Merge pull request #7213 from AnalyticalGraphicsInc/fix-post-process-crash

Fix crash when removing a post-process stage.

Author: lilleyse

CHANGES.md

@@ -27,6 +27,7 @@ Change Log
 * Fixed clipping planes on tilesets not taking into account the tileset model matrix. [#7182](https://github.com/AnalyticalGraphicsInc/cesium/pull/7182)
 * Fixed middle mouse button locked glitch [#7137](https://github.com/AnalyticalGraphicsInc/cesium/pull/7137)
 * Fixed an issue where dynamic Entities on terrain would cause a crash in platforms that do not support depth textures such as Internet Explorer [#7103](https://github.com/AnalyticalGraphicsInc/cesium/issues/7103)
+* Fixed an issue that would cause a crash when removing a post process stage. [#7210](https://github.com/AnalyticalGraphicsInc/cesium/issues/7210)
 
 ### 1.50 - 2018-10-01
 

Source/Scene/PostProcessStageCollection.js

@@ -294,6 +294,9 @@ define([
                 var stages = arraySlice(this._stages);
                 while (stages.length > 0) {
                     var stage = stages.pop();
+                    if (!defined(stage)) {
+                        continue;
+                    }
                     if (defined(stage.selected)) {
                         return true;
                     }

Specs/Scene/PostProcessStageCollectionSpec.js

@@ -73,6 +73,18 @@ defineSuite([
         }).toThrowDeveloperError();
     });
 
+    it('removes a single stage', function() {
+        var stage1 = scene.postProcessStages.add(new PostProcessStage({
+            fragmentShader : 'void main() { gl_FragColor = vec4(1.0, 1.0, 0.0, 1.0); }'
+        }));
+        scene.renderForSpecs();
+        expect(scene).toRender([255, 255, 0, 255]);
+
+        scene.postProcessStages.remove(stage1);
+        scene.renderForSpecs();
+        expect(scene).toRender([0, 0, 0, 255]);
+    });
+
     it('removes stages', function() {
         expect(scene).toRender([0, 0, 0, 255]);