Internal MapUtils.merge to merge maps

src/core/map-utils.js

@@ -0,0 +1,36 @@
+/**
+ * Map utility functions.
+ *
+ * @ignore
+ */
+class MapUtils {
+    /**
+     * Merges multiple maps into a new Map instance. If multiple maps contain the same key, the
+     * value from the later map in the arguments list takes precedence.
+     *
+     * Null or undefined maps are safely handled and skipped during the merge process.
+     *
+     * @param {...(Map|null|undefined)} maps - Maps to merge.
+     * @returns {Map} A new Map containing all entries from the input maps with conflicts resolved.
+     * @example
+     * // Create a merged map where entries from map2 override entries from map1
+     * const mergedMap = MapUtils.merge(map1, map2);
+     */
+    static merge(...maps) {
+        // Start with a copy of the first map for better performance with large maps
+        const result = new Map(maps[0] ?? []);
+
+        // Add entries from remaining maps, overriding existing keys
+        for (let i = 1; i < maps.length; i++) {
+            const map = maps[i];
+            if (map) {
+                for (const [key, value] of map) {
+                    result.set(key, value);
+                }
+            }
+        }
+        return result;
+    }
+}
+
+export { MapUtils };

src/scene/gsplat/gsplat-material.js

@@ -7,7 +7,7 @@ import { ShaderMaterial } from '../materials/shader-material.js';
 import { ShaderChunks } from '../shader-lib/shader-chunks.js';
 
 /**
- * import { GraphicsDevice } from '../../platform/graphics/graphics-device.js'
+ * @import { GraphicsDevice } from '../../platform/graphics/graphics-device.js'
  */
 
 /**

src/scene/shader-lib/programs/lit.js

@@ -4,6 +4,7 @@ import { ShaderGenerator } from './shader-generator.js';
 import { SHADERLANGUAGE_WGSL, SHADERTAG_MATERIAL } from '../../../platform/graphics/constants.js';
 import { ShaderDefinitionUtils } from '../../../platform/graphics/shader-definition-utils.js';
 import { hashCode } from '../../../core/hash.js';
+import { MapUtils } from '../../../core/map-utils.js';
 
 /**
  * @import { GraphicsDevice } from '../../../platform/graphics/graphics-device.js'
@@ -46,10 +47,8 @@ class ShaderGeneratorLit extends ShaderGenerator {
 
         litShader.generateFragmentShader('', litShader.shaderLanguage === SHADERLANGUAGE_WGSL ? options.shaderChunkWGSL : options.shaderChunkGLSL, 'vUv0');
 
-        const includes = new Map(Object.entries({
-            ...Object.fromEntries(litShader.chunks), // chunks collected by the lit shader
-            ...Object.fromEntries(litShader.includes) // includes generated by the lit shader
-        }));
+        // chunks collected by the lit shader + includes generated by the lit shader
+        const includes = MapUtils.merge(litShader.chunks, litShader.includes);
 
         const vDefines = litShader.vDefines;
         options.defines.forEach((value, key) => vDefines.set(key, value));

src/scene/shader-lib/programs/standard.js

@@ -12,6 +12,7 @@ import { LitOptionsUtils } from './lit-options-utils.js';
 import { ShaderGenerator } from './shader-generator.js';
 import { ShaderDefinitionUtils } from '../../../platform/graphics/shader-definition-utils.js';
 import { SHADERTAG_MATERIAL } from '../../../platform/graphics/constants.js';
+import { MapUtils } from '../../../core/map-utils.js';
 
 /**
  * @import { GraphicsDevice } from '../../../platform/graphics/graphics-device.js'
@@ -437,10 +438,8 @@ class ShaderGeneratorStandard extends ShaderGenerator {
         // use the outputs from this standard shader generator as an input to the lit shader generator
         litShader.generateFragmentShader(litShader.chunks.get('stdDeclarationPS'), litShader.chunks.get('stdFrontEndPS'), lightingUv);
 
-        const includes = new Map(Object.entries({
-            ...Object.fromEntries(litShader.chunks), // chunks collected by the lit shader
-            ...Object.fromEntries(litShader.includes) // includes generated by the lit shader
-        }));
+        // chunks collected by the lit shader + includes generated by the lit shader
+        const includes = MapUtils.merge(litShader.chunks, litShader.includes);
 
         const vDefines = litShader.vDefines;
         options.defines.forEach((value, key) => vDefines.set(key, value));

src/scene/shader-lib/shader-utils.js

@@ -6,6 +6,7 @@ import { ShaderGenerator } from './programs/shader-generator.js';
 import { ShaderPass } from '../shader-pass.js';
 import { SHADERLANGUAGE_GLSL, SHADERLANGUAGE_WGSL } from '../../platform/graphics/constants.js';
 import { ShaderChunks } from './shader-chunks.js';
+import { MapUtils } from '../../core/map-utils.js';
 
 /**
  * @import { GraphicsDevice } from '../../platform/graphics/graphics-device.js'
@@ -99,8 +100,8 @@ class ShaderUtils {
             Debug.assert(fragmentCode, 'ShaderUtils.createShader: fragment shader code not provided', options);
 
             // add default shader chunks to includes
-            const fragmentIncludes = options.fragmentIncludes ? new Map([...chunksMap, ...options.fragmentIncludes]) : new Map(chunksMap);
-            const vertexIncludes = options.vertexIncludes ? new Map([...chunksMap, ...options.vertexIncludes]) : new Map(chunksMap);
+            const fragmentIncludes = MapUtils.merge(chunksMap, options.fragmentIncludes);
+            const vertexIncludes = MapUtils.merge(chunksMap, options.vertexIncludes);
 
             shader = new Shader(device, ShaderDefinitionUtils.createDefinition(device, {
                 name: options.uniqueName,