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HorrendousGames
Sourpuss
Registered
31/10/2009
Points
481
  
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6th December, 2010 at 08:26:14 -
I need a bit of help on this one. Basically I thought if I just divide the distance between two points by the time it should take to get there, then it should be somewhat accurate.
However, it's not. Basically all I want is just that, an object that travels from one point to another (both known) and there is a set time to get there, and it has to be dead on. and of course MMF2 doesn't seem to want to calculate floats in terms of XY movements.
I did the distance formula/time: speed = (Sqr(((x2-x1)*(x2-x1))+((y2-y1)*(y2-y1))))/time. I tried this with the bouncing ball movement, but prior to that I used XY movements, and in that case I had a separate X and Y speed (x2-x1)/time and (y2-y1)/time.
Both are extremely inaccurate, the XY movement won't move between numbers and the bouncing ball movement just blows something fierce. Also, i'd have to set up a very forgiving box for them to fit into, so it wouldn't miss/do one of those happy dances where it jumps around.
I might try resetting up on the XY and having another counter that counts down the steps it needs to get to the point, so once that counter reaches zero it stops moving, but I can already imagine it not working.
Solutions?
/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/-=?=-/
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Duke Highway
Registered
11/03/2010
Points
21
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6th December, 2010 at 11:09:46 -
One thing you could try is to use floats by multiplying your formula with 1.0
Then it should be accurate...
 Edited by Duke Highway
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Sketchy
Cornwall UK
Registered
06/11/2004
Points
1971
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6th December, 2010 at 14:05:55 -
You just need to store the X and Y coordinates in alterable values (the built-in "x position" and "y position" can't hold floats, which is why your speed is getting rounded down).
+ whenever...
-> Object: XVel = (X("End") - X("Start")) / Time
-> Object: YVel = (Y("End") - Y("Start")) / Time
+ whenever...
-> Object: XPos = XPos + XVel
-> Object: YPos = YPos + YVel
-> Object: Set X position to XPos("Object")
-> Object: Set Y position to YPos("Object")
Edited by Sketchy
n/a
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DeadmanDines
Best Article Writer
Registered
27/04/2006
Points
4758
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6th December, 2010 at 17:12:19 -
And of course remember that when you're testing it with a bouncing ball, its speed is not in pixels per second, so it won't equate directly into the number of pixels travelled in a certain amount of time.
If you're using a custom movement and you maintain the floats by using Alterable Values as your variables, you should get it pixel perfect.
I used a similar formula for a space shooter where the player's ship projects a copy of itself 3 seconds in the future based on its current speed and angle, and warns of any obstacles within that path.
191 / 9999 * 7 + 191 * 7
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HorrendousGames
Sourpuss
Registered
31/10/2009
Points
481
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6th December, 2010 at 18:50:45 -
That did the trick guys, It's not pixel perfect (barring the accurate representation of time I'm guessing) but it's at least not sticking in places and it hits right around the center of the crosshair (vs. somewhere in the vicinity/not moving on the Y at all).
@Duke - Great trick, I knew about this, but of course it doesn't work with built in XY values, but still good none the less.
@Sketchy - I always wondered why people stored their XY values in alterable values, and now I know two things. 1) More accurate like you described and 2) it's so much easier to copy/paste change the letter than right click, find the object, find the value, do stuff and a second time.
@Deadman dines - Yeah, I kind of figured that, even when changing around my representation of time, it still was really goofy.
Thanks a ton guys.
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That Really Hot Chick
now on the Xbox Live Marketplace!
http://marketplace.xbox.com/en-US/Product/That-Really-Hot-Chick/66acd000-77fe-1000-9115-d80258550942
http://www.create-games.com/project.asp?view=main&id=2160
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