From bf199bbe389c1a8290a5cdcd9d1ee44b7210b73a Mon Sep 17 00:00:00 2001
From: mike-000 <49240900+mike-000@users.noreply.github.com>
Date: Thu, 10 Feb 2022 11:40:44 +0000
Subject: [PATCH] handle WebGL layers

---
 src/ol/source/Raster.js | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/ol/source/Raster.js b/src/ol/source/Raster.js
index dfe0e1df75..d4c1a0f982 100644
--- a/src/ol/source/Raster.js
+++ b/src/ol/source/Raster.js
@@ -917,15 +917,19 @@ function getImageData(layer, frameState) {
   }
   const container = renderer.renderFrame(frameState, null);
   let element;
-  if (container) {
-    element = container.firstElementChild;
-  }
-  if (!(element instanceof HTMLCanvasElement)) {
-    throw new Error('Unsupported rendered element: ' + element);
-  }
-  if (element.width === width && element.height === height) {
-    const context = element.getContext('2d');
-    return context.getImageData(0, 0, width, height);
+  if (container instanceof HTMLCanvasElement) {
+    element = container;
+  } else {
+    if (container) {
+      element = container.firstElementChild;
+    }
+    if (!(element instanceof HTMLCanvasElement)) {
+      throw new Error('Unsupported rendered element: ' + element);
+    }
+    if (element.width === width && element.height === height) {
+      const context = element.getContext('2d');
+      return context.getImageData(0, 0, width, height);
+    }
   }
 
   if (!sharedContext) {