目前，我使用图像 I/O 在 iOS 中加载纹理，并使用 Core Graphics 提取其图像数据。然后我可以将图像数据发送到 OpenGL，如下所示:
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->width, texture->height, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->imageData);
问题是核心图形部分非常慢，我需要使用核心图形进行设置和绘制只是为了提取图像数据......我不想在屏幕上显示它。 iOS 中一定有更高效的提取图像数据的方法吗？...
这是我的代码:
...
myTexRef = CGImageSourceCreateWithURL((__bridge CFURLRef)url, myOptions);
...
MyTexture2D* texture;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
void *imageData = malloc( tileSize.width * tileSize.height * 4 );
CGContextRef imgContext = CGBitmapContextCreate( imageData, tileSize.width, tileSize.height, 8, 4 * tileSize.width, colorSpace, kCGImageAlphaNoneSkipLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease( colorSpace );
CGContextClearRect( imgContext, CGRectMake( 0, 0, tileSize.width, tileSize.height ) );
CGContextTranslateCTM( imgContext, 0, 0 );
...
CGImageRef tiledImage = CGImageCreateWithImageInRect (imageRef, tileArea);
CGRect drawRect = CGRectMake(0, 0, tileSize.width, tileSize.height);
// *** THIS CALL IS REALLY EXPENSIVE!
CGContextDrawImage(imgContext, drawRect, tiledImage);
CGImageRelease(tiledImage);
// TamTexture2D takes the ownership of imageData and will be responsible to free it
texture = new MyTexture2D(tileSize.width, tileSize.height, imageData);
CGContextRelease(imgContext);
最佳答案
如果您正在针对 iOS 5 及更高版本进行开发，GLKTextureLoader就是您要找的:
关于Objective-c : Most efficient way to load a texture to OpenGL，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11347804/