From 4c5f88efedf0defb99f70c3b943c45441c188246 Mon Sep 17 00:00:00 2001
From: Martin Valigursky <mvaligursky@snapchat.com>
Date: Wed, 26 Feb 2025 15:02:11 +0000
Subject: [PATCH] Refactoring clustered lighting shader defines to be available
 as a chunk

---
 src/scene/lighting/lights-buffer.js           | 34 ++++++++-----------
 .../shader-lib/chunks-wgsl/chunks-wgsl.js     |  1 +
 src/scene/shader-lib/chunks/chunks.js         |  1 +
 src/scene/shader-lib/programs/lit-shader.js   |  3 +-
 4 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/src/scene/lighting/lights-buffer.js b/src/scene/lighting/lights-buffer.js
index e1150c4531e..d8a95eb333b 100644
--- a/src/scene/lighting/lights-buffer.js
+++ b/src/scene/lighting/lights-buffer.js
@@ -4,6 +4,8 @@ import { FloatPacking } from '../../core/math/float-packing.js';
 import { LIGHTSHAPE_PUNCTUAL, LIGHTTYPE_SPOT, MASK_AFFECT_LIGHTMAPPED, MASK_AFFECT_DYNAMIC } from '../constants.js';
 import { Texture } from '../../platform/graphics/texture.js';
 import { LightCamera } from '../renderer/light-camera.js';
+import { shaderChunks } from '../shader-lib/chunks/chunks.js';
+import { shaderChunksWGSL } from '../shader-lib/chunks-wgsl/chunks-wgsl.js';
 
 const epsilon = 0.000001;
 
@@ -48,29 +50,21 @@ const TextureIndexFloat = {
     COUNT: 8
 };
 
-let _defines;
+// converts object with properties to a list of these as an example: "#define CLUSTER_TEXTURE_8_BLAH 1"
+const buildShaderDefines = (object, prefix) => {
+    return Object.keys(object)
+    .map(key => `#define ${prefix}${key} ${object[key]}`)
+    .join('\n');
+};
+
+// create a shader chunk with defines for the light buffer textures
+shaderChunks.lightBufferDefinesPS = shaderChunksWGSL.lightBufferDefinesPS = `\n
+    ${buildShaderDefines(TextureIndex8, 'CLUSTER_TEXTURE_8_')}
+    ${buildShaderDefines(TextureIndexFloat, 'CLUSTER_TEXTURE_F_')}
+`;
 
 // A class used by clustered lighting, responsible for encoding light properties into textures for the use on the GPU
 class LightsBuffer {
-    static getShaderDefines() {
-
-        // converts object with properties to a list of these as an example: "#define CLUSTER_TEXTURE_8_BLAH 1"
-        const buildShaderDefines = (object, prefix) => {
-            return Object.keys(object)
-            .map(key => `#define ${prefix}${key} ${object[key]}`)
-            .join('\n');
-        };
-
-        if (!_defines) {
-            _defines =  `\n
-                ${buildShaderDefines(TextureIndex8, 'CLUSTER_TEXTURE_8_')}
-                ${buildShaderDefines(TextureIndexFloat, 'CLUSTER_TEXTURE_F_')}
-            `;
-        }
-
-        return _defines;
-    }
-
     areaLightsEnabled = false;
 
     constructor(device) {
diff --git a/src/scene/shader-lib/chunks-wgsl/chunks-wgsl.js b/src/scene/shader-lib/chunks-wgsl/chunks-wgsl.js
index f3c3b61f2de..878360fa17e 100644
--- a/src/scene/shader-lib/chunks-wgsl/chunks-wgsl.js
+++ b/src/scene/shader-lib/chunks-wgsl/chunks-wgsl.js
@@ -284,6 +284,7 @@ const shaderChunksWGSL = {
     // iridescencePS,
     // iridescenceThicknessPS,
     // iorPS,
+    lightBufferDefinesPS: '',  // this chunk gets genereated at startup
     // lightDeclarationPS,
     // lightDiffuseLambertPS,
     // lightDirPointPS,
diff --git a/src/scene/shader-lib/chunks/chunks.js b/src/scene/shader-lib/chunks/chunks.js
index e41ff3e79e5..bb7117cd58f 100644
--- a/src/scene/shader-lib/chunks/chunks.js
+++ b/src/scene/shader-lib/chunks/chunks.js
@@ -284,6 +284,7 @@ const shaderChunks = {
     iridescencePS,
     iridescenceThicknessPS,
     iorPS,
+    lightBufferDefinesPS: '',  // this chunk gets genereated at startup
     lightDeclarationPS,
     lightDiffuseLambertPS,
     lightDirPointPS,
diff --git a/src/scene/shader-lib/programs/lit-shader.js b/src/scene/shader-lib/programs/lit-shader.js
index 0fd320d56ed..a5f04beff87 100644
--- a/src/scene/shader-lib/programs/lit-shader.js
+++ b/src/scene/shader-lib/programs/lit-shader.js
@@ -19,7 +19,6 @@ import {
 } from '../../constants.js';
 import { shaderChunks } from '../chunks/chunks.js';
 import { ChunkUtils } from '../chunk-utils.js';
-import { LightsBuffer } from '../../lighting/lights-buffer.js';
 import { ShaderPass } from '../../shader-pass.js';
 import { validateUserChunks } from '../chunks/chunk-validation.js';
 import { ChunkBuilder } from '../chunk-builder.js';
@@ -587,7 +586,7 @@ class LitShader {
             #include "lightDeclarationPS, LIGHT_COUNT"
 
             #if defined(CLUSTERED_LIGHTS)
-                ${LightsBuffer.getShaderDefines()}
+                #include "lightBufferDefinesPS"
             #endif
 
             // required lighting functionality