[solved] Getting The Camera's 'AimVector'

[kklouzal]

I'm trying to get the 'AimVector' for the camera which in essence would just be a vector3df() with values in the range of 0,0,0 and 1,1,1.

Basically I need to have a function that takes the current rotation of the camera and applies some maths then spits out a vector3df as described previously. I've done some research on this and I thing it needs to call Sin and Cos on the .X and .Y values but I'm not completely sure and I cant seem to figure out the correct combination on my own.

Any help here from the maths geniuses would be most appreciated.
Thank you for your time!

[Seven]

will this give you what you are looking for?

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vector3df aimVector = camera->getTarget() - camera->getPosition();
aimVector.normalize();
 

[kklouzal]

I don't actually have access to the camera as this is being ran on the server-side, I'm sure there is a way to get it with sin() cos() I just for the life of me cant figure it out.

I believe it its:

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irr::core::vector3df CameraRotation();
irr::core::vector3df AimVector();
 
AimVector.X = Cos(CameraRotation.X);
AimVector.Y = Sin(CameraRotation.Y);
 

But what about the Z axis??

[mongoose7]

vector3df(cos(Y)*cos(X), sin(Y)*cos(X), sin(X))

[kklouzal]

That is definitely not working :P

This is *almost* working, it seems to be quite inaccurate though, nor does it take into account the Z-Axis!

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irr::core::vector3df(cos(irr::core::degToRad(Rot.Y)), sin(irr::core::degToRad(Rot.X)), Rot.Z)

[Foaly]

What about rotationToDirection?
http://irrlicht.sourceforge.net/docu/cl ... a19278474d

irr::core::vector3df cameraDir = rot.rotationToDirection();

[kklouzal]

That's almost exactly the opposite of what I'm trying to do.

I want to input my rotation vector and output the forward vector.

EDIT::

Maybe it would help if I explained the context of what I'm trying to do. I'm trying to do a raytrace from the players position 1000 units out from where he is looking.
I only have access to the players position and the players rotation, based off that I should be able to get a "forward vector" to apply to the equation to figure out my ray's end position.

[kklouzal]

Entity has most graciously posted the highschool grade trig to solve this most simple issue I could not wrap my preschool sized brain around:

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core::vector3df(sin(core::degToRad(rot.Y)), -sin(core::degToRad(rot.X)), cos(core::degToRad(rot.Y))).normalize();

[Foaly]

Did you try my solution? I still think it's the right answer.
vector3df::rotationToDirection() converts a rotation in euler angles (that's the way scene nodes store it) to a normalized direction vector.

If you want to do the opposite (as you said), you can try vector3df::getHorizontalAngle(), which converts a direction to a euler rotation.

[kklouzal]

Foaly I tried to use rotationToDirection() but no matter how I use it when I visualize the raytrace the lines fly out in random directions. This is what I've got at the moment.

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    irr::core::vector3df Rot = GetOwner()->GetRotation();
    irr::core::vector3df StartPos(GetOwner()->GetPosition().x(), GetOwner()->GetPosition().y(), GetOwner()->GetPosition().z());
    //irr::core::vector3df Forward(sin(irr::core::degToRad(Rot.Y)), -sin(irr::core::degToRad(Rot.X)), cos(irr::core::degToRad(Rot.Y)));
    irr::core::vector3df Forward = StartPos.rotationToDirection();
    irr::core::vector3df EndPos = StartPos + (Forward * 1000);

If I uncomment the first Forward and comment the second then the rays trace where I'm looking, but if I look up or down past 90 degrees then it starts to get very inaccurate. using rotationToDirection must require a different formula to get EndPos that I can't figure out.. -.-

[kklouzal]

This is what finally got perfect results:

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    irr::core::vector3df Rot = GetOwner()->GetRotation();
    irr::core::vector3df Forward = irr::core::vector3df(0, 0, 1);
    irr::core::matrix4 m;
    m.setRotationDegrees(Rot);
    m.rotateVect(Forward);
    irr::core::vector3df StartPos(GetOwner()->GetPosition().x(), GetOwner()->GetPosition().y(), GetOwner()->GetPosition().z());
    irr::core::vector3df EndPos = StartPos + (Forward * 1000);

[Seven]

i didnt understand the question before........... here is another way to do it.

http://irrlicht.sourceforge.net/forum/v ... in#p288921

in your case your would just use getPosition() as the start of the line, and getIn() * 1000 as the end.