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    Help with a physics class

    Tom2012Tom2012 Guru
    edited September 2012 in General questions
    I've decided to create a class called SimplePhysics to take some of the work out of adding bodies to sprites.

    Here's what I'd like to be able to do:

    1) Add a sprite to a scene (no problems there)

    2) Simply add:

    SimplePhysics:addSquareBody(someSprite,density,friction,restitution,type);

    3) My class would look a bit like:

    physics.lua

    SimplePhysics = Core.class(Sprite);

    -- Create box2D body

    function SimplePhysics:addSquareBody(imageObject)

    local body = self.world:createBody{type = b2.DYNAMIC_BODY}

    body:setPosition(imageObject:getX(), imageObject:getY());

    body:setAngle(imageObject:getRotation() * math.pi/180);

    local poly = b2.PolygonShape.new()

    poly:setAsBox(imageObject:getWidth()/2, imageObject:getHeight()/2)

    local fixture = body:createFixture{shape = poly, density = 1.0, friction = 0.1, restitution = 0.2}

    imageObject.body = body

    imageObject.body.type = "someType";

    end

    ... with methods for the other body types.

    Does this sound possible?

    Thanks

    Tom
    Lost Caverns - my little game on Play Store - https://play.google.com/store/apps/details?id=com.firecroc.lostcaverns
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    Comments

    • ar2rsawseenar2rsawseen Maintainer
      Sure it is.
      Actually on the context of extending the Gideros, I'm working myself on similar solution, that would add method like createRectangle or createCircle to b2.World class. But would love to hear more about what methods to include ;)

      Maybe be we could share our findings later ;)
      http://appcodingeasy.com/Gideros-Mobile
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    • zaniarzaniar Member
      edited September 2012
      I'm also working on it. I've create physics class. It designed so it will works well with PhysicsEditor. But you can use it without PhysicsEditor. You can get it here: https://github.com/zaniar/gideros_physics.git

      Currently, there is no documentation. Sorry :P
      http://www.nightspade.com
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    • ar2rsawseenar2rsawseen Maintainer
      Thats great @zaniar.

      You can check my version on https://github.com/ar2rsawseen/GiderosInit in the end of init.lua file ;)

      More info on this thread: http://www.giderosmobile.com/forum/discussion/1780/extending-gideros
      http://appcodingeasy.com/Gideros-Mobile
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    • Tom2012Tom2012 Guru
      edited September 2012
      Hi Guys,

      Very cool. Going to check out your solutions now.

      Here's what I made (and I'm a serious newbie hehe) simplephysics.lua

      Heres what it does:

      Create a square body:

      physics = {}
      physics.imageObject = happyBox;
      SimplePhysics:addSquareBody(physics);

      Create a circle body

      physics = {}
      physics.imageObject = circleImage;
      SimplePhysics:addCircleBody(physics);


      Some options

      physics.density = 1.0;
      physics.friction = 0.1;
      physics.restitution = 0.2;
      physics.padding = 5; -- padding around the collision shape

      Turn on debug mode:

      --set up debug drawing
      SimplePhysics:debugDraw(self);

      It seems to work but if someone could let me know what to take out or if what I could improve, please let me know. :-)
      Lost Caverns - my little game on Play Store - https://play.google.com/store/apps/details?id=com.firecroc.lostcaverns
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    • Tom2012Tom2012 Guru
      edited September 2012
      simplephysics.lua


      SimplePhysics = Core.class(Sprite);

      -- Create a square body

      function SimplePhysics:addSquareBody()

      local scene = physics.imageObject:getParent();

      local body = scene.world:createBody{type = b2.DYNAMIC_BODY}

      body:setPosition(physics.imageObject:getX(), physics.imageObject:getY());

      body:setAngle(physics.imageObject:getRotation() * math.pi/180);

      -- Set default values for if they are blank

      if(physics.density == nil) then physics.padding = 1; end
      if(physics.friction == nil) then physics.padding = 0.1; end
      if(physics.restitution == nil) then physics.restitution = 0.2; end
      if(physics.padding == nil) then physics.padding = 0; end

      square = b2.PolygonShape.new();

      square:setAsBox((physics.imageObject:getWidth()/2) - physics.padding, (physics.imageObject:getHeight()/2)-physics.padding)

      local fixture = body:createFixture{shape = square, density = physics.density, friction = physics.friction, restitution = physics.restitution}

      physics.imageObject.body = body;

      physics.imageObject.body.type = "someType";

      end




      -- Create a circle body

      function SimplePhysics:addCircleBody()

      -- Set default values for if they are blank

      if(physics.density == nil) then physics.padding = 1; end
      if(physics.friction == nil) then physics.padding = 0.1; end
      if(physics.restitution == nil) then physics.restitution = 0.2; end
      if(physics.padding == nil) then physics.padding = 0; end

      local scene = physics.imageObject:getParent();

      local body = scene.world:createBody{type = b2.DYNAMIC_BODY}

      body:setPosition(physics.imageObject:getX(), physics.imageObject:getY());

      body:setAngle(physics.imageObject:getRotation() * math.pi/180);

      local radius = ((physics.imageObject:getWidth()/2)-physics.padding);

      local circle = b2.CircleShape.new(0, 0, radius);

      local fixture = body:createFixture{shape = circle, density = physics.density, friction = physics.friction, restitution = physics.restitution}

      physics.imageObject.body = body

      physics.imageObject.body.type = "someType";

      end





      -- Turn on debug draw

      function SimplePhysics:debugDraw(scene)

      -- has to go at end
      local debugDraw = b2.DebugDraw.new()
      scene.world:setDebugDraw(debugDraw)
      scene:addChild(debugDraw);

      end
      Lost Caverns - my little game on Play Store - https://play.google.com/store/apps/details?id=com.firecroc.lostcaverns
      +1 -1Share on Facebook
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