Lib Alpha - Shader API

Last update: Thu Feb 26 2026 00:00:00 GMT+0000 (Coordinated Universal Time)

lib-alpha.glsl

Public Functions: alphaKill


import lib-sampler.glsl

import lib-random.glsl

Opacity map, provided by the engine.


//: param auto channel_opacity

uniform SamplerSparse opacity_tex;

Alpha test threshold.


//: param custom {

//:   "default": 0.33,

//:   "label": "Alpha threshold",

//:   "min": 0.0,

//:   "max": 1.0,

//:   "group": "Common Parameters"

//: }

uniform float alpha_threshold;

Alpha test dithering.


//: param custom {

//:   "default": false,

//:   "label": "Alpha dithering",

//:   "group": "Common Parameters"

//: }

uniform bool alpha_dither;

Emulate alpha test : discard current fragment if its opacity is below a user defined threshold. Should be called AFTER texture sampling calls: it can break derivatives


void alphaKill(float alpha)

{

  float threshold = alpha_dither ? getBlueNoiseThresholdTemporal() : alpha_threshold;

  if (alpha < threshold) discard;

}



void alphaKill(SparseCoord coord)

{

  alphaKill(getOpacity(opacity_tex, coord));

}

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