Demos of the Week: Shaders on Mesa

Nice one (even if my 1st preferred is Felix and the second is CHasoTheory).

@kas1e
HELL YEAH! Keep em coming, Thank You!

"fr-041: debris" would be EPIC."

Here are videos of the mentioned demos running on my Amiga X5000 with Radeon RX550 4GB

E - Departure - https://youtu.be/C-0lVp-xIp4
Felix Workshop - https://youtu.be/gMURMf73t1w
Chaos Theory - https://youtu.be/qDl1TBlNXNA

Also the extreme test of Mesa Showcase demo - https://youtu.be/lBNQD9n0I58

I am still mad about the poor analog audio quality recording out of my AmigaOne X1000 and X5000, because there is still no audio through HDMI driver after all these years! Recording with AHI to audio file is a solution, but it can lead to desynced video. I've tried 3.5 mm, XLR, HDMI embedders and always have this hum. Only not tested method yet is capturing of optical audio signal, but need to buy separate sound card for this.

@drHirudo
You forget that one: https://os4depot.net/share/demo/scene/fr-038_theta.lha

If you have the CPU/GPU power!
Run it it from shell with this -

fr-038_theta fr-038_theta --high --texture-quality ultra

Thanks again kas1e, looking forward to Debris! ;)

@All
Another one, again from ctrl+atl+del French group. Called H-Immersion:



For the AOS4 port, I had to do some heavy lifting: initial generation of textures was taking some time on the CPU,
so I first used them as external files, but it was about 30 MB of data: no way! So, at first I converted all textures
to WebP while keeping 1:1 quality, but it was still 22 MB. Then the small ones were embedded in the binary as WebP,
while the large ones were moved to be generated directly on the GPU, where I calculate many pixels in parallel and keep
the results ready for rendering, without the need for slow CPU generation and extra memory copies.

Music also comes as an external Opus file, as the original SSE-based synthesizer is quite heavy when ported to 20 years
old PPC CPUs. Opus was chosen over MP3 just to save a bit more space as well.

The binary itself also had some work done: getting rid of C++ baggage in file I/O by replacing it with C equivalents,
and shrinking SDL2, which I use together with Mesa.

So all this brings the package down to a reasonable size, while keeping loading/generation time reasonable
(~35s on X1000, ~30s on X5000, but still ~90s on Sam460), and ,thanks to Mesa, all the visuals, shaders and co. remain 1:1 the same.

Thank you for this weeks demo port !
Very nice atmosphere in this one.

Edit: And very interesting to read the explanation on what it takes to port a demo size wize!

@All
Next one for this week!

This time it some mind blowing demo from wellknown demo group "Andromeda Software Development". Demo called LifeForce and were released at Assembly
2007, where it took a well deserved first place. It were shown on Pianeta Amiga 2026 as well, so it's about to time to release:




For the AmigaOS4 port, I reconstructed the demo from the original Windows binary and the supplied Cg shader files. Since the rest of the source code was missing,
with Ghidra's help,i produced a byte-identical reconstruction of the original executable,then translated the recovered routines into C++ and got the demo running on
x86 under WSL2.From there,a native PPC version with the necessary endian fixes were build.

To make it work fast on our old machines, the original CPU-heavy rendering was changed to offload much of the work to the GPU. For example, static meshes stay
in GPU memory, while shaders and compute handle geometry expansion, fluid simulation, cloth, curves and tubes: this removes CPU calculations and repeated
geometry uploads. To avoid hiccups and micro-stalls in the process,the demo compiles and loads all the shaders at once, right at the start, before the demo actually
starts. As a result, it takes about 60-65 seconds to load up on an X1000 at 2 GHz, but in turn you get around 300-500 FPS over the whole demo, with no hiccups.

The whole demo originally used external textures, music and meshes,and the packed size of the original demo was 27 MB. I didn't try to lower it much; I just reduced
the binary size a bit by getting rid of unnecessary C++ baggage and unused SDL2 functions, as well as getting rid of the CgEffects directory, as all the shaders are
now internal. And while the original shaders are no longer used,the final visual result is 1:1 identical to the original demo.

Grab it from os4depot while it hot !

@kas1e

Thank you!

@kas1e

Thanks for these great demos—it's really impressive to see all the possibilities we now have with Mesa. More of this, please...

@kas1e

LifeForce didn't like GART enabled on the Sam460, kept getting random DSI errors.
Worked great with it switched off.
Another really good watch.

Cheers