layer.perspective < number>

Sets the perspective for child layers. Perspective gives depth to 3d properties like rotationX, rotationY. The rotation is set from 1 to Infinity where 1 is a huge perspective. Setting perspective to 0 gives you an isometric effect. Perspective is disabled by default.
译：设置子层的透视。看了3D性能的深度像rotationx，rotationy。旋转是从1到无限的，其中1是一个巨大的视角。设置透视0给你一个等距的效果。默认情况下禁用透视。

layerA = new Layer

# Set the perspective for all sub layers 
layerA.perspective = 100

layerB = new Layer
    parent: layerA
    rotationX: 30
    rotationY: 30