Fix issue with cacheless filters destroying partial rendering content when being rendered

Author: David Gillen

src/easeljs/display/StageGL.js

@@ -1419,8 +1419,7 @@ this.createjs = this.createjs||{};
 		var storeBatchTemp = this._batchTextureTemp;
 
 		var filterCount = manager._filterCount, filtersLeft = filterCount;
-		var backupWidth = this._viewportWidth, backupHeight = this._viewportHeight;
-		this.updateViewport(manager._drawWidth, manager._drawHeight);
+		this._updateDrawingSurface(manager._drawWidth, manager._drawHeight);
 
 		this._batchTextureOutput = (manager._filterCount%2) ? manager._bufferTextureConcat : manager._bufferTextureOutput;
 		this._batchTextureConcat = (manager._filterCount%2) ? manager._bufferTextureOutput : manager._bufferTextureConcat;
@@ -1461,7 +1460,7 @@ this.createjs = this.createjs||{};
 		this._batchTextureConcat = storeBatchConcat;
 		this._batchTextureTemp = storeBatchTemp;
 
-		this.updateViewport(backupWidth, backupHeight);
+		this._updateDrawingSurface();
 		return true;
 	};
 
@@ -1583,30 +1582,17 @@ this.createjs = this.createjs||{};
 	p.updateViewport = function (width, height) {
 		this._viewportWidth = width|0;
 		this._viewportHeight = height|0;
-		var gl = this._webGLContext;
 
-		if (gl) {
-			gl.viewport(0, 0, this._viewportWidth, this._viewportHeight);
-
-			// WebGL works with a -1,1 space on its screen. It also follows Y-Up
-			// we need to flip the y, scale and then translate the co-ordinates to match this
-			// additionally we offset into they Y so the polygons are inside the camera's "clipping" plane
-			this._projectionMatrix = new Float32Array([
-				2 / this._viewportWidth,	0,								0,							0,
-				0,							-2 / this._viewportHeight,		0,							0,
-				0,							0,								1,							0,
-				-1,							1,								0,							1
-			]);
-
-			if (this._bufferTextureOutput !== this && this._bufferTextureOutput !== null) {
-				this.resizeTexture(this._bufferTextureOutput, this._viewportWidth, this._viewportHeight);
-			}
-			if (this._bufferTextureConcat !== null) {
-				this.resizeTexture(this._bufferTextureConcat, this._viewportWidth, this._viewportHeight);
-			}
-			if (this._bufferTextureTemp !== null) {
-				this.resizeTexture(this._bufferTextureTemp, this._viewportWidth, this._viewportHeight);
-			}
+		this._updateDrawingSurface(width, height);
+
+		if (this._bufferTextureOutput !== this && this._bufferTextureOutput !== null) {
+			this.resizeTexture(this._bufferTextureOutput, this._viewportWidth, this._viewportHeight);
+		}
+		if (this._bufferTextureConcat !== null) {
+			this.resizeTexture(this._bufferTextureConcat, this._viewportWidth, this._viewportHeight);
+		}
+		if (this._bufferTextureTemp !== null) {
+			this.resizeTexture(this._bufferTextureTemp, this._viewportWidth, this._viewportHeight);
 		}
 	};
 
@@ -1810,6 +1796,29 @@ this.createjs = this.createjs||{};
 	};
 
 // private methods:
+	/**
+	 * Changes the active drawing surface and view matrix to the correct parameters without polluting the concept
+	 * of the current stage size
+	 * @param  {uint} [w=_viewportWidth] The width of the surface in pixels, defaults to _viewportWidth
+	 * @param  {uint} [h=_viewportHeight] The height of the surface in pixels, defaults to _viewportHeight
+	 */
+	p._updateDrawingSurface = function(w, h) {
+		if(w === undefined){ w = this._viewportWidth; }
+		if(h === undefined){ h = this._viewportHeight; }
+
+		this._webGLContext.viewport(0, 0, w, h);
+
+		// WebGL works with a -1,1 space on its screen. It also follows Y-Up
+		// we need to flip the y, scale and then translate the co-ordinates to match this
+		// additionally we offset into they Y so the polygons are inside the camera's "clipping" plane
+		this._projectionMatrix = new Float32Array([
+			2 / w,		0,			0,			0,
+			0,			-2 / h,		0,			0,
+			0,			0,			1,			0,
+			-1,			1,			0,			1
+		]);
+	};
+
 	/**
 	 * Returns a base texture that has no image or data loaded. Not intended for loading images. In some error cases,
 	 * the texture creation will fail. This function differs from {{#crossLink "StageGL/getBaseTexture"}}{{/crossLink}}