tga.c

   1 #include <GL/gl.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4
   5 #include "tga.h"
   6
   7 TGAimage* read_tga(const char* path) {
   8         FILE* tga_file = fopen(path, "rb");
   9         if (tga_file == NULL) {
  10                 return NULL;
  11         }
  12
  13         TGAheader header;
  14
  15         if (fread(&header, sizeof(TGAheader), 1, tga_file) != 1) {
  16                 fclose(tga_file);
  17                 return NULL;
  18         }
  19
  20         GLenum image_format;
  21         GLint image_components;
  22
  23         if (header.image_bpp == 32) {
  24                 image_format = GL_BGRA_EXT;
  25                 image_components = GL_RGBA8;
  26         }
  27         else if (header.image_bpp == 24) {
  28                 image_format = GL_BGR_EXT;
  29                 image_components = GL_RGB8;
  30         }
  31         else if (header.image_bpp == 8) {
  32                 image_format = GL_LUMINANCE;
  33                 image_components = GL_LUMINANCE8;
  34         }
  35         else {
  36                 fclose(tga_file);
  37                 return NULL;
  38         }
  39
  40         unsigned long image_size = header.image_width * header.image_height * (header.image_bpp >> 3);
  41
  42         GLbyte* bytes = malloc(image_size * sizeof(GLbyte));
  43         if (bytes == NULL) {
  44                 fclose(tga_file);
  45                 return NULL;
  46         }
  47
  48         if (fread(bytes, image_size, 1, tga_file) != 1) {
  49                 free(bytes);
  50                 fclose(tga_file);
  51                 return NULL;
  52         }
  53
  54         fclose(tga_file);
  55
  56         TGAimage* image = malloc(sizeof(TGAimage));
  57         if (image == NULL) {
  58                 return NULL;
  59         }
  60
  61         (*image).header = header;
  62         (*image).image_format = image_format;
  63         (*image).image_components = image_components;
  64         (*image).bytes = bytes;
  65
  66         return image;
  67 }