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SCHG How-to

Resize Levels in Sonic 2

From Sonic Retro

(Original guide by lavagaming1)

In Sonic 2, all acts reference an array which defines starting screen boundaries for the levels. By editing this array, we can resize the initial level boundaries, so let's do that. In s2.asm, search for "LevelSize:" You should see this:

; ===========================================================================
; ----------------------------------------------------------------------------
; LEVEL SIZE ARRAY

; This array defines the screen boundaries for each act in the game.
; ----------------------------------------------------------------------------                                     ;how long                                     ;is level;makeslev                                                ;up                                                       ;dawn
;				xstart	xend	ystart	yend	; ZID ; Zone
LevelSize: zoneOrderedTable 2,8	; WrdArr_LvlSize
	zoneTableEntry.w	$0,	$2FFF,	$0,	$669	; EHZ act 1
	zoneTableEntry.w	$0,	$2940,	$0,	$550	; EHZ act 2
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; EHZ act 3
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; wood zone
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; $03
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$2280,	-$100,	$800	; MTZ act 1
	zoneTableEntry.w	$0,	$1E80,	-$100,	$800	; MTZ act 2
	zoneTableEntry.w	$0,	$2A80,	-$100,	$800	; MTZ act 3
	zoneTableEntry.w	$0,	$3FFF,	-$100,	$800
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; WFZ
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$2800,	$0,	$720	; HTZ act 1
	zoneTableEntry.w	$0,	$3280,	$0,	$720	; HTZ act 2
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; hidden palce
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720	; $09
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
	zoneTableEntry.w	$0,	$2F80,	$0,	$680	; OOZ act 1
	zoneTableEntry.w	$0,	$2D00,	$0,	$680	; OOZ act 2
	zoneTableEntry.w	$0,	$2380,	$3C0,	$720	; MCZ act 1
	zoneTableEntry.w	$0,	$3FFF,	$60,	$720	; MCZ act 2
	zoneTableEntry.w	$0,	$27A0,	$0,	$720	; CNZ act 1
	zoneTableEntry.w	$0,	$2A80,	$0,	$720	; CNZ act 2
	zoneTableEntry.w	$0,	$2780,	$0,	$720	; CPZ act 1
	zoneTableEntry.w	$0,	$2A80,	$0,	$720	; CPZ act 2
	zoneTableEntry.w	$0,	$1000,	$C8,	 $C8	; DEZ
	zoneTableEntry.w	$0,	$1000,  $C8,	 $C8
	zoneTableEntry.w	$0,	$3380,  $0,	$720	; ARZ act 1
	zoneTableEntry.w	$0,	$3FFF,	$180,	$710	; ARZ act 2
	zoneTableEntry.w	$0,	$3FFF,	$0,	$000	; SCZ
	zoneTableEntry.w	$0,	$3FFF,	$0,	$720
    zoneTableEnd

; ===========================================================================

This is the array. Now, let me explain how this works: X-Start: These are all $0 so that the screen boundaries for the level start at the start of the level. Make it a larger value if you want there to be hidden level geometry.

X-End: This is the end of the screen boundaries on the x-axis, usually at the end of the level. I'd suggest making it the current x-position of the signpost or egg-capsule plus $A0.

Y-Start: This is the top of the level, where the camera cuts off. This should be self-explanatory.

Y-End: This is where the death boundary will be at first. Adjust wisely.

These all reference X and Y coordinates in the level, respectively. In Sonic 2, these are easily accessible in ASM format, however if you are modifying S1, it will be a .bin file instead. Hopefully this helps you understand the basics of this topic.

SCHG How-To Guide: Sonic the Hedgehog 2 (16-bit)
Fixing Bugs
Fix Demo Playback | Fix a Race Condition with Pattern Load Cues | Fix Super Sonic Bugs | Use Correct Height When Roll Jumping | Fix Jump Height Bug When Exiting Water | Fix Screen Boundary Spin Dash Bug | Correct Drowning Bugs | Fix Camera Y Position for Tails | Fix Tails Subanimation Error | Fix Tails' Respawn Speeds | Fix Accidental Deletion of Scattered Rings | Fix Ring Timers | Fix Rexon Crash | Fix Monitor Collision Bug | Fix EHZ Deformation Bug | Correct CPZ Boss Attack Behavior | Fix Bug in ARZ Boss Arrow's Platform Behavior | Fix ARZ Boss Walking on Air Glitch | Fix ARZ Boss Sprite Behavior | Fix Multiple CNZ Boss Bugs | Fix HTZ Background Scrolling Mountains | Fix OOZ Launcher Speed Up Glitch | Fix DEZ Giant Mech Collision Glitch | Fix Boss Deconstruction Behavior | Fix Speed Bugs | Fix 14 Continues Cheat | Fix Debug Mode Crash | Fix 99+ Lives
Design Choices
Remove the Air Speed Cap | Disable Floor Collision While Dying | Modify Super Sonic Transformation Methods & Behavior | Enable/Disable Tails in Certain Levels | Collide with Water After Being Hurt | Retain Rings When Returning at a Star Post | Improve the Fade In\Fade Out Progression Routines | Fix Scattered Rings' Underwater Physics | Insert LZ Water Ripple Effect | Restore Lost CPZ Boss Feature | Prevent SCZ Tornado Spin Dash Death | Improve ObjectMove Subroutines | Port S3K Rings Manager | Port S3K Object Manager | Port S3K Priority Manager | Edit Level Order with ASM‎ | Alter Ring Requirements in Special Stages | Make Special Stage Characters Use Normal DPLCs | Speed Up Ring Loss Process | Change spike behaviour in Sonic 2
Adding Features
Create Insta-kill and High Jump Monitors | Create Clone and Special Stage Monitors | Port Knuckles
Sound Features
Expand Music Index to Start at $00 | Port Sonic 1 Sound Driver | Port Sonic 2 Clone Driver | Port Sonic 3 Sound Driver | Port Flamewing's Sonic 3 & Knuckles Sound Driver | Expand the Music Index to Start at $00 (Sonic 2 Clone Driver Version) | Play Different Songs Per Act
Extending the Game
Extend the Level Index Past $10 | Extend the Level Select | Extend Water Tables | Add Extra Characters | Free Up 2 Universal SSTs

|Resize Levels in Sonic 2]]