I am loading DDS textures with the code below, and it works fine for square textures power of two textures, but it will not load textures that are 256*128 for example. I am not sure why that is, it should work as far as I can see. Any suggestions on this?
GLuint ImageUtils::loadDDS(const char * filename)
{
Logger::getInstance()->write(StringUtils::format("Loading DDS Image %s",filename));
unsigned char header[124];
FILE *fp;
/* try to open the file */
fp = fopen(filename, "rb");
if (fp == NULL)
{
Logger::getInstance()->write("Failed to load Image: could not open the file");
return 0;
}
/* verify the type of file */
char filecode[4];
fread(filecode, 1, 4, fp);
if (strncmp(filecode, "DDS ", 4) != 0)
{
fclose(fp);
Logger::getInstance()->write("Failed to load Image: not a direct draw surface file");
return 0;
}
/* get the surface desc */
fread(&header, 124, 1, fp);
unsigned int height = *(unsigned int*)&(header[8 ]);
unsigned int width = *(unsigned int*)&(header[12]);
unsigned int linearSize = *(unsigned int*)&(header[16]);
unsigned int mipMapCount = *(unsigned int*)&(header[24]);
unsigned int fourCC = *(unsigned int*)&(header[80]);
unsigned char * buffer;
unsigned int bufsize;
/* how big is it going to be including all mipmaps? */
bufsize = mipMapCount > 1 ? linearSize * 2 : linearSize;
buffer = (unsigned char*)malloc(bufsize * sizeof(unsigned char));
fread(buffer, 1, bufsize, fp);
/* close the file pointer */
fclose(fp);
unsigned int components = (fourCC == FOURCC_DXT1) ? 3 : 4;
unsigned int format;
switch(fourCC)
{
case FOURCC_DXT1:
format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
break;
case FOURCC_DXT3:
format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
break;
case FOURCC_DXT5:
format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
break;
default:
free(buffer);
Logger::getInstance()->write("Failed to load Image: dds file format not supported (supported formats: DXT1, DXT3, DXT5)");
return 0;
}
// Create one OpenGL texture
GLuint textureID;
glGenTextures(1, &textureID);
// "Bind" the newly created texture : all future texture functions will modify this texture
glBindTexture(GL_TEXTURE_2D, textureID);
glPixelStorei(GL_UNPACK_ALIGNMENT,1);
unsigned int blockSize = (format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) ? 8 : 16;
unsigned int offset = 0;
/* load the mipmaps */
for (unsigned int level = 0; level < mipMapCount && (width || height); ++level)
{
unsigned int size = ((width+3)/4)*((height+3)/4)*blockSize;
glCompressedTexImage2D(GL_TEXTURE_2D, level, format, width, height,
0, size, buffer + offset);
offset += size;
width /= 2;
height /= 2;
}
free(buffer);
//Unbind the texture
glBindTexture(GL_TEXTURE_2D, 0);
Logger::getInstance()->write(StringUtils::format("Loaded DDS Image %s",filename));
return textureID;
}