OpenGL ES 2

[BigMc]

Hi,

I think porting SLUDGE to OpenGL ES 2 would be a big (the biggest?) step needed to make SLUDGE work on mobile devices (speak Android, iOS). Would you be interested in that Trumgottist? Or someone else?

I changed the engine to use vertex arrays instead of glBegin/glEnd, because glBegin/glEnd isn't supported in OpenGL ES. When I was finished, I noticed that the new stuff I added only works in OpenGL ES 1. Textures have to be handled entirely with shaders in OpenGL ES 2, and we would have to use 2, because OpenGL ES 1 doesn't support shaders (and there are already shaders in SLUDGE).

Anyway, using vertex arrays speeded the engine up. Before, activating antialiasing slowed the engine down on my computer, now the noticable difference in speed is gone.

Just wanted to say that and that supporting OpenGL ES 2 would be nice. It should be a reasonable amount of work for someone proficient in OpenGL (compile with OpenGL ES 2 headers instead of GLee.h, change everything that doesn't work). I'm not planning to do it myself in the moment, because with my little knowledge of OpenGL it's not that easy after all.

[Trumgottist]

The main downside to replacing the fixed functionality pipeline completely with shaders is that older computers may not handle it as well, which make me hesitant on that change. That's just my gut reaction though - I haven't looked into ES, so I don't know exactly what's required.

I personally don't have any interest in getting SLUDGE to run on mobile devices, but if someone finds that they can make the graphics rendering work within the constrains of OpenGL ES without making anything worse for the existing platforms, I won't have any objections.

Anyway, using vertex arrays speeded the engine up. Before, activating antialiasing slowed the engine down on my computer, now the noticable difference in speed is gone.

Interesting to hear. I knew that vertex arrays are faster than immediate mode, but I didn't investigate that since I didn't think the speed difference would be noticeable because a typical SLUDGE game use fewer vertices in an entire scene than a modern game use for an arm of a character. Apparently I was wrong. Cool.

[Squinky]

I'm extremely interested in getting SLUDGE to run on mobile devices, but don't have the time or OpenGL knowledge necessary, sadly.

[Mnemonic]

Also keep in mind even older iOS devices only support OpenGL ES 1.1. So if you wanted to support ALL iPhone/iPod Touch versions, you'd need both OGLES 1.1 and 2.0.
I recently ported WME to iOS and it's using 1.1 (via SDL).

[Trumgottist]

I recently ported WME to iOS and it's using 1.1 (via SDL).

Cool. I see that it's also available on Mac. Great news.

[Squinky]

If OpenGL ES 1 would work, then maybe I could try my hand at that to start with. I've got an iPhone 3G I could test on, and might be able to get access to an iPad at some point.

[BigMc]

It's certainly possible, maybe even less work than porting to GLES 2. If removing the shaders has disadvanteges, we could keep them for the systems where they're available. Do all GLES 2 devices also support GLES 1?

EDIT: But maybe not "to start with". Porting to GLES 1 is going the opposite direction as porting to GLES 2.

[Trumgottist]

The shaders can't be removed unless you write some functions in software, or the bug I named "Erwin's bug" will return. (An image with transparent parts could not be added to the backdrop without messing up the alpha channel of the image.) That means that all functions dealing with the backdrop would have to be implemented without using the graphics hardware.

There are currently three uses of shaders in SLUDGE: The most important on is the one I just mentioned. Then there's the one doing AA, and finally there's one for rendering yuv images (which is what you get when decoding movies).

For a mobile engine, you may be better off making a fork so you wouldn't have to keep backwards compatibility with existing SLUDGE games. That way you could re-design things so you wouldn't have to deal with those limitations. (Or use WME - I hear that's a good engine. )

[Squinky]

Hmm. Okay then, porting may not be the best thing for me to do after all.

[BigMc]

Hi and happy new year!

I work on this from time to time in a local git branch and recently progressed far enough to believe that I will finish a OpenGL ES 2 compatible SLUDGE eventually.

If we want to convert our repository to git, now would be a good time, because then I could upload the branch as a branch first and merge later. Otherwise I would commit the changes to svn when I'm done (or almost done). Or make them public elsewhere if someone wants to have a look.

[Trumgottist]

I don't have a git client (other than the command line thing built into the OS, but I'd rather not use that), so I'll happily keep using Subversion.

(Does anyone know a Mac Git client that's as good as Cornerstone is for Subversion?)

[BigMc]

It's basically working now with GLES2 and the games look the same as with ordinary OpenGL. I just have to reenable some things and it's done.

[Black Dahlia]

Hallo Everybody,

I'm new on sludge.
I've tested a prev. Version some times ago and it works well.

The main downside to replacing the fixed functionality pipeline completely with shaders is that older computers may not handle it as well, which make me hesitant on that change.

Thanks for revolution

The new 2.2 fails on my Computer.

Here is the output:

Code:

Error building "scale" shader program!

Is it in future Version possible to have somewhat like a "fallback mode" for older Computers?
Version 2.1.2 seems to fit my needs.

But is the possible code of a "Version 2.1.2 Game" compatible to new(er) Versions (except change to UTF-8)?

Thanks,
Please foregive my english

David

[BigMc]

Hi,

if this is caused by your computer being old, the shader should also fail to build in 2.1.2 and there should be graphical glitches. Could you post your (2.1.2 and 2.2) debug output? How to get that depends on your OS, I only know right now that on Linux you would have to use the option -d1. Also do you know which graphics card you have?

[Black Dahlia]

Hi,

My os is Linux.
I've testet 2.2 on my Windows XP and it fails too.

Output 2.1.2

Code:

Note: Skipped 125 bytes in input
Note: Illegal Audio-MPEG-Header 0x00000000 at offset 22718
Note: Trying to resync...

Output 2.2

Code:

sludge-engine -d1 -a0 Verbcoin1.slg
*** Engine compiled Feb  3 2012 at 00:12:51.
Video mode 768 576 set successfully.
Compiling vertex shader...

Compiling fragment shader...

Shaders compiled.
Shader program linked.
SLUDGE v2.2.0 fatal error!
Initialisation error! Something went wrong before we even got started!

Error building "scale" shader program!

My grafics card:

Code:

00:02.0 VGA compatible controller [0300]: Intel Corporation 82945G/GZ Integrated Graphics Controller [8086:2772] (rev 02)
Subsystem: Elitegroup Computer Systems Device [1019:2687]
Kernel driver in use: i915

If i can do something more please tell.
thanks