A miracle when it works first time!

[Cosmium]

For vertical clipping , if you use a lookup table to get the address of each row, you point rows 192-255 to somewhere harmless, ROM for instance. That way there is no loss of speed. I assume you hold the y address in a single byte so -1 would be 255.

Hey, that's an elegant solution!

Though I think it's handy to calculate ahead of time how many lines of the clipped sprite to draw. That way you can avoid drawing more than necessary as you would if you "blindly" wrote data into ROM over the course of the full sprite height.

[Cosmium]

So I finished writing the part where the sprite should gracefully exit the bottom of the screen. Gave it a test and sure enough there were no "it works first time" miracles on display here either. Just an encore fireworks display!



Luckily it was an easy fix and a silly mistake (aren't they always?!). I'd incorrectly assumed a register had a certain value in it after copying and pasting code. Ugh

I wonder what percentage of programming bugs are due to unfounded assumptions..

[R-Tape]

Yup, even the release version of Exolon has a similar bug.

And so does Rallybug, or at least the paid-for version does. There's very few opportunities to actually reach the outer limits, but it's happen to me.

[Ast A. Moore]

Yup, even the release version of Exolon has a similar bug.

And so does Rallybug, or at least the paid-for version does. There's very few opportunities to actually reach the outer limits, but it's happen to me.

What’s that, you say? A bug in Rallybug? Figures.

[Cosmium]

Capture of the latest amusing bug while optimising my sprite routine. Think it needs a bit more of work.

Funny how tiny and seemingly innocuous changes in the code can lead to such graphic disaster!

[Cosmium]

Don't think I've seen this quirky one before

Check out the copyright year right after this latest programming crash:

[R-Tape]

Is that 1882?! Clive hadn't even started going bald back then.

How is that even possible? Is 'overwrite ROM' enabled in you emulator?

[Cosmium]

How is that even possible? Is 'overwrite ROM' enabled in you emulator?

I had a look at Spin's settings: "Allow ROM editing" and "Allow assembly to ROM" are disabled, and I've since fixed the bug, so I'm not even sure how it happened..

Actually it showed "(c) 1B82...". Wasn't even a number. Weird!

[R-Tape]

Actually it showed "(c) 1B82...". Wasn't even a number. Weird!

Hex. Good to know that Sinclair research will outlive the common era!

[Cosmium]

A few days ago, while programming some fixed-point maths routines, I was suddenly rewarded with this festive-themed crash. Just before the (c) message it kinda looks like a full screens-worth of gaudy xmas wrapping paper, if you squint hard enough!