How does this tell me which one will have the games I want to play?
Which machine do you expect to be most powerful?
- Thread starter GwymWeepa
- Start date
Then Spectrum was certainly more where it was at for "Real Men"ERP said:
Not only reasonable scrolling took all kinds of skill to implement, making it display more then two colors without clashing was an art of its own.And who could forget the joys of updating on particular scanlines in order to display multicolored border
Anyway, weren't some of the ST models equipped with blitters though, making the job a bit easier? (at the cost of making your software not so compatible with the other models)
ERP said:
If scrolling was all that was ever done on the Amiga, true.
But getting the CPU, the Blitter and the Copper to work as a whole took real skill.
Using the blitter to add adresses (by or-ing, or equals an add if there's no carry) to feed a multiple sine plotter executed by the CPU, tripling the amount of work that could be done compared to a simple CPU based one.
ERP said:
Was it harder than on the C64? Where you had to sync the CPU to the video refresh on the exact cycle and yank the video chip so that it thought it had started on a new line and started fetching bitmap data from the middle of a line (and by sliding the syncronization one cycle at a time you get horizontal bitmap scrolling) ? And similar with vertical bitmap scrolling, where you'd trick the video chip to skip 7 lines every line ?
The nostalgia
when one coded for fun rather than for profit.Cheers
Gubbi
archie4oz said:Oh then you won't mind me trolling a little and point out that the Sharp X680x0s pwnz0rs Amigas..
I might have been in another world, but I swear it was Motorola who made the 68000 and all the 680x0s??
Anyway, this generation does reminds me of the Atari ST vs Amiga days. Amiga had better graphics and stereo sound (4 channels) over the ST (3 channels or something like that), but the ST had a faster CPU and a few other things.
Due to creative programmers, they got over the 16 colours on screen limitation and (fake) stereo sound for games.
The ST was able to emulate the Mac (of the day) with 25% better performance... amazing.
Fafalada said:Then Spectrum was certainly more where it was at for "Real Men"
And who could forget the joys of updating on particular scanlines in order to display multicolored border
Anyway, weren't some of the ST models equipped with blitters though, making the job a bit easier? (at the cost of making your software not so compatible with the other models)
I think ERP was comparing only the 16bit gen, or am I wrong in thinking the Spectrum was in the same generation as the C64 (or even before it)?
As for the ST having the Blitter chip later in life, this was the STe version with very similar features to the Amiga, but it was too late then as it was way towards its end of life.
<channels his 80's BBS days>
Ataris rule Amigas drool!
Ok, so maybe I wasn't THAT bad a fanboy, but I did have a lot of Atari computers... Hehe.
Ataris rule Amigas drool!
Ok, so maybe I wasn't THAT bad a fanboy, but I did have a lot of Atari computers... Hehe.
^^ Cristal ball? Ask it if i'm gonna be rich one day!!
Gubbi said:ERP said:
If scrolling was all that was ever done on the Amiga, true.
But getting the CPU, the Blitter and the Copper to work as a whole took real skill.
Using the blitter to add adresses (by or-ing, or equals an add if there's no carry) to feed a multiple sine plotter executed by the CPU, tripling the amount of work that could be done compared to a simple CPU based one.
ERP said:
Was it harder than on the C64? Where you had to sync the CPU to the video refresh on the exact cycle and yank the video chip so that it thought it had started on a new line and started fetching bitmap data from the middle of a line (and by sliding the syncronization one cycle at a time you get horizontal bitmap scrolling) ? And similar with vertical bitmap scrolling, where you'd trick the video chip to skip 7 lines every line ?
The nostalgia
Cheers
Gubbi
Yep made scrolling on a C64 it look trivial.
Basically you could only set the screen address to exact multiple of 256 bytes.
However..... The video chip had 2 bits you could play with, one swapped from internal to external sync (for the optional 70Hz Mono monitor) and the other swapped from 50Hz to 60Hz.
By setting these bits at the right time in a scan line you could force the video chip to keep drawing off the right of the screen. You also had to flip to external sync to make it look like there was an end of line pulse since the video chip wouldn't send one in that state. So an extended line would be longer than the standard 320 pixels. You could also open the left border with a similar trick.
This gave you a total of 4 different possible scanline lengths, so by using combinations od the lengths in the first 6 or so scan lines of the screen you could shift the rest of the screen to be at any address, allowing you to move it one word to the left or right. Now duplicate the svreen 4 times with 4 pixel offsets and you have "hardware" sideways scrolling at 4 pixels.
Some of the ST demos with full screen overdraw and scrolling used "compilers" that would inline the code in a demo between the necessary code to do the scrolling and border extensions. Obviously it also had to pad all code paths to take exactly the same length of time.
Now I've written my fair share of Amiga code, but there is just nothing on the amiga that requires anything like the sort of jumping through hoops in even an average ST demo.
Gubbi said:jvd said:
Basic in 1999
ERP: ouch. That is so much worse than I would've imagined. Suprised Atari could sell the crap.
Cheers
Gubbi
Don't insult the ST, many of us games programmers of certain age have 'fond' memories of the old beast
You could say its designed in the same manner of Cell, nothing fixed function do everything via software
Of course the Amiga with its excellent custom chip, could do lots of cool things but there is a certain achievement getting anything decent out of an ST...Anybody could make the Amiga do pretty things, but get smooth scrolling, 4 channel sample sound, overscan and > 16 colours on an ST took skill
Of course so did self-modifing code on a Amiga via clever use of Copper and Blitter...
Similar threads
