/*
* Simple trackball-like motion adapted (ripped off) from projtex.c
* (written by David Yu and David Blythe). See the SIGGRAPH '96
* Advanced OpenGL course notes.
*
*
* Usage:
*
* o call tbInit() in before any other tb call
* o call tbReshape() from the reshape callback
* o call tbMatrix() to get the trackball matrix rotation
* o call tbStartMotion() to begin trackball movememt
* o call tbStopMotion() to stop trackball movememt
* o call tbMotion() from the motion callback
* o call tbAnimate(GL_TRUE) if you want the trackball to continue
* spinning after the mouse button has been released
* o call tbAnimate(GL_FALSE) if you want the trackball to stop
* spinning after the mouse button has been released
*
* Typical setup:
*
*
void
init(void)
{
tbInit(GLUT_MIDDLE_BUTTON);
tbAnimate(GL_TRUE);
. . .
}
void
reshape(int width, int height)
{
tbReshape(width, height);
. . .
}
void
display(void)
{
glPushMatrix();
tbMatrix();
. . . draw the scene . . .
glPopMatrix();
}
void
mouse(int button, int state, int x, int y)
{
tbMouse(button, state, x, y);
. . .
}
void
motion(int x, int y)
{
tbMotion(x, y);
. . .
}
int
main(int argc, char** argv)
{
. . .
init();
glutReshapeFunc(reshape);
glutDisplayFunc(display);
glutMouseFunc(mouse);
glutMotionFunc(motion);
. . .
}
*
* */
/* functions */
void
tbInit(GLuint button);
void
tbMatrix(void);
void
tbReshape(int width, int height);
void
tbMouse(int button, int state, int x, int y);
void
tbMotion(int x, int y);
void
tbAnimate(GLboolean animate);
