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Mr SQL

Impossible TaffyBall and Revolving Balls CoCo Demo

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Taffy Ball and Revolving Balls Impossible CoCo Demo

Remember those bouncing ball demos?

 

Here is a BASIC demo I wrote for Rainbow magazine that looks impossible from the code:

awesome if someone with the real hardware (NTSC) could upload a vid! :) 

TaffyBallAndRevolvingBalls.thumb.jpg.a24a38b9e798681c813ec9af1e2a752a.jpg

 

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1 hour ago, Mr SQL said:

Taffy Ball and Revolving Balls Impossible CoCo Demo

Remember those bouncing ball demos?

 

Here is a BASIC demo I wrote for Rainbow magazine that looks impossible from the code:

awesome if someone with the real hardware (NTSC) could upload a vid! :) 

TaffyBallAndRevolvingBalls.thumb.jpg.a24a38b9e798681c813ec9af1e2a752a.jpg

 

here you go mate

 

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1 hour ago, Mr SQL said:

Taffy Ball and Revolving Balls Impossible CoCo Demo

Remember those bouncing ball demos?

 

Here is a BASIC demo I wrote for Rainbow magazine that looks impossible from the code:

awesome if someone with the real hardware (NTSC) could upload a vid! :) 

TaffyBallAndRevolvingBalls.thumb.jpg.a24a38b9e798681c813ec9af1e2a752a.jpg

 

here is number 2

 

 

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3 hours ago, Briza1 said:

here you go mate

Thanks Briza! :) Those visuals bring back fond memories! :) 

It was very unexpected to see a demo designed for the CoCo I & II exhibit the interesting graphical Fx only on the CoCo III.

 

The GIME emulating the VDG is quite different than the VDG, we found out about the lack of full semigraphics modes support there but there were other differences discoverable in pmode 3 and 4 characteristics.

 

Here's a related thread about glitches that inspired me to find this demo and an interesting BASIC Programming discussion on the Atari 2600 forums with pictures and discussion of Rainbow and Personal Computer World BASIC type-ins: 

 

 

 

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It has been decades since I looked at Coco code, but I still recognize most of it.

 

What exactly does line 140 do? I realise that it is calling a machine language subroutine, presumably in ROM, but what is the function?

 

 

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2 hours ago, jhd said:

 

It has been decades since I looked at Coco code, but I still recognize most of it.

 

What exactly does line 140 do? I realise that it is calling a machine language subroutine, presumably in ROM, but what is the function?

 

 

Great question! It's part of the sound routine in the BASIC ROM, it is a much briefer duration than sound 100,1.

 

It will use the last tone seeded by the sound command and the routine takes so few cycles to complete that if you call it by itself you may not hear it but you will in a loop. Turn the volume up on Briza's vids and you can hear the sound Fx from it.

 

The amount of time this ROM routine takes to return is key to the demo - the emulated VDG hasn't quite initialized by the time the routine returns, and the GIME is caught in an unprepared state switching pmodes again. A small for-next loop could probably replace it to match the visuals but it was cool to have sound Fx too during smooth animation on the CoCo! :)

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On 6/11/2020 at 10:40 PM, Mr SQL said:

Thanks Briza! :) Those visuals bring back fond memories! :) 

It was very unexpected to see a demo designed for the CoCo I & II exhibit the interesting graphical Fx only on the CoCo III.

 

The GIME emulating the VDG is quite different than the VDG, we found out about the lack of full semigraphics modes support there but there were other differences discoverable in pmode 3 and 4 characteristics.

 

Here's a related thread about glitches that inspired me to find this demo and an interesting BASIC Programming discussion on the Atari 2600 forums with pictures and discussion of Rainbow and Personal Computer World BASIC type-ins: 

 

 

 

Your welcome mate.

 

I was also curious about line 140. I suspected it was causing the sound effects and thanks to your reply to JHD my suspicions were confirmed.

 

laters

 

Briza

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