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/*
* Copyright © 2009 Eric Anholt
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <err.h>
#include <errno.h>
#include <assert.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <getopt.h>
#include <png.h>
#include "glass.h"
/* libpng sucks and I hope I never have to read this file again. */
GLuint load_texture_rgb(const char *filename)
{
GLuint tex;
FILE *f;
png_uint_32 w, h;
int depth;
unsigned char *data;
png_structp png;
png_infop png_info;
int png_type;
int stride;
png_bytep *row_pointers;
int i;
GLenum format;
glGenTextures(1, &tex);
f = fopen(filename, "rb");
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL,
NULL);
assert(png);
png_info = png_create_info_struct(png);
assert(png_info);
if (setjmp(png->jmpbuf)) {
png_destroy_read_struct(&png, &png_info, NULL);
abort();
}
png_init_io(png, f);
png_read_info(png, png_info);
png_get_IHDR(png, png_info, &w, &h, &depth, &png_type,
NULL, NULL, NULL);
/* Give us sensible data. This API is terrible */
png_set_expand(png);
/* No, really. Sensible data. */
if (depth == 16)
png_set_strip_16(png);
/* Not even kidding. */
png_set_gray_to_rgb(png);
png_read_update_info(png, png_info);
stride = png_get_rowbytes(png, png_info);
data = malloc(h * stride);
assert(data);
/* So, you've told us what the stride needs to be, but you make
* us give you pointers to the data? Brilliant.
*/
row_pointers = malloc(sizeof(png_bytep) * h);
assert(row_pointers);
for (i = 0; i < h; i++)
row_pointers[i] = data + i * stride;
png_read_image(png, row_pointers);
glBindTexture(GL_TEXTURE_2D, tex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
switch (png_info->color_type) {
case PNG_COLOR_TYPE_RGB:
format = GL_RGB;
break;
case PNG_COLOR_TYPE_RGBA:
format = GL_RGBA;
break;
default:
abort();
}
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0,
format, GL_UNSIGNED_BYTE, data);
free(data);
free(row_pointers);
png_destroy_read_struct(&png, &png_info, NULL);
return tex;
}
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