// File: lunar.cxx
// Written by Michael Main, Sep 15, 2005
// This is a demonstration game.  The user tries to land a lunar lander.
#include <graphics.h> // Provides bgi graphics
#include <iostream>   // Provides cout
using namespace std;


///////////////////////////////////////////////////////////////////////////////
// Physical constants
const double FORCE_MAIN_THRUSTER = 3000;     // kg m/s^2
const double FORCE_SIDE_THRUSTER = 30;       // kg m/s^2
const double GRAVITY = -9.8/6;               // m/s^2
const double MASS_LANDER = 1000;             // kg
const double STARTING_FUEL = 250;            // kg
const int    DELAY = 10;                     // ms
const double DELTA_T = DELAY/1000.0;         // s

// Graphical constants
const double IMAGE_SIZE = 0.65;
const int WINDOW_WIDTH = static_cast<int>(851*IMAGE_SIZE);
const int WINDOW_HEIGHT = static_cast<int>(608*IMAGE_SIZE);
const int GROUND_ZERO_Y = static_cast<int>(566*IMAGE_SIZE);
const int ROCKET_SIZE = static_cast<int>(100*IMAGE_SIZE);
const double PIXELS_PER_METER = 10; 
const int BACKGROUND_BYTES = 2069656;
const int ROCKET_BYTES = 68896;
///////////////////////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////////////////////
// Function prototypes (in alphabetical order)

// Draw the background image
void draw_background( );

// Draw the lander on the screen.
void draw_lander(
    double x, double y,  // Current x and y positions (m)
    double r,            // Current rotational pos (radians)
    bool main, bool left, bool right // Which thrusters are on
    );

// Write some of the state data to the screen
void draw_stats(
    double vx, double vy,   // Current velocities (m/s)
    double vr,              // Current rotational velocitie (radians/s)
    double fuel,            // Remaining fuel (kg)
    double t                // Current time (s)
    );

///////////////////////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////////////////////
//The main program
int main( )
{
    bool main = false, left = false, right = false; // Are the thrusters on?
    double x = (static_cast<double>(WINDOW_WIDTH)/PIXELS_PER_METER)/2.0;
    double y = (static_cast<double>(GROUND_ZERO_Y)/PIXELS_PER_METER);
    double fuel;                                    // Remaining fuel (kg)
    double vx, vy;                                  // Velocity (m/s)
    double r;                                       // Rotational pos radians
    double vr;                                      // Rotational radians/sec
    double t = 0;                                   // Time since start
    
    initwindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Mario", 0, 0, true);
    do
    {
	// Adjust the control variables: main, left, and right
        	
        // Adjust the physical variables: positions, velocities, fuel, t
	t += DELTA_T;

        // Redraw the screen and delay
	draw_background( );
	draw_lander(x,y,r,main,left,right);
	draw_stats(vx,vy,vr,fuel,t);
	swapbuffers( );
	delay(DELAY);
    } while(true);
    return 0;
}
///////////////////////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////////////////////
void draw_background( )
{
    static bool first = true;
    static char buffer[BACKGROUND_BYTES];

    if (first)
    {
	readimagefile("bg.bmp", 0, 0, WINDOW_WIDTH-1, WINDOW_HEIGHT-1);
	getimage(0, 0, WINDOW_WIDTH-1, WINDOW_HEIGHT-1, buffer);
	first = false;
    }
    else
    {
	putimage(0, 0, buffer, COPY_PUT);
    }
}
///////////////////////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////////////////////
void draw_lander(
    double x, double y,  // Current x and y positions (m)
    double r,            // Current rotational pos (radians)
    bool main, bool left, bool right // Which thrusters are on
    )
{
    static bool first = true;
    static char buffer[8][ROCKET_BYTES];

    if (first)
    {   // Make and store all the different rocket images:
	readimagefile("rocket0.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[0]);
	readimagefile("rocket1.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[1]);
	readimagefile("rocket2.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[2]);
	readimagefile("rocket3.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[3]);
	readimagefile("rocket4.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[4]);
	readimagefile("rocket5.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[5]);
	readimagefile("rocket6.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[6]);
	readimagefile("rocket7.bmp", 0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1);
	getimage(0, 0, ROCKET_SIZE-1, ROCKET_SIZE-1, buffer[7]);
	first = false;
    }
    // Get the right rocket image and put it on the screen:
    putimage(
	static_cast<int>(x*PIXELS_PER_METER),
	static_cast<int>(GROUND_ZERO_Y - y*PIXELS_PER_METER),
	buffer[3],
	OR_PUT
	);
}
///////////////////////////////////////////////////////////////////////////////


///////////////////////////////////////////////////////////////////////////////
void draw_stats(
    double vx, double vy,   // Current velocities (m/s)
    double vr,              // Current rotational velocitie (radians/s)
    double fuel,            // Remaining fuel (kg)
    double t                // Current time (s)
    )
{
    bgiout << "Horizontal velocity (m/s): " << vx << endl;
    bgiout << "Vertical velocity (m/s):   " << vy << endl;
    bgiout << "Rotational velocity (radians/sec): " << vr << endl;
    bgiout << "Remaining fuel (kg): " << fuel << endl;
    bgiout << static_cast<int>(t) << endl;
    outstreamxy(10, 10);
}
///////////////////////////////////////////////////////////////////////////////