Game Programming II

1
Game Programming II

• MULT 120
• Collisions in Flash

2
hitTest Method

• MovieClip.hitTest()
• Usage
• my_mc.hitTest(xNumber, yNumber,
  shapeFlagBoolean) Boolean my_mc.hitTest(target
  Object) Boolean
• Parameters
• x The x coordinate of the hit area on the Stage.
• y The y coordinate of the hit area on the Stage.
• The x and y coordinates are defined in the global
  coordinate space.
• target The target path of the hit area that may
  intersect or overlap with the instance specified
  by my_mc. The target parameter usually represents
  a button or text-entry field.
• shapeFlag A Boolean value specifying whether to
  evaluate the entire shape of the specified
  instance (true), or just the bounding box
  (false). This parameter can be specified only if
  the hit area is identified using x and y
  coordinate parameters.
• Returns
• A Boolean value of true if my_mc overlaps with
  the specified hit area, false otherwise.

3
hitTest Method Examples

• x _root._xmouse
• y _root._ymouse
• if (myClip_mc.hitTest(x, y, true)
• trace(hit the shape)
• if (myClip_mc.hitTest(x, y, false)
• trace(hit within the bounding box)
• if (myClip_mc.hitTest(otherObject)
• trace(hit within the bounding box)
• sample file

4
hitArea method

• MovieClip.hitArea
• Availability
• Flash Player 6.
• Usage
• my_mc.hitAreaObject
• Returns
• A reference to a movie clip.
• Description
• Property designates another movie clip to serve
  as the hit area for a movie clip. If the hitArea
  property does not exist or is null or undefined,
  the movie clip itself is used as the hit area.
  The value of the hitArea property may be a
  reference to a movie clip object.
• You can change the hitArea property at any time
  the modified movie clip immediately takes on the
  new hit area behavior. The movie clip designated
  as the hit area does not need to be visible its
  graphical shape, although not visible, is
  hit-tested. The hitArea property can be read out
  of a prototype object.