4 ms·

Mmmm, I don't think so. The Apple had only blitting, whereas the Atari, Commodore, and TI had hardware sprites. And I have no idea what you mean by "C64 had aw

Mmmm, I don't think so. The Apple had only blitting, whereas the Atari, Commodore, and TI had hardware sprites. And I have no idea what you mean by "C64 had awkward graphics." It integrated ideas already present in the Atari computers, with some advantages and some disadvantages. Both those platforms utterly crushed the primitive graphics and "sound" available on the Apples, with their hardware sprites, fine scrolling, redefinable character sets, and multichannel sound. The Ataris also used intelligent, daisy-chainable peripherals.

aYsY4dDQ2NrcNzA 4y ago
Don’t forget shape tables! https://en.wikipedia.org/wiki/Shape_table https://en.wikipedia.org/wiki/Shape_table
- NonNefarious 4y ago
  Ugh. When I was in junior high and going to the school library to use the Apples, of course I wanted to write games. I kept asking the teacher how to make moving graphics. Needless to say, nobody knew. At some point I got clued into shape tables, plotted one out, and then called upon it in a program. It was no faster than a sequence "drawto" statements. At that point, I had my answer: You don't; at least not on an Apple.
tinus_hn 4y ago
The scrolling model used on the c64 means you have to copy the entire screen which is difficult to do quickly enough to avoid glitches. In contrast for instance the NES outputs the content of a sliding window on a large buffer so you only have to move the window and draw the newly exposed screen area. That way you can create more dynamic games with the same processor.
- NonNefarious 4y ago
  I seriously doubt that. This certainly wasn't true on the Atari. The Atari had fine scrolling and no need even to redraw newly exposed areas. The screen was, as you describe, merely a window upon as much memory as you had available. Because the Ataris and Commodores had redefinable character sets, you could create graphic elements as characters and build huge maps and scroll around them smoothly with ease.
  - tinus_hn 4y ago
    It’s a 1mhz processor and for scrolling to be smooth you need to move 2k of memory within one frame. That means if you get the timing right you have at most 1 million/60 clock ticks, which is about 16666, to do the scrolling and everything else you need to do. You really can’t do that ‘with ease’ which is why c64 games typically divide up the screen so the scrolling area is smaller.
    - NonNefarious 4y ago
      You don't move the memory at all. You move the window. If that's not clear at this point in the discussion (let alone 30 years later) I don't know what to tell you.
satisfice 4y ago
It by “blitting” you mean the Apple had a single 6502 chip which could move bytes around, then yes. But it had no dedicated blitting chip like the Amiga had (which I never got to work). The Atari graphics were awkward, too, or so I was told by my boss at the time who did the Atari versions of our products. Good though. What I mean by awkward is just that I was surprised, as someone with no training in computer engineering, how many little quirks you had to work around. Apple graphics were primitive compared to the others, using a seven bit architecture for pixels and the high bit used for color information. At least the C64 had all eight bits for pixels, which made rendering a little faster. C64 sprites were interesting, but like the OP said we had to do tricks with interrupts to reuse them as the screen rastered. I guess another reason I said awkward is that we had to do every trick we could to squeeze the art into memory. Alphabet Zoo was shipped as a 16k cartridge. I did an entire game with art in 16 kilobytes! I used nine bytes to encode my name, then later I needed those nine back again… so no easter egg for me.
- OnlyMortal 4y ago
  The Amiga 500 blitter was nothing to write home about, in my experience. Slow. But, moving 16bit words was a huge improvement compared to the C64 for obvious reasons. The one thing the C64 missed was full screen hardware scrolling. I don’t mean the pixel shifting. I’m aware there’s a clever hack to get full screen scrolling - even at Sonic the Hedgehog rates. This game leverages that: https://m.youtube.com/watch?v=ldo2ewLBt3Y https://m.youtube.com/watch?v=ldo2ewLBt3Y
NonNefarious 4y ago
Blitting refers to rewriting bytes, yes. It does not imply dedicated hardware to do so, which is why Apple games flickered. Calling Atari and Commodore graphics "awkward" in the scenario you describe sounds like laziness in learning and taking advantage of new graphics hardware. The sole "awkward" thing on the Atari was that, for some reason, the sprites were as tall as the screen and therefore the only way to achieve vertical movement of a sprite was indeed to move it through memory. But you could do this even in BASIC by setting the sprite data up in a character string and using the fast string functions to move it. Both the Atari and Commodore made graphics programming decidedly non-awkward by providing automated collision detection between the sprites, and also with the background. Moving sprites around during screen refresh was common on both platforms. On the Atari, the technique (called a display-list interrupt) could also be used to put 256 colors on the screen at once and simulate multi-color sprites. An innovative use of display-list interrupts gave rise to this cool effect that was called (by LucasArts if I recall) "altered-perspective scrolling." Check it out here in BallBlazer, a soccer-type game written for the Ataris: https://youtu.be/_tkwWD_BWWQ?t=631 https://youtu.be/_tkwWD_BWWQ?t=631
- satisfice 4y ago
  No, Apple games did not flicker. We used screen swapping to stop that. It's the first lesson I learned as a video game programmer: flicker not allowed. I don't know what your deal is with the word "awkward." As someone who wrote a lot of games on Apple, C64, and one each on the PC and Amiga, I've earned the right to use whatever innocuous word I want to describe a vague feeling that I have. Mind you, all that more than 35 years ago. Perhaps I am misremembering how non-awkward it all was. I did not do anything with the Atari. I was merely told by my boss and friend Dale Disharoon how strange he found it. Yes, we liked the C64 collision detection. The main awkwardness about the C64 was, at the time I was first working with it, that it was all undocumented. I just think it's awkward to call information to get the phone number of a writer of a magazine article in Toronto to find out how to work the vertical blank interrupt, since there was no reference manual at that time. The Amiga manuals were full of errors when they first came out. I suppose I am a lazy learner. As you can read all about in my book about being a high school dropout, published by Simon and Schuster (get your copy in Korean today!). Also see page 60 of this issue of Compute Gazette (https://archive.org/details/1983-11-computegazette/page/n59/mode/2up https://archive.org/details/1983-11-computegazette/page/n59/...).

aYsY4dDQ2NrcNzA 4y ago

Don’t forget shape tables! https://en.wikipedia.org/wiki/Shape_table https://en.wikipedia.org/wiki/Shape_table

NonNefarious 4y ago
Ugh. When I was in junior high and going to the school library to use the Apples, of course I wanted to write games. I kept asking the teacher how to make moving graphics. Needless to say, nobody knew. At some point I got clued into shape tables, plotted one out, and then called upon it in a program. It was no faster than a sequence "drawto" statements. At that point, I had my answer: You don't; at least not on an Apple.

tinus_hn 4y ago

The scrolling model used on the c64 means you have to copy the entire screen which is difficult to do quickly enough to avoid glitches. In contrast for instance the NES outputs the content of a sliding window on a large buffer so you only have to move the window and draw the newly exposed screen area. That way you can create more dynamic games with the same processor.

NonNefarious 4y ago
I seriously doubt that. This certainly wasn't true on the Atari. The Atari had fine scrolling and no need even to redraw newly exposed areas. The screen was, as you describe, merely a window upon as much memory as you had available. Because the Ataris and Commodores had redefinable character sets, you could create graphic elements as characters and build huge maps and scroll around them smoothly with ease.
- tinus_hn 4y ago
  It’s a 1mhz processor and for scrolling to be smooth you need to move 2k of memory within one frame. That means if you get the timing right you have at most 1 million/60 clock ticks, which is about 16666, to do the scrolling and everything else you need to do. You really can’t do that ‘with ease’ which is why c64 games typically divide up the screen so the scrolling area is smaller.
  - NonNefarious 4y ago
    You don't move the memory at all. You move the window. If that's not clear at this point in the discussion (let alone 30 years later) I don't know what to tell you.

satisfice 4y ago

It by “blitting” you mean the Apple had a single 6502 chip which could move bytes around, then yes. But it had no dedicated blitting chip like the Amiga had (which I never got to work). The Atari graphics were awkward, too, or so I was told by my boss at the time who did the Atari versions of our products. Good though. What I mean by awkward is just that I was surprised, as someone with no training in computer engineering, how many little quirks you had to work around. Apple graphics were primitive compared to the others, using a seven bit architecture for pixels and the high bit used for color information. At least the C64 had all eight bits for pixels, which made rendering a little faster. C64 sprites were interesting, but like the OP said we had to do tricks with interrupts to reuse them as the screen rastered. I guess another reason I said awkward is that we had to do every trick we could to squeeze the art into memory. Alphabet Zoo was shipped as a 16k cartridge. I did an entire game with art in 16 kilobytes! I used nine bytes to encode my name, then later I needed those nine back again… so no easter egg for me.

OnlyMortal 4y ago
The Amiga 500 blitter was nothing to write home about, in my experience. Slow. But, moving 16bit words was a huge improvement compared to the C64 for obvious reasons. The one thing the C64 missed was full screen hardware scrolling. I don’t mean the pixel shifting. I’m aware there’s a clever hack to get full screen scrolling - even at Sonic the Hedgehog rates. This game leverages that: https://m.youtube.com/watch?v=ldo2ewLBt3Y https://m.youtube.com/watch?v=ldo2ewLBt3Y

NonNefarious 4y ago

Blitting refers to rewriting bytes, yes. It does not imply dedicated hardware to do so, which is why Apple games flickered. Calling Atari and Commodore graphics "awkward" in the scenario you describe sounds like laziness in learning and taking advantage of new graphics hardware. The sole "awkward" thing on the Atari was that, for some reason, the sprites were as tall as the screen and therefore the only way to achieve vertical movement of a sprite was indeed to move it through memory. But you could do this even in BASIC by setting the sprite data up in a character string and using the fast string functions to move it. Both the Atari and Commodore made graphics programming decidedly non-awkward by providing automated collision detection between the sprites, and also with the background. Moving sprites around during screen refresh was common on both platforms. On the Atari, the technique (called a display-list interrupt) could also be used to put 256 colors on the screen at once and simulate multi-color sprites. An innovative use of display-list interrupts gave rise to this cool effect that was called (by LucasArts if I recall) "altered-perspective scrolling." Check it out here in BallBlazer, a soccer-type game written for the Ataris: https://youtu.be/_tkwWD_BWWQ?t=631 https://youtu.be/_tkwWD_BWWQ?t=631

satisfice 4y ago
No, Apple games did not flicker. We used screen swapping to stop that. It's the first lesson I learned as a video game programmer: flicker not allowed. I don't know what your deal is with the word "awkward." As someone who wrote a lot of games on Apple, C64, and one each on the PC and Amiga, I've earned the right to use whatever innocuous word I want to describe a vague feeling that I have. Mind you, all that more than 35 years ago. Perhaps I am misremembering how non-awkward it all was. I did not do anything with the Atari. I was merely told by my boss and friend Dale Disharoon how strange he found it. Yes, we liked the C64 collision detection. The main awkwardness about the C64 was, at the time I was first working with it, that it was all undocumented. I just think it's awkward to call information to get the phone number of a writer of a magazine article in Toronto to find out how to work the vertical blank interrupt, since there was no reference manual at that time. The Amiga manuals were full of errors when they first came out. I suppose I am a lazy learner. As you can read all about in my book about being a high school dropout, published by Simon and Schuster (get your copy in Korean today!). Also see page 60 of this issue of Compute Gazette (https://archive.org/details/1983-11-computegazette/page/n59/mode/2up https://archive.org/details/1983-11-computegazette/page/n59/...).