Is there anything wrong with my texture loading method ?
- by José Joel.
I'm a noob in openGL and trying to learn as much as possible. I'm using this method to load my openGL textures, loading every .png as RGBA4444. I'm doing anything incorrect ?
- (void)loadTexture:(NSString*)nombre {
CGImageRef textureImage =[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:nombre ofType:nil]].CGImage;
if (textureImage == nil) {
NSLog(@"Failed to load texture image");
return;
}
textureWidth = NextPowerOfTwo(CGImageGetWidth(textureImage));
textureHeight = NextPowerOfTwo(CGImageGetHeight(textureImage));
imageSizeX= CGImageGetWidth(textureImage);
imageSizeY= CGImageGetHeight(textureImage);
GLubyte *textureData = (GLubyte *)calloc(1,textureWidth * textureHeight * 4); // Por 4 pues cada pixel necesita 4 bytes, RGBA
CGContextRef textureContext = CGBitmapContextCreate(textureData, textureWidth,textureHeight,8, textureWidth * 4,CGImageGetColorSpace(textureImage),kCGImageAlphaPremultipliedLast );
CGContextDrawImage(textureContext, CGRectMake(0.0, 0.0, (float)textureWidth, (float)textureHeight), textureImage);
//Convert "RRRRRRRRRGGGGGGGGBBBBBBBBAAAAAAAA" to "RRRRGGGGBBBBAAAA"
void *tempData = malloc(textureWidth * textureHeight * 2);
unsigned int* inPixel32 = (unsigned int*)textureData;
unsigned short* outPixel16 = (unsigned short*)tempData;
for(int i = 0; i < textureWidth * textureHeight ; ++i, ++inPixel32)
*outPixel16++ =
((((*inPixel32 >> 0) & 0xFF) >> 4) << 12) | // R
((((*inPixel32 >> 8) & 0xFF) >> 4) << 8) | // G
((((*inPixel32 >> 16) & 0xFF) >> 4) << 4) | // B
((((*inPixel32 >> 24) & 0xFF) >> 4) << 0); // A
free(textureData);
textureData = tempData;
CGContextRelease(textureContext);
glGenTextures(1, &textures[0]);
glBindTexture(GL_TEXTURE_2D, textures[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4 , textureData);
free(textureData);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
}
And this is my dealloc method:
- (void)dealloc {
glDeleteTextures(1,textures);
[super dealloc];
}
