Drag only to the right

Solar2D General Questions/Discussion
#1

I am building some demos and i want o move some fruits only to the right, i saw this demo on the corona website

local function onTouch( event )  
 local t = event.target  
   
 -- Print info about the event. For actual production code, you should  
 -- not call this function because it wastes CPU resources.  
 printTouch(event)  
   
 local phase = event.phase  
 if "began" == phase then  
 -- Make target the top-most object  
 local parent = t.parent  
 parent:insert( t )  
 display.getCurrentStage():setFocus( t )  
   
 -- Spurious events can be sent to the target, e.g. the user presses   
 -- elsewhere on the screen and then moves the finger over the target.  
 -- To prevent this, we add this flag. Only when it's true will "move"  
 -- events be sent to the target.  
 t.isFocus = true  
   
 -- Store initial position  
 t.x0 = event.x - t.x  
 t.y0 = event.y - t.y  
 elseif t.isFocus then  
 if "moved" == phase then  
 -- Make object move (we subtract t.x0,t.y0 so that moves are  
 -- relative to initial grab point, rather than object "snapping").  
 t.x = event.x - t.x0  
 t.y = event.y - t.y0  
 elseif "ended" == phase or "cancelled" == phase then  
 display.getCurrentStage():setFocus( nil )  
 t.isFocus = false  
 end  
 end  
   
 -- Important to return true. This tells the system that the event  
 -- should not be propagated to listeners of any objects underneath.  
 return true  
end

the full code, to try is here:

http://developer.anscamobile.com/content/drag-me

my goal is only to drag to the right direction i know that i need to change the t.x variable but i dont know how i can do to only drag to the right, if anyone know this little issue and can help will be great for me.

Thanks people [import]uid: 26056 topic_id: 23327 reply_id: 323327[/import]

#2

All you’ll need to do is verify that the position the user has dragged to is to the right of the original touch input:

if "moved" == phase then -- Check that the event location is to the right of our original touch: local horizontalDrag = event.x - t.x0 if (horizontalDrag \> 0) then--we are moving right -- Make object move (we subtract t.x0,t.y0 so that moves are -- relative to initial grab point, rather than object "snapping"). t.x = horizontalDrag t.y = event.y - t.y0 end else... [import]uid: 87138 topic_id: 23327 reply_id: 93405[/import]

#3

Yeh it works, thanks Revaerie :slight_smile: [import]uid: 26056 topic_id: 23327 reply_id: 93513[/import]