Alpha Testing

Similar to the Z-Testing node and Stencil Testing nodes, the alpha value of a fragment can be used to reject it before the respective pixel is drawn.

The Alpha Testing node compares the alpha value of the fragment (after it has been lit and textures have been blended) to the value specified in RefAlpha using the operation set in Function:

• Always: The fragment always passes the test.
• GreaterEqual: The fragment passes the test if its alpha value is greater than or equal to the reference value.
• NotEqual: The fragment passes the test if its alpha value is not equal to the reference value.
• Greater: The fragment passes the test if its alpha value is greater than (not equal) to the reference value.
• LessEqual: The fragment passes the test if its alpha value is less than or equal to the reference value.
• Equal: The fragment passes the test if its alpha value is equal to the reference value.
• Less: The fragment passes the test if its alpha value is less than (not equal) to the reference value.
• Never: The fragment is never passes the test.

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