[Home](./index.md) > [server](./server.md) > [ParticleEmitterOptions](./server.particleemitteroptions.md) > [alphaTest](./server.particleemitteroptions.alphatest.md) ## ParticleEmitterOptions.alphaTest property The alpha test value, discards particle texture pixels with alpha opacity less than this value. Defaults to 0.5. **Signature:** ```typescript alphaTest?: number; ```