SDL2 + POGL2 + PDL confluence

[Chris Marshall]

PDL/SDL/OpenGL users-

With the recently announced SDL2 release and in-progress work
to provide perl bindings for the same, I wanted to share my
thoughts for leveraging joint capabilities of these three
modules with a couple of specific points.

1) SDL2 brings integrated hardware acceleration via Direct3D and/or
OpenGL to both 2D and 3D graphics. This offers the possiblity
of using modern OpenGL API features like renderbuffers for
computation and display.

2) PDL provides a high level array computation language that
can be used as a back-end engine for SDL applications and
visualization. The PDL::Graphics::TriD currently uses
the OpenGL-1.x fixed pipeline interface.

3) Perl OpenGL currently supports the original fixed-pipeline
display process of OpenGL-1.x and some 2.x functionality.
Work is underway to update the support to modern OpenGL
APIs such as OpenGL-3.x, OpenGLES,...

The common thread here is OpenGL, and I think that by updating
the OpenGL use and interfaces to the modern programmable display
pipeline we can generate significant synergy between the
projects:

1) Update Perl OpenGL to modern OpenGL (In progress by slowed
by the fact that my development time is spread too thin.
Am I the only one with a whole slew of projects for which
I know *exactly* what and how to do them but not having
the time to execute? :-)

2) Refactor PDL::Graphics::TriD to use modern OpenGL for
display rather than the fixed-function pipeline of OpenGL
API 1.x.

3) Update PDL to support (simply) the use of arbitrary
sources of data (e.g., I'm thinking framebuffer and
renderbuffer objects but deliberately being more
general since I could also imagine some sort of
generator that could act like a piddle for computation
with PDL).

4) Add GPGPU support to PDL computation.

5) Add support to the perl SDL2 interface to allow easy
mix and match operation with PDL for computation, IO,
and visualization. I could see PDL+GPGPU computing
working well with realtime game or display computations.

Well, the above ideas have a some hand waving to make them
happen, but I think the pieces are there.

Comments?
Chris

[Kartik Thakore]

Hey Chris,

I am definitely interested in helping with this. Perhaps we should make a test module that tests just these integration.

It will get latest branches of the 3 projects and run tests.

What do you think?

[Chris Marshall]

On Thu, Aug 15, 2013 at 6:05 PM, Kartik Thakore
<thakore...@gmail.com> wrote:
>
> I am definitely interested in helping with this. Perhaps we should make a
> test module that tests just these integration.
>
> It will get latest branches of the 3 projects and run tests.
>
> What do you think?

I'm glad to see the interest but most of the base work
is still needing to be done as far as the OpenGL stuff.
We need modern OpenGL support in POGL before a lot of
the specific development can occur.

However, one important piece that could be investigated
is how we could make conversion between SDL2 objects
and PDL objects work. Ideally we could have a fast
conversion to take a piddle and use it for an SDL2 surface
or texture or whatever and similarly for the other direction.

Currently, the approach used for SDL is to create the PDL
object with the right sized data segment and then pass that
to SDL to make a surface from that. I'm not sure what would
work for SDL2 stuff.

--Chris

[Kartik Thakore]

I think it will with SDL_Texture. 

http://wiki.libsdl.org/moin.fcg/SDL_Texture

[Mason James]

On 2013-08-17, at 1:37 AM, Chris Marshall wrote:

> On Thu, Aug 15, 2013 at 6:05 PM, Kartik Thakore
> <thakore...@gmail.com> wrote:
>>
>> I am definitely interested in helping with this. Perhaps we should make a
>> test module that tests just these integration.
>>
>> It will get latest branches of the 3 projects and run tests.
>>
>> What do you think?
>
> I'm glad to see the interest but most of the base work
> is still needing to be done as far as the OpenGL stuff.
> We need modern OpenGL support in POGL before a lot of
> the specific development can occur.
>
> However, one important piece that could be investigated
> is how we could make conversion between SDL2 objects
> and PDL objects work. Ideally we could have a fast
> conversion to take a piddle and use it for an SDL2 surface
> or texture or whatever and similarly for the other direction.
>
> Currently, the approach used for SDL is to create the PDL
> object with the right sized data segment and then pass that
> to SDL to make a surface from that. I'm not sure what would
> work for SDL2 stuff.
>
> --Chris

hi Chris,

i was looking at elmex's construder code recently, and noticed that the passing of an SDL surface to OpenGL was done by dumping the SDL surface to a BMP temp file (via File::Temp), then loading the BMP with OpenGL.

obviously this solution is a little slower than others, but... it should 'just work' without much effort

we could always use this lazy technique for initial testing, until a more 'correct' solution is sorted with SDL_Texture :)


Mason

[Kartik Thakore]

There is no need to. I made a PDL to SDL_surface work before. And in SDL2 you can create template from surface.

[Mason James]

On 2013-08-19, at 4:20 AM, Kartik Thakore wrote:

> There is no need to. I made a PDL to SDL_surface work before. And in SDL2 you can create template from surface.

awesome, thanks Kartik


and slightly off-topic but…
has anyone managed to build POGL on debian-wheezy lately? i'm getting a segfault :/


----------------------------------------------
root@vbox1:~# git clone git://git.code.sf.net/p/pogl/code pogl-code
Cloning into 'pogl-code'...
Resolving deltas: 100% (667/667), done.

root@vbox1:~# cd pogl-code/

root@vbox1:~/pogl-code# perl Makefile.PL interface=FREEGLUT verbose
$verbose set to 1
found libs:
GL = 'GL'
GLU = 'GLU'
GLUT = 'glut'
Testing for OpenGL Extensions
Testing GLUT version
glversion: cd utils;make -f Makefile GLUT_LIB=glut GLUT_DEF=HAVE_GLUT clean;make -f Makefile GLUT_LIB=glut GLUT_DEF=HAVE_GLUT
OpenGL Warning: XGetVisualInfo returned 0 visuals for 0x85e72c0
OpenGL Warning: Retry with 0x8002 returned 0 visuals
Segmentation fault
make: *** [glversion.txt] Error 139

rm -f glversion.txt
rm -f glversion
rm -f glversion.o
cc -I/usr/include -I/usr/X11R6/include -I/usr/local/include -I/usr/openwin/include -DHAVE_GLUT -c glversion.c
cc glversion.o -L/usr/lib -L/usr/X11R6/lib -L/usr/local/lib -L/usr/openwin/lib -L/usr/lib/xorg/modules -L/usr/X11R6/lib/modules -L/usr/lib/xorg/modules/extensions -L/usr/X11R6/lib/modules/extensions -lGL -lglut -lGLU -lXi -lXmu -lXext -lX11 -lm -o glversion
chmod u+x glversion
./glversion > glversion.txt


get_extensions: no extensions found in utils/glversion.txt

----------------------------------------------

[Mason James]

On 2013-08-19, at 7:43 PM, Mason James wrote:

>
> On 2013-08-19, at 4:20 AM, Kartik Thakore wrote:
>
>> There is no need to. I made a PDL to SDL_surface work before. And in SDL2 you can create template from surface.
>
> awesome, thanks Kartik
>
>
> and slightly off-topic but…
> has anyone managed to build POGL on debian-wheezy lately? i'm getting a segfault :/
>
>

hi All

i had another go at this, and fixed my build problem (some missing GL libraries)
i managed to sort a working travis buildbot for the repo too - using xvfb, a virtual X11 framebuffer tool

this 'xvfb' technique should allow us to get a passing build of the framebuffer tests on the SDL2 repo :)


https://github.com/KohaAloha/POGL/commit/3feb44a192f8b35625daf4c2fc74615d55883c0f
https://travis-ci.org/KohaAloha/POGL/builds/10618263


cheers, Mason

[Mason James]

hi Peeps

I've managed to sort some working travis buildbots for the various SDL_perl repos

we now have passing builds for the 'master' branch of...

SDL -> https://travis-ci.org/PerlGameDev/SDL
SDL2 -> https://travis-ci.org/PerlGameDev/SDL2
Alien-SDL -> https://travis-ci.org/PerlGameDev/Alien-SDL
Alien-SDL2 -> https://travis-ci.org/PerlGameDev/Alien-SDL2


cheers, Mason

[Kartik Thakore]

Awesome work! Thank you!