g08-01.cpp

游戏开发数据结构Data Structures for Game Programmers

// ============================================================================
// G08-01.cpp
// Storing Resources Using Hash Tables
// ============================================================================
#include "SDLGUI.h"
#include "HashTable.h"
#include <stdlib.h>
#include <string.h>


// ============================================================================
//  Global Constants
// ============================================================================
const char PROGRAM_NAME[]   = "Game Demo 08-01: Resource Demo";
const int WIDTH             = 800;
const int HEIGHT            = 600;
const int ITEMS             = 32;
const int ARIAL             = 0;


// ============================================================================
//  Classes
// ============================================================================
class String
{
public:
    char m_string[64];

    // empty constructor
    String() 
    {
        strcpy( m_string, "" );    
    }

    // copy-string constructor
    String( char* p_string )
    {
        strcpy( m_string, p_string );
    }

    // == operator
    bool operator== ( String& p_right )
    {
        return !strcmp( m_string, p_right.m_string);
    }
};


// ============================================================================
//  String Hasher
// ============================================================================
unsigned long int StringHash( String p_string )
{
    unsigned long int hash = 0;
    int i;
    int length = strlen( p_string.m_string );
    for( i = 0; i < length; i++ )
    {
        hash += ( (i + 1) * p_string.m_string[i] );
    }
    return hash;
}


// ============================================================================
//  Global Variables
// ============================================================================
SDLGUI* g_gui;

// The Resource hash table:
HashTable< String, SDL_Surface* > g_table( 7, StringHash );

char g_name[16] = "";

SDL_Surface* g_resource = 0;


// ============================================================================
//  Functions
// ============================================================================
void Find()
{
    // create a string with the contents of the textbox.
    String str( g_name );

    // create a hash entry.
    HashEntry< String, SDL_Surface* >* entry;

    // search for the resource
    entry = g_table.Find( str );

    if( entry != 0 )
        g_resource = entry->m_data;
    else
        g_resource = 0;
}


int main( int argc, char* argv[] )
{
    // declare coordinates.
    int x, y;

    // declare event holder
    SDL_Event event;

    // set our at exit function
    atexit( SDL_Quit );

    //initialize systems
    SDL_Init( SDL_INIT_VIDEO | SDL_INIT_TIMER );
    TTF_Init();

    SDL_EnableUNICODE( true );

    
    // create the GUI and set the caption.
    g_gui = new SDLGUI( WIDTH, HEIGHT, ITEMS, WHITE );
    SDL_WM_SetCaption( PROGRAM_NAME, 0); 
    g_gui->SetFont( "arial.ttf", ARIAL, 20, TTF_STYLE_NORMAL );


    // add the resources to the hash table.
    g_resource = SDL_LoadBMP( "sky.bmp" );
    g_table.Insert( "sky", g_resource );

    g_resource = SDL_LoadBMP( "water.bmp" );
    g_table.Insert( "water", g_resource );

    g_resource = SDL_LoadBMP( "fire.bmp" );
    g_table.Insert( "fire", g_resource );

    g_resource = SDL_LoadBMP( "water2.bmp" );
    g_table.Insert( "water2", g_resource );

    g_resource = SDL_LoadBMP( "snow.bmp" );
    g_table.Insert( "snow", g_resource );

    g_resource = SDL_LoadBMP( "vortex.bmp" );
    g_table.Insert( "vortex", g_resource );

    g_resource = SDL_LoadBMP( "stone.bmp" );
    g_table.Insert( "stone", g_resource );

    // clear the resource pointer.
    g_resource = 0;


    // add a text box, and set the focus.
    g_gui->AddTextBox( 0, 0, 128, TTF_FontHeight( g_gui->GetFont(ARIAL)),
                       g_name, 15, ARIAL, BLACK, WHITE, true, Find );
    g_gui->SetFocus( 0 );



    // main message loop.
    while( 1 )
    {
        //look for an event
        if( SDL_PollEvent( &event ) )
        {
            //an event was found
            if( event.type == SDL_QUIT ) 
                break;
            if( event.type == SDL_MOUSEBUTTONDOWN ) 
            {
                // get the mouse state.
                SDL_GetMouseState( &x, &y );

                // tell the GUI that a button has been pressed
                g_gui->MouseDown( x, y );
            }
            if( event.type == SDL_MOUSEBUTTONUP ) 
            {
                // get the mouse state.
                SDL_GetMouseState( &x, &y );

                // tell the GUI that a button has been released
                g_gui->MouseUp( x, y );
            }
            if( event.type == SDL_KEYDOWN )
            {
                // a key was pressed.
                if( event.key.keysym.sym == SDLK_ESCAPE )
                {
                    // if ESC was pressed, quit the program.
                    SDL_Event quit;
                    quit.type = SDL_QUIT;
                    SDL_PushEvent( &quit );
                }


                // tell the GUI that a key was pressed.
                g_gui->KeyDown( event.key.keysym.sym, 
                                event.key.keysym.mod,
                                event.key.keysym.unicode );
            }
        }   // end event loop.


        // tell the GUI to redraw itself
        g_gui->Draw();

        if( g_resource != 0 )
            g_gui->Blit( g_resource, 188, 44 );

        // tell the GUI to update itself
        g_gui->Update();

    }
  
    // done
    return 0;
}