How to make space Spartans

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mapes
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How to make space Spartans

Post by mapes » Sun Nov 24, 2019 8:12 am

To make an uzebox game like space Spartans for the intellivision what are the limitations that may prevent completing it?

Here is what I am thinking...

The game needs x and y scrolling.
The game limit is 3 enemy ships on the screen at on time, but have various sizes depending on how close it is (Sprite limit?)
The game has several sound effects and voice with a smart priority stack. Can we play audio files sound effects, and sprites without running out of memory or cycles?

If so, is there a recommended video mode besides 3? Perhaps the 3d mode (RLE I think it was)?

Regarding voice, the Arduino platform has talkie which I have dabled with and it works pretty good. I don't know if soundfx and the voice could be done at the same time on the same atmega644.

Thoughts?

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Jubatian
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Re: How to make space Spartans

Post by Jubatian » Sun Nov 24, 2019 11:07 am

Video mode:

I made some checks on this. The 3D area is 150 pixels wide (if I counted right), it seems to be that it should be 8 cycles / pixel (the usual 160 pixels wide mode of old microcomputers, 1x NTSC colorclock), vertically it is double-scanned.

The closest match at the moment in my opinion is Mode 72, the background is simple enough so it doesn't bloat size, Mode 72 has "hardware" sprites (Hsync sprites), which gives you the freedom you need for designing a VSync mixer and streaming audio from SD card as there is no VBlank activity related to the display (you don't need to draw sprites as it happens in HSync).

Audio:

If choosing Mode 72, you have VSync mixer. I have some kernel hacks related to VSync mixer, which you could also use if you like so to save RAM, and in general, with VSync mixing it is not that difficult to roll entirely your own audio code.

So I think it is pretty much doable!

CunningFellow
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Re: How to make space Spartans

Post by CunningFellow » Sun Nov 24, 2019 11:49 am

If you wanted to make the arcade sections of Space Spartans either vectors or polygons then the RLE or T2K video modes could work.

If you wanted to have the visuals true to the 1981 game and have chunky scaled sprites then one of the sprite modes such as mode 72 that Jubatian is suggesting would be the go.

With T2K mode you could make the arcade sections look more like Star Wars.

With the RLE mode you might (with great effort) make it look more like Rebel Assault.

So the questions is do you want to just recreate the game play or do you want to recreate the look/visuals.

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Jubatian
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Re: How to make space Spartans

Post by Jubatian » Sun Nov 24, 2019 12:28 pm

CunningFellow wrote:
Sun Nov 24, 2019 11:49 am
So the questions is do you want to just recreate the game play or do you want to recreate the look/visuals.
Could depend on trade-off between audio or video as well. With Mode 72, the VBlank is free to be utilized heavily for audio, such as even streaming from SD, to potentially enhance that aspect of the game. If T2K's video mode was used, there wouldn't be that much freedom for Audio (as it uses SD, and it is a 2bpp mode overlaid on it, requiring lots of VBlank time to do the drawing). If you released the RLE mode, then that could open up possibilities, however it may prove to be a bit too complex to use.

Mode 72, depending on how much ROM you are willing to hurl at the code tiles producing its background could also enhance video. There is also an option there to scroll every scanline individually which may be interesting for starfield effects.

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mapes
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Re: How to make space Spartans

Post by mapes » Tue Nov 26, 2019 2:26 am

@jubatian

Do yo have the framework of a mode 72 game I could use to build upon with x and y scrolling? I was not very good at writing any of my games from complete scratch.

I can work on the game design, but I will definitely need the uzebox community for many complex aspects of the game (sound effects, voice, etc).

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Jubatian
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Re: How to make space Spartans

Post by Jubatian » Tue Nov 26, 2019 7:00 pm

mapes wrote:
Tue Nov 26, 2019 2:26 am
@jubatian

Do yo have the framework of a mode 72 game I could use to build upon with x and y scrolling? I was not very good at writing any of my games from complete scratch.

I can work on the game design, but I will definitely need the uzebox community for many complex aspects of the game (sound effects, voice, etc).
Actual game no, but a demo doing just about everything the mode is capable to is there:

https://github.com/Jubatian/uzebox/blob ... emo/main.c

This is the code of this demo: http://uzebox.org/wiki/File:Mode72_example.png

Hope this can be useful for a start! Alec and CunningFellow might be more knowledgeable on the audio part, CunningFellow for the SD streaming aspects if you would like to recreate the speech aspect.

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