//
// The camera is placed in such a way
// it can display the content of the BBox
// In all regards, it is also placed along the negative Z axis
// Looking towards the positive Z axis
// with a (0,1,0) Up vector
//
public override void LookAt(BoundingBox BBox, LookAtDirection dir = LookAtDirection.POSITIVE_Z)
{
Reset();
_bbox = BBox;
_center = (BBox.Maximum + BBox.Minimum) / 2;
Vector3 LMax = BBox.Maximum - BBox.Minimum;
float lmax = Math.Max(LMax.Z, Math.Max(LMax.X, LMax.Y));
Vector3 translation = _center;
translation.Z = -(lmax / (float)Math.Tan(_camera.Fov) + lmax / 2 + _center.Z);
_cameraWorldTransform = Matrix.Translation(translation);
_camera.WorldTransform = _cameraWorldTransform;
Matrix r = Matrix.Identity;
if (dir == LookAtDirection.POSITIVE_Z)
{
r = Matrix.Identity;
}
else if (dir == LookAtDirection.NEGATIVE_Z)
{
r = Matrix.RotationY((float)Math.PI);
}
else if (dir == LookAtDirection.POSITIVE_X)
{
r = Matrix.RotationY((float)Math.PI / 2f);
}
else if (dir == LookAtDirection.NEGATIVE_X)
{
r = Matrix.RotationY(-(float)Math.PI / 2f);
}
else if (dir == LookAtDirection.POSITIVE_Y)
{
r = Matrix.Translation(-_center) * Matrix.RotationX(-(float)Math.PI / 2f) * Matrix.Translation(_center);
}
else if (dir == LookAtDirection.NEGATIVE_Y)
{
r = Matrix.Translation(-_center) * Matrix.RotationX((float)Math.PI / 2f) * Matrix.Translation(_center);
}
_cameraWorldTransform = Matrix.Translation(translation) * r;
_camera.WorldTransform = _cameraWorldTransform;
}
public abstract void LookAt(BoundingBox BBox, LookAtDirection dir = LookAtDirection.POSITIVE_Z);