Compileable version of Alien Breed 3D II - The Killing Grounds

[pipper]

I understand the issue now, just need a proper fix.
The mouse look has the ability to move the center of the rendering "MIDDLEY" up and down pixel by pixel.
A globale variable "SBIGMIDDLEY" is pointing to the middle of the screen as a byte offset (basically MIDDLEY * 320). Now the mouse can move that center up and down even to odd lines.
The other code in double height floor drawing assumed that the center of the screen is aligned to an even line and offsets its drawing accordingly.
But if it already starts at and odd line, all lines produced will end up on odd lines. And these will be skipped from C2P and do not show up on the screen.

[Karlos]

@pipper did you say you'd incorporated the TKG-RTG patch into the codebase or did I just fantasise it?

[Karlos]

Regarding the floor issue, would just clearing the lowest bit of the line number solve it? It would always be even then (this assumes the value isn't used elsewhere and is bit affected by sign issues).

[pipper]

I submitted a patch to fix the floor in double height rendering last night. Maybe not the most elegant of fixes and it might introduce some texture wobble... but eventually this mode should be implemented differently anyways.

I did not include the TKG-RTG patch - I don't have sources for it. But the recent work to make everything more system friendly and using Intuition screens is a step in that direction.

[vroom6sri]

Is there a possibility for any further speed gain by “turning off” (like it’s that simple!!!) the floor and ceiling parts of the rendering and having flat colours or a similar low detail effect instead?

[pipper]

There’s code in there to render floors and ceiling without gouraud shading, but it makes them look flat and you’ll loose “depth cueing”. This is actually already a “setting” inside the code, but not made available as option. One could relatively easily put that on a function key

[vroom6sri]

Your coding-fu is amazing! You are one with the matrix.

[abu_the_monkey]

@pipper

Had a quick look at your latest version with the fix for doubleheight rendering and it seems to work just fine. I will have a more indepth look later. I have not checked how you have achieved it but I was thinking (like karlos) that maybe you could just clear the least significant bit or test and add/sub 1 if it was odd but if you have plans to rewrite the floor/ceiling render routines that's cool.

As ever awesome job

[pipper]

Great!

It’s looking at bit 0 of the MIDDLEY variable and adjusts the render buffer pointer to the middle line accordingly. It’s not really a mathematically correct solution, since moving the start line of the rendering up and down should also affect the sampling of the floor (instead of just pushing it up and down on the screen). But that would require more work to get “snap floor rendering to even lines only” working than I’m willing to spend on it.
As I said, I’d we can get “just render to a buffer of half the height” mode working, the extra doubleheight floor setup code can go away completely and the maths would all fall out nicely.

[abu_the_monkey]

[Angus]

Just seen this thread - very cool. :-)

[Karlos]

@abu_the_monkey

I've just tried running the build you posted to The Zone earlier in my UAE install but I just get an 8000 0003 guru, whichever binary I use.

UAE Settings are

CPU:
040 + internal FPU, JIT (16MB cache), fastest possible
Chipset: AGA (A1200), wait for blitter enabled, Sprites and Playfields collision detection
RAM: 2MB chip, 256MB Z3 fast
ROM: A1200, KS 40.68
OS: Basic 3.9, bb2

I've extracted the version of my mod you posted here and tried to run with that, so maybe it's the problem.

[Karlos]

I've managed to run it with the base executable and with the turbo patch, so it's something new, I guess

[abu_the_monkey]

I will have a look.

have you tried it with jit turned off?

[Karlos]

I haven't but I will. Just testing on a Linux laptop running WinUAE via Wine so there's many points of failure possible. I had not realised how excruciating the game would be on keyboard only lol.

[Karlos]

@pipper - do you prefer issues via GitHub? There's a longstanding gameplay bug that's quite annoying and would be a good fix for playability. Specifically, taking environment damage from floors. This happens the moment you enter a zone with floor damage. This is a bit daft if you are jumping or flying and not in contact with the surface. I did make some use of this to have rooms with water and an acid floor underneath to give the impression that you are swimming in something dangerous, but overall, it's a bug as far as I'm concerned.

[pipper]

On GitHub we can keep track of things better. I have not looked into gameplay code at all. I just noticed that when the machine is running fast (like in an emulator), some events happen really fast, like enemies spewing bullets at you or weapon animations.

Also, I wondered if we can get Bartman’s Amiga VSCode extension to work. It supports debugging the running emulator. Ot should be perfect, since we’re not dealing with C stdlib or STL in this project…

[abu_the_monkey]

here, when using winuae jit, as well as what you mention, the doors don't open, floating enemies bob up and down at warp factor snot and some of the lighting fx look like they would bring on an epileptic fit.

[Karlos]

I think the original game basically doesn't have any notion of constant time for certain events. Probably because the expected frame rate was always going to be around 10-15 FPS on what was at the time the fastest kit, there was likely little thought put into what happens at higher frame rates. All the weapon animations in my mod are too fast to see because it just plays the individual weapon frames on each new frame. You don't see the grenade launcher clip rotate, or the empty barrels of the boomstick. The chaingun rotation is completely broken as again, the original frame rate was just about right for continuous motion loop but now it turns fast and pauses waiting for the next shot fired

[pipper]

https://github.com/mheyer32/alienbre...hires.s#L10069

This is where I believe floor damage is indiscriminately applied. There needs to be a check for flying or jumping...