Fixture:getBoundingBox
Returns the points of the fixture bounding box. In case the fixture has multiple children a 1-based index can be specified. For example, a fixture will have multiple children with a chain shape.
topLeftX, topLeftY, bottomRightX, bottomRightY = Fixture:getBoundingBox( index )
index (1) number A bounding box of the fixture.
topLeftX number The x position of the top-left point.
topLeftY number The y position of the top-left point.
bottomRightX number The x position of the bottom-right point.
bottomRightY number The y position of the bottom-right point.