Actionscript Sonic Engine

What's the point of it with no loop-de-loops?

 

Wow, flash Sonic games with good physics can actually happen now.

Thank you, sir, thank you.

My only complaint is that it seems either slow, or icy to walk...probably just me though.

Any chance of slopes, I think the Physics Guide covers them enough.

 

Neat stuff. I look forward to seeing how this goes. Right now though you need to fix Sonic's inability to jump while rolling.

 

Nice work Elratauru. I hope you do push through with perfect or near perfect physics of the classics.

 

you could remove half the features and call it a sonic 4 engine

ZING

 

Very nice. I might take a look at it to figure out a way to make the collision work properly. If I can find my Flash Games Programming Boog for AS 2.0 that is.

 

Good progress. Perhaps we'll get Flash-based fangames with decent controls now instead of the messy physics they usually have.

 

Holding both left and right while at a decent speed will make you skid without slowdown. This plagued your earlier engine test too.

 

I have noticed, that there is no code for the dec...
I have replicated the code from here: http://info.sonicretro.org/SPG:Running to AS, it includes the dec movement.

Code (Text):

1.     if (Key.isDown(37))
2.     {
3.         if (xspeed > 0)
4.         {
5.             xspeed -= dec;
6.         }
7.         else
8.         if (xspeed > -max)
9.         {
10.             xspeed = xspeed - acc;
11. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (xspeed < -max)
12. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
13. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed = -max;
14. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
15. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
16. &nbsp;&nbsp;&nbsp;&nbsp;}
17. &nbsp;&nbsp;&nbsp;&nbsp;else
18. &nbsp;&nbsp;&nbsp;&nbsp;if (Key.isDown(39))
19. &nbsp;&nbsp;&nbsp;&nbsp;{
20. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (xspeed < 0)
21. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
22. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed += dec;
23. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
24. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;else
25. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (xspeed < max)
26. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
27. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed = xspeed + acc;
28. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (xspeed > max)
29. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{
30. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed = max;
31. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
32. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}
33. &nbsp;&nbsp;&nbsp;&nbsp;}
34. &nbsp;&nbsp;&nbsp;&nbsp;else if (xspeed < 0 && !Key.isDown())
35. &nbsp;&nbsp;&nbsp;&nbsp;{
36. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed = xspeed + frc;
37. &nbsp;&nbsp;&nbsp;&nbsp;}
38. &nbsp;&nbsp;&nbsp;&nbsp;else if (xspeed > 0 && !Key.isDown())
39. &nbsp;&nbsp;&nbsp;&nbsp;{
40. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;xspeed = xspeed - frc;
41. &nbsp;&nbsp;&nbsp;&nbsp;}

Takes up less space too (well... I think it does). With decceleration, it takes away any floaty/icy feel.

It also seems to work if the variables are litterally the correct values like so:

Code (Text):

1. &nbsp;&nbsp;&nbsp;&nbsp;var acc = 0.046875;
2. &nbsp;&nbsp;&nbsp;&nbsp;var dec = 0.5;
3. &nbsp;&nbsp;&nbsp;&nbsp;var frc = 0.046875;
4. &nbsp;&nbsp;&nbsp;&nbsp;var max = 6;
5. &nbsp;&nbsp;&nbsp;&nbsp;var grav = 0.21875;

Just trying to help!

Oh, does air drag work, or is there no fancy calculations? I can't see any evidence if there is.

 

I think air drag is this:

Code (Text):

1. if (yspeed < 0 and yspeed > -4)
2. {
3. &nbsp;&nbsp;&nbsp;&nbsp;xspeed = xspeed - ( ( xspeed / 0.125 ) / 256 );
4. }

Actually, does Actionscript have a 'div' equivilent? (I'm currently messing around with the engine because it's cool).

 

I noticed one issue that hasn't been addressed yet. When you tap the jump button, Sonic will raise slightly and remain there until you jump again.

 

That's the aforementioned collision errors at work.

 

I don't get that. My jumping is fine.

The only problem I get with collision is the fact that he land at different heights each time, some sort of (when not airborne, snap y to...) code is needed for the moment.

 

This might be intentional but if you hold the jump button down you can keep on jumping without Sonic coming out of a ball for the split second he lands on the ground.

 

Keeping a hold of down and left/right from a standstill makes Sonic snap very quickly back and forth between rolling and walking.