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ArborealSeer
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section for GL?

Sun May 20, 2012 5:10 pm

seems like all discussion of OpenGL ES is fragmented as there isn't a place for it, and i guess a lot of the info applies to multiple languages, so is this a good idea?
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cheery
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Re: section for GL?

Sun May 20, 2012 5:34 pm

Yes it is. Though there's not much talk about GL here yet.


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abishur
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Re: section for GL?

Sun May 20, 2012 7:04 pm

There's not a section for it because the pi doesn't use it as I understand things ;-)

Nevermind, your thread title says GL, but looking back at your post you say GLES (which the pi does support)
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ArborealSeer
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Re: section for GL?

Mon May 21, 2012 6:42 am

thats for projects, not discussion of using the api itself.
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theHetman
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Re: section for GL?

Mon May 21, 2012 7:33 am

I think there should be a more general "Graphics APIs and GPU" section under programming. I agree that general graphics programming questions are getting fragmented already and it would be nice to have them all together.

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Jim Manley
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Re: section for GL?

Mon May 21, 2012 8:55 am

YES!!! We absolutely need a place to talk about GLES itself, regardless of the language binding. There are precious few examples of OGLES 2.0 outside of iOS and, to some degree, Android, and those have Objective C and Java bindings, respectively, which are very different from the Pi C bindings. We need an effort to port as many representative OGL/iOS-Android-OGLES examples to Pi OGLES as is possible as soon as is practical. The principal strength of the Pi is 3-D graphics, 3-D graphics, and 3-D graphics, in that order, and should be the number one focus of promotion of the Pi. Not doing so is just disappointing and frustrating people who see that infernal "An ARM GNU/Linux box for $25" motto on every Foundation site page, and it's not going to change unless the CPU is vastly upgraded, which ain't gonna happen anytime soon.

One of my purposes for the Pi-finity! educational game is to help teach OGLES development, since much, if not all, of the code will be open-source, and it will include puzzles/problems/missions that will require varying levels of software to be developed as part of the game play. If I ever get things working well enough, I would very much like for there to be porting tools to help accelerate movement of code from OGL and iOS/Android OGLES to Pi OGLES, perhaps even frameworks that would allow running the code in those foreign implementations unmodified on the Pi as wrapped code modules. Yes, I do know how hard that could be, that's why it hasn't been done before.

I'm looking at various OGL(ES) frameworks/environments to see if anything like this has been done elsewhere, but, so far, no joy. Any suggestions and evaluations would be greatly appreciated, especially given the Pi memory/CPU limitations.
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ArborealSeer
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Re: section for GL?

Mon May 21, 2012 11:50 am

I've got a bunch of "OpenGL ES" threads bookmarked, if a section appears i'll link em up so a mod can bring them over.

I guess any queries about "How do I access the GPU" can go in there too, a sticky might help!
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theHetman
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Re: section for GL?

Mon May 21, 2012 2:20 pm

My plan is to write a bunch of simple learning demos for OGL ES 2.0 and maybe port a few of the pretty ones over as well. I used to be a games programmer in a former life but that was OpenGL 1.x. I only played with vertex shaders in the very early days (on the XBOX) and so I want to learn ES 2.0 get get up to speed on what can be done with it.

If there are not many demos for ES 2.0 at least there are good books on the subject. There is almost nothing on OpenVG. It doesn't seem so widely supported and most implementations out there sit on top of ES 2.0.

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ArborealSeer
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Re: section for GL?

Tue May 22, 2012 9:54 pm

i definitely think this section is needed. i missed a post by the guy above asking for something i could have linked many hours ago, and found another post in yet another section on the topic that was from yesterday..
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theHetman
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Re: section for GL?

Tue May 22, 2012 10:15 pm

ArborealSeer wrote:i definitely think this section is needed. i missed a post by the guy above asking for something i could have linked many hours ago, and found another post in yet another section on the topic that was from yesterday..
Yes, I have a "watch" on several threads but those emails get annoying after a while. Maybe if someone posted in "Forum Glitches" a mod with enough privileges would see it.

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Jim Manley
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Re: section for GL?

Tue May 22, 2012 10:33 pm

Published in 2008, the OpenGL ES 2.0 Programming Guide is getting a bit long in the tooth, but, it does cover the basics. It's the first book that comes up in the list on the following page, and there are other books on OGLES in the list that goes on for two more web pages. Most are for iOS and Android, which only matters in the code examples - the OGLES API calls are the same as for embedded Linux:

http://my.safaribooksonline.com/search/ ... ming+Guide

You can access the book on-line on a free trial basis for 10 days or 1,000 page views if you provide a credit card number and then cancel before the trial expires and the card is charged for unlimited access. Most of the examples will run on the Pi, and the remainder will run with a bit of tweaking, as has been done here:

http://benosteen.wordpress.com/2012/04/ ... -x-windows
The best things in life aren't things ... but, a Pi comes pretty darned close! :D
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redneon
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Re: section for GL?

Wed May 23, 2012 9:51 am

I like to see a GPU coding section too.

gladoscc
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Re: section for GL?

Wed May 23, 2012 11:14 pm

Yeah, there needs to be more documentation for GLES on the Pi.

finnw
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Re: section for GL?

Thu May 24, 2012 3:03 am

gladoscc wrote:Yeah, there needs to be more documentation for GLES on the Pi.
Yes, especially a "GLSL quirks" page.

Things I've noticed so far:
  • The == operator on floats tests for bitwise equality, so for example 0.0 == -0.0 evaluates to false
  • exp(-inf) returns +inf
  • All numeric types are represented as 32-bit floats (precision specifiers are ignored.)

finnw
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Re: section for GL?

Thu May 24, 2012 3:49 am

finnw wrote:All numeric types are represented as 32-bit floats (precision specifiers are ignored.)
Oh, and it also means you can have infinities and NaNs in int variables :shock:

shirro
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Re: section for GL?

Thu May 24, 2012 4:47 am

finnw wrote:
  • All numeric types are represented as 32-bit floats (precision specifiers are ignored.)
Thanks. I didn't think lowp, mediump and highp were making any difference when I was trying to speed up some things. I would love to see all this stuff dumped somewhere.

I am really new to opengl and have no idea what I am doing but isn't it usual for vendors to have a list of the stuff their hardware does/doesn't support and how to tweak things to take best advantage. There is no point keeping that stuff secret because people will work it out from experience and document it eventually.

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Jim Manley
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Re: section for GL?

Thu May 24, 2012 6:15 am

Broadcom hasn't really been in the business of supporting 3-D graphics the way the dedicated graphics card manufacturers have been, and I get the impression that they've been sticking in support for OGLES and VG more as feature checklist items than well-supported primary features. This isn't surprising for the BCM2835 SoC in the Pi considering that its primary market has been for digital video streaming devices, e.g., the Roku 2 series. Dom and other volunteer engineers for the Foundation work on Broadcom products in their day jobs, and it's pretty clear their volunteer workload is far beyond their ability to keep up with it. Unless Broadcom gets commercial customers that need the OGLES implementation-specific information discussed above, I'm guessing that our only recourse will be to do it ourselves. If only software could automate such tasks and make our lives easier ... ):

There are obviously conformance tools for validating OGLES certification, but, those are very likely expensive (tens of thousands of dollars per seat is typical) and they probably only certify that implementations perform within the requirements, not how they vary within the specs or, just as interesting, may exceed particular specs.
The best things in life aren't things ... but, a Pi comes pretty darned close! :D
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
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ArborealSeer
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Re: section for GL?

Thu May 24, 2012 4:34 pm

^ indeed.. also there current GLSL post has raised an interesting response from Dom.

/ jokingly..

however, without a dedicated Graphics Programming section to house it, it'll only go and get lost...
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stowelly
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Re: section for GL?

Tue May 29, 2012 8:39 am

I would really like somewhere I could find info about opengl on the pi easily. so far it doesnt seem very clear on how well it is supported on the device, and it is something I would imagine a lot of devs want to do with it!!

jmacey
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Re: section for GL?

Thu May 31, 2012 6:53 pm

That would be good as I mainly do OpenGL programming, I looked for a section and posted in C/C++



Jon

chris_c
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Re: section for GL?

Fri Jun 01, 2012 9:45 pm

I'd love to a specific forum for GLES / GPU stuff too, it would probably speed up the development too...

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