HowToC:FollowAnObject
From S2PLOT
(Difference between revisions)
Revision as of 23:35, 19 August 2008
[edit]
How to follow an object with the camera
Using handles, you can easily detect when an object has been right-clicked. With two pretty simple bits of code, you can then make the camera keep focussed on that object.
1. use a handle callback to register the most recently selected handle:
// define an S2PLOT OpenGL callback function */
void openglcb(void) {
// store the state
glPushAttrib(GL_ALL_ATTRIB_BITS);
// turn on blending
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
// draw a transparent orange quad
glBegin(GL_QUADS);
glColor4f(0.8, 0.3, 0.0, 0.5);
glVertex3f(-3., -3., -3.);
glVertex3f(-3., 3., -3.);
glVertex3f( 3., 3., -3.);
glVertex3f( 3., -3., -3.);
glEnd();
// restore the state
glPopAttrib();
}
