autoclear scene moved to prepassrenderer

src/PostProcesses/RenderPipeline/Pipelines/defaultRenderingPipeline.ts

@@ -501,6 +501,7 @@ export class DefaultRenderingPipeline extends PostProcessRenderPipeline implemen
             postProcess.autoClear = false;
         } else {
             postProcess.autoClear = true;
+            this._scene.autoClear = false;
             this._hasCleared = true;
         }
 
@@ -524,6 +525,7 @@ export class DefaultRenderingPipeline extends PostProcessRenderPipeline implemen
         if (!this._buildAllowed) {
             return;
         }
+        this._scene.autoClear = true;
 
         var engine = this._scene.getEngine();
 
@@ -628,6 +630,11 @@ export class DefaultRenderingPipeline extends PostProcessRenderPipeline implemen
             this._scene.postProcessRenderPipelineManager.attachCamerasToRenderPipeline(this._name, this._cameras);
         }
 
+        // In multicamera mode, the scene needs to autoclear in between cameras.
+        if (this._scene.activeCameras && this._scene.activeCameras.length > 1) {
+            this._scene.autoClear = true;
+        }
+
         if (!this._enableMSAAOnFirstPostProcess(this.samples) && this.samples > 1) {
             Logger.Warn("MSAA failed to enable, MSAA is only supported in browsers that support webGL >= 2.0");
         }
@@ -717,7 +724,7 @@ export class DefaultRenderingPipeline extends PostProcessRenderPipeline implemen
         this.onBuildObservable.clear();
         this._disposePostProcesses(true);
         this._scene.postProcessRenderPipelineManager.detachCamerasFromRenderPipeline(this._name, this._cameras);
-
+        this._scene.autoClear = true;
         if (this._resizeObserver) {
             this._scene.getEngine().onResizeObservable.remove(this._resizeObserver);
             this._resizeObserver = null;

src/Rendering/prePassRenderer.ts

@@ -540,7 +540,8 @@ export class PrePassRenderer {
         const secondaryCamera = camera && this._scene.activeCameras && !!this._scene.activeCameras.length && this._scene.activeCameras.indexOf(camera) !== 0;
         this._postProcessesSourceForThisPass = this._getPostProcessesSource(prePassRenderTarget, camera);
         this._postProcessesSourceForThisPass = (this._postProcessesSourceForThisPass.filter((pp) => { return pp != null; }));
-
+        this._scene.autoClear = true;
+        
         const cameraHasImageProcessing = this._hasImageProcessing(this._postProcessesSourceForThisPass);
         this._needsCompositionForThisPass = !cameraHasImageProcessing &&
             !this.disableGammaTransform &&