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/*
* texture.c
*
* Handle textures
*
* (c) 2008 Thomas White <taw27@cam.ac.uk>
*
* thrust3d - a silly game
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <png.h>
#include <stdlib.h>
#include <glew.h>
#include <glu.h>
#include "render.h"
static int texture_load_png(char *filename, GLuint *name) {
FILE *fh;
png_bytep header;
png_structp png_ptr;
png_infop info_ptr;
png_infop end_info;
unsigned int width;
unsigned int height;
unsigned int bit_depth;
unsigned int channels;
png_bytep *row_pointers;
unsigned int x;
unsigned int y;
uint8_t *texels;
/* Open file */
fh = fopen(filename, "rb");
if ( !fh ) {
return 1;
}
/* Check it's actually a PNG file */
header = malloc(8);
fread(header, 1, 8, fh);
if ( png_sig_cmp(header, 0, 8)) {
fprintf(stderr, "Texture file '%s' is not a PNG file.\n", filename);
free(header);
fclose(fh);
return 1;
}
free(header);
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if ( !png_ptr ) {
fprintf(stderr, "Couldn't create PNG read structure.\n");
fclose(fh);
return 1;
}
info_ptr = png_create_info_struct(png_ptr);
if ( !info_ptr ) {
png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
fprintf(stderr, "Couldn't create PNG info structure.\n");
fclose(fh);
return 1;
}
end_info = png_create_info_struct(png_ptr);
if ( !end_info ) {
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
printf("Couldn't create PNG end info structure.\n");
fclose(fh);
return 1;
}
if ( setjmp(png_jmpbuf(png_ptr)) ) {
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fh);
fprintf(stderr, "PNG read failed.\n");
return 1;
}
png_init_io(png_ptr, fh);
png_set_sig_bytes(png_ptr, 8);
/* Read! */
png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
width = png_get_image_width(png_ptr, info_ptr);
height = png_get_image_height(png_ptr, info_ptr);
bit_depth = png_get_bit_depth(png_ptr, info_ptr);
channels = png_get_channels(png_ptr, info_ptr);
if ( bit_depth != 8 ) {
fprintf(stderr, "Texture image '%s' doesn't have 8 bits per channel per pixel.\n", filename);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fh);
return 1;
}
if ( channels != 4 ) {
fprintf(stderr, "Texture image '%s' doesn't have 4 channels.\n", filename);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fh);
return 1;
}
/* Get image data */
row_pointers = png_get_rows(png_ptr, info_ptr);
texels = malloc(4*width*height);
for ( y=0; y<height; y++ ) {
for ( x=0; x<width; x++ ) {
unsigned int r, g, b, a;
r = row_pointers[y][(channels*x)+0];
g = row_pointers[y][(channels*x)+1];
b = row_pointers[y][(channels*x)+2];
a = row_pointers[y][(channels*x)+3];
texels[4*(x + width*(height-1-y)) + 0] = r;
texels[4*(x + width*(height-1-y)) + 1] = g;
texels[4*(x + width*(height-1-y)) + 2] = b;
texels[4*(x + width*(height-1-y)) + 3] = a;
}
}
glGenTextures(1, name);
glBindTexture(GL_TEXTURE_2D, *name);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGBA8, width, height, GL_RGBA, GL_UNSIGNED_BYTE, texels);
free(texels);
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fh);
return 0;
}
void texture_load(RenderContext *ctx, char *name) {
GLuint colourmap, normalmap;
char colourmap_filename[256];
char normalmap_filename[256];
snprintf(colourmap_filename, 255, "%s/textures/%s.png", DATADIR, name);
snprintf(normalmap_filename, 255, "%s/textures/%s-normals.png", DATADIR, name);
if ( texture_load_png(colourmap_filename, &colourmap) != 0 ) {
fprintf(stderr, "Couldn't load texture '%s'\n", name);
return;
}
ctx->textures[ctx->num_textures].texname = colourmap;
if ( texture_load_png(normalmap_filename, &normalmap) == 0 ) {
ctx->textures[ctx->num_textures].normalmap = normalmap;
ctx->textures[ctx->num_textures].has_normals = 1;
} else {
ctx->textures[ctx->num_textures].has_normals = 0;
}
ctx->textures[ctx->num_textures].name = strdup(name);
ctx->num_textures++;
}
Texture *texture_lookup(RenderContext *ctx, const char *name) {
int i, found;
found = 0;
for ( i=0; i<ctx->num_textures; i++ ) {
if ( strcmp(ctx->textures[i].name, name) == 0 ) {
found = 1;
break;
}
}
if ( found == 0 ) {
return NULL;
}
return &(ctx->textures[i]);
}
void texture_free_all(RenderContext *ctx) {
int i;
for ( i=0; i<ctx->num_textures; i++ ) {
glDeleteTextures(1, &(ctx->textures[ctx->num_textures].texname));
}
}
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