OpenGL on OS4?

Hi all,

I know we have MiniGL but I found this on Wikipedia:
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thus my question, is it possible to have OpenGL on OS4? What do we need?

@Elwood

MiniGL on the Quake series is not necessary on WINDOWS because the graphics cards manufacturers supply OpenGL drivers for them. Also, some gaming PCs use only DirectX and have no support for OpenGL at all.

The most complete OpenGL implementation available for free is Mesa. It is a software-only implementation of OpenGL except that it can be modified to run hardware accelerated.

Getting a Radeon-specific version of OpenGL would require more money than the Amiga community can offer them.

@Elwood

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Time and money. If I had both, I'd have an OpenGL running already. Problem is I get sidetracked a lot, so I cannot work on it a lot..

@Samurai_Crow

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Hum, we won't have any gfx driver delivered by the manufacturer anytime soon so be it MiniGL or whatever it's the same.

Just to be sure I understand what OpenGL is, tell me if I'm wrong. It's an API, i.e you write in your code glClear(). This function existing in your gfx card driver will produce the result on screen, right?
So we could have either OpenGL glClear() => gfx driver or MiniGL glClear() => gfx driver, right?
In this case, I would prefer to see OpenGL, a widely used API, on OS4 instead of MiniGL.


Also note this:
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@Rogue
I never meant it was you alone that should do it

@Elwood

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You're pretty-much right about OpenGL and MiniGL. MiniGL is simply a cut-down implementation of OpenGL. It supports some of the OpenGL API, but not all. If a program written using OpenGL only uses features that MiniGL has, it can run via MiniGL without problems. We're going to have to live with MiniGL for now.

Hans

@Hans

Is it possible to have a rough idea of the difference between both needed efforts? Does OpenGL need twice time than MiniGL? 5 times?

Thanks.

@Elwood

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No idea really, but the difference is quite large. Updating MiniGL would require a major update to Warp3D in order to support new features such as shading. Added to that the existing code-base supports a subset of OpenGL v1.4. So you're talking about updating an old code-base with a handful of people working in their spare time. It's always going to lag behind the current state of the art. Also, you're still hampered by limitations caused by the current graphics-system (a.k.a. Picasso96). The one advantage would be that you'd see more regular updates, instead of a long wait and then one big giant leap with a HW accelerated MESA port.

Contrast this with porting MESA. It's got a large code base that's (AFAIK) up to date with the current OpenGL specification; it has a large team of people; and it has existing hardware driver APIs that could probably be used. It makes sense to take advantage of the large code-base and development team. Most importantly, once the port is done, we'll be completely up-to-date in one step, and should remain there, courtesy of the MESA team.

If you ask Rogue, he'll tell you that they want to replace the graphics system with a new one that supports 3D hardware properly, and port MESA. It's going to take time though. In the meantime, a few others and myself are updating MiniGL a bit to add support for a few more OpenGL functions. Hopefully this will give people something to play with until the MESA port arrives.

Hans

@Hans

Fully understood. Thanks.

@Rogue and all the amigans

Well maybe i am saying something stupid ( hope no.. )

you said that if you had money and time we could have open gl..

Open GL is not open library right ? is something that a developper should pay to have it right ? like direct x ?

What do you think if we do a bounty to collect money to have open gl on amiga os 4.0 ? could it be done ?

@Elwood
@nubechecorre

afaik "Mesa" is an Implimentation of the "OpenGL" specification,

OpenGL being full definition,
MiniGL being minimal function definition,

Mesa and Drivers being implimentation...

Rogue and Hans please correct me if I am wrong

@Hans
@Rogue

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Your efforts are very much appreciated, thank you very much

@Elwood

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Sorry, but you are comparing apples and oranges.

An "OpenGL" does not exist, it's a standard API that someone can implement.

There are two possibilities: Implementing the OpenGL API, or porting an existing implementation.

Implementing a full OpenGL is an effort beyond anything that the Amiga developers can pull off. So the only viable solution is a port of an existing OpenGL. Most likely Mesa.

Porting Mesa is a no-brainer. Doing the hardware drivers for it is another matter. A software-only mesa port can be done in several hours (already did that). That does not give you a usable OpenGL implementation, though.

Implementing a hardware driver requires a lot more work and knowledge about the chip. And even then, there's other things to consider, namely interaction with the existing "2d" graphics driver, contention for the hardware, etc.

This is not something that can be done cleanly by a third party, as Hans-J?rg and me had to learn with Warp3D. Any solution that you can do "from outside" has to cope with a lot of shortcomings. The result will never be optimal, and will not allow the full capabilities of the hardware to be used.

@Hans

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May I ask something else. If you get MESA, MiniGL or anything similar that will mean that you have 3D hardware properly? What is the main problem (except drivers of course!) to have fully 3D hardware capabilities?

I do not understand it, that's why I am asking! :)

And then, what else is needed in order to have that sexy 3D Hardware Desktop Cube or something similar on our Amiga OS4?

another solution could be pray ATI to release drivers, with OpenGL implementation, open source...

@Cool_amigaN

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There is no problem. The drivers ARE the problem.

As I said above, porting Mesa (and thus a fully OpenGL 2.1 compliant implementation) is a no-brainer, that will give you a fully compliant software-rendering implementation.

The problem is creating a driver, and integrating it into the system.

There seems to be a lot of misconception about what OpenGL is.

OpenGL is a specification, nothing more, nothing less. It's a description of a bunch of API calls and what they are supposed to do, much like e.g. the sockets API of the original BSD is. Like with the BSD network layer, a number of implementations may exist.

Mesa3D is one such implementation. As a matter of fact, it is more like a set of library routines that can be used to create an OpenGL implementation. One such implementation is OSMesa, included with the Mesa source code, which is an off-screen memory buffer implementation of OpenGL 2.1.

More importantly, there are external things beside OpenGL that need to fit in. The OpenGL specification does not say anything about a "struct Window", about a X11 "Window", or a Win32 Window. There is always a "native binding" part, a part that glues the OpenGL API calls to render to a "struct Window" or "struct BitMap".

Finally, the most important thing, there is a hardware dependent part that instructs the graphics hardware to render USING the graphics hardware. This part is called a "driver". In the past, attempts were made to use Warp3D as a driver, and in fact, StormMESA did do that (more or less) successful. However, for several reasons, this is not feasible anymore, one of them being that Warp3D does not support hardware T&L.

Writing a hardware driver for Mesa does require both intimate knowledge of Mesa's internals, as well as intimate knowledge of the hardware, AND intimate knowledge of the underlying operating system. For that reason, you cannot just simply compile Mesa on AmigaOS 4.0 and get a working 3D hardware acceleration.

Now, we do face a number of issues with this. Even if we assume someone had the time, knowledge, and means to implement this, we have some architectural problems. For one thing, there is a second entity (Picasso96) fighting for the control of the graphics hardware. Warp3D has to take a lot of tight corners to work at all, and it doesn't work as well as it could.

What people do not seem to understand is that having a MiniGL itself is not the biggest issue, especially with the latest additions of Display Lists. In most cases, a program (especially games) do not use all of OpenGL (who has ever used the imaging subset, I wonder). A game like Quake 3 uses only what is in MiniGL anyway. The problem with the current MiniGL is that is does not use hardware accelerated T&L. If it had that, and a few added features (like selection) then the whole discussion wouldn't be so much in focus anymore. An additional problem is the speed at which the hardware evolves and keeping track of that, and keeping step with the latest developments like OpenGL 2.0 and the GLSL. Mesa does that to a certain degree, but even they have some trouble (lack of documentation from graphics cards manufacturers for example).

What needs to be done is a few fundamental changes in the graphics subsystem to allow an OpenGL port (and that means ANY OpenGL, not just Mesa but even a custom, vendor-specific implementation) to integrate with the graphics system in a consistent, supported, system-friendly and FAST way. Right now, this is not possible. It will require work, work that needs to be performed by the AmigaOS team (and WILL be), and cannot be performed by third parties because anything that third parties will come up with will only be a hack, as Warp3D is now.

@afxgroup

That doesn't work either. See my post. It's not only the drivers. For the same reason you cannot use ATI's Windows driver on Linux, and vice versa.

@tfrieden

Thanks very much for the answer!

I am asking bacause I took part recently in the presentation of OS4 on classic in Greece 5 days ago and I was amazed to see some TTF Fonts Antialised, video playback, moving drawers all over the screen with no major fallback of the system. So I supposed that OS4 was making full use of 3D hardware allready!

Frankly, I can't understand how the other way is true, I can't believe that all these heavy tasks were proccesed by the cpu :)

Ok now, who is gonna make a driver to have 3D desktop? :)

@Cool_amigaN

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It doesn't use any 3d hardware for this.

@Elwood

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Actually, I am about the only one that could do it, or someone/some group from the AmigaOS team. This is no task that could be performed by any outsider, it ties too deeply into the system itself.