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Make a mesh face the camera?

Blitz3D Forums/Blitz3D Beginners Area/Make a mesh face the camera?

Kippykip(Posted 2013) [#1]
How can I make a mesh rotate towards the cameras position?
I looked at something on as3, but when doing it in blitz3d, I use Z instead of y, and I only want it to rotate yaw
Instead, the object just spins around when you move
help?
			For c.Obj=Each Obj
				zDifference# = EntityZ(player) - EntityZ(c\evilcube)
				xDifference# = EntityX(player) - EntityX(c\evilcube)
				radiansToDegrees# = 180/Pi
				RotateEntity(c\evilcube, EntityPitch(c\evilcube),ATan2(zDifference, xDifference) * radiansToDegrees,EntityRoll(c\evilcube))
			Next

It was based of this: http://as3gametuts.com/2013/06/08/top-down-rpg-shooter-3/


Kryzon(Posted 2013) [#2]
http://blitzbasic.com/b3ddocs/command.php?name=DeltaYaw&ref=3d_cat


Yasha(Posted 2013) [#3]
VectorYaw should return the result you want if I understand correctly. Ninja'd with a better command.

Aside from that, no built in B3D command uses radians for any purpose (they all accept or return their values in degrees) so that radians-to-degrees conversion will be throwing the result way off.


Matty(Posted 2013) [#4]
Lots of ways, align to vector, pointentity, deltayaw,


Kippykip(Posted 2013) [#5]
Found DeltaYaw to be very buggy, sometimes even get "Memory access violation"
But got the other method working!
RotateEntity(c\mesh, 0,ATan2(EntityZ(player) - EntityZ(c\mesh), EntityX(player) - EntityX(c\mesh))+90,0)

Basically got rid of the "radiansToDegrees# = 180/Pi" thing and made it all in 1 line thanks to Yasha

Thanks for the others helping anyway!


Kryzon(Posted 2013) [#6]
Hello.
You're not supposed to use it with RotateEntity, which only admits absolute rotation values. It'll look like it's missing the target.

DeltaYaw returns a relative value, so you use it with TurnEntity like Floyd exemplified in that documentation thread linked previously (it's the last post, at the bottom of that thread).
It also shouldn't give a MAV error unless you supply null entities to it.

I did just benchmark the two ways (RotateEntity with ATan2 vs TurnEntity with DeltaYaw), and surprisingly using RotateEntity with ATan2 is the faster method.