Code: 3d_underwater_world/clipping.h

This is an example OpenGL SDL application which creates an animated 3D underwater world (screenshot), with "Thunderbird 4" with headlights moving on a spline path, a randomly generated sand terrain, sunken ship/submarine/treasure chest models, and swaying fish and seaweed. It is designed to demonstrate basic OpenGL features, and the structure is as follows:

#ifndef CLIPPING_H_INCLUDED
#define CLIPPING_H_INCLUDED
#include "global.h"
#include "vectors.h"

/**
* The hyperplanes of a frustrum
* projection.
*/
class FrustrumClipper
{
    public:
        // hyperplanes
        HyperPlane nr;
        HyperPlane fr;
        HyperPlane left;
        HyperPlane right;
        HyperPlane top;
        HyperPlane bottom;
        // init
        FrustrumClipper() {}
        FrustrumClipper(FrustrumClipper* f);
        void set(FrustrumClipper* f);
        // sets the frustrum's clipping planes
        // to the frustrum defined by these
        // parameters
        void set(float viewingAngle,
            float aspectRatio, float nearD, float farD,
            const Vec3* pos, const Vec3* obj, const Vec3* above);
        // transform this using a transformation matrix
        void transform(Mat4* t);
        // inside the frustrum?
        bool inside(const Vec3* p);
};

/*
* CameraView class
* Stores information about the current orienation
* and direction of the camera, and methods to determine
* if a point, or object is in view.
*/
class CameraView
{
      private:
          // frustrum for clipping
          FrustrumClipper frust;
          // perspective constants
          GLfloat viewingAngle;
          GLfloat aspectRatio;
          GLfloat nearD;
          GLfloat farD;
          // camera orientation
          Vec3 pos; // position of the camera
          Vec3 obj; // forward
          Vec3 above; // upward
          Vec3 side; // normal to plane of pos,obj,above
      public:
        // constructor
        CameraView(GLfloat viewingAngle,
            GLfloat aspectRatio, 
            GLfloat nearD,
            GLfloat farD);
        // set location and orientation
        void set(const Vec3* pos, 
            const Vec3* obj,
            const Vec3* above);
        // is in view?
        bool inView(Vec3* p) { return frust.inside(p); }
        // set gl lookat to this orientation
        void lookAt();
        // rotate vertically
        void rotateVert(float angle);
        // rotate horizontally
        void rotateHoriz(float angle);
        // move forward
        void moveForward(float dist);
        // move up
        void moveUp(float dist);
        // get position
        void getPosition(Vec3* r);
        // get forward vector
        void getForwardVector(Vec3* r);
};

#endif

3D Underwater World (using OpenGL and SDL)

clipping.h