christmas noise

src/gfx.c

@@ -232,7 +232,10 @@ GLuint createWhiteNoiseTexture(int width, int height)
 
 void generateBlueNoisePoints(vec2* points, int m, int n)
 {
-    vec2 firstSample = {randomFloat(), randomFloat()};
+    float start = now();
+    float elapsed;
+    int candidatesTested = 0;
+
     struct Candidate
     {
         vec2 pos;
@@ -245,7 +248,6 @@ void generateBlueNoisePoints(vec2* points, int m, int n)
         // generate a bunch of candidates
         int count = m * i;
         struct Candidate candidates[count];
-        //int closest = -1;
 
         for (int j = 0; j < count; j++)
         {
@@ -264,9 +266,18 @@ void generateBlueNoisePoints(vec2* points, int m, int n)
                 if (distance < c->distance)
                 {
                     c->distance = distance;
-                    //closest = k;
                 }
             }
+
+            candidatesTested += i;
+
+            float killAfter = 10.0;
+            elapsed = now() - start;
+            if (elapsed > killAfter)
+            {
+                printf("noise generation took too long, exiting\n");
+                exit(1);
+            }
         }
 
         // of our candidates, now determine which of them has the furthest
@@ -284,6 +295,13 @@ void generateBlueNoisePoints(vec2* points, int m, int n)
 
         glm_vec2_copy(candidates[furthest].pos, points[i]);
     }
+
+    elapsed = now() - start;
+    printf("generated %d blue noise (m=%d) points from %d candidates in %fs\n",
+        n,
+        m,
+        candidatesTested,
+        elapsed);
 }
 
 GLuint createBlueNoiseTexture(int width, int height)
@@ -306,19 +324,17 @@ GLuint createBlueNoiseTexture(int width, int height)
 
     float* data = (float*)malloc(length*sizeof(float));
 
+    // blue noise gen parameters
+    int m = 10;     // roughly controls the evenness...?
+    int n = 100;    // number of points to generate
+
+    // for each channel
+    for (int channel = 0; channel < channels; channel++)
+    {
         // generate a bunch of points
-    int m = 100;
-    int n = 100;
         vec2 points[n];
         generateBlueNoisePoints(points, m, n);
 
-    // use those points to generate a texture
-
-    //for (int i = 0; i < length; i++)
-    //{
-    //    data[i] = randomFloat();
-    //}
-
         for (int i = 0; i < width*height; i++)
         {
             int pixelIdx = i;
@@ -328,15 +344,21 @@ GLuint createBlueNoiseTexture(int width, int height)
             float v = y / (float)height;
             vec2 pixel = {u,v};
 
+            float value = 0.0f;
+            int componentIdx = i * channels + channel;
             for (int j = 0; j < n; j++)
             {
                 float d = glm_vec2_distance(points[j], pixel);
+                //value += 1.0f / (d*d);
+
                 float r = 0.01;
                 if (d < r)
                 {
-                data[i * channels + 2] = 1.0;
+                    data[componentIdx] = 1.0;
                 }
             }
+            //data[componentIdx] = value / (float)n;
+        }
     }
 
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0, GL_RGBA, GL_FLOAT, data);

src/gfx.h

@@ -10,6 +10,7 @@
 
 #include "io.h"
 #include "random.h"
+#include "clock.h"
 
 struct Shaders
 {