Sometimes UK software companies did get it right at the high end!

[oky2000]

I think we all know how awful Shadow of the Beast turned out on the Atari ST, and we also know why! (terrible underwhelming technical ability of conversion team).

 

But sometimes it is nice to see somebody doing it correctly and to the best of the ability of the machine (as much as we can reasonably expect from a commercial time limited development in the era of ST/Amiga).

 

OK enough of the build up...but is it me or does everyone else instantly look at/play Wrath of the Demon and then think this proves that Shadow of the Beast on the ST could have been so much better and it would be a little bit like this in technical quality?

 

It's a really high end piece of software. The horizontal scrolling, the animation, the speed and the graphics (note the colour palette selection is not to my preference but 2 minutes with a paint app using an actual 16 colour image shows it can be made too look much more like the Amiga version just by changing the palette registers from the screenshot). In fact it made the Amiga version a little underwhelming to me...an Amiga 1000 all time fan!

 

Or maybe I just have too much free time on my hands?

 

 

[ParanoidLittleMan]

Why, oh why that game is here (YTL): http://atari.8bitchip.info/fromhd.php

And why here writes what writes ? : http://atari.8bitchip.info/SCRSH/wrathod.html

 

I think that you are too harsh toward SOB authors. It is not that bad on ST, and keep in mind that Wrath needs 1MB RAM, while SOB 512KB.

[MaDDuck]

Holy cow! That looks terrific.

 

I hope it plays as good as it looks.

[+rdemming]

Yes, Shadow of the Beast was relying a lot on the scrolling features of the Amiga graphics chips so converting it to the ST has a lot of trade-offs.

 

The Atari ST (not STE) does not have hardware support for scrolling with one pixel at the time. It does not even have support for horizontal scrolling at all. You can only adjust the screen address in 256 byte increments. So all the scrolling must be done in software..

 

For scrolling other that 16 pixel increments, you need to shift the graphics but shifting operations are very time consuming. One method to speed this up is pre-shifting the graphics but this takes up more memory. For pixel scrolling you need 16 shifted versions of the graphics. Also the sprite graphics needs to be shifted and copied to the screen memory. With 512KB there is just not enough memory to use pre-shifted graphics on the scale that SotB needs thus it needs to shift graphics "on the fly" which is slow.

 

As WotD requires 1MB it has 512B extra memory it can use for pre-shifting the graphics. Thus it does not need to shift graphics on the fly but only needs to copy the pre-shifted graphics to the screen memory speeding things up very much.

 

Robert

[Lynxpro]

Yes, Shadow of the Beast was relying a lot on the scrolling features of the Amiga graphics chips so converting it to the ST has a lot of trade-offs.

 

The Atari ST (not STE) does not have hardware support for scrolling with one pixel at the time. It does not even have support for horizontal scrolling at all. You can only adjust the screen address in 256 byte increments. So all the scrolling must be done in software..

 

For scrolling other that 16 pixel increments, you need to shift the graphics but shifting operations are very time consuming. One method to speed this up is pre-shifting the graphics but this takes up more memory. For pixel scrolling you need 16 shifted versions of the graphics. Also the sprite graphics needs to be shifted and copied to the screen memory. With 512KB there is just not enough memory to use pre-shifted graphics on the scale that SotB needs thus it needs to shift graphics "on the fly" which is slow.

 

As WotD requires 1MB it has 512B extra memory it can use for pre-shifting the graphics. Thus it does not need to shift graphics on the fly but only needs to copy the pre-shifted graphics to the screen memory speeding things up very much.

 

Robert

 

 

 

But which has more powerful hardware scrolling, the Amiga or the STe? Years later, it's still disappointing that the STe didn't do 32 colors on screen at once like the Amiga. Hell, they should've went up to the Genesis/MegaDrive's color abilities by then.

 

Personally, I think the STe's DMA audio sounds better than the Amiga's PAULA. However, there's only a handful of games from that era that ever did anything with those abilities. And even though I was a hardcore ST fan back in the day, I do think the YM2149 sucks. The YM2151 would've been a different story.

[+rdemming]

 

But which has more powerful hardware scrolling, the Amiga or the STe? Years later, it's still disappointing that the STe didn't do 32 colors on screen at once like the Amiga. Hell, they should've went up to the Genesis/MegaDrive's color abilities by then.

 

Personally, I think the STe's DMA audio sounds better than the Amiga's PAULA. However, there's only a handful of games from that era that ever did anything with those abilities. And even though I was a hardcore ST fan back in the day, I do think the YM2149 sucks. The YM2151 would've been a different story.

 

You are right that the STE capabilities were underused. There were only a few STE enhanced games and most only used the extended color pallette (e.g. for more smooth gradients for background rasters) or DMA sound. And there were even less games that were STE only.

As there was still a large ST user base compared to STE users, software companies understandably targeted the "lowest common denominator". There are not many systems that were enhanced versions of an older system that spawned lots of enhanced software (how many games used the enhanced features of the C128 or Amiga ECS (Enhanced Chip Set)?). Maybe the MSX 2 is the most successful "enhanced" machine.

 

I know only a little about the Amiga scrolling capabilities but Amiga scrolling has some advantages to STE hardware scrolling. First, the Amiga has a dual play-field option where two sets of bitplanes can scroll independently while the STE can only scroll all 4 planes at the same time. Dual play-field enables parallax scrolling on the same line (were the foreground has a transparent part showing the background that moves at different speed) while on the STE you need to scroll for example 3 bitplanes by hardware and the fourth by software.

 

The STE can update the screen address while displaying the screen enabling parallax scrolling of different lines (e.g. different parts of the screen scroll at different speeds) but this needs using horizontal blank interrupts. The Amiga has a copper chip that can update memory addresses at various screen positions without the need for the CPU thus this is much more efficient.

 

So I think the Amiga still wins from the STE in the scrolling department.

 

The STE digital sound is only better because it can use higher sample rates than the Amiga (50KHz vs. 28KHz I believe). But the STE has only two channels (left & right) and only only 4 replay rates (6.25, 12.5, 25 and 50KHZ). Thus for tracker music, the sound channels must be mixed by software and the frequency adjusted (re-sampling) by software before that can be played at a fixed output frequency. But the Amiga can play 4 channels independently at various replay rates thus avoiding the need for software mixing and re-sampling thus it involves very little CPU time compared to the STE.

 

Robert

[oky2000]

Why, oh why that game is here (YTL): http://atari.8bitchip.info/fromhd.php

And why here writes what writes ? : http://atari.8bitchip.info/SCRSH/wrathod.html

 

I think that you are too harsh toward SOB authors. It is not that bad on ST, and keep in mind that Wrath needs 1MB RAM, while SOB 512KB.

I am being harsh, but Enchanted Land shows with some clever design even a 512kb ST can do better arcade type game engines (with some limitations sure).

 

2Mb!!! Glad I have a couple of Mega STs I bought decades ago to try it out with health trainer option from a hard disk, I had forgotten about that site, thanks for reminding me

[oky2000]

 

You are right that the STE capabilities were underused. There were only a few STE enhanced games and most only used the extended color pallette (e.g. for more smooth gradients for background rasters) or DMA sound. And there were even less games that were STE only.

As there was still a large ST user base compared to STE users, software companies understandably targeted the "lowest common denominator". There are not many systems that were enhanced versions of an older system that spawned lots of enhanced software (how many games used the enhanced features of the C128 or Amiga ECS (Enhanced Chip Set)?). Maybe the MSX 2 is the most successful "enhanced" machine.

 

I know only a little about the Amiga scrolling capabilities but Amiga scrolling has some advantages to STE hardware scrolling. First, the Amiga has a dual play-field option where two sets of bitplanes can scroll independently while the STE can only scroll all 4 planes at the same time. Dual play-field enables parallax scrolling on the same line (were the foreground has a transparent part showing the background that moves at different speed) while on the STE you need to scroll for example 3 bitplanes by hardware and the fourth by software.

 

The STE can update the screen address while displaying the screen enabling parallax scrolling of different lines (e.g. different parts of the screen scroll at different speeds) but this needs using horizontal blank interrupts. The Amiga has a copper chip that can update memory addresses at various screen positions without the need for the CPU thus this is much more efficient.

 

So I think the Amiga still wins from the STE in the scrolling department.

 

The STE digital sound is only better because it can use higher sample rates than the Amiga (50KHz vs. 28KHz I believe). But the STE has only two channels (left & right) and only only 4 replay rates (6.25, 12.5, 25 and 50KHZ). Thus for tracker music, the sound channels must be mixed by software and the frequency adjusted (re-sampling) by software before that can be played at a fixed output frequency. But the Amiga can play 4 channels independently at various replay rates thus avoiding the need for software mixing and re-sampling thus it involves very little CPU time compared to the STE.

 

Robert

 

Not really sure on how the STE works but the Amiga's memory was rated at double the speed that the CPU and trio of customs chips worked at so the whole thing is clock doubled because in each tick of the 7.1mhz cycle both the CPU and custom chips can access the memory (which is why you get Fast/Chip RAM ratios), and as I understand it Agnus (the one that contains the blitter) essentially controls the Copper and DACs as far as flowing the data around the bus goes. So if you get everything timed just right you are using a true clock doubled system (which means 14mhz computer and blitter) 2 decades before Intel Centrino laptops.

 

You can play back 56khz samples if you have an A500plus/A600 but only when using 32khz line mode (ie PC style flicker free hi-res modes) like non-interlaced PAL modes or 800x600. You can't process the sound much on either but as you say the Amiga can play any channel at any speed up to 28khz and apply 6 bit volume control to each DAC. Overlaying the 2 left and 2 right channels and setting the volumes correctly for the two stereo pairs and supply the correct waveforms in perfect sync to all 4 chanels you can even play 14bit samples on an Amiga 1200 (not sure if the DMA bus speed is high enough for the A500/600).

[+rdemming]

I am being harsh, but Enchanted Land shows with some clever design even a 512kb ST can do better arcade type game engines (with some limitations sure).

 

Clever design is a bit of an understatement in the case of Enchanted Lands. It uses sync scrolling to assist in the smooth scrolling. But sync scrolling only enables steps of 16 pixels so for the pixel scrolling it needs shifted copies of the screen data increasing the memory needed. To save memory it does not do double buffering meaning that sprites are drawn just before that part of the screen is displayed and erased after that part of the screen is displayed. This results in very complex code which is probably why Enchanted Lands is the only game that has smooth whole screen 4-plane 8-directional scrolling.

 

Vertical sync scrolling is easier so there are more examples of that (Leaving Teramis, Lethal Xcess, No Buddies Land).

 

 

 

Not really sure on how the STE works but the Amiga's memory was rated at double the speed that the CPU and trio of customs chips worked at so the whole thing is clock doubled because in each tick of the 7.1mhz cycle both the CPU and custom chips can access the memory (which is why you get Fast/Chip RAM ratios)

 

Most 68000 instructions only occupy the bus half of the cycles. So in an ST one half of the bus-cycles are used by the 68000 and the other half of the bus cycles by the DMA system (screen, disk IO) without affecting the 68000 speed. The Amiga doing the same (thus is has not double speed RAM) although because there are more custom chips accessing the memory than an ST it occasionally uses more than half of the bus cycles and then blocks the CPU. Hence the Amiga fast ram is a bit faster than Amiga chip ram.

 

Unlike the Amiga blitter, the ST blitter halts the CPU completely when it is working.

 

Robert

[+rdemming]

BTW. On Atari Forum the SotB programmer did tell something about SotB trade-offs he had to make for the Atari conversion.