Jerky

SDL Development
1

Hi Guys
As always the more i play with SDL the more i love it, but i have a
small problem i have nearly finished my first game using SDL, with double
buffering, and the main loop is doing just the drawing,

DrawMap()
DrawSprites()
DrawScore … etc

while the movement is done under a timer, i also have two other timers for
background animation etc. My problem is that every now and then the game
Jerks, all the sprites start really bad jerky movements like the screen has
not been updated for 3-8 moves. it does this for a short time and settles
down again to smooth

Any Ideas?

Trish x

2

Hello Patricia,

Monday, August 21, 2006, 1:02:50 PM, you wrote:

Hi Guys
As always the more i play with SDL the more i love it, but i have a
small problem i have nearly finished my first game using SDL, with double
buffering, and the main loop is doing just the drawing,

DrawMap()
DrawSprites()
DrawScore … etc

while the movement is done under a timer, i also have two other timers for
background animation etc. My problem is that every now and then the game
Jerks, all the sprites start really bad jerky movements like the screen has
not been updated for 3-8 moves. it does this for a short time and settles
down again to smooth

What platform are you running on? Is it possible some background task
is periodically waking up and disturbing your game?–
Best regards,
Peter mailto:@Peter_Mulholland

3

Hi,

I have the same problem, when Eclipse is running. Maybe this is a
problem with Sun’s JRE in general.

Weigo

Patricia Curtis wrote:> Hi Guys

     As always the more i play with SDL the more i love it, but i

have a small problem i have nearly finished my first game using SDL,
with double buffering, and the main loop is doing just the drawing,

DrawMap()
DrawSprites()
DrawScore … etc

while the movement is done under a timer, i also have two other timers
for background animation etc. My problem is that every now and then
the game Jerks, all the sprites start really bad jerky movements like
the screen has not been updated for 3-8 moves. it does this for a
short time and settles down again to smooth

Any Ideas?

Trish x

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

4

Hi Guys
As always the more i play with SDL the more i love it, but i
have a small problem i have nearly finished my first game using SDL,
with double buffering, and the main loop is doing just the drawing,

DrawMap()
DrawSprites()
DrawScore … etc

while the movement is done under a timer, i also have two other timers
for background animation etc. My problem is that every now and then
the game Jerks, all the sprites start really bad jerky movements like
the screen has not been updated for 3-8 moves. it does this for a
short time and settles down again to smooth

Any Ideas?

Trish x

You may want to check out David Olofson’s fixed rate pig example here:

http://olofson.net/mixed.html

It may be necessary to implement some kind of floating point/fixed point
scaling of the game logic and animation instead of running them on
timers. The scaling factor will be based on the frame rate.

I don’t think timers a guaranteed to be triggered on the exact time you
specify, its more like “in the general region” of the time you specify.

HTH

  • Tom
5

Eclipse is well known for being a resource eater under WinXP. Maybe give your app a higher priority?

Ed

Matthias Weigand wrote: Hi,

I have the same problem, when Eclipse is running. Maybe this is a
problem with Sun’s JRE in general.

Weigo

Patricia Curtis wrote:> Hi Guys

     As always the more i play with SDL the more i love it, but i

have a small problem i have nearly finished my first game using SDL,
with double buffering, and the main loop is doing just the drawing,

DrawMap()
DrawSprites()
DrawScore … etc

while the movement is done under a timer, i also have two other timers
for background animation etc. My problem is that every now and then
the game Jerks, all the sprites start really bad jerky movements like
the screen has not been updated for 3-8 moves. it does this for a
short time and settles down again to smooth

Any Ideas?

Trish x

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

SDL mailing list
SDL at libsdl.org
http://www.libsdl.org/mailman/listinfo/sdl

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