phaserjs#3673 fix nested mask behaviour for Phaser.CANVAS mode

Author: scott.liu

src/gameobjects/container/ContainerCanvasRenderer.js

@@ -54,7 +54,12 @@ var ContainerCanvasRenderer = function (renderer, container, interpolationPercen
 
     var alpha = container._alpha;
     var scrollFactorX = container.scrollFactorX;
-    var scrollFactorY = container.scrollFactorY;
+	var scrollFactorY = container.scrollFactorY;
+	
+	if (container.mask) {
+		container.mask.preRenderCanvas(renderer, null, camera);
+	}
+
 
     for (var i = 0; i < children.length; i++)
     {
@@ -85,7 +90,11 @@ var ContainerCanvasRenderer = function (renderer, container, interpolationPercen
         //  Restore original values
         child.setAlpha(childAlpha);
         child.setScrollFactor(childScrollFactorX, childScrollFactorY);
-    }
+	}
+	
+	if (container.mask) {
+		container.mask.postRenderCanvas(renderer);
+	}	
 };
 
 module.exports = ContainerCanvasRenderer;

src/renderer/canvas/CanvasRenderer.js

@@ -765,10 +765,18 @@ var CanvasRenderer = new Class({
 
         ctx.globalAlpha = alpha;
 
-        ctx.imageSmoothingEnabled = !(!this.antialias || frame.source.scaleMode);
+		ctx.imageSmoothingEnabled = !(!this.antialias || frame.source.scaleMode);
+		
+		if (sprite.mask) {
+			sprite.mask.preRenderCanvas(this, sprite, camera);
+		}
 
         ctx.drawImage(frame.source.image, frameX, frameY, frameWidth, frameHeight, x, y, frameWidth / res, frameHeight / res);
 
+		if (sprite.mask) {
+			sprite.mask.postRenderCanvas(this, sprite, camera);
+		}  
+
         ctx.restore();
     },