alphaTestRef

uniform float alphaTestRef;

This value stores the alpha value that Iris recommends you discard pixels bellow. This value is commonly 0.1, but can change in certain cases (therefore it is recommended to use the uniform over a hardcoded value). The value is also affected by the alphaTest directive. It is normally used like this:

if (albedoOut.a < alphaTestRef) discard;

Note

This uniform is designed to work with the modern syntax for fragment shader outputs (out). When Using the legacy syntax (gl_FragData) this uniform is not necessary as the alpha test will be performed automatically.