tga.c

   1 #include <GL/gl.h>
   2
   3 #include <stdlib.h>
   4 #include <stdio.h>
   5
   6 #include "tga.h"
   7
   8 TgaImage* readTga(const char* path) {
   9         FILE* tgaFile = fopen(path, "rb");
  10         if (tgaFile == NULL) {
  11                 return NULL;
  12         }
  13
  14         TgaHeader header;
  15
  16         if (fread(&header, sizeof(TgaHeader), 1, tgaFile) != 1) {
  17                 fclose(tgaFile);
  18                 return NULL;
  19         }
  20
  21         GLenum imageFormat;
  22         GLint imageComponents;
  23
  24         switch (header.imageBpp) {
  25                 case 32:
  26                         imageFormat = GL_BGRA_EXT;
  27                         imageComponents = GL_RGBA8;
  28                         break;
  29                 case 24:
  30                         imageFormat = GL_BGR_EXT;
  31                         imageComponents = GL_RGB8;
  32                         break;
  33                 case 8:
  34                         imageFormat = GL_LUMINANCE;
  35                         imageComponents = GL_LUMINANCE8;
  36                         break;
  37                 default:
  38                         fclose(tgaFile);
  39                         return NULL;
  40         }
  41
  42         unsigned long imageSize = header.imageWidth * header.imageHeight * (header.imageBpp >> 3);
  43
  44         GLbyte* bytes = malloc(imageSize * sizeof(GLbyte));
  45         if (bytes == NULL) {
  46                 fclose(tgaFile);
  47                 return NULL;
  48         }
  49
  50         if (fread(bytes, imageSize, 1, tgaFile) != 1) {
  51                 free(bytes);
  52                 fclose(tgaFile);
  53                 return NULL;
  54         }
  55
  56         fclose(tgaFile);
  57
  58         TgaImage* image = malloc(sizeof(TgaImage));
  59         if (image == NULL) {
  60                 return NULL;
  61         }
  62
  63         (*image).header = header;
  64         (*image).imageFormat = imageFormat;
  65         (*image).imageComponents = imageComponents;
  66         (*image).bytes = bytes;
  67
  68         return image;
  69 }