Difference between revisions of "Remove the Air Speed Cap"
From Sonic Retro
(Created page with '''(Guide written by Selbi; code by Puto, taken from the Sonic 1 Speed Cap page)'' In Sonic 1 is a function, that limits Sonic's …') |
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''(Guide written by [[Selbi]]; code by [[Puto]], taken from the [[SCHG How-to:Remove the Speed Cap|Sonic 1 Speed Cap page]])'' | ''(Guide written by [[Selbi]]; code by [[Puto]], taken from the [[SCHG How-to:Remove the Speed Cap|Sonic 1 Speed Cap page]])'' | ||
| − | In [[Sonic 1]] is a function, that limits Sonic's top speed when you are | + | In [[Sonic 1]] is a function, that limits Sonic's top speed when you are keep pressing in the direction you are looking at (you can feel that best when running down a hill). In [[Sonic 2]] this function doesn't apply; well, at least not completely. Running on the ground works just fine, but in the air you still have it. So let's fix that: |
| − | Go to ''Sonic_ChgJumpDir'', which should look like this: | + | Go to ''Sonic_ChgJumpDir'', which should look like this in Xenowhirl's 2007 Sonic 2 disassembly: |
<asm>Sonic_ChgJumpDir: | <asm>Sonic_ChgJumpDir: | ||
move.w (Sonic_top_speed).w,d6 | move.w (Sonic_top_speed).w,d6 | ||
| Line 38: | Line 38: | ||
Do the same thing after '''''blt.s + ; if new speed is less than the maximum, branch''''' by using these lines: | Do the same thing after '''''blt.s + ; if new speed is less than the maximum, branch''''' by using these lines: | ||
<asm> sub.w d5,d0 ; +++ air speed cap fix | <asm> sub.w d5,d0 ; +++ air speed cap fix | ||
| − | cmp.w d6,d0 ; +++ speed cap fix | + | cmp.w d6,d0 ; +++ air speed cap fix |
| − | bge.s + ; +++ | + | bge.s + ; +++ air speed cap fix</asm> |
The final result should look like this: | The final result should look like this: | ||
Revision as of 08:40, 5 August 2010
(Guide written by Selbi; code by Puto, taken from the Sonic 1 Speed Cap page)
In Sonic 1 is a function, that limits Sonic's top speed when you are keep pressing in the direction you are looking at (you can feel that best when running down a hill). In Sonic 2 this function doesn't apply; well, at least not completely. Running on the ground works just fine, but in the air you still have it. So let's fix that:
Go to Sonic_ChgJumpDir, which should look like this in Xenowhirl's 2007 Sonic 2 disassembly: <asm>Sonic_ChgJumpDir: move.w (Sonic_top_speed).w,d6 move.w (Sonic_acceleration).w,d5 asl.w #1,d5 btst #4,status(a0) ; did Sonic jump from rolling? bne.s Obj01_Jump_ResetScr ; if yes, branch to skip midair control move.w x_vel(a0),d0 btst #2,(Ctrl_1_Held_Logical).w beq.s + ; if not holding left, branch
bset #0,status(a0) sub.w d5,d0 ; add acceleration to the left move.w d6,d1 neg.w d1 cmp.w d1,d0 ; compare new speed with top speed bgt.s + ; if new speed is less than the maximum, branch move.w d1,d0 ; limit speed in air going left, even if Sonic was already going faster (speed limit/cap) + btst #3,(Ctrl_1_Held_Logical).w beq.s + ; if not holding right, branch
bclr #0,status(a0) add.w d5,d0 ; accelerate right in the air cmp.w d6,d0 ; compare new speed with top speed blt.s + ; if new speed is less than the maximum, branch move.w d6,d0 ; limit speed in air going right, even if Sonic was already going faster (speed limit/cap)
- Obj01_JumpMove
+ move.w d0,x_vel(a0)</asm> If you look closely, you will notice that this code works excactly like in Sonic 1. This is good, because we can use the excact same methods to fix it. After the line bgt.s + ; if new speed is less than the maximum, branch add these lines: <asm> add.w d5,d0 ; +++ air speed cap fix cmp.w d1,d0 ; +++ air speed cap fix ble.s + ; +++ air speed cap fix</asm> Do the same thing after blt.s + ; if new speed is less than the maximum, branch by using these lines: <asm> sub.w d5,d0 ; +++ air speed cap fix cmp.w d6,d0 ; +++ air speed cap fix bge.s + ; +++ air speed cap fix</asm>
The final result should look like this: <asm>Sonic_ChgJumpDir: move.w (Sonic_top_speed).w,d6 move.w (Sonic_acceleration).w,d5 asl.w #1,d5 btst #4,status(a0) ; did Sonic jump from rolling? bne.s Obj01_Jump_ResetScr ; if yes, branch to skip midair control move.w x_vel(a0),d0 btst #2,(Ctrl_1_Held_Logical).w beq.s + ; if not holding left, branch
bset #0,status(a0) sub.w d5,d0 ; add acceleration to the left move.w d6,d1 neg.w d1 cmp.w d1,d0 ; compare new speed with top speed bgt.s + ; if new speed is less than the maximum, branch add.w d5,d0 ; +++ air speed cap fix cmp.w d1,d0 ; +++ air speed cap fix ble.s + ; +++ air speed cap fix move.w d1,d0 ; limit speed in air going left, even if Sonic was already going faster (speed limit/cap) + btst #3,(Ctrl_1_Held_Logical).w beq.s + ; if not holding right, branch
bclr #0,status(a0) add.w d5,d0 ; accelerate right in the air cmp.w d6,d0 ; compare new speed with top speed blt.s + ; if new speed is less than the maximum, branch sub.w d5,d0 ; +++ air speed cap fix cmp.w d6,d0 ; +++ air speed cap fix bge.s + ; +++ air speed cap fix move.w d6,d0 ; limit speed in air going right, even if Sonic was already going faster (speed limit/cap)
- Obj01_JumpMove
+ move.w d0,x_vel(a0)</asm>