<Rensoupp's vc3-2022 entry v4>

Author: <Rensoupp>
Category: <Christmas Challenge>
System:   <Atari 8bit>
Language: <kickasm 5.23>
Len source code: <100000 bytes>
Len exe file:    <74 bytes>
Len code only:   <68 bytes> 
Instructions:
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Altirra 4+ emulator drag and drop.

The system must be set to 600/800XL PAL or NSTC with at least 64KB of RAM. This is important because the screen address is hardcoded in my entry. It is possible to grab the screen address but that would require extra setup code which wouldn't be fair compared to the C64 where I suppose the screen address is always the same since there's only 1 model.

For firmwares:

Either 1. Operating System: Altirra OS (tested with 3.34). BASIC: Atari Basic rev.C or Altirra Basic (tested with 1.58). Basic MUST BE enabled (This is important because when returning from my entry, Altirra OS boots back into its own welcome screen while Basic leaves the star on screen)

Or 2. Operating System: Atari XL/XE OS ver.2. Basic: Same as above (Atari or Altirra Basic). Basic does NOT need to be enabled because when returning from my entry, the OS goes into Basic, leaving the screen intact.

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Description:
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Drawing is done in 4 parts. each part is a triangle

1.
__
\|

2.
__
|/

3. and 4. are just flipped around the horizontal axis

The idea is to reuse the same drawing routine for all 4 parts. Drawing is always done from right to left and top to bottom.

For 1. you start with the maximum number of '*' and decrease by 1 for each line, adding the width of a scanline to the screen Ptr.

For 2. Same as 1. except you add the width of a scanline+1 so that the triangle is flipped around the vertical axis.

For 3. & 4. same as 1. & 2. except you start from the minimum number of '*' and increase by 1 for each line. This requires some self modifying code to save a bit of space.

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Comments:
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Doesn't use any OS/Basic code or data.
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