Is there a way to point the camera in the direction of a specific vector in Javafx8? - javafx-8

Question

I've looked around for awhile and I can't seem to find a way to point a camera in a direction say [1, 2, 3] without calculating the angles between everything. I'm actually new to 3d graphics in general so I don't know if I'm missing something simple.

Answer 1

I have edited my answer to provide an example of how to manipulate the Affine transform
relative to current position in scene. Which is a very useful Transform for 3D space.
I will cover the basics with code, I do suggest you read up on Transformation Matrices.
This is a good Tutorial and cover everything in "layman's" terms.
So first define a few Callbacks for getting both rows and cols from the affine matrix:
public Affine affine = new Affine();
//Points: fwd, right, up Point3D: pos
//Forward / look direction
Callback<Transform, Point3D> forwardColCallback = (a) -> {
return new Point3D(a.getMzx(), a.getMzy(), a.getMzz());
};
Callback<Transform, Point3D> forwardRowCallback = (a) -> {
return new Point3D(a.getMxz(), a.getMyz(), a.getMzz());
};
// up direction
Callback<Transform, Point3D> upColCallback = (a) -> {
return new Point3D(a.getMyx(), a.getMyy(), a.getMyz());
};
Callback<Transform, Point3D> upRowCallback = (a) -> {
return new Point3D(a.getMxy(), a.getMyy(), a.getMzy());
};
// right direction
Callback<Transform, Point3D> rightColCallback = (a) -> {
return new Point3D(a.getMxx(), a.getMxy(), a.getMxz());
};
Callback<Transform, Point3D> rightRowCallback = (a) -> {
return new Point3D(a.getMxx(), a.getMyx(), a.getMzx());
};
//position
Callback<Transform, Point3D> positionCallback = (a) ->{
return new Point3D(a.getTx(), a.getTy(), a.getTz());
};
Point3D getForwardCol(){
return forwardColCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getForwardRow(){
return forwardRowCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getRightDirection(){
return rightDirCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getRightRow(){
return rightRowCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getUpCol(){
return upColCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getUpRow(){
return upRowCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Point3D getPosition(){
return positionCallback.call(getTransformableNode().getLocalToSceneTransform());
}
Ok, Now lets build some methods to use those.
Translations:
private void moveForward() {
affine.setTx(getPosition().getX() + speed * getForwardRow().x);
affine.setTy(getPosition().getY() + speed * getForwardRow().y);
affine.setTz(getPosition().getZ() + speed * getForwardRow().z);
}
private void strafeLeft() {
affine.setTx(getPosition().getX() + speed * -getRightRow().x);
affine.setTy(getPosition().getY() + speed * -getRightRow().y);
affine.setTz(getPosition().getZ() + speed * -getRightRow().z);
}
private void strafeRight() {
affine.setTx(getPosition().getX() + speed * getRightRow().x);
affine.setTy(getPosition().getY() + speed * getRightRow().y);
affine.setTz(getPosition().getZ() + speed * getRightRow().z);
}
private void moveBack() {
affine.setTx(getPosition().getX() + speed * -getForwardRow().x);
affine.setTy(getPosition().getY() + speed * -getForwardRow().y);
affine.setTz(getPosition().getZ() + speed * -getForwardRow().z);
}
private void moveUp() {
affine.setTx(getPosition().getX() + speed * -getUpRow().x);
affine.setTy(getPosition().getY() + speed * -getUpRow().y);
affine.setTz(getPosition().getZ() + speed * -getUpRow().z);
}
private void moveDown() {
affine.setTx(getPosition().getX() + speed * getUpRow().x);
affine.setTy(getPosition().getY() + speed * getUpRow().y);
affine.setTz(getPosition().getZ() + speed * getUpRow().z);
}
For Rotations you could do something like this by adding a Translate and the 3 respective Rotate transforms:
// mouse coordinates not implemented in this example
// You would need to define them
scene.setOnMousePressed(me->{
t.setX(getPosition().getX());
t.setY(getPosition().getY());
t.setZ(getPosition().getZ());
affine.setToIdentity();
rotateY.setAngle(
MathUtils.clamp(((rotateY.getAngle() + moveDelta.getX() * (speed * 0.05)) % 360 + 540) % 360 - 180, -360, 360)
); // horizontal
rotateX.setAngle(
MathUtils.clamp(((rotateX.getAngle() - moveDelta.getY() * (speed * 0.05)) % 360 + 540) % 360 - 180, -90, 90)
); // vertical
affine.prepend(t.createConcatenation(rotateY.createConcatenation(rotateX)));
}
);