The Amiga Boing Ball Explained
41–50 of 65 posts
Re: The Amiga Boing Ball Explained
#42Earlier quoted context omitted.
It's worth mentioning the reveal, which the page omits entirely, and was the astonishing bit of the CES demo at the time. In the original demo they were showing the normal desktop screen, showing window dragging, resizing, showing text editors, clocks, shell and what not. Running 640x480 4 colour. The whole time you could hear the bang bang of the boing ball bouncing, but see nothing. At some point a viewer asks "wha…
Windows let each application (or even window, it's been a long time I don't remember the specifics) define its own palette in 256-color (8-bit) mode. You had reserved colors to make sure the gui looked the same but you'd get all kinds of strange artifacts when you switched to an application that had a custom palette but you could still see other applications windows. It was years where you had to make the trade off o…
XWindows had that too, which when combined with point-to-focus resulted in all sorts of nasty flashing.
Re: The Amiga Boing Ball Explained
#43In what language is this animation written?
Probably Assembly. It was the primary language for demo's and games for the Amiga.
Re: The Amiga Boing Ball Explained
#44Obligatory link any time palette cycling images are mentioned: http://www.effectgames.com/demos/canvascycle/?sound=0 All images there are completely static 256 color bitmaps with only the mapping from color index to RGB value changed.
And, newly obligatory link to the GDC talk where the artist explains his technique. http://www.gdcvault.com/play/1023586/8-Bit-8-Bitish-Graphics
this talk is one of my favorites from recent memory, seriously recommend for any graphics enthusiasts.
Re: The Amiga Boing Ball Explained
#45Wait, that's how it worked? That's it? It was a trick? That demo was my introduction to the Amiga. Whenever I met an Amiga fan later in life I would picture that demo in my head. Adult, programmer me knows all too well that demos are marketing material, aka "lies you can't be sued for", but really faking 3D rendering is pretty low even by marketing standards. I am extremely disappointed. This kind of screws with the…
At that time, computer graphics was often a choice between tricks or nothing.
You could say it's still true, a lot of graphics in AAA console/PC games could be called fake same way. Precomputed physics and such. That subsurface scattering? Fake. Soft shadows? Fake. Fluid dynamics? Fake.
Although, Amiga could have rendered that in real time too. Just two bitplanes and a smallish area.
Re: The Amiga Boing Ball Explained
#46The video of the Boing Ball:
https://www.youtube.com/watch?v=-ga41edXw3A&t=26s
I remember what were the effective limits at these times and to me it still looks impressive.
As an example, the observer would never get the idea that it's done by changing "the beginning of the screen" as the grid background stays on the same place all the time, and just the ball (with the shadow) moves.
Also note the change of the rotation direction as the ball hits the wall.
Re: The Amiga Boing Ball Explained
#47In what language is this animation written?
I'd guess BCPL. Most early Amiga software was written in it.
Re: The Amiga Boing Ball Explained
#48Earlier quoted context omitted.
It might be obvious from the name, but there's also just one bit per pixel in a bitplane, and then you stack five bitplanes to get 32 colors. You can have different offsets into each bitplane, which is why the grid could stay in the same place while the ball bounced. The Amiga only supported bitplanes and not "chunky" modes like VGA where you have one byte per pixel. This made graphics with 256 colors (supported by t…
This also let you make "memory peekers". It was just a simple assembly program that would offset the pointer to a bitplane based on the mouse vertical movement. You could "look" at the RAM and it was one way to rip images since you would see the bitmaps of images from the game still in RAM after the reset.
Yeah, that was a great way to "visualize" chip RAM contents.
Curiously, on some later A500 OCS models, you could also see that into "slow RAM" expansion module range! Just needed to point bitplane pointers above 0x80000.
It appeared at 0xc00000 for the CPU and 0x80000 for chipset.
Re: The Amiga Boing Ball Explained
#49In what language is this animation written?
I'd guess BCPL. Most early Amiga software was written in it.
Only the file system portion (dos.library) was written in BCPL (ported from TRIPOS in two or three weeks). The kernel (exec.library) was in assembly, and the GUI (intuition.library) was written in C.
Re: The Amiga Boing Ball Explained
#50Wait, that's how it worked? That's it? It was a trick? That demo was my introduction to the Amiga. Whenever I met an Amiga fan later in life I would picture that demo in my head. Adult, programmer me knows all too well that demos are marketing material, aka "lies you can't be sued for", but really faking 3D rendering is pretty low even by marketing standards. I am extremely disappointed. This kind of screws with the…
My memory of the era is that no one would have thought they were actually 3d rendering in real time: that was Just Not Possible.
I'll point out that once they finally, FINALLY made a memory card for the Commodore 64, that plugged into the megabyte-per-second DMA port, there was a similar bouncing ball demo done for the C-64. Purely by loading whole frames into the memory card and blasting them onscreen as needed, like a page flip.