From 3a0ccfdbe8539a63afadac18e03b09fea08e52ab Mon Sep 17 00:00:00 2001
From: ktyl <me@ktyl.dev>
Date: Wed, 1 Mar 2023 00:55:04 +0000
Subject: [PATCH] christmas noise

---
 src/gfx.c | 76 +++++++++++++++++++++++++++++++++++--------------------
 src/gfx.h |  1 +
 2 files changed, 50 insertions(+), 27 deletions(-)

diff --git a/src/gfx.c b/src/gfx.c
index 039cbdc..803ace3 100644
--- a/src/gfx.c
+++ b/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)
@@ -306,36 +324,40 @@ GLuint createBlueNoiseTexture(int width, int height)
 
     float* data = (float*)malloc(length*sizeof(float));
 
-    // generate a bunch of points
-    int m = 100;
-    int n = 100;
-    vec2 points[n];
-    generateBlueNoisePoints(points, m, n);
+    // blue noise gen parameters
+    int m = 10;     // roughly controls the evenness...?
+    int n = 100;    // number of points to generate
 
-    // 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++)
+    // for each channel
+    for (int channel = 0; channel < channels; channel++)
     {
-        int pixelIdx = i;
-        int x = pixelIdx % width;
-        int y = pixelIdx / width;
-        float u = x / (float)width;
-        float v = y / (float)height;
-        vec2 pixel = {u,v};
+        // generate a bunch of points
+        vec2 points[n];
+        generateBlueNoisePoints(points, m, n);
 
-        for (int j = 0; j < n; j++)
+        for (int i = 0; i < width*height; i++)
         {
-            float d = glm_vec2_distance(points[j], pixel);
-            float r = 0.01;
-            if (d < r)
+            int pixelIdx = i;
+            int x = pixelIdx % width;
+            int y = pixelIdx / width;
+            float u = x / (float)width;
+            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++)
             {
-                data[i * channels + 2] = 1.0;
+                float d = glm_vec2_distance(points[j], pixel);
+                //value += 1.0f / (d*d);
+
+                float r = 0.01;
+                if (d < r)
+                {
+                    data[componentIdx] = 1.0;
+                }
             }
+            //data[componentIdx] = value / (float)n;
         }
     }
 
diff --git a/src/gfx.h b/src/gfx.h
index 1c30422..b83c652 100644
--- a/src/gfx.h
+++ b/src/gfx.h
@@ -10,6 +10,7 @@
 
 #include "io.h"
 #include "random.h"
+#include "clock.h"
 
 struct Shaders
 {