event.contact

Overview

During a collision, there are multiple contact points that occur. You can manipulate these contact points to create certain effects.

Gotchas

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

Properties

• 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).
• event.contact.tangentSpeed — specifies the tangential speed ("conveyer belt" motion) along the collision surface, 0 by default (read or write).

Example

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

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 } )

local function onCollision( self, event )

   local collideObject = event.other
   if ( collideObject.surfaceType == "superbounce" ) then
      event.contact.bounce = 20  -- Magnify bounce for this specific collision
   end
end

ball.collision = onCollision
ball:addEventListener( "collision" )