3d architecture computer graphics game game engine head first real time real-time computing 3d computer graphics software development video game development 3d computer graphics software quake o3d graphics programmer mathematics opengl physics mathematical optimization verlet integration linear complementarity problem complementarity theory deformable body rigid body dynamics computer science video game design collision detection geometry interpolation bézier curve binary space partitioning curves differential geometry of curves engineering software engineering differential equation computational physics physics engine fluid dynamics dynamical simulation stability