event.contact

Overview

During a pre-collision, there are multiple contact points that occur. You can manipulate these contact points to create certain effects like one-sided platforms.

Gotchas

You should not hold onto the contact object. It is only valid in the scope of your collision listener.

Properties

• event.contact.isEnabled — enables or disables the collision associated with the contact.
• event.contact.isTouching — indicates whether the two objects are touching (read only).
• event.contact.bounce — specifies the bounce factor of the collision (read or write).
• event.contact.friction — specifies the friction factor of the collision (read or write).

Example

local platform = display.newRect( 0, 0, 280, 30 )
platform.x, platform.y = display.contentCenterX, display.contentCenterY+80
platform.collType = "passthru"
physics.addBody( platform, "static", { bounce=0.0, friction=0.3 } )

local function preCollisionEvent( self, event )

   local collideObject = event.other
   if ( collideObject.collType == "passthru" ) then
      event.contact.isEnabled = false  -- Disable this specific collision
   end
end

local ball = display.newCircle( 0, 0, 15 )
ball.x, ball.y = display.contentCenterX, display.contentCenterY-40
physics.addBody( ball, "dynamic", { bounce=0.0, radius=20 } )

ball.preCollision = preCollisionEvent
ball:addEventListener( "preCollision", ball )