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Rendering Layers
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As most rendering engines, HOOPS Luminate can generate rendering layers while it computes an image.

.. include:: /tasks/ta_ca/ta_ca_rendering/tk_setting_up_rendering_layers.rst

Usual rendering layers are color, depth, normal, reflection, refraction, ...

.. figure:: render_layers.png
    :align: center
    
    **An example of software rendering layers**


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The Masking Render Layer
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The ``RED::LT_MASK`` rendering layer is very special. Unlike other rendering layers, it's not an output of the rendering; This special layer can be used as an input to the rendering, and can be used to specify which pixels in an image have to be processed. It can be used for a variety of tasks that may require to only recompute some pixels in an image for instance.


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The Computed Render Layer
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The ``RED::LT_COMPUTED`` rendering layer is another special layer. It indicates which pixels in the image have been calculated 'so far' by the ``RED::IWindow::FrameTracingImageLayers`` method. It can be used as an indication of which portions in an image have been really processed. This layer must be carefully used as the rendering engine feedback may reconstruct an image whose contents are not finalized while the image calculation is not over.

 
