Which Amiga games ARE better than on the ST?

[dlfrsilver]

Originally Posted by AestheticDebris

It's exactly the same code between the Spectrum and Amstrad versions. I can beat them both on the same muscle memory, every enemy attacks in the same way at the same point.The graphics have been reworked, but they also clearly aren't from the Amiga or ST version in either case.

Batman the movie and Robocop were drawn for CPC on an Atari ST (the ocean classic setup at this time for developpement of CPC games).

They both were drawn with EDSPR and EDMAP (these tools was used to make Snow Bros on Amiga, but they were compatible with the CPC 160x200 mode 0 16 colors pixel size). The tools in question were made by John Brandwood.

I have some magazine screenshots where you can see Dawn Drake doing the CPC batman sprite on her Atari ST.

The CRTC controls the position of the screen, the length of hsync and vsync pulses and the memory addresses the gate array uses to read an interpret screen bytes. You can use this in simple ways to do coarse character based scrolling or to double buffer the display (not often used on 64K games because each screen buffer is 16K and sacrificing half the RAM for double buffering is usually too extravagant). You can also abuse it by doing things like setting very short hsync pulses that the monitor will ignore, but will trick the rest of the system into displaying a second "frame" within a single pass of the display beam (known as rupture splitting). You can also cause some CRTCs to display border colour mid screen, or bend the screen by making rapid changes to screen position and relying on the analogue response of the monitor.

If the CRTC emulation is incorrect, colors gets messed up, and the CRTC has counters, but those also obey to timings. These timings are internal to the CRTC, they are not at the charge of the CPU.

But everything to do with on screen colours or pixels is a result of changes to gate array registers. And only the CPU can change those, so mid screen colour changes have to be done with timed CPU code. Even on the Plus machines (which so have a form of copper-like DMA-based processor, that is intended for audio but can be abused to generate frequent line interrupts) there is no way of changing colours other than the CPU doing it.

Sure, you ask the CPU to reload or change some colors, but then the CRTC do the job.

I know this not because someone explained it to me, but because I've coded for these machines for decades and I'm well aware of what they can (and can't) do.

CNGSOFT explained me many times how the CRTC worked, the fact that it has its own timings, what it can do as well.

[Gerry]

Originally Posted by alexh

I am not 100% sure about Wings of Death but Thalion first year titles the Amiga ports were done by their sound guy Jochen "MadMax" Hippel in his "spare time". They were not priority, contained lots of ST specific code that should have been removed, the reason was economics, the Amiga versions made little or no money and so had to be "acceptable" in the shortest possible time.

According to the manual and the credits in the WoD intro, the programming of both Atari ST & Amiga version of Wings of Death was done by Marc Rosocha.

[AestheticDebris]

Originally Posted by dlfrsilver

I have some magazine screenshots where you can see Dawn Drake doing the CPC batman sprite on her Atari ST.

Yes. The Spectrum graphics were also drawn on the ST. It's how Ocean did game development by that point. It doesn't make any of them a port from the ST version.

Originally Posted by dlfrsilver

Sure, you ask the CPU to reload or change some colors, but then the CRTC do the job.

CNGSOFT explained me many times how the CRTC worked, the fact that it has its own timings, what it can do as well.

The CRTC generates signals which tell the Gate Array what to draw. They are DISPTMG, which means "draw the border", RA and MA, which are supposed to be character locations (the 6845 was intended for character based displays) but which are combined with the Gate Arrays internal colour clock CCLK to define which memory byte to read. It also sends HSYNC and VSYNC signals and the Gate Array will output black regardless of palette selection when it does (this is about as near as the CRTC ever gets to handling colour as a few demos exploit the way certain CRTCs behave with HSYNC or VSYNC pulses too short for the monitor to recognize).

Everything else about the display is handled by the Gate Array itself, including colour and screen mode changes. Changing a colour mid screen requires that the CPU wait for the desired position (usually by using one of the six raster interrupts, which is why many games have their stats panel at exactly the same point) and then writing to the Gate Array registers (0 to select a Pen, 1 to change it's colour). Writing to the colour register will take effect almost immediately (and annoyingly a couple of pixels earlier on a Plus model)

You can certainly create similar visual effects to the Amiga copper, but it's 100% down to CPU time. And you can create lots of cool effects by (ab)using the CRTC, but they're all to do with moving, bending, stretching, scrolling or repeating the screen and nothing to do with colours (notwithstanding the weird "bits of HSYNC mid scanline" side effects)

This feels like it's going way off topic from the ST though, happy to chat in another thread about it if you want to learn more.

[Shiftcode]

Jet Set Willy, of course ! :-D Cann't prevent myself for beeing a very bad clown ! :-)

[CCCP alert]

Depends on how you look at it really, yes the framerate on Stunt Car Racer on the ST is a little bit faster BUT without that gut wrenching creaking boards sound effect when you went round those banked turns at max speed and the chassis breaking sound effect that makes your teeth hurt it is not really that great. engine noise was awesome too. in fact if there ever was an update for 030/040 type Amigas the sound is the one thing that doesn't any work on improving it IMO

[Korban]

Originally Posted by ransom1122

What do people think about Teenage Mutant Hero Turtles: The Coin-Op!
Is it better on ST as it has music, or is the gfx & scrolling better on Amiga or exact?

I was surprised with the Atari ST version.
Or more accurately surprised at the Amiga version after seeing the ST version.
It absolutely reeks of ST-port-itis.
It's similar, but a little better than the Amiga version. The music, gameplay tweaks, plus being faster and a touch more responsive make a reasonable difference to how the game plays.

Would have been a great game with the ST's speed plus a little more fluidity.
I still thought the Amiga version was okay-ish though and had some good fun in 2 player mode with my brother and some friends "back in the day".

[Retro1234]

Originally Posted by dlfrsilver

Batman the movie and Robocop were drawn for CPC on an Atari ST (the ocean classic setup at this time for developpement of CPC games).

They both were drawn with EDSPR and EDMAP (these tools was used to make Snow Bros on Amiga, but they were compatible with the CPC 160x200 mode 0 16 colors pixel size). The tools in question were made by John Brandwood.

Love to see some pics or even video of EDSPR and EDMAP.