Question

I’m new to Corona and game development. I am making a simple game with physics to move objects with touch. Here is my code

local physics = require"physics";
local gameUI = require("gameUI")

physics.setDrawMode( "normal" )
physics.setScale( 40)
physics.setPositionIterations( 60 )

physics.start();

local _H=display.contentHeight;
local _W=display.contentWidth;

local crat1=display.newImageRect("crate1.png",40,40)
crat1.x=20;crat1.y=200;
physics.addBody(crat1,"dynamic",{density=-1000,bounce=0.1,friction=100});

local function dragBody_call(event)
--Calling drawBody() From gameUI
gameUI.dragBody(event);

end    

crat1:addEventListener( "touch", dragBody_call) -- make object draggable

In the simulator, movement and touch events are working perfectly and it also runs on Android device. Physics works perfectly and I can also move objects with Touch but it’s very laggy and very hard to move a objects. And sometime it does not move. It’s not as smooth as simulator. How can I fix this?

Answer 1

I think the the problem is your

physics.setPositionIterations( 60 )

According to the docs

The default value is 8, which means that the engine will iterate
through eight position approximations per frame for each object.
Increasing this number will cause fewer momentary inaccuracies
(overlapping objects. etc.) but will increase computational overhead.
The default value should be good for most general cases.

See here http://docs.coronalabs.com/api/library/physics/setPositionIterations.html

Remove that line or if you REALLY need performance, increase it by a smaller value. Say to 12 or 16.