Dispatch precompose and postcompose events for WebGL layers

src/ol/renderer/webgl/Layer.js

@@ -88,6 +88,45 @@ class WebGLLayerRenderer extends LayerRenderer {
     this.helper;
 
     layer.addChangeListener(LayerProperty.MAP, this.removeHelper_.bind(this));
+
+    this.dispatchPreComposeEvent = this.dispatchPreComposeEvent.bind(this);
+    this.dispatchPostComposeEvent = this.dispatchPostComposeEvent.bind(this);
+  }
+
+  /**
+   * @param {WebGLRenderingContext} context The WebGL rendering context.
+   * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
+   * @protected
+   */
+  dispatchPreComposeEvent(context, frameState) {
+    const layer = this.getLayer();
+    if (layer.hasListener(RenderEventType.PRECOMPOSE)) {
+      const event = new RenderEvent(
+        RenderEventType.PRECOMPOSE,
+        undefined,
+        frameState,
+        context
+      );
+      layer.dispatchEvent(event);
+    }
+  }
+
+  /**
+   * @param {WebGLRenderingContext} context The WebGL rendering context.
+   * @param {import("../../PluggableMap.js").FrameState} frameState Frame state.
+   * @protected
+   */
+  dispatchPostComposeEvent(context, frameState) {
+    const layer = this.getLayer();
+    if (layer.hasListener(RenderEventType.POSTCOMPOSE)) {
+      const event = new RenderEvent(
+        RenderEventType.POSTCOMPOSE,
+        undefined,
+        frameState,
+        context
+      );
+      layer.dispatchEvent(event);
+    }
   }
 
   /**

src/ol/renderer/webgl/PointsLayer.js

@@ -450,7 +450,11 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
 
     const renderCount = this.indicesBuffer_.getSize();
     this.helper.drawElements(0, renderCount);
-    this.helper.finalizeDraw(frameState);
+    this.helper.finalizeDraw(
+      frameState,
+      this.dispatchPreComposeEvent,
+      this.dispatchPostComposeEvent
+    );
     const canvas = this.helper.getCanvas();
 
     if (this.hitDetectionEnabled_) {

src/ol/renderer/webgl/TileLayer.js

@@ -552,7 +552,11 @@ class WebGLTileLayerRenderer extends WebGLLayerRenderer {
       }
     }
 
-    this.helper.finalizeDraw(frameState);
+    this.helper.finalizeDraw(
+      frameState,
+      this.dispatchPreComposeEvent,
+      this.dispatchPostComposeEvent
+    );
 
     const canvas = this.helper.getCanvas();