Whats wrong with https://github.com/PerlGameDev/SDL_Manual/blob/master/code_listings/pdl.pl ?
On Mon, Sep 24, 2012 at 12:36 PM, Chris Marshall <devel.chm...@gmail.com>wrote: > Looking back through the code to the original SDL_Perl > I found version 2.0.5 which allows one to actually create > an SDL surface from pixel data. More recent versions > appear to copy the data and as far as I can tell, there is > no way to directly create an SDL surface from external > data. > > If that is the case (that SDL_CreateRGBSurfaceFrom is > not accessible from the perl API), have you implemented > another approach to achieve this? > > Regards, > Chris > > On Mon, Sep 24, 2012 at 12:07 PM, Chris Marshall <devel.chm...@gmail.com> > wrote: > > On Mon, Sep 24, 2012 at 10:41 AM, Tobias Leich <em...@froggs.de> wrote: > >> Hi Chris, > >> > >> The performance is poor of course. > >> > >> I tried to use the piddle's pointer (->dataref or so) but it looks like > >> it is not pointing to a usable memory area. > > > > $piddle->get_dataref returns a scalar reference to a perl > > PV whose string content _is_ the data block. You should > > be able to get the starting location for the pixel data (i.e., > > the string) via SvPV. > > > >> It looks like there are more than 4 bytes per pixel, and libSDL can't > >> handle that. > > > > Per the above, the get_dataref returns an RV to an Sv with > > the data in the string. It is just a contiguous block of memory. > > As far as I know, all the SDL memory buffers are just > > contiguous blocks of memory (ignoring variations due to > > stride, alignment,...) > > > >> The pdl.pl example is working, I see colored squares. > > > > I don't know what the output should look like. I'm > > cc-ing our PDL mailing list in the hopes that someone > > with access to both PDL and SDL can give it a try. > > > > Is there a cygwin install of SDL and libSDL? > > > >> I think we should need to improve our examples btw, there is not a > >> single comment, thats bad. > >> In the pdl.pl is a var $ref, which is never used. Thats a bit > confusing. > > > > I think the ref is from a previous iteration in the code > > trying to get things working. > > > > Speaking of documentation, do you have any on the > > actual perl<->libSDL bindings an data structures? Trying > > to read XS is not the simplest way to sort things out--- > > especially since I am far for an expert on some of the > > tricky XS technologies. > > > > --Chris > > > >> Cheers, Tobias > >> > >> Am 24.09.2012 16:09, schrieb Chris Marshall: > >>> I took a look at the gist and it looks reasonable > >>> (I can't run it because I don't have the SDL module > >>> and lib installed on my system), however... > >>> > >>> I would expect the performance to be *very* poor > >>> since the image data is essentially being converted > >>> from packed byte data to a perl list and then poked > >>> a byte at a time into the SDL surface data. > >>> > >>> The better approach would be to wrap a PDL object > >>> (a.k.a. piddle) into an SDL surface. Then you could > >>> just lock, copy the data via a PDL direct assignment, > >>> unlock and use SDL. There is an examples/pdl.pl > >>> that shows how to do the wrapping. > >>> > >>> BUT, I took a look at the xs code and it appears > >>> that your SDL_Surface objects no longer use a > >>> packed-string representation for the SDL surface > >>> data. If that is the case, I would be surprised if > >>> the pdl.pl example works at all now. > >>> > >>> If someone could verify this, I would appreciate it. > >>> If that is the case, it should be straightforward to > >>> modify the SDL_CreateRGBSurfaceFrom routine > >>> to allow for a SvPV for pixel data as one alternative. > >>> > >>> Given the power of PDL for whole-image data > >>> manipulation, allowing for easy interoperability > >>> with the current SDL module would benefit both > >>> our user and developer communities. > >>> > >>> Regards, > >>> Chris > >>> > >>> > >>> On Sun, Sep 23, 2012 at 3:07 PM, Tobias Leich <em...@froggs.de> wrote: > >>>> Hi, Andrei asked some days ago how to load an image via PDL and but it > >>>> in a Surface to use it in SDL. > >>>> > >>>> The example is here: https://gist.github.com/3772701 > >>>> > >>>> I'll put that in the examples folder too. > >>>> > >>>> Cheers, Tobias > >> >
