Thin emulation?

I posted on AW.net some time back and got a few supportive responses about thin emulation. Now I'm wondering if it would be a good bounty for Power2People or AmigaBounty to have Classic Amiga graphics chipset capabilities written in the form of a fragment shader program for Gallium drivers.

Here's how it would work: It would open up 256-color palette-mapped layers using 8-bit alpha-only framebuffer objects. Some values of the palette would correspond to a 1-dimensional texture indexed by the Y coordinate of the screen to produce copper-rainbow effects. The 0 value of all of the framebuffers would pass through to the lower-priority framebuffers in the background. If the fragment shader program defining this could handle up to 10 layers, it would make all of the sprite/playfield capabilities of the Classics available to high-end graphics card systems such as the SAM 4x0 series and AmigaOnes.

The catch is, it won't work efficiently layered on top of Mesa or OpenGL since all framebuffers are 16 or 32-bits. Gallium3D supports 8-bit framebuffers though. This could make emulators much MUCH faster because it would offload most of the capabilities of the AGA chipset onto the graphics card.

Does anyone think this would make a good bounty? (And before anyone asks, I've got my hands full with existing projects to do it myself.)

its sounds like an idea but how hard would it be to make. anyway there is work in prograss with jit into uae.i think sooner or later there should make puae to os 4.x

but the idea it sounds good thoug evry thing thease days is the gpu and not cpu anymore. i dont care iff the x1000 is not 4 giga hertz its duel core and 2 megahert and its amiga. soo iff a good,good fx card driver comes avaible it will rock.
i personli think that hans should focus on the very high end gfx card and not the middle class ones at the same time as the high end...skip the r600 and do r700 insted

This is getting a little bit off topic but I'll comment a little about Gallium drivers.

The NVIdia graphics cards that work on the Gallium drivers on AROS should work on OS 4 if there is no endian-specific code in them. There are Radeon Gallium3D drivers as well, but LLVM is required by those. I've already accepted a bounty to port LLVM to AROS but if it is successful, I could try porting to AmigaOS 4.x as well.

what are wee talking now. are you gonna give the nvidia drivers a go now ore are you gonna try make some expermential AGA emu om the gpu ???

anyway iff you are into drivers. nvidia have sterro drivers for almost all there cards these days. i remember back in 2002 i got my first pc later on i upgraded to nvidia 5600 ultra with 256 of mem. it had the 3d driver and i got a pair of 3d glasses from edimsional. funny how much pepole talks about it. i had these glasses for like 10 years. and i have been playing.dod, wolfenstien enamy T. and so on. evry thing thats works with opengl works with 3d drivers on crt monitors. and allso on lcd iff its over 100 hertz.
i remember offering the friden brothers a pair iff there want to make 3d suport for amiga os 4.x
iff you are game i am willing to give you the same offer if you are serius about it, and the friden broters or hans can help you out with dirctions.just so none off the dev is cutting the stick the other one is sitting on

There is a Wikipedia article about Gallium3D drivers.

Gallium3D drivers are slated to come in a future version of AmigaOS 4.x.

I'm talking about code that will bypass OpenGL and access the graphics drivers directly to implement AGA chipset features.

you mean adding this to E-UAE or directly inside AmigaOS so that it could use chipset depending apps directly?

@DAX

Preferably as a shared library so that software could run from a common source code with people writing software for Classic Amiga. EUAE could access it among others programs.

@Samurai_Crow
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Wouldn't it be easier to use what is available in EUAE now and make ocs-ecs.library, aga.library, etc and build on top of that?

Easier? Maybe, but it would also be DEAD SLOW. E-UAE does thick emulation. Thin emulation would be executable by the shaders in the graphics card and would run much faster since it would leave the CPU alone for executing the actual code and the JIT besides.

On the SAM 440 series, the graphics cards or on-board chips are fast but the CPU is not very fast by today's standards. The SAM 460 fixes the CPU speed problem partially but still has underutilized graphics capabilities on its graphics card. Only an AmigaOne X1000 would have the brute force to make thick emulation work.

Thick emulation works well on MicroA1-c machines because the Radeon 7000 chips have no shader capabilities. On modern graphics cards, the chips can be programmed to run simple programs on each pixel displayed so that some Copper-style capabilities can be regained by the system.

For example, Total Chaos AGA runs dog slow on my Intel Mac running E-UAE even though the JIT is active. The reason for this is that the chipset emulation is much slower than the processor emulation. I suspect P-UAE would be more compatible but still slow. I want chipset emulation on NextGen Amigas to be uniquely capable of emulation of Classic capabilities that even WinUAE struggles with. Of course DirectX is more able than OpenGL in this regard so I want to close the gap.

@Samurai_Crow

thanks, I have a better understanding now at what are you aiming with this approach. Sounds interesting.

do it, do it
send troels a message on the amiga bounty page...
i am sure hee will help getting the bounty in order.
i my self only have a micro soo it would be very nice. and even more iff jit comes around allso,only thing left is to hope paue will come sooner or later

@retro

I decided to go with Power2People.org since AmigaBounty is OS4 only and doesn't require that the code be released as open-source. AROS has Gallium3D drivers working right now and once OS4 gets the Gallium drivers it should be easy to port from there to here. If nobody accepts the bounty right away, then writing both versions in parallel should be possible.

BTW, the Radeon 7000 chips in a MicroA1 won't be able to run shader programs. They use what's called a "fixed-function pipeline" that works differently. It'll need thick emulation on the MicroA1 or else use the hack to allow a graphics card to plug into the PCI slot.

@Samurai_Crow

All of this sounds interesting, and even with Gallium support i think it will be not problematic to put all that code to aga.library (for example). And let's be that library use galium, but still it can be as a library for end users.

But i see there is some problems: For end users will not enough to have support "just" AGA features for example. They (users) of course will in interest to run just a apps/demos/games which bang hw. So need to emulate cia, paula and so on, because without, emulation of only one chip will make no sense in real use.

@kas1e

There will still need to be an emulation layer over the top of the shader for the CIA timers and Paula and so on. That shouldn't need to be in the library though.

A full thick emulation layer could still use the shader routine to boost the speed of the graphics emulation. The planar to chunky conversions would still need to take place in the thick emulator application, for example, so incorporating CIAgent and Nalle Puh or something similar shouldn't kill the performance.

I think the important thing is to keep the emulation thin by mapping old functionality into the modern equivalents as closely as possible.

I just mean that its all the same hard, as write e-uae from scartch. Years, and years, and only in case of very big motivation , energy and time something can be done from that ideas.

But sure, theoritically its all possible and interesting.

btw. NallePuh not works anymore as far as i remember (but sources are available, so can be changed) and ciaagent not avail in sources as far as i remember, and it not have full support for all the cia stuff :(

This type of thing could mean to the chipset part what jit means to the CPU part, much needed with ultra chipset intensive games.

Someone should definitively do it...

Since AROS already has the Gallium3D drivers ported to it, I decided to post the Bounty to Power2People.org instead of AmigaBounty. Discussion about the details should continue on AROS-Exec.org.

I was thinking if it could be possible and useful to use Xena chip to emulate CIA's.

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Seems to me it generated more interest here though...

I started out with this thread on AROS-Exec. I guess that's all that needs to be discussed.