Object moving choppy

truongminhthinh · May 26, 2015, 2:01am

I new to corona sdk. My first game is in development and I found a problem with moving object. I’m trying to animate/moving the cloud from left to right constantly and it’s really choppy, not smooth.

I decided to write a simple code to test, the same problem even it’s very simple code on both simulator and device. See below (main.lua):

-- Hide the status bar. display.setStatusBar(display.HiddenStatusBar) local cloud = display.newImage( "cloud.png", 300, 100) cloud.xScale = 0.4 cloud.yScale = 0.4 local speed = 0.5 local lastTime = system.getTimer( ) local function frameUpdate( event ) local currentTime = system.getTimer( ) local elapse = currentTime - lastTime lastTime = currentTime cloud.x = cloud.x - elapse \* speed if (cloud.x \< -100) then cloud.x = display.contentWidth + cloud.width end end Runtime:addEventListener( "enterFrame", frameUpdate )

Here is the video I recorded so everyone can understand the choppy issue https://www.dropbox.com/s/x6spi7mlivvrx74/corona_test_moving.mov?dl=0. Do I make any mistake? I searched around but did not find any solution for this.

Please help and thanks in advance!

roaminggamer · May 26, 2015, 5:19am

You’re not accounting for the fact that frame times vary.

One frame may take 20 ms, another 16, another 10, etc.

I answered a similar question here:

https://forums.coronalabs.com/topic/56853-stuttering-when-moving-display-objects-across-screen/

truongminhthinh · May 26, 2015, 10:01am

Hi roaminggamer. I have modified my code as below:

local speed = 100 -- strip out other line I posted -- local currentTime = system.getTimer( ) local dt = currentTime - lastTime lastTime = currentTime local dx = dt \* speed \* 0.001 cloud.x = cloud.x - dx -- -- strip out other line I posted

That will calculate dx by time has passed in every frame. The problem still exist :(.

I also tried to log the dt out in the console and noted that there are many big stutter time almost constantly happen. See the log.

Corona Simulator[8969:403112] 16.959

Corona Simulator[8969:403112] 14.88

Corona Simulator[8969:403112] 15.917

Corona Simulator[8969:403112] 15.381

Corona Simulator[8969:403112] 16.279

Corona Simulator[8969:403112] 22.121

Corona Simulator[8969:403112] 9.4779999999996

Corona Simulator[8969:403112] 15.892

Corona Simulator[8969:403112] 23.623

Corona Simulator[8969:403112] 9.2939999999999

Corona Simulator[8969:403112] 16.029

Corona Simulator[8969:403112] 15.074

Corona Simulator[8969:403112] 16.339

Corona Simulator[8969:403112] 15.864

Corona Simulator[8969:403112] 17.545

Corona Simulator[8969:403112] 14.664

Corona Simulator[8969:403112] 15.819

Corona Simulator[8969:403112] 17.14

Corona Simulator[8969:403112] 14.412

Corona Simulator[8969:403112] 26.372

Corona Simulator[8969:403112] 6.6419999999998

Corona Simulator[8969:403112] 15.63

Corona Simulator[8969:403112] 16.32

Corona Simulator[8969:403112] 15.388

Corona Simulator[8969:403112] 16.038

Corona Simulator[8969:403112] 15.15

Corona Simulator[8969:403112] 17.113

Corona Simulator[8969:403112] 15.713

Corona Simulator[8969:403112] 15.351000000001

Corona Simulator[8969:403112] 16.003

Corona Simulator[8969:403112] 15.996

Corona Simulator[8969:403112] 22.138

Corona Simulator[8969:403112] 10.069

Corona Simulator[8969:403112] 16.653

Corona Simulator[8969:403112] 16.086

I also look into your answer in the post you referenced me. Try to run all your suggestion code but they’re stuttering the same as the video I attached. Anything I should do to make it smooth? Thanks!

roaminggamer · May 26, 2015, 4:24pm

Are you trying to run at 60 FPS? It looks like you’re doing too much work in some frames and this is killing your frame rates.

Try setting fps = 30 in config.lua.

application = { content = { width=320, height=480, fps = 30, scale = "letterbox" }, }

truongminhthinh · May 27, 2015, 12:18am

My test has 24 lines of code like I posted above, just moving an image constantly from right to left of course at 60 fps.

As you said, I have set the fps to 30 and noted that there’re not many stutter dt like in fps60. It’s strange. With the fps30 the cloud moving isn’t quite smooth as expected.

I’m using the latest daily build SDK. Don’t know why at fps60 it’s quite stutter, may it be a bug with the Corona SDK? I see many people have the same problem.

roaminggamer · May 27, 2015, 4:20pm

Your best bet is to make a very small example (I mean less than 50 lines of code) that demonstrates and reproduces the issue. Then you can file a bug. Don’t forget to give details (in the bug):

Devices(s)
Corona SDK version

truongminhthinh · May 27, 2015, 5:22pm

This is my code, I have made some optimization but the choppy frames still exist.

local getTimer = system.getTimer local cloud = display.newImage( "cloud.png", 300, 100) cloud.xScale = 0.4 cloud.yScale = 0.4 local w = cloud.width local haftW = cloud.width \* 0.5 local speed = -200 -- move from right to left local lastTime = getTimer( ) local function frameUpdate( event ) local currentTime = getTimer( ) local dt = currentTime - lastTime lastTime = currentTime --print(dt) local dx = dt \* speed \* 0.001 cloud:translate(dx, 0) if (cloud.x \< -haftW) then cloud:translate(display.contentWidth + w, 0) end end Runtime:addEventListener( "enterFrame", frameUpdate )

Full zip project here https://www.dropbox.com/s/kkok4m5g8htz01v/TestSmooth.zip?dl=0

All corona simulator and Android emulator and my device Xperia Z1 have the same stutter issue. Check this video as a demonstration https://goo.gl/bSfQyI

I’m using Corona SDK version 2015.2642.

The choppy frames appear frequently rather randomly.

Please help and thanks so much!

roaminggamer · May 27, 2015, 5:29pm

download link is disabled.

truongminhthinh · May 27, 2015, 5:36pm

Here it is https://www.dropbox.com/s/kkok4m5g8htz01v/TestSmooth.zip?dl=0

roaminggamer · May 27, 2015, 11:34pm

It looks pretty smooth on device, but it is jerky in the simulator.
I made some changes (see TestSmooth_mod folder in zip).
I also made an alternate using transition.

These all look jerky in the simulator, but fine on my Generation 1 Nexus 7

Hope this helps.

https://github.com/roaminggamer/RG_FreeStuff/raw/master/AskEd/2015/05/TestSmooth.zip

truongminhthinh · May 28, 2015, 3:39am

Thanks for your help roaming! I tried on my Z1 but it still gets jerky. The Nexus 7 of my friend looks fine.

roaminggamer · May 26, 2015, 5:19am