Extend the water tables in Sonic 2

(Original guide by Dani)

If you have tried to add water to a zone ID between $00 and $07, you may have noticed strange effects with the water, such as the entire level filling with water or no water showing up at all (only the water line). To correct this problem, several changes need to be done to your disassembly. (This guide will use the Xenowhirl 2007 Sonic 2 disassembly; other disassemblies may vary.)

First, find the section marked loc_402C and find the following line: <asm> subi.w #$800,d0</asm>

and either comment it out or delete it entirely.

Next, locate the following: <asm>WaterHeight:

   dc.w  $600, $600, $600, $600
   dc.w  $600, $600, $600, $600
   dc.w  $600, $600, $600, $710
   dc.w  $600, $600, $410, $510</asm>

and change it to: <asm>WaterHeight:

   dc.w  $600, $600; EHZ
   dc.w  $600, $600; Zone 01
   dc.w  $600, $600; WZ
   dc.w  $600, $600; Zone 03
   dc.w  $600, $600; MZ
   dc.w  $600, $600; MZ3
   dc.w  $600, $600; WFZ
   dc.w  $600, $600; HTZ
   dc.w  $600, $600; HPZ
   dc.w  $600, $600; Zone 09
   dc.w  $600, $600; OOZ
   dc.w  $600, $600; MCZ
   dc.w  $600, $600; CNZ
   dc.w  $600, $710; CPZ
   dc.w  $600, $600; DEZ
   dc.w  $410, $510; ARZ
   dc.w  $600, $600; SCZ</asm>

Next, in the section marked DynamicWater, locate the following line: <asm> subi.w #$800,d0</asm>

and either comment it out or delete it entirely.

Next, locate this section: <asm>Dynamic_water_routine_table:

   dc.w DynamicWaterNull - Dynamic_water_routine_table; 0
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 3
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 4
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 5
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 6
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 7
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 8
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 9
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 10
   dc.w DynamicWaterCPZ2 - Dynamic_water_routine_table; 11 ; the only one that does anything
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 12
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 13
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 14
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 15</asm>

and replace the section with: <asm>Dynamic_water_routine_table:

   dc.w DynamicWaterNull - Dynamic_water_routine_table; EHZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; EHZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 01-1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 01-2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; WZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; WZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 03-1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 03-2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; MZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; MZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; MZ3
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 05-2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; WFZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; WFZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; HTZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; HTZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; HPZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; HPZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 09-1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; 09-2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; OOZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; OOZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; MCZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; MCZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; CNZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; CNZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; CPZ1
   dc.w DynamicWaterCPZ2 - Dynamic_water_routine_table; CPZ2 ; the only one that does anything
   dc.w DynamicWaterNull - Dynamic_water_routine_table; DEZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; DEZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; ARZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; ARZ2
   dc.w DynamicWaterNull - Dynamic_water_routine_table; SCZ1
   dc.w DynamicWaterNull - Dynamic_water_routine_table; SCZ2</asm>

Once these changes have been made, you will be able to add water to any zone in Sonic the Hedgehog 2. If you run into any problems, please let me know and/or get it working and edit this article.

SCHG How-to

Extend the water tables in Sonic 2

From Sonic Retro