Store rendererd source on the layer instead of the layer state

src/ol/layer/Layer.js

@@ -57,7 +57,6 @@ import {listen, unlistenByKey} from '../events.js';
  * @typedef {Object} State
  * @property {import("./Layer.js").default} layer Layer.
  * @property {number} opacity Opacity, the value is rounded to two digits to appear after the decimal point.
- * @property {import("../source/Source.js").default|undefined} source Source being rendered (only for multi-source layers).
  * @property {boolean} visible Visible.
  * @property {boolean} managed Managed.
  * @property {import("../extent.js").Extent} [extent] Extent.

src/ol/layer/WebGLTile.js

@@ -325,6 +325,12 @@ class WebGLTileLayer extends BaseTileLayer {
      */
     this.sources_ = options.sources;
 
+    /**
+     * @type {SourceType|null}
+     * @private
+     */
+    this.renderedSource_ = null;
+
     /**
      * @type {number}
      * @private
@@ -373,10 +379,7 @@ class WebGLTileLayer extends BaseTileLayer {
    * @return {SourceType} The source being rendered.
    */
   getRenderSource() {
-    return (
-      /** @type {SourceType} */ (this.getLayerState().source) ||
-      this.getSource()
-    );
+    return this.renderedSource_ || this.getSource();
   }
 
   /**
@@ -426,7 +429,7 @@ class WebGLTileLayer extends BaseTileLayer {
     const layerRenderer = this.getRenderer();
     let canvas;
     for (let i = 0, ii = sources.length; i < ii; ++i) {
-      this.getLayerState().source = sources[i];
+      this.renderedSource_ = sources[i];
       if (layerRenderer.prepareFrame(frameState)) {
         canvas = layerRenderer.renderFrame(frameState);
       }

test/rendering/cases/webgl-invisible-group/main.js

@@ -0,0 +1,27 @@
+import Group from '../../../../src/ol/layer/Group.js';
+import Map from '../../../../src/ol/Map.js';
+import OSM from '../../../../src/ol/source/OSM.js';
+import TileLayer from '../../../../src/ol/layer/WebGLTile.js';
+import View from '../../../../src/ol/View.js';
+
+new Map({
+  layers: [
+    new Group({
+      visible: false,
+      layers: [
+        new TileLayer({
+          source: new OSM(),
+        }),
+      ],
+    }),
+  ],
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    zoom: 0,
+  }),
+});
+
+render({
+  message: 'webgl tile layer in an invisible group is not rendered',
+});