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How can i detect collision ? — Gideros Forum
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    How can i detect collision ?

    coderontheroadcoderontheroad Member
    edited February 2014 in General questions
    Hi,

    I am trying to make space fighting game :) So i made player space ship and i made enemy ships and player ship can throw laser... I have two main function. startPlane() is create the player ship and add events when player touch the screen, ship throw laser. startEnemies() is create the enemies and start to enemy movement.

    When player touch the screen, event start the fire() function. And fire function create the fire object and start the moveFire function. moveFire function is add -y for move the fire. Now, how can i detect when laser hit the enemy ?
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    Comments

    • piepie Member
      Hi,
      I'd say to look for TNTcollision Engine to check points/shapes collisions without physics (it's a "plugin" for gideros).

      If you like to engage with physics/gravity and forces you can try box2d (already available in gideros).

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    • HarrisonHarrison Member
      edited February 2014
      this looks like what you are looking for
      i didnt make this. It's @WauloK 's
      http://bluebilby.com/2013/05/08/gideros-mobile-tutorial-creating-your-first-game/
      check out :hitTestPoint
      _________________________________________________________________________________
      local function goTouch(gameOverImage, event)
      -- See if the Game Over object was touched
      if gameOverImage:hitTestPoint(event.touch.x, event.touch.y) then
      gameoverImg:removeEventListener(Event.TOUCHES_END, goTouch)
      -- Clean up our objects
      stage:removeChild(gameoverImg)
      gameoverImg=nil
      local i
      for i = 1,MAXNUMBEROFENEMIES do
      stage:removeChild(enemyShape[i])
      enemyShape[i]=nil
      end
      stage:removeChild(player)
      player=nil
      stage:removeChild(hiScoreText)
      hiScoreText=nil
      stage:removeChild(scoreText)
      scoreText=nil
      -- Restart the game
      startGame()
      end
      end
      “ The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time. ” - Tom Cargill
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    • ar2rsawseenar2rsawseen Maintainer
      Accepted Answer
      1) @pie mentioned TNT collision engine
      2) @Harrison mentioned hitTestPoint
      3) Using box2d physics engine
      3) using bounding box check:
      function Sprite:collidesWith(sprite2)
	local x,y,w,h = self:getBounds(stage)
	local x2,y2,w2,h2 = sprite2:getBounds(stage)
 
	return not ((y+h < y2) or (y > y2+h2) or (x > x2+w2) or (x+w < x2))
end
 
--usage like
if fire:collidesWith(enemy) then
    --enemy is hit
end
      http://appcodingeasy.com/Gideros-Mobile
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    • coderontheroadcoderontheroad Member
      Thanks for the answers :)
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    • seppseppseppsepp Member
      It would be cool to have a user defined bounding box, one that would be smaller than the actual sprite. Currently I'm using @ar2rsawseen's mentioned 4) Sprite:collidesWith. My hacky workaround is another bounding box sprite which is invisible =| .
      Soledad - Charity Game | Birds and Trees
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    • amin13aamin13a Member
      What about rotated sprites?
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    • seppseppseppsepp Member
      edited June 2014
      This one might be a good start to read, @anim13a: http://giderosmobile.com/forum/discussion/comment/12190#Comment_12190
      Soledad - Charity Game | Birds and Trees
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