Vertical plane movement with touch events

Dikkesnoek

Hello Gideros friends,

At I am working on a horizontal shooter. Controlling the plane smootly in vertical direction is quiet a challenge. This is what I want to accomplish. When I move my thumb vertically (up/down) over a part of the screen, the plane must be controlled from top to bottom. Has anyone some tips/hints to do this? Below you can find a piece of my code wich will do a part of the job:

function ShootGame:onTouchesMove(event)   local planeMinY = 0 -- Plane can reach the top. local planeMaxY = resolution:getGameHeight() - plane:getHeight() -- Plane can reach the bottom. local planeMovement = 15   if (plane.touchId == event.touch.id) and plane.dragging then   local dx = event.touch.x - startTouchX local dy = event.touch.y - startTouchY   -- Get the absolute movement in x and y direction. local fingerMovementXY = math.floor(math.sqrt(math.pow(dx, 2) + math.pow(dy, 2)))   -- Finger up more than 1px. if (dy < - 1) then targetPlaneY = plane.y - (fingerMovementXY * planeMovement) -- New plane position. if targetPlaneY < planeMinY then targetPlaneY = planeMinY end   startTouchX = event.touch.x -- Set new startX. startTouchY = event.touch.y -- Set new startY. end -- Finger down more than 1px. if (dy > 1) then targetPlaneY = plane.y + (fingerMovementXY * planeMovement) if targetPlaneY > planeMaxY then targetPlaneY = planeMaxY end   startTouchX = event.touch.x -- Set new startX. startTouchY = event.touch.y -- Set new startY. end end end   function ShootGame:onEnterFrame() // THIS IS A PART OF THE COMPLETE FUNCTION   -- Move the plane in vertical direction. if (plane ~= nil) then if (plane.y > targetPlaneY) then -- Move down. plane.y = plane.y - 2 end if (plane.y < targetPlaneY) then -- Move up. plane.y = plane.y + 2 end plane:setPosition(plane.x, plane.y) end end

It will work, but it is not moving in a nice way. Do think I need to use some math functions to move the plane more smoothly? Thanks in advance,

Marc

ar2rsawseen

@Dikkesnoek do you really want to move it with constant +2/-2 units?
Wouldn't you want to move it to the amount fingers have moved vertically?

Dikkesnoek

Hi ar2rsawseen,

I was just experimenting. The plane is in a fixed horizontal position. The background is scrolling. By placing your thumb on the right side of the screen you can move the plane vertically. Challenge is to let the plane move smoothly from top to bottom by moving your finger over a small range. So for example if I have a resolution of 1500x500, when I move my thumb 1 pixel the plane has to move 10 pixels and when I move it 25 pixels it will be move to top or bottom (250 pixels). I am not shure what the optimum values are. See it as an analog joystick.

Best regards,

Marc

amin13a

Hi.
the onTouchesMove method is not a proper place for moving spaceship because event.x and event.y is not consistent and smooth.
Try onEnterFrame and place your logic there.
you can obtain starting place from onTouchesDown.
Create a table with 10-20 member and save (currentPlace - startingPlace) there and update it in onTouchesMove.
The average of this table can be the input for onEnterFrame.

Dikkesnoek

Hi,

Thanks for your reply. In the code above the fingermovement will be determined in the onTouchedMove. The planemovement will be done in the onEnterFrame.

Regards,

Marc