diff --git a/src/scene/shader-lib/programs/lit-shader.js b/src/scene/shader-lib/programs/lit-shader.js
index 75984428c0c..9d688bfcb78 100644
--- a/src/scene/shader-lib/programs/lit-shader.js
+++ b/src/scene/shader-lib/programs/lit-shader.js
@@ -13,6 +13,7 @@ import {
     SPRITE_RENDERMODE_SLICED, SPRITE_RENDERMODE_TILED, shadowTypeInfo, SHADER_PREPASS,
     lightTypeNames, lightShapeNames, spriteRenderModeNames, fresnelNames, blendNames, lightFalloffNames,
     cubemaProjectionNames, specularOcclusionNames, reflectionSrcNames, ambientSrcNames,
+    ditherNames,
     REFLECTIONSRC_NONE
 } from '../../constants.js';
 import { ChunkUtils } from '../chunk-utils.js';
@@ -513,6 +514,12 @@ class LitShader {
         this._setupLightingDefines(hasAreaLights, options.clusteredLightingEnabled);
     }
 
+    preparePrepassPass() {
+        const { options } = this;
+        this.fDefineSet(options.alphaTest, 'LIT_ALPHA_TEST');
+        this.fDefineSet(true, 'STD_OPACITY_DITHER', ditherNames[options.opacityShadowDither]);
+    }
+
     prepareShadowPass() {
 
         const { options } = this;
@@ -548,8 +555,10 @@ class LitShader {
         this.includes.set('frontendDeclPS', frontendDecl ?? '');
         this.includes.set('frontendCodePS', frontendCode ?? '');
 
-        if (options.pass === SHADER_PICK || options.pass === SHADER_PREPASS) {
+        if (options.pass === SHADER_PICK) {
             // nothing to prepare currently
+        } else if (options.pass === SHADER_PREPASS) {
+            this.preparePrepassPass();
         } else if (this.shadowPass) {
             this.prepareShadowPass();
         } else {