TurboTrack
A library for navigating around 3d space using a trackball-style input. Provides the Holroyd and Shoemake trackball algorithms [1]. The library currently supports both Eigen and glm as data representation.
Usage
Link to the CMake target turbotrack, afterwards you can use the library like this:
#include <turbotrack.hpp>
Eigen::Quaternionf current_orientation;
// on mouse movement
Eigen::Vector2f old_mouse_pos /* = ... */, new_mouse_pos /* = ... */;
const Eigen::Quaternionf rot = turbotrack::mouse_move(old_mouse_pos, new_mouse_pos, radius);
current_orientation = rot * current_orientation;Make sure that you first transform the mouse coordinates to have 0 at the centre of the screen. If the rotation is wrong then you might have to flip the y coordinate on the inputs to mouse_move.
Experiment with the radius to get something that feels right for your application. Just over half the window width seems to be a good starting point.
Eigen / glm
Use the CMake cache variable TURBOTRACK_LINALG_LIBRARY to select either EIGEN or GLM as the linear algebra backend.
// set(TURBOTRACK_LINALG_LIBRARY "EIGEN" CACHE)
Eigen::Quaternionf turbotrack::mouse_move(
const Eigen::Vector2f &old_pos,
const Eigen::Vector2f &new_pos,
float radius = 1.0,
turbotrack::TrackballType type = turbotrack::TrackballType::holroyd
);
// set(TURBOTRACK_LINALG_LIBRARY "GLM" CACHE)
glm::quat turbotrack::mouse_move(
const glm::vec2 &old_pos,
const glm::vec2 &new_pos,
float radius = 1.0,
turbotrack::TrackballType type = turbotrack::TrackballType::holroyd
);Scope
For now this library only deals with the view rotation, not translation. This might be expanded in the future, depending on my needs / time.
References
[1] K. Henriksen, J. Sporring, and K. Hornbæk. Virtual Trackballs Revisited. DSAGM, 2002.