Not built into pygame, but there is a good one on the pygame wiki: http://pygame.org/wiki/2DVectorClass
On Wed, Jul 20, 2011 at 04:33:16PM +0200, Nathan BIAGINI wrote: > There is a pygame object to create a 2d vector? > > 2011/7/20 Joe Ranalli <[email protected]> > > Yes a vector is probably appropriate. > > On Wed, Jul 20, 2011 at 10:20 AM, Nathan BIAGINI <[email protected]> > wrote: > > Ok. But all the calcul of how long the bullet will take to reach the > target etc... will be made byn using vector? I mean, using a vector > still viable? > > 2011/7/20 Joe Ranalli <[email protected]> > > It depends what you're trying to do. > > If you draw the straight line between the tower and the enemy and > use that vector to translate a bullet each tick, the bullets might > miss the enemy. Think about it this way, the bullet moves 2 steps > toward the enemy, then the enemy moves 1 step, then the bullet moves > 2, etc. Because the enemy moves the bullet will have to change its > direction through the flight. So you could calculate the direction > vector between the bullet and the enemy every tick and have the > bullet move that direction. That would make the bullets kind of arc > to the target. > > If you want to have the bullet go straight to the right spot, you > need to: > 1) calculate how long the bullet will take to get to the enemy > 2) calculate where the enemy will be at that time (newposition) > 3) calculate how long it will take the bullet to get to newposition > 4) recalculate newposition based on the new time > > Technically you could iterate that repeatedly until newposition > converges. Practically, iterating once probably gets you close > enough unless the movement is extremely complicated. > > On Wed, Jul 20, 2011 at 9:14 AM, Nathan BIAGINI > <[email protected]> wrote: > > Hi everyone, > > i would like to know what are the common way to handle > "trajectory" in a 2d game. In fact, i think of writing a tower > defense game and i wonder how to handle the trajectory of the > missile launch by the towers. I though of getting the pos of the > tower and the target and create a vector between this two > entitites to make a sprite translation of this vector but there is > maybe some tricky stuff to do it. > > Thanks in advance and happy game making all :-)
