Physics Calculation Question in Developer Help

ID:264974
 
Aug 9 2011, 6:37 am
Code:
proc
        bulletPreCalculate(part/gun/gun,mob/m)
            var
                d=sqrt(((px-m.px)^2) + ((py-m.py)^2))//distance from the person firing the bullet to the person being targetted converted into a scalar
                t//the time it would take the bullet to reach the mob under normal circumstances
                v=gun.bulletSpeed//the velocity of the bullet
            t=(d/v)//time is equal to distance over time
            var
                dx//new x to aim at
                dy//new y to aim at
            dx=(t*m.vel_x)//distance = time times velocity
            dy=(t*m.vel_y)//^^^^
            //done
            if(!m.vel_x&&!m.vel_y)
                return list(m.px,m.py)
            return list(dx,dy)


Problem description:
I'm trying to make a pre-calculation procedure so that when aiming at a mob, it's more accurate, because right now, it just aims at where they were, which will yield annoying gameplay if ever an enemy is moving with more than a velocity of 1.5 pixels/30/s (which is frequently). Right now , whenever they're moving it aims at the bottom right corner (I've also noticed the distance, d, has extremely variant numbers, i.e: when I print out the distance, it's 256 or so pixels between me and the tile two tiles away, 4 pixels away from the tile right in front of me, and like 310 pixels away for any tile further than 3 tiles away)
#1 Aug 9 2011, 6:54 am (Edited on Aug 9 2011, 7:06 am)
In DM ^ is not power, two multiplication signs (**) is power, or you could multiply manually.
> proc
>       bulletPreCalculate(part/gun/gun,mob/m)
>           var
>               d=sqrt(((px-m.px)**2) + ((py-m.py)**2))
>           // ...()


See if everything is correct now.
#2 Aug 9 2011, 6:55 am
In response to Zaoshi (#1)
It's not? o.o
#3 Aug 9 2011, 7:10 am
In response to Zaoshi (#1)
Ah, well, I found that that does work, but using a scalar for the bullet velocity doesn't work; so when combining the velocities, do I add them, or multiply them?
#4 Aug 9 2011, 7:10 am
In response to Ill Im (#2)
Well it should calculate distance correctly now, are you sure you pass correct values? Try to output them and calculate manually.
#5 Aug 9 2011, 7:12 am
In response to Ill Im (#3)
You add them.
#6 Aug 9 2011, 7:15 am
In response to Zaoshi (#4)
Oh, I meant "its not" as in exponent isn't upper carret