
#ifndef __trackball_h__
#define __trackball_h__



// called with the start position and the window origin + size
void startTrackball (long x, long y, long originX, long originY, long width, long height);

// calculated rotation based on current mouse position
void rollToTrackball (long x, long y, float rot [4]); // rot is output rotation angle

// add a GL rotation (dA) to an existing GL rotation (A)
void addToRotationTrackball (float * dA, float * A);


#endif