the purpose is to learn the SDL libraries and build a pong game

In order to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:

install SDL libraries

I feel that this project will be tough and hope I am able to complete it by the end of the semester

I have commented my procedure in the code itself, see code section, I hope that was ok to do

Upon completion of the project, if there is an applicable collection of created code, place a copy of your finished code within <code> </code> blocks here.

 
//The headers
#include"SDL/SDL.h"
#include"SDL/SDL_image.h"
#include"SDL/SDL_ttf.h"
#include<string>
#include<stdio.h>
#include<math.h>
 
 
//The screen attributes
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
const int SCREEN_BPP = 32;
 
//The frame rate
const int FRAMES_PER_SECOND = 20;
 
//The dimensions of the ball
const int BALL_WIDTH = 35;
const int BALL_HEIGHT = 35;
 
//The dimensions of the paddles
const int PADDLE_WIDTH = 15;
const int PADDLE_HEIGHT = 85;
 
//The surfaces
SDL_Surface *ball = NULL;
SDL_Surface *background = NULL;
SDL_Surface *screen = NULL;
SDL_Surface *paddleL = NULL;
SDL_Surface *paddleR = NULL;
 
//The event structure
SDL_Event event;
 
//The font
TTF_Font *font = NULL;
 
//The color of the font
SDL_Color textColor = { 255, 255, 255 };
 
//The left paddle that will move
class PaddleL
{
    private:
 
         //The velocity of left paddle
        int xVel, yVel;
 
    public:       
        //Initializes the variables for left paddle
        PaddleL();
        SDL_Rect boxL;     
        //Takes key presses and adjusts left paddle's velocity
        void handle_input();
 
        //Moves left paddle
        void move();
 
        //Shows left paddle on the screen
        void show();
};
 
//The right paddle that will move
class PaddleR
{
    private:
 
        //The velocity of right paddle
        int xVel, yVel;
 
    public:
 
        //Initializes the variables for right paddle
        PaddleR();
        SDL_Rect boxR;   
        //Takes key presses and adjusts right paddle's velocity
        void handle_input();
 
        //Moves right paddle
        void move();
 
        //Shows right paddle on the screen
        void show();
};
 
//The ball that will move around the screen
class Ball
{
    public:
        //Initializes the variables
        Ball();
        SDL_Rect collbox;
        int xVel, yVel;
 
        //Resets ball to center of screen
        void reset();
 
        //Takes key presses and adjusts the ball's velocity
        void handle_input();
 
        //Moves the ball
        void move();
 
        //Shows the ball on the screen
        void show();
};
 
//The timer
class Timer
{
    private:
        //The clock time when the timer started
        int startTicks;
 
        //The ticks stored when the timer was paused
        int pausedTicks;
 
        //The timer status
        bool paused;
        bool started;
 
    public:
        //Initializes variables
        Timer();
 
        //The various clock actions
        void start();
        void stop();
        void pause();
        void unpause();
 
        //Gets the timer's time
        int get_ticks();
 
        //Checks the status of the timer
        bool is_started();
        bool is_paused();
};
 
SDL_Surface *load_image( std::string filename )
{
    //The image that's loaded
    SDL_Surface* loadedImage = NULL;
 
    //The optimized surface that will be used
    SDL_Surface* optimizedImage = NULL;
 
    //Load the image
    loadedImage = IMG_Load(filename.c_str());
 
    //If the image loaded
    if(loadedImage != NULL)
    {
        //Create an optimized surface
        optimizedImage = SDL_DisplayFormat(loadedImage);
 
        //Free the old surface
        SDL_FreeSurface(loadedImage);
 
        //If the surface was optimized
        if(optimizedImage != NULL)
        {
            //Map the color key
            Uint32 colorkey = SDL_MapRGB( optimizedImage->format, 255, 255, 255);
 
            //Set all pixels of color R 255, G 255, B 255 (white) to be transparent
            SDL_SetColorKey( optimizedImage, SDL_SRCCOLORKEY, colorkey );
        }
    }
 
    //Return the optimized surface
    return optimizedImage;
}
 
void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination, SDL_Rect* clip = NULL)
{
    //Holds offsets
    SDL_Rect offset;
 
    //Get offsets
    offset.x = x;
    offset.y = y;
 
    //Blit
    SDL_BlitSurface(source, clip, destination, &offset);
}
 
bool check_collision( SDL_Rect A, SDL_Rect B)
{
    //The sides of the rectangles
    int leftA, leftB;
    int rightA, rightB;
    int topA, topB;
    int bottomA, bottomB;
 
    //Calculate the sides of rect A and rect B
    leftA = A.x;
    rightA = A.x + A.w;
    topA = A.y;
    bottomA = A.y + A.h;
 
    leftB = B.x;
    rightB = B.x + B.w;
    topB = B.y;
    bottomB = B.y + B.h;
 
    //If any of the sides from A are outside of B
    if( bottomA <= topB)
    {
        return false;
    }
 
    if( topA >= bottomB )
    {
        return false;
    }
 
    if( rightA<=leftB)
    {
        return false;
    }
 
    if( leftA>=rightB)
    {
        return false;
    }
 
    //If none of the sides from A are outside B
    return true;
}
 
bool init()
{
    //Initialize all SDL subsystems
    if(SDL_Init( SDL_INIT_EVERYTHING ) == -1)
    {
        return false;
    }
 
    //Set up the screen
    screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE); 
 
    //If there was an error in setting up the screen
    if(screen == NULL)
    {
        return false;
    }
 
    //Initialize SDL_ttf
    if( TTF_Init() == -1 )
    {
        return false;
    }
 
    //Set the window caption
    SDL_WM_SetCaption("Hit space bar to begin", NULL);
 
    //If everything initialized fine
    return true;
}
 
bool load_files()
{
    //Load the images
    ball = load_image("tennisBall.bmp");
    background = load_image("Background.bmp");
    paddleL = load_image("paddleRed.bmp");
    paddleR = load_image("paddleBlue.bmp");
 
    //Open the font
    font = TTF_OpenFont("lazy.ttf", 89);
 
    //If there was a problem in loading the font
    if(font == NULL)
    {
        return false;
    }
 
    //If there was a problem loading the ball
    if(ball == NULL)
    {
        return false;
    }
 
    //If there was a problem in loading the background
    if(background == NULL)
    {
        return false;
    }
 
    //If there was a problem in loading a paddle
    if(paddleL == NULL || paddleR == NULL)
    {
        return false;
    }
 
    //If everything loaded fine
    return true;
}
 
void clean_up()
{
    //Free the surfaces
    SDL_FreeSurface(ball);
    SDL_FreeSurface(background);
    SDL_FreeSurface(paddleL);
    SDL_FreeSurface(paddleR);
 
    //Close the font
    TTF_CloseFont(font);
 
    //Quit SDL_ttf
    TTF_Quit();
 
    //Quit SDL
    SDL_Quit();
}
 
PaddleL::PaddleL()
{
    //Initialize the offsets
    boxL.x = 0;
    boxL.y = SCREEN_HEIGHT/2 - PADDLE_HEIGHT/2;
 
    //Set the collision box's dimensions
    boxL.w = PADDLE_WIDTH;
    boxL.h = PADDLE_HEIGHT;
 
    //Initialize the velocity
    xVel = 0;
    yVel = 0;
}
 
PaddleR::PaddleR()
{
    //Initialize the offsets
    boxR.x = 625;
    boxR.y = SCREEN_HEIGHT/2 - PADDLE_HEIGHT/2;
 
    //Set the collision box's dimensions
    boxR.w = PADDLE_WIDTH;
    boxR.h = PADDLE_HEIGHT;
 
    //Initialize the velocity
    xVel = 0;
    yVel = 0;
}
 
void PaddleL::handle_input()
{
    //If a key was pressed 
    if( event.type == SDL_KEYDOWN )
    {
        //Adjust the velocity
        switch( event.key.keysym.sym )
        {
            case SDLK_a: yVel -= PADDLE_HEIGHT/9; break;
            case SDLK_z: yVel += PADDLE_HEIGHT/9; break;
        }
    }
    //If a key was released
    else if( event.type == SDL_KEYUP )
    {
        //Adjust the velocity
        switch( event.key.keysym.sym )
        {
            case SDLK_a: yVel += PADDLE_HEIGHT/9; break;
            case SDLK_z: yVel -= PADDLE_HEIGHT/9; break;
        }
    }
}
 
void PaddleR::handle_input()
{
    //If a key was pressed 
    if( event.type == SDL_KEYDOWN )
    {
        //Adjust the velocity
        switch( event.key.keysym.sym )
        {
            case SDLK_UP: yVel -= PADDLE_HEIGHT/9; break;
            case SDLK_DOWN: yVel += PADDLE_HEIGHT/9; break;
        }
    }
    //If a key was released
    else if( event.type == SDL_KEYUP )
    {
        //Adjust the velocity
        switch( event.key.keysym.sym )
        {
            case SDLK_UP: yVel += PADDLE_HEIGHT/9; break;
            case SDLK_DOWN: yVel -= PADDLE_HEIGHT/9; break;
        }
    }
}
 
void PaddleL::move()
{
    //Move the paddle up or down
    boxL.y += 2*yVel;
 
    //If the paddle went to far up or down
    if( (boxL.y<0) || (boxL.y + PADDLE_HEIGHT > SCREEN_HEIGHT) )
    {
        //Move back
        boxL.y -= 2*yVel;
    }
}
 
void PaddleR::move()
{
    //Move the paddle up or down
    boxR.y += 2*yVel;
 
    //If the paddle went to far up or down
    if( (boxR.y<0) || (boxR.y + PADDLE_HEIGHT > SCREEN_HEIGHT) )
    {
        //Move back
        boxR.y -= 2*yVel;
    }
}
 
void PaddleL::show()
{
    //Show the Paddle
    apply_surface(boxL.x, boxL.y, paddleL, screen);
}
 
void PaddleR::show()
{
    //Show the Paddle
    apply_surface(boxR.x, boxR.y, paddleR, screen);
}
 
Ball::Ball()
{
    //Initialize the offsets
    collbox.x = SCREEN_WIDTH/2 - BALL_WIDTH/2;
    collbox.y = SCREEN_HEIGHT/2 - BALL_HEIGHT/2;
 
    //Set the square's dimensions
    collbox.w = BALL_WIDTH - 5;
    collbox.h = BALL_HEIGHT - 5;
 
    //Initialize the velocity
    xVel = 0;
    yVel = 0;
}
 
void Ball::reset()
{
    //Reset the offsets
    collbox.x = SCREEN_WIDTH/2 - BALL_WIDTH/2;
    collbox.y = SCREEN_HEIGHT/2 - BALL_HEIGHT/2;
 
    //Reset the velocity
    xVel = 0;
    yVel = 0;
}
 
void Ball::handle_input()
{
    int lORr; //To determine if the ball starts going left or right
 
    //If a key was pressed 
    if( event.type == SDL_KEYDOWN )
    {
        //Assign random initial velocity
        if( event.key.keysym.sym == SDLK_SPACE )
        {
            lORr = rand()%2;
            if(lORr == 0){            
                xVel = rand()%5+10;
                yVel = rand()%15;
            }
            if(lORr == 1){
                xVel = (rand()%5+10*-1);
                yVel = (rand()%15)*-1;
            }                
        }
    }
}
 
void Ball::move()
{
    //Move the ball left or right
    collbox.x += xVel;
 
    //Move the ball up or down
    collbox.y += yVel;
 
    //If the ball went to far up or down
    if( (collbox.y<0) || (collbox.y + BALL_HEIGHT > SCREEN_HEIGHT) ) 
    {
        //Move back
        yVel = -1*yVel;
    }
}
 
void Ball::show()
{
    //Show the ball
    apply_surface(collbox.x, collbox.y, ball, screen);
}
 
Timer::Timer()
{
    //Initialize the variables
    startTicks = 0;
    pausedTicks = 0;
    paused = false;
    started = false;
}
 
void Timer::start()
{
    //Start the timer
    started = true;
 
    //Unpause the timer
    paused = false;
 
    //Get the current clock time
    startTicks = SDL_GetTicks();
}
 
void Timer::stop()
{
    //Stop the timer
    started = false;
 
    //Unpause the timer
    paused = false;
}
 
void Timer::pause()
{
    //If the timer is running and isn't already paused
    if( (started == true) && (paused == false) )
    {
        //Pause the timer
        paused == true;
 
        //Calculate the paused ticks
        pausedTicks = SDL_GetTicks() - startTicks;
    }
}
 
void Timer::unpause()
{
    //If the timer is paused
    if(paused == true)
    {
        //Unpause the timer
        paused = false;
 
        //Reset the starting ticks
        startTicks = SDL_GetTicks() - pausedTicks;
 
        //Reset the paused ticks
        pausedTicks = 0;
    }
}
 
int Timer::get_ticks()
{
    //If the timer is running
    if(started == true)
    {
        //If the timer is paused
        if(paused == true)
        {
            //Return the number of ticks when the timer was paused
            return pausedTicks;
        }
        else
        {
            //Return the current time minus the start time
            return SDL_GetTicks() - startTicks;
        }
    }
 
    //If the timer isn't running
    return 0;
}
 
bool Timer::is_started()
{
    return started;
}
 
bool Timer::is_paused()
{
    return paused;
}
 
int main( int argc, char* args[] )
{
    //The surface for the winning message
    SDL_Surface *message = NULL;
 
    //Quit flag
    bool quit = false;
 
    //The ball that will be used
    Ball myBall;
 
    //The paddles that will be used
    PaddleL paddleL;
    PaddleR paddleR;
 
    //The frame rate regulator
    Timer fps;
 
    //Initialize
    if(init() == false)
    {
        return 1;
    }
 
    //Load the files
    if(load_files() == false)
    {
        return 1;
    }
 
 
 
    //While the user hasn't quit
    while( quit == false )
    {
        //Start the frame timer
        fps.start();
 
        //While there's events to handle
        while( SDL_PollEvent(&event) )
        {
            //Handle events for the ball
            myBall.handle_input();
 
            //Handle events for the paddles
            paddleL.handle_input();
            paddleR.handle_input();
 
            //If the user has Xed the window
            if (event.type == SDL_QUIT)
            {
                //Quit the program
                quit = true;
            }
        }
 
        //Move the ball
        myBall.move();
 
        //If the ball hits left paddle
        if(check_collision(myBall.collbox, paddleL.boxL) == true )
        {   
            //Bounce ball back
            myBall.xVel = rand()%30+15;
            //Bounce ball back
 
	    if( myBall.yVel == 0 ) {
		 myBall.yVel = 1 ;
	    }
 
		myBall.yVel = (myBall.yVel/(abs(myBall.yVel)?myBall.yVel:1) )*rand()%20;
 
        }
 
        //If the ball hits right paddle
        if((check_collision(myBall.collbox, paddleR.boxR) == true) )
        {   
             //Bounce ball back
            myBall.xVel = (rand()%30+15)*-1;
 
	    if( myBall.yVel == 0 ) {
		 myBall.yVel = 1 ;
	    }
 
 
	    myBall.yVel = (myBall.yVel/(abs(myBall.yVel)?myBall.yVel:1) )*rand()%20;
 
        }
 
        //Move the paddles
        paddleL.move();
        paddleR.move();
 
        //Apply the background to the screen
        apply_surface(0, 0, background, screen);
 
        //Show the ball on the screen
        myBall.show();
 
        //If the ball goes off the left side of the screen
        if( (myBall.collbox.x + BALL_WIDTH) < 0)
        {
            //Print a message saying left paddle wins
            message = TTF_RenderText_Solid(font, "SCORE BITCH!!", textColor);
 
            //If a message needs to be displayed
            if( message != NULL )
            {
                //Apply the background to the screen
                apply_surface( 0, 0, background, screen );
 
                //Apply the message centered on the screen
                apply_surface( ( SCREEN_WIDTH - message->w ) / 2, ( SCREEN_HEIGHT - message->h ) / 2, message, screen );
 
                //Null the surface pointer
                message = NULL;
            }
 
            //If space bar is hit then reset the ball
            if( event.key.keysym.sym == SDLK_SPACE )
            {
                myBall.reset();
            }           
        }
 
        //If the ball goes off the right side of the screen
        if( myBall.collbox.x > SCREEN_WIDTH)
        {
            //Print a message saying left paddle wins
            message = TTF_RenderText_Solid(font, "SCORE BITCH!!", textColor);
 
            //If a message needs to be displayed
            if( message != NULL )
            {
                //Apply the background to the screen
                apply_surface( 0, 0, background, screen );
 
                //Apply the message centered on the screen
                apply_surface( ( SCREEN_WIDTH - message->w ) / 2, ( SCREEN_HEIGHT - message->h ) / 2, message, screen );
 
                //Null the surface pointer
                message = NULL;
            } 
 
            //If space bar is hit then reset the ball
            if( event.key.keysym.sym == SDLK_SPACE )
            {
                myBall.reset();
            }           
        }
 
        //Show the paddles on the screen
        paddleL.show();
        paddleR.show();
 
        //Update the screen
        if( SDL_Flip( screen ) == -1 )
        {
            return 1;
        }
 
        //Cap the frame rate
        if(fps.get_ticks() < 1000 / FRAMES_PER_SECOND)
        {
            SDL_Delay( (1000/ FRAMES_PER_SECOND) - fps.get_ticks() );
        }
    }
 
    //Clean up
    clean_up();
 
    return 0;
}
 
 

Again, if there is associated code with the project, and you haven't already indicated how to run it, provide a sample run of your code:

lab46:~/src/$ g++ -o pong cong2.cpp -lSDL -lSDL_image -lSDL_ttf

lab46:~/src/$  ./pong

This project was really stressing and frustrating at first but after a while I really started to catch on and it was pretty fun!

In performing this project, the following resources were referenced:

• http://www.lazyfoo.net/SDL_tutorials/
• http://www.cplusplus.com/forum/
• http://www.dreamincode.net/forums/forum/15-c-and-c/
• lair help from matt and other, thanks!!!