extract noise to file
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3a0ccfdbe8
commit
2883c69346
202
src/gfx.c
202
src/gfx.c
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@ -1,5 +1,4 @@
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#include "gfx.h"
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#include "random.h"
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float vertices[] = {
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// position color uvs
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@ -196,184 +195,33 @@ int createTextures(int width, int height, struct Shaders shaders, struct Texture
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return 0;
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}
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// creates a noise texture in active texture 1
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GLuint createWhiteNoiseTexture(int width, int height)
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{
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// same init steps as with a regular texture
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GLuint texture;
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glGenTextures(1, &texture);
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glActiveTexture(GL_TEXTURE1);
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glBindTexture(GL_TEXTURE_2D, texture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_REPEAT);
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int channels = 4; // rgba
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int length = width*height*channels;
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printf("generating %d random floats\n", length);
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float* data = (float*)malloc(length*sizeof(float));
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for (int i = 0; i < length; i++)
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{
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data[i] = randomFloat();
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}
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0, GL_RGBA, GL_FLOAT, data);
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glBindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
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glGenerateMipmap(GL_TEXTURE_2D);
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free(data);
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return texture;
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}
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void generateBlueNoisePoints(vec2* points, int m, int n)
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{
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float start = now();
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float elapsed;
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int candidatesTested = 0;
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struct Candidate
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{
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vec2 pos;
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// distance to closest point already in pattern
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float distance;
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};
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for (int i = 0; i < n; i++)
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{
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// generate a bunch of candidates
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int count = m * i;
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struct Candidate candidates[count];
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for (int j = 0; j < count; j++)
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{
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struct Candidate* c = &candidates[j];
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c->pos[0] = randomFloat();
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c->pos[1] = randomFloat();
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// the largest distance we should expect is sqrt(2),
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// so pick a maximum larger than that
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c->distance = 1.5;
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// get the distance of the closest point already in the pattern
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for (int k = 0; k < i; k++)
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{
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float distance = glm_vec2_distance(c->pos, points[k]);
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if (distance < c->distance)
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{
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c->distance = distance;
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}
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}
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candidatesTested += i;
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float killAfter = 10.0;
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elapsed = now() - start;
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if (elapsed > killAfter)
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{
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printf("noise generation took too long, exiting\n");
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exit(1);
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}
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}
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// of our candidates, now determine which of them has the furthest
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// closest-distance
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int furthest = -1;
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float furthestDistance = 0.0;
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for (int j = 0; j < count; j++)
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{
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if (candidates[j].distance > furthestDistance)
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{
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furthest = j;
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furthestDistance = candidates[j].distance;
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}
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}
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glm_vec2_copy(candidates[furthest].pos, points[i]);
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}
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elapsed = now() - start;
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printf("generated %d blue noise (m=%d) points from %d candidates in %fs\n",
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n,
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m,
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candidatesTested,
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elapsed);
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}
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GLuint createBlueNoiseTexture(int width, int height)
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{
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// same init steps as with a regular texture
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GLuint texture;
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glGenTextures(1, &texture);
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glActiveTexture(GL_TEXTURE1);
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glBindTexture(GL_TEXTURE_2D, texture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_REPEAT);
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int channels = 4; // rgba
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int length = width*height*channels;
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//printf("generating %d random floats\n", length);
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printf("generating blue noise\n");
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float* data = (float*)malloc(length*sizeof(float));
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// blue noise gen parameters
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int m = 10; // roughly controls the evenness...?
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int n = 100; // number of points to generate
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// for each channel
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for (int channel = 0; channel < channels; channel++)
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{
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// generate a bunch of points
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vec2 points[n];
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generateBlueNoisePoints(points, m, n);
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for (int i = 0; i < width*height; i++)
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{
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int pixelIdx = i;
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int x = pixelIdx % width;
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int y = pixelIdx / width;
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float u = x / (float)width;
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float v = y / (float)height;
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vec2 pixel = {u,v};
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float value = 0.0f;
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int componentIdx = i * channels + channel;
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for (int j = 0; j < n; j++)
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{
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float d = glm_vec2_distance(points[j], pixel);
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//value += 1.0f / (d*d);
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float r = 0.01;
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if (d < r)
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{
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data[componentIdx] = 1.0;
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}
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}
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//data[componentIdx] = value / (float)n;
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}
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}
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0, GL_RGBA, GL_FLOAT, data);
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glBindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
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glGenerateMipmap(GL_TEXTURE_2D);
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free(data);
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return texture;
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}
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GLuint createNoiseTexture(int width, int height)
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{
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//return createWhiteNoiseTexture(width, height);
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return createBlueNoiseTexture(width, height);
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// same init steps as with a regular texture
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GLuint texture;
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glGenTextures(1, &texture);
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glActiveTexture(GL_TEXTURE1);
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glBindTexture(GL_TEXTURE_2D, texture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_REPEAT);
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int channels = 4; // rgba
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int length = width*height*channels;
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float* data = (float*)malloc(length*sizeof(float));
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//writeWhiteNoiseToTexture(data, width, height);
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writeBlueNoiseToTexture(data, width, height);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0, GL_RGBA, GL_FLOAT, data);
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glBindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
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glGenerateMipmap(GL_TEXTURE_2D);
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free(data);
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return texture;
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}
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GLuint createWriteOnlyTexture(int width, int height)
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@ -6,11 +6,8 @@
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#include <SDL2/SDL.h>
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#include <SDL2/SDL_opengl.h>
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#include <cglm/vec2.h>
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#include "io.h"
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#include "random.h"
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#include "clock.h"
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#include "noise.h"
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struct Shaders
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{
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@ -0,0 +1,131 @@
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#include "noise.h"
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void writeWhiteNoiseToTexture(float* data, int width, int height)
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{
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int channels = 4; // rgba
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int length = width*height*channels;
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printf("generating %d random floats\n", length);
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for (int i = 0; i < length; i++)
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{
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data[i] = randomFloat();
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}
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}
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void generateBlueNoisePoints(vec2* points, int m, int n)
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{
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float start = now();
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float elapsed;
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int candidatesTested = 0;
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struct Candidate
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{
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vec2 pos;
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// distance to closest point already in pattern
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float distance;
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};
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for (int i = 0; i < n; i++)
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{
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// generate a bunch of candidates
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int count = m * i;
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struct Candidate candidates[count];
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for (int j = 0; j < count; j++)
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{
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struct Candidate* c = &candidates[j];
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c->pos[0] = randomFloat();
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c->pos[1] = randomFloat();
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// the largest distance we should expect is sqrt(2),
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// so pick a maximum larger than that
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c->distance = 1.5;
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// get the distance of the closest point already in the pattern
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for (int k = 0; k < i; k++)
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{
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float distance = glm_vec2_distance(c->pos, points[k]);
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if (distance < c->distance)
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{
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c->distance = distance;
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}
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}
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candidatesTested += i;
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float killAfter = 10.0;
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elapsed = now() - start;
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if (elapsed > killAfter)
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{
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printf("noise generation took too long (%fs), exiting\n", elapsed);
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exit(1);
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}
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}
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// of our candidates, now determine which of them has the furthest
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// closest-distance
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int furthest = -1;
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float furthestDistance = 0.0;
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for (int j = 0; j < count; j++)
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{
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if (candidates[j].distance > furthestDistance)
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{
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furthest = j;
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furthestDistance = candidates[j].distance;
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}
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}
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glm_vec2_copy(candidates[furthest].pos, points[i]);
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}
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elapsed = now() - start;
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printf("generated %d blue noise (m=%d) points from %d candidates in %fs\n",
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n,
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m,
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candidatesTested,
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elapsed);
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}
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void writeBlueNoiseToTexture(float* data, int width, int height)
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{
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printf("generating blue noise\n");
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int channels = 4;
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// blue noise gen parameters
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int m = 10; // roughly controls the evenness...?
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int n = 100; // number of points to generate
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// for each channel
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for (int channel = 0; channel < channels; channel++)
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{
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// generate a bunch of points
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vec2 points[n];
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generateBlueNoisePoints(points, m, n);
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for (int i = 0; i < width*height; i++)
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{
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int pixelIdx = i;
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int x = pixelIdx % width;
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int y = pixelIdx / width;
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float u = x / (float)width;
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float v = y / (float)height;
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vec2 pixel = {u,v};
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//float value = 0.0f;
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int componentIdx = i * channels + channel;
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for (int j = 0; j < n; j++)
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{
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float d = glm_vec2_distance(points[j], pixel);
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//value += 1.0f / (d*d);
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float r = 0.01;
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if (d < r)
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{
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data[componentIdx] = 1.0;
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}
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}
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//data[componentIdx] = value / (float)n;
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}
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}
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}
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@ -0,0 +1,13 @@
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#pragma once
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#include "GL/glew.h"
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#include <cglm/vec2.h>
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#include "io.h"
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#include "random.h"
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#include "clock.h"
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void writeWhiteNoiseToTexture(float* data, int width, int height);
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void generateBlueNoisePoints(vec2* points, int m, int n);
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void writeBlueNoiseToTexture(float* data, int width, int height);
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