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Difference between revisions of "SPG:Rolling"

From Sonic Retro

(Rolling Jump)
m (h3s -> h2s, +sortfix)
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The following only applies when [[Sonic]] is on flat, dry land with no special power-ups.  Curves, water physics, [[Super Sonic]], and [[Speed Shoes]] will be covered in separate guides.
 
The following only applies when [[Sonic]] is on flat, dry land with no special power-ups.  Curves, water physics, [[Super Sonic]], and [[Speed Shoes]] will be covered in separate guides.
  
===Friction===
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==Friction==
  
 
When Sonic rolls up by pressing {{down}} on the directional pad, he can no longer accelerate.  No matter how hard or how long you press in the direction of his motion, he'll behave as if you weren't doing a thing.  The only thing that happens in this case is friction, here a value of 0.0234375, half of normal so that it feels like he's rolling smoothly like a wheel or a ball.  The Mega Drive actually calculates rolling friction by halving the normal friction value.  If you use the Game Genie to alter the friction value, rolling friction is always half.
 
When Sonic rolls up by pressing {{down}} on the directional pad, he can no longer accelerate.  No matter how hard or how long you press in the direction of his motion, he'll behave as if you weren't doing a thing.  The only thing that happens in this case is friction, here a value of 0.0234375, half of normal so that it feels like he's rolling smoothly like a wheel or a ball.  The Mega Drive actually calculates rolling friction by halving the normal friction value.  If you use the Game Genie to alter the friction value, rolling friction is always half.
  
===Deceleration===
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==Deceleration==
  
 
However, Sonic ''can'' decelerate while rolling.  If you hold in the opposite direction of his motion, X speed will be slowed by 0.125.  Additionally, unlike normal walking, friction is still in effect while rolling, even if you press in a direction.  So, in effect, while decelerating, X speed slows by 0.125+0.0234375, or 0.1484375, every step.
 
However, Sonic ''can'' decelerate while rolling.  If you hold in the opposite direction of his motion, X speed will be slowed by 0.125.  Additionally, unlike normal walking, friction is still in effect while rolling, even if you press in a direction.  So, in effect, while decelerating, X speed slows by 0.125+0.0234375, or 0.1484375, every step.
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Strangely, the same deceleration anomaly happens while rolling as while running.  If absolute X speed is less than 0.1484375, when this value is subtracted, instead of just setting X speed to zero, X speed is set to .5 in the opposite direction.  Thus, bizarrely, Sonic can turn around while rolling, even though he can't accelerate!  This is fixed in Sonic 3 and Knuckles, so apparently the programmers themselves found this undesirable.
 
Strangely, the same deceleration anomaly happens while rolling as while running.  If absolute X speed is less than 0.1484375, when this value is subtracted, instead of just setting X speed to zero, X speed is set to .5 in the opposite direction.  Thus, bizarrely, Sonic can turn around while rolling, even though he can't accelerate!  This is fixed in Sonic 3 and Knuckles, so apparently the programmers themselves found this undesirable.
  
===Criteria===
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==Criteria==
  
 
In Sonic 1 and 2, Sonic can't roll up unless his absolute X speed is greater than 0.53125.
 
In Sonic 1 and 2, Sonic can't roll up unless his absolute X speed is greater than 0.53125.
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In Sonic 3 and Knuckles, probably as a way to combat the anomaly associated with turning around while rolling in the previous games, Sonic unrolls if absolute X speed falls below .5.
 
In Sonic 3 and Knuckles, probably as a way to combat the anomaly associated with turning around while rolling in the previous games, Sonic unrolls if absolute X speed falls below .5.
  
===Rolling Jump===
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==Rolling Jump==
  
 
In Sonic 1, 2, 3, and Knuckles, you can't control Sonic's trajectory through the air with the directional buttons if you jump while rolling.  This makes it kind of hard to Spindash to gain speed, and then make a precise jump. Though, in Sonic 3 and in Sonic & Knuckles, you can regain control of the directional keys if you perform a [[W Kaiten Attack]].
 
In Sonic 1, 2, 3, and Knuckles, you can't control Sonic's trajectory through the air with the directional buttons if you jump while rolling.  This makes it kind of hard to Spindash to gain speed, and then make a precise jump. Though, in Sonic 3 and in Sonic & Knuckles, you can regain control of the directional keys if you perform a [[W Kaiten Attack]].
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However, in Sonic CD, you can control a jump made while rolling, as if it were a totally normal jump.  This is probably more fair to the player.
 
However, in Sonic CD, you can control a jump made while rolling, as if it were a totally normal jump.  This is probably more fair to the player.
 
 
[[Category:Sonic Physics Guide]]
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[[Category:Sonic Physics Guide|Rolling]]

Revision as of 10:57, 1 June 2010

Notes:

Research applies to all four of the Genesis/Mega Drive games, and Sonic CD.

The following only applies when Sonic is on flat, dry land with no special power-ups. Curves, water physics, Super Sonic, and Speed Shoes will be covered in separate guides.

Friction

When Sonic rolls up by pressing Down on the directional pad, he can no longer accelerate. No matter how hard or how long you press in the direction of his motion, he'll behave as if you weren't doing a thing. The only thing that happens in this case is friction, here a value of 0.0234375, half of normal so that it feels like he's rolling smoothly like a wheel or a ball. The Mega Drive actually calculates rolling friction by halving the normal friction value. If you use the Game Genie to alter the friction value, rolling friction is always half.

Deceleration

However, Sonic can decelerate while rolling. If you hold in the opposite direction of his motion, X speed will be slowed by 0.125. Additionally, unlike normal walking, friction is still in effect while rolling, even if you press in a direction. So, in effect, while decelerating, X speed slows by 0.125+0.0234375, or 0.1484375, every step.

Strangely, the same deceleration anomaly happens while rolling as while running. If absolute X speed is less than 0.1484375, when this value is subtracted, instead of just setting X speed to zero, X speed is set to .5 in the opposite direction. Thus, bizarrely, Sonic can turn around while rolling, even though he can't accelerate! This is fixed in Sonic 3 and Knuckles, so apparently the programmers themselves found this undesirable.

Criteria

In Sonic 1 and 2, Sonic can't roll up unless his absolute X speed is greater than 0.53125.

In Sonic 3 and Knuckles, this value is increased to 1.03125. This is very convenient, because you have to hold down to Spindash. If Sonic had to be perfectly still before he could duck, you'd have trouble performing the Spindash quickly and easily.

In Sonic 3 and Knuckles, probably as a way to combat the anomaly associated with turning around while rolling in the previous games, Sonic unrolls if absolute X speed falls below .5.

Rolling Jump

In Sonic 1, 2, 3, and Knuckles, you can't control Sonic's trajectory through the air with the directional buttons if you jump while rolling. This makes it kind of hard to Spindash to gain speed, and then make a precise jump. Though, in Sonic 3 and in Sonic & Knuckles, you can regain control of the directional keys if you perform a W Kaiten Attack.

However, in Sonic CD, you can control a jump made while rolling, as if it were a totally normal jump. This is probably more fair to the player.