Cross-platform BBC BASIC and GPU shaders

[Cross-platform BBC BASIC for SDL 2.0]

Some members of this forum will appreciate this, I’m sure…

I’ve just seen this from Richard Russell:

https://youtu.be/5GPfWg0nAY4

He posted the code for it here:

https://www.bbcbasic.co.uk/forum/viewtopic.php?f=12&t=118

I’ve run the code under the Windows edition of BBC BASIC for SDL 2.0, and it runs flawlessly on my desktop PC.

One day we’ll see this shader being loaded into a GPU (of a Raspberry Pi, perhaps?) by an ARM BBC BASIC program under RISC OS, yes? :-)

David.
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http://www.proggies.uk/riscosstuff/index_riscos.html

I’ve just seen this from Richard Russell:

I presume you missed the Announcement posting from David Fuegey where he’s offerring a small reward.

I quote:

This interpreter is written in C, but with a version of the SDL that is not available under RISC OS.
Find a solution to provide a native or SDL 1.2 port and win the sum of 1000 €.

Reading between the lines I think Richards health is failing (we’re all falling apart) and he wants the whole thing to live on.
There are probably copies of that source all over by now so the chance of it going AWOL is much reduced.

I’ve just seen this from Richard Russell:

Bloody amazing! And although being quite familiar with BBC BASIC, I don’t understand a bit of the code. It seems, for example, that DATA may contain complete instructions and functions and all that. This is really high level coding, at least for me.

And although being quite familiar with BBC BASIC, I don’t understand a bit of the code. It seems, for example, that DATA may contain complete instructions and functions and all that.

The hard work isn’t being done by BB4W, though, is it? Unless I’ve misunderstood, the DATA statements are just holding the non-BASIC code for the GPU to process.

ETA: Yes: in fact, the contents of the DATA statements are just concatenated into memory, then passed to GPU calls in PROCcompileshader to compile them into routines which can then be used to do the work.

ETA: Yes: in fact, etc…

Ah, but then the BBC BASIC part seems hardly more than a wrap around the actual engine. Bit disappointing, actually.

Disappointing? I thought it was clear enough that BASIC is being used to (effectively) load a shader into the GPU, and that the GPU is doing practically all of the work. For some users of the ‘Russell branch’ of BBC BASIC (there might some of those here!), it’s an interesting development. Perhaps a sufficiently skilful (and motivated) RISC OS user can devise a way of loading (perhaps via ARM BBC BASIC) a shader like that Seascape one into a GPU, and set it in motion? I suspect there’s a lot of groundwork to be done before that can happen.

Incidentally, Richard has just released a video of another pretty GPU shader in action:

https://www.youtube.com/watch?v=gqe5PGzROos

David.
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