For rotation around the z-axis:

x' = x cos za - y sin za;
y' = x sin za + y cos za;

For rotation around the x-axis:

y' = y cos xa - z sin xa;
z' = y sin xa + cos xa;

For rotation around the y-axis:

x' = x cos ya + z sin ya;
z' = - x sin ya + z cos ya;

Of course, x', y' and z' are the new coordinates. I'll let you figure out how to plug this into your code. It's not hard, but not as simple as you hoped.

BOOL RotatePoint(CVector* point, float xa, float ya, float za);
{
point.screen_x = // Rotated x around xa, ya, and xa.
point.screen_y = // Same as above but for y
point.screen_z = // Ditto

return TRUE;
}

Any help would be great! Thanks!