# G3X_AlphaTest

## C Specification

  `#include <nitro/gx/g3x.h>`
  `void G3X_AlphaTest(BOOL enable, int ref);
  `

## Arguments

enable | Sets whether a-test occurs
ref | When the alpha-test is performed, pixels where alpha<=`ref` will not be rendered

## Return Values

None.

## Description

This function controls the alpha-test. When `enable` is not `FALSE`, the alpha value of the fragment after texture blending is compared to `ref`. The fragment is not rendered if it is less than the set value. When `enable` is `FALSE`, alpha testing does not occur.
Caution: A polygon (wire frame display) is not drawn when alpha=0 and ref is set as 31.

## See Also

## Revision History

01/19/2004 Initial version

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