Add KHR_materials_transmission export support (playcanvas#8277)

willeastcott · Copilot · web-flow · commit 61b1485628db · 2025-12-19T13:51:33.000Z
* Add KHR_materials_transmission export support

* Update src/extras/exporters/gltf-exporter.js

Co-authored-by: Copilot &lt;175728472+Copilot@users.noreply.github.com&gt;

---------

Co-authored-by: Copilot &lt;175728472+Copilot@users.noreply.github.com&gt;
diff --git a/src/extras/exporters/gltf-exporter.js b/src/extras/exporters/gltf-exporter.js
@@ -125,6 +125,7 @@ const textureSemantics = [
     'emissiveMap',
     'metalnessMap',
     'normalMap',
+    'refractionMap',
     'specularityFactorMap',
     'specularMap'
 ];
@@ -499,6 +500,21 @@ class GltfExporter extends CoreExporter {
             }
         }
 
+        // KHR_materials_transmission
+        if (mat.useDynamicRefraction && (mat.refraction !== 0 || mat.refractionMap)) {
+            const transmissionExt = {};
+
+            if (mat.refraction !== 0) {
+                transmissionExt.transmissionFactor = mat.refraction;
+            }
+
+            this.attachTexture(resources, mat, transmissionExt, 'transmissionTexture', 'refractionMap', json);
+
+            if (Object.keys(transmissionExt).length > 0) {
+                this.addExtension(json, output, 'KHR_materials_transmission', transmissionExt);
+            }
+        }
+
         // KHR_materials_unlit
         if (!mat.useLighting) {
             this.addExtension(json, output, 'KHR_materials_unlit');
