PacManPlus Posted November 16, 2021 Share Posted November 16, 2021 (edited) Hi guys: For those of you that don't know, I have re-started porting 'Defender' to the 7800. I started from scratch as I wanted to use 320B mode and I had an idea for the terrain (use 320A mode for that). However, I'm finding that I'm having issues with the scanner area: As you can see, I have a 16x4 tile grid, which works out to be 64x30 pixels. (The bottom two scan lines are the scanner box itself). When I did this the first time, I blocked out an area of (added) memory, made the DL point to that area of RAM and just updated it each frame. This time, I would really like to not use expanded memory (I want to see if I can do this within the limits of the vanilla console). I tried using DL entries for each of the 'dots', but because of the character modes used (score, ships in reserve, etc) I can only get 4 sprite DLs in the zone before I run out of Maria cycles. Flickering at 30Hz is not out of the question, but even then I'll only get 8. I won't go more than 30Hz as then it gets bad. I know Atari has done this with Defender and Defender II on the 2600 (with Defender II only adding 128 more bytes of memory), so there has to be some sort of trick of doing this without using much memory. (I would try and read the Defender II code but there is no disassembly of it that I know of). Does anyone have any ideas? Thanks, Bob Edited November 16, 2021 by PacManPlus 37 2 Quote Link to comment Share on other sites More sharing options...
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