3d projectiles?

[jrhetf4xb]

It has been bugging me for a while but why don't most projectile systems offer 3d collision detection as well? The way I imagine it is like a simple check with GetUnitFlyHeight() (of course combined with a normal XY group enum), something like:

if (RAbsBJ(GetUnitFlyHeight(collidedTarget) - GetUnitFlyHeight(projectile)) <= PROJECTILE_RADIUS) then 
    //... all that stuff

Or maybe I'm missing something?

 

[SerraAvenger]

It has been bugging me for a while but why don't most projectile systems offer 3d collision detection as well? The way I imagine it is like a simple check with GetUnitFlyHeight() (of course combined with a normal XY group enum), something like:

if (RAbsBJ(GetUnitFlyHeight(collidedTarget) - GetUnitFlyHeight(projectile)) <= PROJECTILE_RADIUS) then 
    //... all that stuff

Or maybe I'm missing something?

Please print GetUnitFlyHeight of flying units to the screen. Then also raise the terrain upon which the unit is standing and print GetUnitFlyHeight of that to the screen.

I guess the main problem lies somewhere around this. I haven't used Wc3 for ages, so I can't really tell.

IIRC, Azlier made some nice scripts to figure out the real z coordinate of a unit. Dunno, though.

 

[Trollvottel]

There some points you forgot.
1. The thing SerraAvenger mentioned: If there are different terrain heights, there will be different z-heights of units that have the same flying height.
the Z-height is just flying height of unit + GetLocationZ at it's position.

2. You cant calculate the distance like this. If you do it like this, you will get a cube in which you pick the units and not a sphere.

Do it like this:

Pick units in Radius PROJECTILE_RADIUS at position X,Y
Now use pythagoras (pseudocode):

If ((projectileX-collidedTargetX)² + (projectileY-collidedTargetY)² + (projectileZ-collidedTargetZ)² <= PROJECTILE_RADIUS) then
Do all that stuff

 

[Sgqvur]

>It has been bugging me for a while but why don't most projectile systems offer 3d collision detection as well?

Which systems are you referring?

One thing no system has is 3d collision of units to destructables due to no GetDestructableZ =/.


OT: What was the better way of doing collisions The GroupEnumUnitsInRange or with a Rect entering event? One of them wasn't suitable for very high speed projectiles but I forgot which one.

 

[jrhetf4xb]

Yes, terrain height would definitely be included but it was a quick example.
And I have no idea (my math level being low also included ). how Pythagoras theorem would have anything to do with spherical shapes...

> Which systems are you referring?
All submitted?

> One thing no system has is 3d collision of units to destructables due to no GetDestructableZ =/.
Meh, unit to unit has a chance to be used more

 

[Trollvottel]

K, image example following.
hope you understand it.


lol, drnk on teh internetz

/edit: the center of the point is your object. the square on is the one with which you check collision.

/€²: There is a mistake in the image. in the left circle the square should be closer to the center so that it seems to be in range (so it is in the circle).

 

[Accname]

you should also keep in mind the wc3 engine auto-adjusts flying heights of flying units when they come close to cliffs. between 2 cliff levels the flying height of the unit will not be equal to the actual height in which it is displayed on the screen.

 

[jrhetf4xb]

^ Wouldn't that affect the dummy units (projectiles) as well?

I'm not sure I quite understand but from the calculations it seems that (looking at the right image):
d should be less than r so that the projectile can collide, right?

 

[Trollvottel]

jop, thats right. and for that you need my calculations. your calculations would pick units in a cylinder (i drew the square in which you picked the units).

 

[jrhetf4xb]

Makes perfect sense now that I think of it, thanks for the tip