Question

Assume that we are writing a game like Minecraft in C++. We will have a World class that stores a 3-dimensional array of "Voxels". A voxel is a simple element of volume (think Pixel, but 3D). Your task for this assignment is to create a world, set some Voxels and display them.

You are provided with a simple class for a Voxel that stores a RGB color value, as well as a character code for the type of element.

You are also provided with a simple class for a World that stores a 3-Dimensional array, named boxes, that stores, 100 x 100 x 100 different Voxel objects. Because this large array is stored directly in the World class, you should not create a World object as a normal local stack variable. Depending on your environment this would likely even cause a segmentation fault. Instead you should use a Pointer to a world object, and dynamically allocate it using the "new" command.

As a side note, for all the reasons mentioned, a better design for the world class would be to have it contain a dynamically allocated array, and only store the pointer internally. But this is a little harder for us to practice...

Here is my check07b.cpp file:

#include <iostream>
using namespace std;

#include "voxel.h"
#include "world.h"

/**************************************************************
* Function: main
* Purpose: The driver for the program. Creates a world, sets
* some Voxels and displays them.
**************************************************************/
int main()
{
   cout << "Starting Program.\n";

   // First, we create a voxel for air
   Voxel air(180, 200, 255, 'A');

   // Next, we create a voxel for grass
   Voxel grass(25, 255, 50, 'G');

   cout << "Ending Program.\n";
   return 0;
}

Here is voxel.cpp:

#include "voxel.h"

#include <iostream>
using namespace std;

void Voxel :: display() const
{
   cout << "(" << red << ", " << green << ", " << blue << ") - ";
   cout << typeCode;
}

voxel.h:

#ifndef VOXEL_H
#define VOXEL_H
class Voxel
{
private:
   // stores an integer for Red, Blue, and Green
   // The astute coder will observe the great ineffiency here
   int red;
   int green;
   int blue;

   // Stores a character code for a particular type
   char typeCode;

public:
   Voxel() : red(0), green(0), blue(0), typeCode('_') { }
   Voxel(int red, int green, int blue, char type)
      : red(red), green(green), blue(blue), typeCode(type) { }

   /******************************************************
    * Function: Display
    * Description: Displays the value of a Voxel.
    ******************************************************/
   void display() const;
};

#endif

world.cpp:

#include "voxel.h"
#include "world.h"

#include <iostream>
using namespace std;

World::World()
{
   cout << "Initializing the world and connecting to server...\n";
   // we are not really connecting to a server, just pretending
}

World::~World()
{
   cout << "Disconnecting from the server and saving state...\n";
   // Shh... we're not actually doing anything :-)
}
Voxel World::getBox(int x, int y, int z) const
{
   return boxes[x][y][z];
}

void World::setBox(int x, int y, int z, const Voxel & box)
{
   boxes[x][y][z] = box;
}
void World::display()
{
   cout << "Hello from your world.\n";
}
void World::displayBox(int x, int y, int z)
{
   cout << "The value at (" << x << ", " << y << ", " << z << ") is: ";
   boxes[x][y][z].display();
   cout << endl;
}

world.h:

#ifndef WORLD_H
#define WORLD_H

#include "voxel.h"
class World
{
private:
   Voxel boxes[100][100][100];

public:
   World();
   ~World();

   Voxel getBox(int x, int y, int z) const;
   void setBox(int x, int y, int z, const Voxel & box);
   void display();
   void displayBox(int x, int y, int z);
};

#endif

Here's what I have to do:

1. Declare a new World object. Make sure to use pointers and dynamic allocation.
2. Call the "display" method on your World object.
3. Code is in place to create a Voxel for air. Call the setBox method on your World object to set it at position: (50, 60, 70).
4. Code is in place to create a Voxel for grass. Call the setBox method on your World object to set it at position: (45, 20, 10).
5. Call the displayBox method (on your World object) twice to diplay the two Voxels you just set.
6. Finally, make sure to free up the memory taken by your World object by deleting it.

Sample output:

The following is an example of output for this program:

Starting Program.

Initializing the world and connecting to server...

Hello from your world.

The value at (50, 60, 70) is: (180, 200, 255) - A

The value at (45, 20, 10) is: (25, 255, 50) - G

Disconnecting from the server and saving state...

Ending Program.

Thanks in advance!

Answer 1

// voxel.h

#ifndef VOXEL_H
#define VOXEL_H

class Voxel
{
private:
// stores an integer for Red, Blue, and Green
// The astute coder will observe the great ineffiency here
int red;
int green;
int blue;

// Stores a character code for a particular type
char typeCode;

public:
Voxel() : red(0), green(0), blue(0), typeCode('_') { }
Voxel(int red, int green, int blue, char type)
: red(red), green(green), blue(blue), typeCode(type) { }

/******************************************************
* Function: Display
* Description: Displays the value of a Voxel.
******************************************************/
void display() const;
};

#endif
//end of voxel.h

// voxel.cpp

#include "voxel.h"

#include <iostream>
using namespace std;

void Voxel :: display() const
{
cout << "(" << red << ", " << green << ", " << blue << ") - ";
cout << typeCode;
}

//end of voxel.cpp

// world.h

#ifndef WORLD_H
#define WORLD_H

#include "voxel.h"
class World
{
private:
Voxel boxes[100][100][100];

public:
World();
~World();

Voxel getBox(int x, int y, int z) const;
void setBox(int x, int y, int z, const Voxel & box);
void display();
void displayBox(int x, int y, int z);
};

#endif

//end of world.h

// world.cpp

#include "voxel.h"
#include "world.h"

#include <iostream>
using namespace std;

World::World()
{
cout << "Initializing the world and connecting to server...\n";
// we are not really connecting to a server, just pretending
}

World::~World()
{
cout << "Disconnecting from the server and saving state...\n";
// Shh... we're not actually doing anything :-)
}
Voxel World::getBox(int x, int y, int z) const
{
return boxes[x][y][z];
}

void World::setBox(int x, int y, int z, const Voxel & box)
{
boxes[x][y][z] = box;
}
void World::display()
{
cout << "Hello from your world.\n";
}
void World::displayBox(int x, int y, int z)
{
cout << "The value at (" << x << ", " << y << ", " << z << ") is: ";
boxes[x][y][z].display();
cout << endl;
}

//end of world.cpp

// check07b.cpp

#include <iostream>
using namespace std;

#include "voxel.h"
#include "world.h"

/**************************************************************
* Function: main
* Purpose: The driver for the program. Creates a world, sets
* some Voxels and displays them.
**************************************************************/
int main()
{
cout << "Starting Program.\n";

// First, we create a voxel for air
Voxel air(180, 200, 255, 'A');

// Next, we create a voxel for grass
Voxel grass(25, 255, 50, 'G');
// Declare a new World object. Make sure to use pointers and dynamic allocation.
World *world = new World();
// check if world object is created successfully
if(world != NULL)
{
   //Call the "display" method on your World object.
   world->display();
   //Call the setBox method on your World object to set air at position: (50, 60, 70).
   world->setBox(50,60,70,air);
   // Call the setBox method on your World object to set grass at position: (45, 20, 10).
   world->setBox(45,20,10,grass);
   // Call the displayBox method (on your World object) twice to diplay the two Voxels you just set.
   world->displayBox(50,60,70);
   world->displayBox(45,20,10);
   // Finally, make sure to free up the memory taken by your World object by deleting it.
   delete world;
}else
   cout<<"Unable to create object for World"<<endl;

cout << "Ending Program.\n";
return 0;
}

//end of check07b.cpp

Output: