What screen coordinate system is used in Irrlicht?

pir · Post by **pir** » Wed Apr 29, 2009 8:24 pm

I'm trying to do pick selection by using ISceneCollisionManager::getSceneNodeFromScreenCoordinatesBB.
What is the screen coordinate system used when defining the screen coordinates to use?
Is the coordinates of the upper left corner (0,0) and lower right (width, height)? I've tried to search the forum and documentation about this, but without any luck.

hope someone have time to answer my question.

tomhancocks · Post by **tomhancocks** » Wed Apr 29, 2009 9:10 pm

0,0 is the upper left, and width,height is indeed the lower right.

Systemerror · Post by **Systemerror** » Thu Apr 30, 2009 10:44 am

It uses the right handed cartesian co ordinate system (X, Y, Z)

X = width
Y = height
Z = 3D line between the two

Y(height)
| _ X(twidth)
/
Z(towards the viewer)

Like my graph? lol

hybrid · Post by **hybrid** » Thu Apr 30, 2009 11:01 am

screen has no z axis, and the rest is not important then.

Systemerror · Post by **Systemerror** » Thu Apr 30, 2009 1:32 pm

Oops, sorry I just skimmed through his first post, well atleast he knows for future refference

hybrid · Post by **hybrid** » Thu Apr 30, 2009 3:50 pm

Oh, in that case: Irrlicht uses a left-handed systm, just as DirectX.

Acki · Post by **Acki** » Thu Apr 30, 2009 9:16 pm

Systemerror wrote: X(height going downwards)
| _ Y(to the right)
/
Z(towards the viewer)

Like my graph? lol

maybe if it was correct...

X - you're wrong: it goes to the right !!!
Y - you're wrong: it goes up !!!
Z - you're wrong: it's the opposite direction !!!

Systemerror · Post by **Systemerror** » Thu Apr 30, 2009 10:11 pm

That's what tiredness does to you, it's not what I meant.

Now edited to right handed system even though Irrlicht uses the left like D3D, I suddenly started thinking of OpenGL strangly enough - old habbits ....