nuclide/Documentation/Materials/commands/alphafunc.md

Materials: Commands

alphafunc

Syntax

alphaFunc

Overview

Determines the alpha test function used when rendering this surface.

Valid values are GT0, LT128, and GE128. These correspond to GREATER THAN 0, LESS THAN 128, and GREATER THAN OR EQUAL TO 128.

This function is used when determining if a pixel should be written to the frame-buffer. For example, if GT0 is specified, the only the portions of the texture map with corresponding alpha values greater than zero will be written to the framebuffer. By default alpha testing is disabled.

Both alpha testing and normal alpha blending can be used to get textures that have see-through parts. The difference is that alphaFunc is an all-or-nothing test, while blending smoothly blends between opaque and translucent at pixel edges.

Alpha test can also be used with depthWrite, allowing other effects to be conditionally layered on top of just the opaque pixels by setting depthFunc to equal.