Implementing the IRenderer3D interface

The IRenderer3D interface defines the following methods:

public RenderingState getRenderingState();
public ImageProcessor render(RenderingState kf);
public ImagePlus getImage();

An implementing class typically keeps references to the input image stack, to the 3rd party rendering engine and to a RenderingState object:

private ExtRenderingState rs;
private ImagePlus input;
// private final ThridPartyRenderer renderer;

The constructor initializes the 3rd party renderer and the RenderingState object:
public ExtRenderer(ImagePlus input) {
	this.input = input;
	// renderer = new ThirdPartyRenderer();

	float[] pdIn = new float[] {
		(float)input.getCalibration().pixelWidth,
		(float)input.getCalibration().pixelHeight,
		(float)input.getCalibration().pixelDepth
	};

	float[] pdOut = new float[] {pdIn[0], pdIn[0], pdIn[0]};

	float[] rotcenter = new float[] {
			input.getWidth()   * pdIn[0] / 2,
			input.getHeight()  * pdIn[1] / 2,
			input.getNSlices() * pdIn[2] / 2};

	CombinedTransform transformation = new CombinedTransform(
							pdIn, pdOut, rotcenter);

	this.rs = new ExtRenderingState(0, transformation);
}

The most important method is render(): It uses the 3rd party rendering engine to produce an output image:

public ImageProcessor render(RenderingState rs) {
	double brightness = rs.getNonchannelProperty(
				ExtRenderingState.BRIGHTNESS);
	// renderer.setBrightness(brightness);
	
	float[] matrix = rs.getFwdTransform().
				calculateInverseTransform();
	// renderer.setTransformation(matrix);

	ImageProcessor output = null;
	// output = renderer.render();

	return output;
}