有用的代码片段记录

从纹理获取CVPixelBufferRef对象

id<MTLTexture>生成CVPixelBufferRef

- (CVPixelBufferRef)getPixelBufferFromBGRAMTLTexture:(id<MTLTexture>)texture {
    
    CVPixelBufferRef pxbuffer = NULL;
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
                             [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
                             nil];
    
    size_t imageByteCount = texture.width * texture.height * 4;
    void *imageBytes = malloc(imageByteCount);
    NSUInteger bytesPerRow = texture.width * 4;
    MTLRegion region = MTLRegionMake2D(0, 0, texture.width, texture.height);
    [texture getBytes:imageBytes bytesPerRow:bytesPerRow fromRegion:region mipmapLevel:0];
    
    CVPixelBufferCreateWithBytes(kCFAllocatorDefault,texture.width,texture.height,kCVPixelFormatType_32BGRA,imageBytes,bytesPerRow,NULL,NULL,(__bridge CFDictionaryRef)options,&pxbuffer);
    
    free(imageBytes);
    
    return pxbuffer;
}

CVPixelBufferRef生成UIImage

- (UIImage *)imageFromPixelBuffer:(CVPixelBufferRef)pixelBufferRef {
    CVImageBufferRef imageBuffer =  pixelBufferRef;
    
    CVPixelBufferLockBaseAddress(imageBuffer, 0);
    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);
    size_t width = CVPixelBufferGetWidth(imageBuffer);
    size_t height = CVPixelBufferGetHeight(imageBuffer);
    size_t bufferSize = CVPixelBufferGetDataSize(imageBuffer);
    size_t bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer, 0);
    
    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, baseAddress, bufferSize, NULL);
    
    CGImageRef cgImage = CGImageCreate(width, height, 8, 32, bytesPerRow, rgbColorSpace, kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrderDefault, provider, NULL, true, kCGRenderingIntentDefault);
    UIImage *image = [UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);
    CGDataProviderRelease(provider);
    CGColorSpaceRelease(rgbColorSpace);
    
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
    return image;
}

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