XMAS-Demo 2020 by 8-Bit-Shack
screenshot added by tomtom0674 on 2020-12-14 20:17:44
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release date : december 2020
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added on the 2020-12-14 20:17:44 by tomtom0674 tomtom0674

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This year's XMAS-Demo is a feasibility study combining the DOLORes library (DOUBLE LORES) with MockingBoard music and a particle simulation state machine (well it is not really an XMAS-Demo theme ;-)).

The latest DSK-image with some background information can be found here:

Some technical information:

1. The DOLORES library and the PT3-player module reside below the DOS 3.3 area

2. The state machine for the particle simulation is located directly before the both modules starting from $6000, so a CALL 24576 restarts the demo after "quitting".

3. Half of the zero page is used for DOLORES and PT3-player variables. Some of the rest is used by the particle state machine. The page is saved during the algorithm startup and restored when leaving the demo which keeps the Apple in "normal" working state afterwards. Maybe not necessarily needed - I like this feature of a clean quit from the demo algorithm

4. The song data is loaded from $2000. Theoretically using the current memory layout the maximum song file length could be 16 kB (PT3-file / Vortex-Tracker)

5. AUX memory is used by the DOLORES library: parts of the machine code is copied to AUX RAM. When using the SCRN-function DOLORES switches to AUX memory as well as when using the flood fill algorithm which builds its search trees completely in the AUX memory area.

6. The interrupt handler for the sound file playback got an extra JSR to a user defined routine that will manage things that need timed action for the demo algorithm. Here I am reversing gravity direction each 10 s so the pixels will move back after a simulation and the Galton board will be simulated over and over again without any need for user interaction (standalone demo function)

7. The modular setup enables the creation of new games or demos by using the DOLORES and PT3-player framework and add just your own code. The PT3 player uses about 15% of the cycles when playing music files.

I am happy to discuss the technical stuff in more detail if anybody is interested! Merry XMAS and have a save time!
rulez added on the 2020-12-15 04:31:32 by g0blinish g0blinish
rulez added on the 2020-12-15 10:49:02 by gorgh gorgh

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