| File Name: | Forest Flood Generator |
| Submitted: | 2017-07-01 08:55:49 PM by ShUriK KiD |
| Authors: | ShUriK KiD |
| Tool: | PIXI |
| Type: | Generator |
| Dynamic: | No |
| Disassembly: | No |
| Includes GFX: | No |
| Description: | This generator will spawn Sprites (configurable) on the right side of the screen at the low tide height. Additionally it makes the tides more dangerous by pulling the player additionally downwards (also configurable). Using this without SA-1 is not 100% recommended, it will cause slowdown really fast. Usage note: Your level must be at least 3 screens long, else the generated sprites will always float upwards. You must use the Layer 3 Tides (low only) or the Sprites will spawn in thin air and do nothing. How to configure stuff is included in the ASM file. Example usage: https://www.youtube.com/watch?v=CAAN8rbiFdA |
Code
LDA !E4,x ; Sprite X low STA $0110 LDA !14E0,x ; Sprite X high STA $0111 REP #$20 LDA $0110 SEC SBC #$0001 STA $0110 SEP #$20 LDA $0111 STA !14E0,x LDA $0110 STA !E4,x
-> The $0110/$0111 are not remapped for SA-1. In this case luckily they point to something valid so it doesn't crash, however...
-> There is no reason to use Free RAM here at all. XBA swaps the top and bottom bit of A allowing you to construct a 16 bit value from 2 8 bit values without using RAM like this. (Also, DEC instead of SEC : SBC #$0001)