Class: BitmapMask

Phaser.Display.Masks. BitmapMask

A Bitmap Mask combines the alpha (opacity) of a masked pixel with the alpha of another pixel. Unlike the Geometry Mask, which is a clipping path, a Bitmap Mask behaves like an alpha mask, not a clipping path. It is only available when using the WebGL Renderer.

A Bitmap Mask can use any Game Object to determine the alpha of each pixel of the masked Game Object(s). For any given point of a masked Game Object's texture, the pixel's alpha will be multiplied by the alpha of the pixel at the same position in the Bitmap Mask's Game Object. The color of the pixel from the Bitmap Mask doesn't matter.

For example, if a pure blue pixel with an alpha of 0.95 is masked with a pure red pixel with an alpha of 0.5, the resulting pixel will be pure blue with an alpha of 0.475. Naturally, this means that a pixel in the mask with an alpha of 0 will hide the corresponding pixel in all masked Game Objects A pixel with an alpha of 1 in the masked Game Object will receive the same alpha as the corresponding pixel in the mask.

The Bitmap Mask's location matches the location of its Game Object, not the location of the masked objects. Moving or transforming the underlying Game Object will change the mask (and affect the visibility of any masked objects), whereas moving or transforming a masked object will not affect the mask.

The Bitmap Mask will not render its Game Object by itself. If the Game Object is not in a Scene's display list, it will only be used for the mask and its full texture will not be directly visible. Adding the underlying Game Object to a Scene will not cause any problems - it will render as a normal Game Object and will also serve as a mask.


new BitmapMask(scene, renderable)

Parameters:
Name Type Description
scene Phaser.Scene

The Scene which this Bitmap Mask will be used in.

renderable Phaser.GameObjects.GameObject

A renderable Game Object that uses a texture, such as a Sprite.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 9)

Members


bitmapMask :Phaser.GameObjects.GameObject

A renderable Game Object that uses a texture, such as a Sprite.

Type:
Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 61)

dirty :boolean

Whether the Bitmap Mask is dirty and needs to be updated.

Type:
  • boolean
Since: 3.0.0
Default Value:
  • true
Source: src/display/mask/BitmapMask.js (Line 90)

invertAlpha :boolean

Whether to invert the mask's alpha.

If true, the alpha of the masking pixel will be inverted before it's multiplied with the masked pixel. Essentially, this means that a masked area will be visible only if the corresponding area in the mask is invisible.

Type:
  • boolean
Since: 3.1.2
Source: src/display/mask/BitmapMask.js (Line 118)

mainFramebuffer :WebGLFramebuffer

The framebuffer to which a masked Game Object is rendered.

Type:
  • WebGLFramebuffer
Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 100)

mainTexture :WebGLTexture

The texture used for the main framebuffer.

Type:
  • WebGLTexture
Since: 3.0.0
Default Value:
  • null
Source: src/display/mask/BitmapMask.js (Line 80)

maskFramebuffer :WebGLFramebuffer

The framebuffer to which the Bitmap Mask's masking Game Object is rendered.

Type:
  • WebGLFramebuffer
Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 109)

maskTexture :WebGLTexture

The texture used for the mask's framebuffer.

Type:
  • WebGLTexture
Since: 3.0.0
Default Value:
  • null
Source: src/display/mask/BitmapMask.js (Line 70)

renderer :Phaser.Renderer.Canvas.CanvasRenderer|Phaser.Renderer.WebGL.WebGLRenderer

A reference to either the Canvas or WebGL Renderer that this Mask is using.

Type:
Since: 3.11.0
Source: src/display/mask/BitmapMask.js (Line 52)

Methods


destroy()

Destroys this BitmapMask and nulls any references it holds.

Note that if a Game Object is currently using this mask it will not automatically detect you have destroyed it, so be sure to call clearMask on any Game Object using it, before destroying it.

Since: 3.7.0
Source: src/display/mask/BitmapMask.js (Line 234)

postRenderCanvas(renderer)

This is a NOOP method. Bitmap Masks are not supported by the Canvas Renderer.

Parameters:
Name Type Description
renderer Phaser.Renderer.Canvas.CanvasRenderer | Phaser.Renderer.WebGL.WebGLRenderer

The Canvas Renderer which would be rendered to.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 221)

postRenderWebGL(renderer)

Finalizes rendering of a masked Game Object.

This resets the previously bound framebuffer and switches the WebGL Renderer to the Bitmap Mask Pipeline, which uses a special fragment shader to apply the masking effect.

Parameters:
Name Type Description
renderer Phaser.Renderer.Canvas.CanvasRenderer | Phaser.Renderer.WebGL.WebGLRenderer

The WebGL Renderer to clean up.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 191)

preRenderCanvas(renderer, mask, camera)

This is a NOOP method. Bitmap Masks are not supported by the Canvas Renderer.

Parameters:
Name Type Description
renderer Phaser.Renderer.Canvas.CanvasRenderer | Phaser.Renderer.WebGL.WebGLRenderer

The Canvas Renderer which would be rendered to.

mask Phaser.GameObjects.GameObject

The masked Game Object which would be rendered.

camera Phaser.Cameras.Scene2D.Camera

The Camera to render to.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 206)

preRenderWebGL(renderer, maskedObject, camera)

Prepares the WebGL Renderer to render a Game Object with this mask applied.

This renders the masking Game Object to the mask framebuffer and switches to the main framebuffer so that the masked Game Object will be rendered to it instead of being rendered directly to the frame.

Parameters:
Name Type Description
renderer Phaser.Renderer.Canvas.CanvasRenderer | Phaser.Renderer.WebGL.WebGLRenderer

The WebGL Renderer to prepare.

maskedObject Phaser.GameObjects.GameObject

The masked Game Object which will be drawn.

camera Phaser.Cameras.Scene2D.Camera

The Camera to render to.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 174)

setBitmap(renderable)

Sets a new masking Game Object for the Bitmap Mask.

Parameters:
Name Type Description
renderable Phaser.GameObjects.GameObject

A renderable Game Object that uses a texture, such as a Sprite.

Since: 3.0.0
Source: src/display/mask/BitmapMask.js (Line 161)