prevent from dragging a shape over other shape

newwork01

Hi Everyone,
Im new to gideros . In Drag Me Example, I want to prevent from dragging a shape over other shape ( means it will stop when hit other shape ) . How can i implement the code ?

hgvyas123

You can try TntCollision Engine or

http://giderosmobile.com/forum/discussion/121/simple-collision-detection/p1

to check for the collision if they collide stop moving them else allow

ar2rsawseen

@hgvyas123 unfortunately thats not that easy, if you determine that they collide and stop move them, then you can't also move the figure back from the collided figure, because you will be ignoring all movements.

You also need to take an account the side of collision, the vector, etc.

more and more I started thinking that it might be easier to implement through dragging box2d bodies, unless I'm missing some obvious solution

http://appcodingeasy.com/Gideros-Mobile/Dragging-Box2d-object-in-Gideros-Mobile

hgvyas123

hmmm right little tweak needed here is the solution

--[[ Drag the shapes around with your mouse or fingers This code is MIT licensed, see <a href="http://www.opensource.org/licenses/mit-license.php" rel="nofollow">http://www.opensource.org/licenses/mit-license.php</a> (C) 2010 - 2011 Gideros Mobile ]]   local myShapes = {}   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   local function onMouseDown(self, event) if self:hitTestPoint(event.x, event.y) then self.isFocus = true self.x0 = event.x self.y0 = event.y   event:stopPropagation() end end   local function onMouseMove(self, event) if self.isFocus then self.lastX,self.lastY = self:getPosition() local dx = event.x - self.x0 local dy = event.y - self.y0 self:setX(self:getX() + dx) self:setY(self:getY() + dy) self.x0 = event.x self.y0 = event.y for i=1,#myShapes do if myShapes[i] ~= self then if self:collidesWith(myShapes[i]) then self:setPosition(self.lastX,self.lastY) end   end end   event:stopPropagation() end end   local function onMouseUp(self, event) if self.isFocus then self.isFocus = false   event:stopPropagation() end end     for i=1,5 do local shape = Shape.new() shape:setLineStyle(3, 0x000000) shape:setFillStyle(Shape.SOLID, 0xff0000, 0.5) shape:beginPath() shape:moveTo(0, 0) shape:lineTo(100, 0) shape:lineTo(100, 50) shape:lineTo(0, 50) shape:closePath() shape:endPath()   shape:setX(math.random(0, 320 - 100)) shape:setY(math.random(0, 480 - 50))   shape.isFocus = false   shape:addEventListener(Event.MOUSE_DOWN, onMouseDown, shape) shape:addEventListener(Event.MOUSE_MOVE, onMouseMove, shape) shape:addEventListener(Event.MOUSE_UP, onMouseUp, shape)   stage:addChild(shape) table.insert(myShapes,shape) end   local info = TextField.new(nil, "drag the shapes around with your mouse or fingers") info:setPosition(23, 50) stage:addChild(info)

hgvyas123

basically i store position of shape before moving it and later i check whether it collides or not and if they collide i reset shape's position to last stored value

ar2rsawseen

@hgvyas123 hmm, yes that is a nice workaround, kudos!