Star Trip by Osmium Path

[Optimus]

A new demo for 64k CPCs (disk or casette) from us, featuring our new realtime 3d polygon engine on CPC!
I was inspired by some old demos like Face Hugger's Ultimate megademo where they were trying to do actual realtime 3D.
Featuring some complex 3d stuff, scripting space scene with multiple objects, some non-convex more complex objects like a very lowres torus and maybe the first time ever antialiased lines on CPC! And Glenz.

https://www.pouet.net/prod.php?which=101163

[Prodatron]

Great, I really like this!

[Targhan]

This is absolutely brilliant! It also seems to manage clipping gracefully. This is very inspiring. Congratulations!

[Optimus]

Thanks!

The funny thing though is it's not fully ready yet, clipping only works on bottom now. I wanted to cover all cases but vast difference needed to be done. I spend one or two days to convert the original code to at least handle the bottom clip.
Initially you code an engine show an object on the center of the screen, then I think I'd like some of them to come from bottom like the spaceship to make it more interesting than popping all of them from the distance.

So the old code wasn't tailored to this, it only projected and saved 8bit coords from 16bit rotated values. I had to extend stored values to 16bit and do extra checks. On bottom it was easier. On top I would have to recalculate the slope to find the X coordinate when Y comes from outside. On X edges I'd need to do something similar or deeper into the filledges code. It became complicated as I previously fought to use the registers as much as possible, avoid memory, pop values from stack, etc.

So yeah,. I just did the minimal necessary to at least have clip from the bottom screen. In the future I can extend the engine. I even had plans to do a Mode 0 version so that with more colors I could have some smoother gradients for normal lighting (in retrospect though I could have dithered mode 1 blocks but no time) or even attempt gouraud but I leave this for our next demo.

[GUNHED]

That's very nice actually. Now go and make a little game out of it! 

[Optimus]

Good idea, I already while working on the demo had in my mind how to use this engine for games project in the future. Hopefully something lighter with nicer framerate. Or not, depending on the game genre.

[GUNHED]

Frame rate is cool! Just go for a smaller project, then you got a better chance to finish it. 
Later on, in "Optimus Osmium Orbital-race II" you still can add features and make a bigger thing. 

[Optimus]

I just released a presentation video going into algorithms, challenges and a little bit of z80 assembly of my 3D engine.
There are also previews of the interactive port and some old DSK with the very early stages.

I thought it might be useful or interesting to someone even though it turned up later lengthy (granted because of the many areas I wanted to expand on)