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Phaser . Display . Masks . BitmapMask

This is a beta release of our new docs system. Found an issue?
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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.

Note: You cannot combine Bitmap Masks and Blend Modes on the same Game Object. You can, however, combine Geometry Masks and Blend Modes together.

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.

Constructor:

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

Members

Description:

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

Type:
Since: 3.0.0
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dirty: boolean
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Description:

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

Type:
boolean
Default: true
Since: 3.0.0
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invertAlpha: boolean
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Description:

Whether to invert the masks 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
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<readonly> isStencil: boolean
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Description:

Is this mask a stencil mask?

Type:
boolean
Since: 3.17.0
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mainFramebuffer: WebGLFramebuffer
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Description:

The framebuffer to which a masked Game Object is rendered.

Type:
WebGLFramebuffer
Since: 3.0.0
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mainTexture: WebGLTexture
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Description:

The texture used for the main framebuffer.

Type:
WebGLTexture
Default: null
Since: 3.0.0
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maskFramebuffer: WebGLFramebuffer
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Description:

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

Type:
WebGLFramebuffer
Since: 3.0.0
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maskTexture: WebGLTexture
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Description:

The texture used for the masks framebuffer.

Type:
WebGLTexture
Default: null
Since: 3.0.0
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Description:

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

Type:
Since: 3.11.0
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Methods

clearMask()
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Description:

Deletes the mainTexture and maskTexture WebGL Textures and deletes the mainFramebuffer and maskFramebuffer too, nulling all references.

This is called when this mask is destroyed, or if you try to creat a new mask from this object when one is already set.

Examples:
Since: 3.50.0
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createMask()
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Description:

Creates the WebGL Texture2D objects and Framebuffers required for this mask. If this mask has already been created, then clearMask is called first.

Examples:
Since: 3.50.0
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destroy()
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Description:

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.

Examples:
Since: 3.7.0
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postRenderCanvas(renderer)
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Description:

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.

Examples:
Since: 3.0.0
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postRenderWebGL(renderer)
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Description:

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.

Examples:
Since: 3.0.0
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preRenderCanvas(renderer, mask, camera)
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Description:

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.

Examples:
Since: 3.0.0
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preRenderWebGL(renderer, maskedObject, camera)
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Description:

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.

Examples:
Since: 3.0.0
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setBitmap(renderable)
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Description:

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.

Examples:
Since: 3.0.0
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