Hi Kartik- I don't have a working SDL module install that I could check things out on. The posted gist seemed like a regression of using direct PDL manipulation to read and copy the image data to an SDL surface.
The pdl.pl example seemed ok to me until I tried looking at the latest XS code where it seemed that the SDL module doesn't not accept a packed string data as input to the "surface from" routines. --Chris On Mon, Sep 24, 2012 at 12:39 PM, Kartik Thakore <thakore.kar...@gmail.com> wrote: > 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 >> >> > >
