From b433cfb792429a63a460d4c3d2ce5a21a026d168 Mon Sep 17 00:00:00 2001
From: David Manthey <david.manthey@kitware.com>
Date: Wed, 26 Jun 2019 08:54:19 -0400
Subject: [PATCH] Explicitly exit retired renderers.

Before, this was waiting for GC to clean up unused renderers, which
might not happen if renderers were created and destroyed without a major
GC event.  If GC didn't occur, the webgl context wouldn't be released.
This explicitly exits the renderers (and explicitly loses the webgl
context) as soon as the renderer is no longer in use (due to
autosharing).
---
 src/webgl/layer.js | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/webgl/layer.js b/src/webgl/layer.js
index 80faf8789e..1de01d8644 100644
--- a/src/webgl/layer.js
+++ b/src/webgl/layer.js
@@ -136,8 +136,6 @@ var webgl_layer = function () {
       map._updateAutoshareRenderers = function () {
         var layers = map.sortedLayers(),
             renderer,
-            used_canvases = [],
-            canvases = [],
             rerender_list = [],
             opacity;
         layers.forEach(function (layer) {
@@ -149,12 +147,10 @@ var webgl_layer = function () {
               rerender_list.push(layer.renderer());
             }
             renderer = layer.renderer();
-            used_canvases.push(renderer.canvas()[0]);
             opacity = layer.opacity();
           } else {
             if (layer.renderer() !== renderer) {
               rerender_list.push(layer.renderer());
-              canvases.push(layer.renderer().canvas()[0]);
               layer.switchRenderer(renderer, false);
               rerender_list.push(layer.renderer());
             }
@@ -169,15 +165,13 @@ var webgl_layer = function () {
         });
         layers.forEach(function (layer) {
           if (rerender_list.indexOf(layer.renderer()) >= 0) {
-            layer.renderer()._render();
+            layer.renderer()._renderFrame();
             rerender_list = rerender_list.filter((val) => val !== layer.renderer());
           }
         });
-        canvases.forEach(function (canvas) {
-          if (used_canvases.indexOf(canvas) < 0) {
-            canvas.remove();
-            used_canvases.push(canvas);
-          }
+        /* explicitly exit any renderers we no longer use */
+        rerender_list.forEach(function (renderer) {
+          renderer._exit();
         });
       };