iOS OpenGL Texture 转为 UIImage 的方法
调用该方法前，需要先绑定纹理并且设置为激活状态！
- (UIImage *)imageFromTextureWithwidth:(int)width height:(int)height {
// glActiveTexture(GL_TEXTURE1); 先绑定某个纹理
int size = width * height * 4;
GLubyte *buffer = malloc(size);
glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer, size, NULL);
int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4 * width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
UIImage *image = [UIImage imageWithCGImage:imageRef];
free(buffer);
return image;
}
