_THEATRIX: A C++ GAMES CLASS LIBRARY_
by Al Stevens

Listing One

// ------- skater.cpp
#include <theatrix.h>
const int sidesteps = 25;  // number of steps in lateral movement
const int fwdsteps = 12;   // number of steps in front/rear movement
const int sstepincr = 5;   // lateral x coordinate increments
const int fstepincr = 3;   // front/rear y coordinate increments
// ------- a moving sprite
class Skater : public Player    {
    short int steps;    // number of steps taken current segment
    short int mode;     // 1-8 = skating pattern #; 11-13 = splash
    friend class Pond;
    void OnEnter(int);
protected:
    DECLARE_CUELIST
public:
    Skater();
    virtual ~Skater() { }
    void update_position();
};
// ---- event message map for Skater class
CUELIST(Skater)
    KEYSTROKE('\r', OnEnter)
ENDCUELIST
// ---- construct a moving sprite
Skater::Skater() : Player("skater.gfx", "skater.sfx")
{
    setxy(90,145);  // initial position on pond
    set_imageno(1); // first skater frame
    appear();
    steps = 0;
    mode = 1;
}
// --- skater frame animation entry point (once every tick)
void Skater::update_position()
{
    switch (mode)    {
        case 1:
        case 3:
        case 5:
        case 7:
            // --- side to side movement
            if (++steps == sidesteps)    {
                steps = 0;
                set_imageno(++mode);
                break;
            }
            if (mode & 2) // modes 3 and 7: to the left
                setx(getx() - sstepincr);
            else          // modes 1 and 5: to the right
                setx(getx() + sstepincr);
            break;
        case 2:
        case 4:
        case 6:
        case 8:
            // --- front or back movement
            if (++steps == fwdsteps)    {
                steps = 0;
                if (mode == 8)
                    mode = 0;
                set_imageno(++mode);
                break;
            }
            if (mode < 6)  // modes 2 and 4: away from the screen
                sety(gety() - fstepincr);
            else           // modes 6 and 8: toward the screen
                sety(gety() + fstepincr);
            break;
        case 9:
            setinterval(3);  // slow down refresh rate
            set_imageno(13); // 1st frame of ice-breaking splash
            mode++;
            play_sound_clip(1);
            break;
        case 10:
            set_imageno(12); // 2nd frame of ice-breaking splash
            mode++;
            break;
        case 11:
            set_imageno(13); // 3rd frame of ice-breaking splash
            mode++;
            break;
        case 12:
            set_imageno(11); // hole in ice
            mode++;
            steps = 0;
            break;
        default:
            if (steps++ == 30)
                stop_director();
            break;
    }
}
// ---- pressed Enter, break the ice
void Skater::OnEnter(int)
{
    if (mode < 9)    {
        int yp = 35;
        if (mode == 3 || mode == 7)
            yp = 25;
        else if (mode > 3 && mode < 7)
            yp = 15;
        setxy(getx()-10, gety() + yp);
        mode = 9;
    }
}
// ---- stationary sprites
class Stander : public Player    {
public:
    Stander() : Player("skater.gfx") { }
};
// ---- the scene: a skating pond
class Pond : public SceneDirector    {
    Stander *stander1;
    Stander *stander2;
    Skater *skater;
    void on_timer();
public:
    Pond();
    ~Pond();
};
// ---- construct the scene
Pond::Pond() : SceneDirector("pond.pcx")
{
    // --- most distant stationary sprite
    stander1 = new Stander;
    stander1->set_imageno(10);
    stander1->setxy(180,100);
    stander1->appear();
    // --- closest stationary sprite
    stander2 = new Stander;
    stander2->set_imageno(9);
    stander2->setxy(140,130);
    stander2->appear();
    // --- moving sprite
    skater = new Skater;
}
Pond::~Pond()
{
    delete skater;
    delete stander2;
    delete stander1;
}
// ---- called after each timer tick
void Pond::on_timer()
{
    SceneDirector::on_timer();
    if (skater->steps == 0)    {
        switch (skater->mode)    {
            case 1:
                // -- front lateral segment
                //    set moving sprite in front of others
                MoveZToFront(skater);
                break;
            case 3:
            case 7:
                // -- center lateral segment
                //    set moving sprite between other two
                ChangeZOrder(skater,stander2);
                break;
            case 5:
                // -- rear lateral segment
                //    set moving sprite behind others
                ChangeZOrder(skater,stander1);
                break;
            default:
                break;
        }
    }
}
int main(int argc,char *argv[])
{
    process_cmdline(argc,argv);
    Pond *pond = new Pond;  // scene director
    begin("Pond");          // launch scene
    delete pond;
    return 0;
}