ios - 如何将 CVPixelBuffer 设置为顶点着色器的输入？

Question

我想使用 Apple Metal 渲染路径来处理 CVPixelBuffer。

如何转换 CVPixelBuffer 使其符合顶点着色器的输入？不确定如何从 CVPixelBuffer 中提取颜色/位置值，以便我能够从主机设置它们。

Answer 1

这是我用来将 CVPixelBuffer 数据转换为 Metal 纹理的代码。

#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
  CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);

  id<MTLTexture> texture = nil;

  {
    size_t width = CVPixelBufferGetWidth(pixelBuffer);
    size_t height = CVPixelBufferGetHeight(pixelBuffer);

    MTLPixelFormat pixelFormat = MTLPixelFormatBGRA8Unorm;

    CVMetalTextureRef metalTextureRef = NULL;
    CVReturn status = CVMetalTextureCacheCreateTextureFromImage(NULL, _textureCache, pixelBuffer, NULL, pixelFormat, width, height, 0, &metalTextureRef);
    if(status == kCVReturnSuccess)
    {
      texture = CVMetalTextureGetTexture(metalTextureRef);
      if (self.delegate){
        [self.delegate textureUpdated:texture];
      }
      CFRelease(metalTextureRef);
    }
  }
}

获得纹理后，只需将其传递给 renderCommandEncoder。如果您需要这方面的帮助，请在评论中告诉我。