Stopwatch();
+        stopwatch.Start();
 
         Color32[] colors = new Color32[numVerts];
-        float[] ys = new float[numVerts];
-        for (int i = 0; i < numVerts; i++)
-        {
-            ys[i] = mesh.vertices[i].y;
-        }
+        Vector3[] vertices = mesh.vertices;
+        Vector3[] normals = mesh.normals;
 
-        mesh.RecalculateNormals();
         Debug.Log("mesh vertices: " + numVerts);
         Debug.Log("mesh normals: " + mesh.normals.Length);
 
         float subdivRecip = 1.0f / (float)(subdivisions + 1);
-        int index = 0;
+        int index = -1;
         for (int z = 0; z < subdivisions + 1; z++)
         {
             for (int x = 0; x < subdivisions + 1; x++)
             {
-                if (ys[index] <= maxWaterHeight)
+                index++;
+                colors[index] = cliffColor;
+                float height = vertices[index].y;
+                // If vertex height less than water, give water color
+                if (height <= maxWaterHeight)
                 {
                     float xDiv = (float)x * subdivRecip * 2 + 200;
                     float zDiv = (float)z * subdivRecip * 2 + 300;
                     float perl = Mathf.PerlinNoise(xDiv, zDiv);
                     colors[index] = waterColor.Evaluate(perl);
+                    continue;
+                }
+                if (Vector3.Dot(normals[index], Vector3.up) < 0.5f)
+                {
+                    colors[index] = cliffColor;
+                    continue;
                 }
                 else
                 {
-                    if (Vector3.Dot(mesh.normals[index], Vector3.up) < 0.5f)
-                    {
-                        colors[index] = cliffColor;
-                        index++;
-                        continue;
-                    }
-                    else
+                    float xDiv = (float)x * subdivRecip * 8;
+                    float zDiv = (float)z * subdivRecip * 8;
+                    float perl = Mathf.PerlinNoise(xDiv, zDiv);
+                    colors[index] = terrainColorPerlin.Evaluate(perl);
+
+                    if(height > snowHeightMin)
                     {
-                        float xDiv = (float)x * subdivRecip * 8;
-                        float zDiv = (float)z * subdivRecip * 8;
-                        float perl = Mathf.PerlinNoise(xDiv, zDiv);
-                        colors[index] = terrainColorPerlin.Evaluate(perl);
-
-                        if(ys[index] > snowHeightMin)
-                        {
-                            // TODO: altitude based exponent / frequency
-
-                            xDiv = (float)x * subdivRecip * 16 + 1000;
-                            zDiv = (float)z * subdivRecip * 16 + 1000;
-                            float heightMult = (ys[index] - snowHeightMin) / (snowHeightMax - snowHeightMin);
-                            float heightMultClamp = Mathf.Min(heightMult, 1.0f);
-
-                            float perlVal = Mathf.PerlinNoise(xDiv, zDiv);
-                            perl = Mathf.Pow(perlVal, snowExponent)  * heightMult;
-                            colors[index] = Color.Lerp(colors[index], Color.white, perl);
-                        }
-                    }
-                }
+                        // TODO: altitude based exponent / frequency
 
+                        xDiv = (float)x * subdivRecip * 16 + 1000;
+                        zDiv = (float)z * subdivRecip * 16 + 1000;
+                        float heightMult = (height - snowHeightMin) / (snowHeightMax - snowHeightMin);
+                        float heightMultClamp = Mathf.Min(heightMult, 1.0f);
 
-                index++;
+                        float perlVal = Mathf.PerlinNoise(xDiv, zDiv);
+                        perl = Mathf.Pow(perlVal, snowExponent)  * heightMult;
+                        colors[index] = Color.Lerp(colors[index], Color.white, perl);
+                    }
+                }
             }
         }
 
         mesh.SetColors(colors);
         Debug.Log("DONE");
 
-        System.DateTime after = System.DateTime.Now;
-        System.TimeSpan diff = after.Subtract(before);
-        Debug.Log("duration of coloring (ms): " + diff.Milliseconds);
-
+        stopwatch.Stop();
+        UnityEngine.Debug.Log ("Coloring time taken: "+(stopwatch.Elapsed));
     }
 }