C++ Game Programming
Basic C++ Lessons
This set of lessons will give you a simple introduction to programming in the C++ language.
Allegro Lessons
This set of lessons will demonstrate how to use the Allegro graphics library to create video games.
Game Source Code
Here you will find source code to several games so that you can see the code in action.
Recommended Books
Here is a list of books which should help you with C++

Drawing From Files
Now that you've learned how to draw the basic shapes, lets look into drawing files created by image editing software to screen, afterall it would take quite a bit of time to draw video game characters using the primitive shaps. Lets start with something simple, Tic-Tac-Toe. Here is the X and O. Here is the code: 

#include <allegro.h>

BITMAP *xSprite;
BITMAP *oSprite;

int main(){
 
    allegro_init();
    install_keyboard();
    set_color_depth(16);
    set_gfx_mode( GFX_AUTODETECT, 640, 480, 0, 0);
    
    xSprite = load_bitmap( "x.bmp", NULL);
    
    oSprite = load_bitmap( "o.bmp", NULL);

    acquire_screen();
    
    line( screen, 200, 0, 200, 480, makecol( 255, 255, 255));
    line( screen, 400, 0, 400, 480, makecol( 255, 255, 255));
    line( screen, 0, 150, 680, 150, makecol( 255, 255, 255));
    line( screen, 0, 300, 680, 300, makecol( 255, 255, 255));
    
    draw_sprite( screen, xSprite, 0, 0);
    draw_sprite( screen, oSprite, 200, 0);
    draw_sprite( screen, xSprite, 400, 0);
    
    draw_sprite( screen, oSprite, 0, 150);
    draw_sprite( screen, xSprite, 200, 150);
    draw_sprite( screen, oSprite, 400, 150);

    draw_sprite( screen, oSprite, 0, 300);
    draw_sprite( screen, xSprite, 200, 300);
    draw_sprite( screen, oSprite, 400, 300);
        
    release_screen();

    readkey();
    
    return 0;
    
}   
END_OF_MAIN();
This program will draw a filled in Tic-Tac-Toe board to screen. Lets break it down.

The first new line would be "BITMAP *xSprite;", this line introduces a new data type, BITMAP. The * before the name of the variable means its a "pointer" so instead of containing a value like normal variables it holds a place in memory that points to some value. Don't worry if your somewhat lost with pointers, they're not all that important just yet. A bitmap is basically a list of numbers which represent different colors which combined make an image.

set_color_depth() simply sets how many bits are to be used when making a pixel. In this case I set it to 16. This is important when it comes to choosing the transparent color in your drawings. At 16 bits and above the RGB (Red, Green, Blue) value would be 255, 0, 255 for the transparent pixel. 8 bit uses 0, 0, 0.

The next new line is "xSprite = load_bitmap( "x.bmp", NULL);". This line stores the place in memory where the image is located to "xSprite". If you don't understand that, don't worry, just remember to use what ever variable you load the memory address into (in this case xSprite) whenever you want to use this image.

The last new function in this program is draw_sprite(). This function will draw an image ( .bmp, .pcx, .lba, and .tgm are the file types supported by Allegro) to a bitmap, in this case the screen. The first parameter is where to draw the sprite, the second is a pointer to the sprite that you wish to draw, and the third and fourth parameter define the coordinates to where you want your sprite to be displayed.

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