[NTLUG:Discuss] Javascript and 'onMouseMove' events.

[Steve Baker]

Thanks - but I really want to know about the horrible update rates I'm
getting from 'onMouseMove' - the cursor thing is just an incidental part
of what is a complicated set of game-related stuff.

David Simmons wrote:
> 
> http://www.permadi.com/tutorial/cssCustomCursor/
> http://webdesign.about.com/od/styleproperties/a/aa060607.htm
> 
>> I've been playing with writing a browser-based game in JavaScript
> (using
>> 'canvas' graphics) recently. I want to use a full-color
> shape instead of
>> the mouse cursor - so I'm using 'onMouseMove'
> events and redrawing the
>> shape as needed. Everything works as
> programmed - but the timing is
>> terrible.
>>
>>
> The cursor will alternately track smoothly for about a half second -
>> then freeze for another half second. Suspecting performance
> problems, I
>> started trimming the game code back and back until I
> had NOTHING but a
>> simple sprite redraw in the 'onMouseMove'
> event...and the result is the
>> same.
>>
>> I know
> my sprite redraws are fast enough because during the half second
> where everything works OK they track nicely. If I were to draw an 'X'
> in
>> the onMouseMove function and then move the mouse rapidly from
> left to
>> right, I'd get something like:
>>
>>
> XXXXXX       XXXXX       XXXXXX     XXXXXXX     XXXXXXX
>> I'm doing this in FireFox on OpenSuse 11.0 64bit on a really
> fast
>> computer - but I've seen the same behavior on other systems
> too.
>> Is there something inherent in the scheduling of
> browsers that makes
>> this inevitable - or is there some 'trick'
> to make this work OK?
>> Thanks...
>>
>>
>  -- Steve.
>>
>>
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