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update: change buffer to double*

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wyj
2025-12-07 12:14:14 -05:00
parent b00e652394
commit 41f24e88e9
6 changed files with 33 additions and 18 deletions
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src/write_png.c
+13 -8
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@@ -1,7 +1,9 @@
#include <spng.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include "write_png.h"
#include "common.h"
static inline double linear_to_srgb(double x){
if (x <= 0.0) return 0.0;
@@ -10,40 +12,43 @@ static inline double linear_to_srgb(double x){
return 1.055 * pow(x, 1.0/2.4) - 0.055;
}
int buffer_normalize_srgb(double (*buffer)[3], int W, int H) {
int buffer_normalize_srgb(double *buffer, int W, int H) {
double max = 0;
for (int j = 0; j < H; j++) {
for (int i = 0; i < W; i++) {
for (int c = 0; c < 3; c++) {
if (max < buffer[j*W + i][c]) max = buffer[j*W + i][c];
if (max < buffer[color_index(i, j, c)]) max = buffer[color_index(i, j, c)];
}
}
}
printf("max in the buffer: %g\n", max);
if (max == 0) return 1;
for (int j = 0; j < H; j++) {
for (int i = 0; i < W; i++) {
for (int c = 0; c < 3; c++) {
buffer[j*W + i][c] /= max;
buffer[j*W+i][c] = linear_to_srgb(buffer[j*W+i][c]);
buffer[color_index(i, j, c)] /= max;
buffer[color_index(i, j, c)] = linear_to_srgb(buffer[color_index(i, j, c)]);
}
}
}
return 0;
}
int write_png(char *filename, double (*buffer)[3], int W, int H) {
int write_png(char *filename, double *buffer, int W, int H) {
buffer_normalize_srgb(buffer, W, H);
size_t bufsize = W*H*3;
uint8_t *img = (uint8_t *)malloc(bufsize);
printf("bufsize: %d\n", bufsize);
uint8_t *img = (uint8_t *)malloc(bufsize*sizeof(uint8_t));
if (!img) {return 1;}
for (int j = 0; j < H; j++) {
for (int i = 0; i < W; i++) {
for (int c = 0; c < 3; c++) {
int v = (int)lrint(buffer[j*W*i][c]);
int v = (int)lrint(buffer[color_index(i,j,c)]*255);
if (v < 0) v = 0;
if (v > 255) v = 255;
img[j*W*3+i*3+c] = (uint8_t) v;
img[color_index(i, j, c)] = (uint8_t) v;
printf("i: %d, j: %d, c:%d, buffer=%g, v=%d\n", i,j,c,buffer[color_index(i, j, c)],v);
}
}
}