[PD] Re: scaling pix_draw in GEM ,and GEM performance question

[guenter geiger]

For fading, use the OpenGL objects color and alpha.
With color you can set the transparency by changing the the alpha channel,
and the alpha object does nothing more than enabling alpha blending.

Other than pix_gain this uses OpenGL hardware and is therefore a lot
faster.

Guenter


On Wed, 11 Sep 2002, Jim Ruxton wrote:

> Thanks Mark, Chris and Guenter for the suggestion to check that GL was
> working. I looked at my X windows config file and it looks like GLcore
> wasn't enabled. I did enable it and Gem seems to be running better. I'll
> have a look at hdparm as well Chris,. One thing I would like to be able
> to do is fade out a running mpeg movie. I tried using pix_gain which
> works but slows down the mpeg movie. Can anyone suggest another way that
> is less processor intensive. Thanks for all the help.
> Jim
>
> >>I second guenter's post about not having hardware GL working.  did
> >>you get the nvidia drivers off the nvidia site?  the ones that come
> >>with the linux distros are not the real drivers.
> >>
> >>also, what size are these textures?  and how many do you have?  you
> >>could be running out of vram if you are trying to use a lot of large
> >>textures.
> >>
> >>you are obviously using a laptop (geforce2go) so the hard drive could
> >>be slowing you down if it is full or you are trying to load massive
> >>amounts of data like 640x480 uncompressed movies or lots of files at
> >>once.  also i find that sometimes dma transfers are off by default in
> >>linux.  check man hdparm and
> >>http://linux.oreillynet.com/pub/a/linux/2000/06/29/hdparm.html for
> >>more info.  this can make a big difference in disk transfer speed.
> >>
> >>as far as the image distortion goes, this could be a case of resizing
> >>the texture to a power of two.  i'm pretty sure that GEM supports
> >>non-power of two textures tho...
> >>
> >>for resizing: mapping the movie onto a quad and resizing/scaling the
> >>quad should be the fastest method.
> >>
> >>cgc
> >>
> >>
> >>
> >>>Hi,
> >>>
> >>>I am having trouble scaling images using pix_draw. I thought I could
> >>>scale an image using scale or scaleXYZ before pix_draw but it seems
> >>>like these objects   have no effect. I can scale an image by texture
> >>>mapping onto a square and resizing it but I find it is slower than
> >>>pix_draw in this case. When rendering movies I've found  that
> >>>texture mapping is faster but the image is more distorted. I'm using
> >>>GEM 0.87 under Linux. Is this a problem with pix_draw or is it
> >>>supposed to work this way? I have a fast processor ( 1 GHz) a good
> >>>video card (Nvidia 2Go) and I find movies are playing  quite slowly.
> >>>I only have 128 MB ram. Just ordered another 256 MB hoping this will
> >>>speed things up. Wondering what other people are using to get
> >>>realtime playback with MPEGs in Linux?
> >>>Thanks,
> >>>Jim
> >>>
> >>>
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> >>--
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