Boosting Flight Sims

[Solid Snake]

Hi all. One thing that the Amiga was popular for was flight sims. The 7MHz A500 was good at creating 3D graphics. I loved playing many favourites: F/A-18 Interceptor, Gunship 2000, F-19 Stealth Fighter, Birds of Prey, Combat Air Patrol, Falcon, Coala, TFX, F-29 Retaliator and Jet Pilot to name a few.

Revisiting these games on a A1200 (14MHz) OS3.1 with 4MB Fast Ram, you can see the speed of the game improves in some cases. Is the speed limited by the graphics engine employed? It is obvious that the speed becomes smoother by adding some accelerator board.

My question for the technical boffins on the board is this. What sort of performance boost can be achieved by applying certain third party patches (e.g. fastexec, syspatch, setpatch, blazewcp, optimised 68020 maths libraries) and which ones would you recommend installing for the above set-up?

[fxgogo]

So I think we would see different results on different games. 005agima proved on his TY channel that F/A-18 Intercepter was not only smoother, but it was accelerating the game time, which is not ideal. Ideally, we want a faster frame rate but the game time stays the same.

[musashi5150]

Originally Posted by Solid Snake

Is the speed limited by the graphics engine employed? It is obvious that the speed becomes smoother by adding some accelerator board.

Yes, the Blitter. It's used for rendering probably all filled 3D in traditional Amiga games and the speed of it has never improved from A1000/A500 days.

By fitting a faster processor you are getting improvements for the 3D math and other game logic, and the use of FastRAM which does help to some extent as you have noticed. But ultimately the rendering is bottlenecked by being reliant on the Blitter.

[Weasel Fierce]

In a way, wouldn't the bottleneck help avoid the DOS problem where games became unplayable because they were tied purely to CPU speed?

[Daedalus]

Not every 3D game uses the blitter - some like Frontier are almost entirely CPU rendered. And given how relatively sparse Amiga 3D games tend to be, drawing the screen is only a bottleneck at relatively high refresh rates, and once you reach 50/60FPS, you don't get any faster because the game will invariably be synced to the vertical blank, and outputting faster than that is simply pointless.

But the benefits do indeed depend on how the game's written. Given the variable nature of drawing a 3D screen, many games take the frame time into account so the game runs consistently, and adding a faster CPU results in a smoother experience. Birds of Prey and Frontier are two of my favourites, and IMHO both are borderline unplayable on a stock A500, they start to be enjoyable on an A1200, but given an '030 and fast RAM they really come alive.

Others, like F/A-18 don't fully take the frametime into account and make assumptions about the speed of the machine, resulting in poor scaling as mentioned above. Others like F1GP restrict the framerate to solve that problem, so adding CPU speed doesn't really help. Patching of such games is needed to properly take advantage of faster CPUs.

[Solid Snake]

What a fantastic discussion. What amazes me to this day is how Bob Dinnerman coded a fast 3D game such as FA/18 on a stock A500. His code proves a realistic flight sim was feasible on the Amiga. He could of written a superb sequel for the A1200 - imagine that! Bob was the blitter (chip) master.

[Seiya]

Generally with 3D flight simulator i saw change of frame rate from A500, A1200, 68030 and 68040. I stopped with 68040.
FastExec is excellent only if you have 68040 and 68060 and of course Cyberpatcher or Oxypatcher.
I used also "Patchmatfor020" that is a tool that recompile in realtime executables and otpimize che code for 68020 or better and generate new executable file. (this tool of course don't make miracles, but i saw difference, very little, but there are).

[Nightshft]

Originally Posted by Solid Snake

What a fantastic discussion. What amazes me to this day is how Bob Dinnerman coded a fast 3D game such as FA/18 on a stock A500. His code proves a realistic flight sim was feasible on the Amiga. He could of written a superb sequel for the A1200 - imagine that! Bob was the blitter (chip) master.

Yes, and it's such a shame that his engine can't use acc's without affecting simulation speed. I tried it myself and IIRC sim time was factor 1.5 or 2 using a middle tier acceleration card. Imagine how cool Interceptor running at 50 fps would be.
Still my favourite Amiga Flight Sim though.