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user:mwitter3:portfolio:sysprogproject1 [2013/04/26 13:57] – [Prerequisites] mwitter3user:mwitter3:portfolio:sysprogproject1 [2013/11/20 13:45] (current) – [Code] mwitter3
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 +======Project: Tutorials for making pong======
  
 +A project for systems programming by Matt Witter during the Spring 2013 semester.
 +
 +This project was begun on January 23 and is anticipated to take most of the spring semester. You can find most of the tutorials I did in my systemprog folder.
 +
 +=====Objectives=====
 +This wasn't originally suppose to be a project but it turned in to one when I ran out of time to make another game. The point of this project is to work up to making pong. The tutorials will help build up the ideas or concepts that we need to make a game.
 +
 +=====Prerequisites=====
 +In order to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:
 +
 +  * http://www.lazyfoo.net
 +
 +=====Background=====
 +State the idea or purpose of the project. What are you attempting to pursue? I'm attempting to get through tutorials 1-18 and then move on to making pong. I got through the tutorials but I didnt get very far in pong.
 +=====Scope=====
 +Well this wasn't really meant to be a project but once it got close I kind of turned it into one. I just went through the tutorials until I got to 18 and attempted pong. I didn't get very far in pong mostly because I had about a week left and I was trying to get it but I had to catch up on some of Joe's stuff.
 +
 +
 +
 +=====Procedure=====
 +The procedure was just going through the tutorials on lazyfoo.net
 +
 +=====Code=====
 +Here's one of the final tutorials for lazyfoo.net. It is one of the final collision detection tutorials either 17 or 18
 +
 +<code c>
 +#include "SDL/SDL.h"
 +#include "SDL/SDL_image.h"
 +#include <string>
 +
 +//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 dimenions of the square
 +const int SQUARE_HEIGHT = 20;
 +const int SQUARE_WIDTH = 20;
 +
 +//the surfaces
 +SDL_Surface *square = NULL;
 +SDL_Surface *screen = NULL;
 +
 +//the event structure
 +SDL_Event event;
 +
 +//the wall
 +SDL_Rect wall;
 +
 +//the square
 +class Square
 +{
 + private:
 + //the coolision box of the square
 + SDL_Rect box;
 +
 + //the velocity of the square
 + int xVel, yVel;
 +
 + public:
 + //initalizes the variables
 + Square():
 +
 + //take key presses and adjusts the squares velocity
 + void handle_input();
 +
 + //moves the square
 + void move();
 +
 + //shows the square on the screen
 + void show();
 +};
 +
 +//timer class
 +class Timer
 +{
 + private:
 + //the clocks 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:
 + //initalized the variables
 + Timer();
 +
 + //the various clock actions
 + void start();
 + void stop();
 + void pause();
 + void unpause();
 +
 + //gets the timers time
 + int get_ticks();
 +
 + //checks that status of the timer
 + bool is_started;
 + bool is_paused;
 +};
 +
 +SDL_Surface *load_image(std::string filename)
 +{
 + //the image thats loaded
 + SDL_Surface* loadedImage = NULL;
 +
 + //the optimized surface taht will be used
 + SDL_Surface* optimizedImage = NULL;
 +
 + //load the image
 + loadedImage = IMG_Load(filename.c_str());
 +
 + //if the image loaded
 + if(loadedImage != NULL)
 + {
 + //create the optmized surface
 + optimizedImage = SDL_DisplayFormat(loadedImage);
 +
 + //free the old surface
 + SDL_FreeSurface(loadedImage);
 +
 + //if the surface was optimized
 + if(optimizedImage != NULL)
 + {
 + //color key surface
 + SDL_SetColorKey(optimizedImage, SDL_SRCCOLORKEY, SDL_MapRGB( optimizedImage->format, 0, 0xFF, 0xFF));
 + }
 + }
 +
 + //return the optimized surface
 + return optimizedImage;
 +}
 +
 +void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination, SD:_Rect* clip = NULL)
 +{
 + //holds offsets
 + SDL_Rect offset;
 +
 + //get offsets
 + offset.x = x;
 + offset.y = y;
 +
 + //blit
 + SDL_BlitSurface(source, clip, destination, &offset);
 +}
 +
 +bool init()
 +{
 + //initalize 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;
 + }
 +
 + //set the window caption
 + SDL_WM_SetCaption("move square", NULL);
 +
 + //if everything initialized fine
 + return true;
 +}
 +
 +bool load_files()
 +{
 + //load the background image
 + square = load_image("square.bmp");
 +
 + //if there was a problem loading image
 + if(square == NULL)
 + {
 + return false;
 + }
 +
 + //if everything loaded fine
 + return true;
 +}
 +
 +void clean_up()
 +{
 + //free the surface
 + SDL_FreeSurface(square);
 +
 + //quit SDL
 + SDL_Quit();
 +}
 +
 +//the square
 +class Square
 +{
 + private:
 + //the collision box of the square
 + SDL_Rect box;
 +
 + //the velocity of the square
 + int xVel, yVel;
 +
 + public:
 + //initalize the variables
 + square();
 +
 + //takes key presses and adjusts the squares velocity
 + void handle_input();
 +
 + //moves the square
 + void move();
 +
 + //shows the square on the screen
 + void show();
 +};
 +
 +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
 + leftA = A.x;
 + rightA = A.x + A.w;
 + topA = A.y;
 + bottomA = A.y + A.h;
 +
 + //calculate the sides of rect B
 + 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 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;
 +}
 +
 +Square::Square()
 +{
 + //initialize the offsets
 + box.x = 0;
 + box.y = 0;
 +
 + //set the squares dimensions
 + box.w = SQUARE_WIDTH;
 + box.h = SQUARE_HEIGHT;
 +
 + //initialize the velocity
 + xVel = 0;
 + yVel = 0;
 +}
 +
 +void Square::move()
 +{
 + //move the square left or right
 + box.x += xVel;
 +
 + //if the square went too far to the left or right or has collided with the wall
 + if((box.x < 0) || (box.x + SQUARE_WIDTH > SCREEN_WIDTH ) || (check_collision(box, wall)))
 + {
 + //move back
 + box.x -= xVel;
 + }
 +
 + //move the square up or down
 + box.y += yVel;
 +
 + //if the square went too far up or down or has collided with the wall
 + if((box.y < 0) || (box.y + SQUARE-HEIGHT > SCREEN_HEIGHT) || (check_collision(box, wall)))
 + {
 + //move back
 + box.y -= yVel;
 + }
 +}
 +
 +void Square::handle_input()
 +{
 +    //If a key was pressed
 +    if( event.type == SDL_KEYDOWN )
 +    {
 +        //Adjust the velocity
 +        switch( event.key.keysym.sym )
 +        {
 +            case SDLK_UP: yVel -= SQUARE_HEIGHT / 2; break;
 +            case SDLK_DOWN: yVel += SQUARE_HEIGHT / 2; break;
 +            case SDLK_LEFT: xVel -= SQUARE_WIDTH / 2; break;
 +            case SDLK_RIGHT: xVel += SQUARE_WIDTH / 2; break;
 +        }
 +    }
 +    //If a key was released
 +    else if( event.type == SDL_KEYUP )
 +    {
 +        //Adjust the velocity
 +        switch( event.key.keysym.sym )
 +        {
 +            case SDLK_UP: yVel += SQUARE_HEIGHT / 2; break;
 +            case SDLK_DOWN: yVel -= SQUARE_HEIGHT / 2; break;
 +            case SDLK_LEFT: xVel += SQUARE_WIDTH / 2; break;
 +            case SDLK_RIGHT: xVel -= SQUARE_WIDTH / 2; break;
 +        }
 +    }
 +}
 +
 +void Square::show()
 +{
 +    //Show the square
 +    apply_surface( box.x, box.y, square, 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[] )
 +{
 +    //Quit flag
 +    bool quit = false;
 +
 +    //The square
 +    Square mySquare;
 +
 +    //The frame rate regulator
 +    Timer fps;
 +
 +    //Initialize
 +    if( init() == false )
 +    {
 +        return 1;
 +    }
 +
 +    //Load the files
 +    if( load_files() == false )
 +    {
 +        return 1;
 +    }
 +
 +    //Set the wall
 +    wall.x = 300;
 +    wall.y = 40;
 +    wall.w = 40;
 +    wall.h = 400;
 +
 +    //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 square
 +            mySquare.handle_input();
 +
 +            //If the user has Xed out the window
 +            if( event.type == SDL_QUIT )
 +            {
 +                //Quit the program
 +                quit = true;
 +            }
 +        }
 +
 +        //Move the square
 +        mySquare.move();
 +
 +        //Fill the screen white
 +        SDL_FillRect( screen, &screen->clip_rect, SDL_MapRGB( screen->format, 0xFF, 0xFF, 0xFF ) );
 +
 +        //Show the wall
 +        SDL_FillRect( screen, &wall, SDL_MapRGB( screen->format, 0x77, 0x77, 0x77 ) );
 +
 +        //Show the square on the screen
 +        mySquare.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;
 +
 +</code>
 +
 +=====Execution=====
 +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:
 +
 +<cli>
 +lab46:~/src/cprog$ ./collision
 +lab46:~/src/cprog$ 
 +</cli>
 +=====Reflection=====
 +Comments/thoughts generated through performing the project, observations made, analysis rendered, conclusions wrought. What did you learn from doing this project? I mostly learned that making little games has a lot more to it than I thought before doing this. Pong is a pretty hard game to make.
 +
 +=====References=====
 +In performing this project, the following resources were referenced:
 +
 +  * www.lazyfoo.net