// DEMO7_4.CPP 8-bit double buffering demo

// INCLUDES ///////////////////////////////////////////////

#define WIN32_LEAN_AND_MEAN  // just say no to MFC

#define INITGUID

#include <windows.h>   // include important windows stuff
#include <windowsx.h> 
#include <mmsystem.h>
#include <iostream.h> // include important C/C++ stuff
#include <conio.h>
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h> 
#include <math.h>
#include <io.h>
#include <fcntl.h>

#include <ddraw.h> // include directdraw

// DEFINES ////////////////////////////////////////////////

// defines for windows 
#define WINDOW_CLASS_NAME "WINCLASS1"

// default screen size
#define SCREEN_WIDTH    640  // size of screen
#define SCREEN_HEIGHT   480
#define SCREEN_BPP      8    // bits per pixel

// TYPES //////////////////////////////////////////////////////

// basic unsigned types
typedef unsigned short USHORT;
typedef unsigned short WORD;
typedef unsigned char  UCHAR;
typedef unsigned char  BYTE;

// MACROS /////////////////////////////////////////////////

#define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)
#define KEYUP(vk_code)   ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)


// initializes a direct draw struct
#define DDRAW_INIT_STRUCT(ddstruct) { memset(&ddstruct,0,sizeof(ddstruct)); ddstruct.dwSize=sizeof(ddstruct); }

// GLOBALS ////////////////////////////////////////////////
HWND      main_window_handle = NULL; // globally track main window
int       window_closed      = 0;    // tracks if window is closed
HINSTANCE hinstance_app      = NULL; // globally track hinstance

// directdraw stuff

LPDIRECTDRAW7         lpdd         = NULL;   // dd object
LPDIRECTDRAWSURFACE7  lpddsprimary = NULL;   // dd primary surface
LPDIRECTDRAWSURFACE7  lpddsback    = NULL;   // dd back surface
LPDIRECTDRAWPALETTE   lpddpal      = NULL;   // a pointer to the created dd palette
LPDIRECTDRAWCLIPPER   lpddclipper  = NULL;   // dd clipper
PALETTEENTRY          palette[256];          // color palette
PALETTEENTRY          save_palette[256];     // used to save palettes
DDSURFACEDESC2        ddsd;                  // a direct draw surface description struct
DDBLTFX               ddbltfx;               // used to fill
DDSCAPS2              ddscaps;               // a direct draw surface capabilities struct
HRESULT               ddrval;                // result back from dd calls
DWORD                 start_clock_count = 0; // used for timing

UCHAR                 *double_buffer = NULL;  // pointer to double buffer

char buffer[80];                             // general printing buffer

// FUNCTIONS //////////////////////////////////////////////

LRESULT CALLBACK WindowProc(HWND hwnd, 
						    UINT msg, 
                            WPARAM wparam, 
                            LPARAM lparam)
{
// this is the main message handler of the system
PAINTSTRUCT		ps;		// used in WM_PAINT
HDC				hdc;	// handle to a device context
char buffer[80];        // used to print strings

// what is the message 
switch(msg)
	{	
	case WM_CREATE: 
        {
		// do initialization stuff here
        // return success
		return(0);
		} break;
   
	case WM_PAINT: 
		{
		// simply validate the window 
   	    hdc = BeginPaint(hwnd,&ps);	 
        
        // end painting
        EndPaint(hwnd,&ps);

        // return success
		return(0);
   		} break;

	case WM_DESTROY: 
		{

		// kill the application, this sends a WM_QUIT message 
		PostQuitMessage(0);

        // return success
		return(0);
		} break;

	default:break;

    } // end switch

// process any messages that we didn't take care of 
return (DefWindowProc(hwnd, msg, wparam, lparam));

} // end WinProc

///////////////////////////////////////////////////////////

int Game_Main(void *parms = NULL, int num_parms = 0)
{
// this is the main loop of the game, do all your processing
// here

UCHAR *primary_buffer = NULL; // used as alias to primary surface buffer

// make sure this isn't executed again
if (window_closed)
   return(0);

// for now test if user is hitting ESC and send WM_CLOSE
if (KEYDOWN(VK_ESCAPE))
   {
   PostMessage(main_window_handle,WM_CLOSE,0,0);
   window_closed = 1;
   } // end if

// erase double buffer
memset((void *)double_buffer,0, SCREEN_WIDTH*SCREEN_HEIGHT);

// you would perform game logic...
       
// draw the next frame into the double buffer
// plot 5000 random pixels
for (int index=0; index < 5000; index++)
    {
    int   x   = rand()%SCREEN_WIDTH;
    int   y   = rand()%SCREEN_HEIGHT;
    UCHAR col = rand()%256;
    double_buffer[x+y*SCREEN_WIDTH] = col;
    } // end for index

// copy the double buffer into the primary buffer
DDRAW_INIT_STRUCT(ddsd);

// lock the primary surface
lpddsprimary->Lock(NULL,&ddsd, DDLOCK_SURFACEMEMORYPTR | DDLOCK_WAIT,NULL);

// get video pointer to primary surfce
primary_buffer = (UCHAR *)ddsd.lpSurface;       

// test if memory is linear
if (ddsd.lPitch == SCREEN_WIDTH)
   {
   // copy memory from double buffer to primary buffer
   memcpy((void *)primary_buffer, (void *)double_buffer, SCREEN_WIDTH*SCREEN_HEIGHT);
   } // end if
else
   { // non-linear

   // make copy of source and destination addresses
   UCHAR *dest_ptr = primary_buffer;
   UCHAR *src_ptr  = double_buffer;

   // memory is non-linear, copy line by line
   for (int y=0; y < SCREEN_HEIGHT; y++)
       {
       // copy line
       memcpy((void *)dest_ptr, (void *)src_ptr, SCREEN_WIDTH);

       // advance pointers to next line
       dest_ptr+=ddsd.lPitch;
       src_ptr +=SCREEN_WIDTH;

       // note: the above code code be replaced with the simpler
       // memcpy(&primary_buffer[y*ddsd.lPitch], double_buffer[y*SCREEN_WIDTH], SCREEN_WIDTH);
       // but it is much slower due to the recalculation and multiplication each cycle

       } // end for

   } // end else

// now unlock the primary surface
if (FAILED(lpddsprimary->Unlock(NULL)))
   return(0);

// wait a sec
Sleep(500);

// return success or failure or your own return code here
return(1);

} // end Game_Main

////////////////////////////////////////////////////////////

int Game_Init(void *parms = NULL, int num_parms = 0)
{
// this is called once after the initial window is created and
// before the main event loop is entered, do all your initialization
// here

// create IDirectDraw interface 7.0 object and test for error
if (FAILED(DirectDrawCreateEx(NULL, (void **)&lpdd, IID_IDirectDraw7, NULL)))
   return(0);

// set cooperation to full screen
if (FAILED(lpdd->SetCooperativeLevel(main_window_handle, 
                                      DDSCL_FULLSCREEN | DDSCL_ALLOWMODEX | 
                                      DDSCL_EXCLUSIVE | DDSCL_ALLOWREBOOT)))
   return(0);

// set display mode to 640x480x8
if (FAILED(lpdd->SetDisplayMode(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP,0,0)))
   return(0);

// clear ddsd and set size
DDRAW_INIT_STRUCT(ddsd); 

// enable valid fields
ddsd.dwFlags = DDSD_CAPS;

// request primary surface
ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;

// create the primary surface
if (FAILED(lpdd->CreateSurface(&ddsd, &lpddsprimary, NULL)))
   return(0);

// build up the palette data array
for (int color=1; color < 255; color++)
    {
    // fill with random RGB values
    palette[color].peRed   = rand()%256;
    palette[color].peGreen = rand()%256;
    palette[color].peBlue  = rand()%256;

    // set flags field to PC_NOCOLLAPSE
    palette[color].peFlags = PC_NOCOLLAPSE;
    } // end for color

// now fill in entry 0 and 255 with black and white
palette[0].peRed     = 0;
palette[0].peGreen   = 0;
palette[0].peBlue    = 0;
palette[0].peFlags   = PC_NOCOLLAPSE;

palette[255].peRed   = 255;
palette[255].peGreen = 255;
palette[255].peBlue  = 255;
palette[255].peFlags = PC_NOCOLLAPSE;

// create the palette object
if (FAILED(lpdd->CreatePalette(DDPCAPS_8BIT | DDPCAPS_ALLOW256 | 
                                DDPCAPS_INITIALIZE, 
                                palette,&lpddpal, NULL)))
return(0);

// finally attach the palette to the primary surface
if (FAILED(lpddsprimary->SetPalette(lpddpal)))
   return(0);

// allocate double buffer
if ((double_buffer=new UCHAR[SCREEN_WIDTH * SCREEN_HEIGHT])==NULL)
   return(0);

// return success or failure or your own return code here
return(1);

} // end Game_Init

/////////////////////////////////////////////////////////////

int Game_Shutdown(void *parms = NULL, int num_parms = 0)
{
// this is called after the game is exited and the main event
// loop while is exited, do all you cleanup and shutdown here


// first the palette
if (lpddpal)
   {
   lpddpal->Release();
   lpddpal = NULL;
   } // end if

// now the primary surface
if (lpddsprimary)
   {
   lpddsprimary->Release();
   lpddsprimary = NULL;
   } // end if

// now blow away the IDirectDraw4 interface
if (lpdd)
   {
   lpdd->Release();
   lpdd = NULL;
   } // end if

// release the memory used for double buffer
if (double_buffer)
   {
   delete double_buffer;
   double_buffer = NULL;
   } // end if

// return success or failure or your own return code here
return(1);

} // end Game_Shutdown

// WINMAIN ////////////////////////////////////////////////

int WINAPI WinMain(	HINSTANCE hinstance,
					HINSTANCE hprevinstance,
					LPSTR lpcmdline,
					int ncmdshow)
{

WNDCLASSEX winclass; // this will hold the class we create
HWND	   hwnd;	 // generic window handle
MSG		   msg;		 // generic message
HDC        hdc;      // graphics device context

// first fill in the window class stucture
winclass.cbSize         = sizeof(WNDCLASSEX);
winclass.style			= CS_DBLCLKS | CS_OWNDC | 
                          CS_HREDRAW | CS_VREDRAW;
winclass.lpfnWndProc	= WindowProc;
winclass.cbClsExtra		= 0;
winclass.cbWndExtra		= 0;
winclass.hInstance		= hinstance;
winclass.hIcon			= LoadIcon(NULL, IDI_APPLICATION);
winclass.hCursor		= LoadCursor(NULL, IDC_ARROW); 
winclass.hbrBackground	= (HBRUSH)GetStockObject(BLACK_BRUSH);
winclass.lpszMenuName	= NULL;
winclass.lpszClassName	= WINDOW_CLASS_NAME;
winclass.hIconSm        = LoadIcon(NULL, IDI_APPLICATION);

// save hinstance in global
hinstance_app = hinstance;

// register the window class
if (!RegisterClassEx(&winclass))
	return(0);

// create the window
if (!(hwnd = CreateWindowEx(NULL,                  // extended style
                            WINDOW_CLASS_NAME,     // class
						    "DirectDraw 8-Bit Double Buffering Demo", // title
						    WS_POPUP | WS_VISIBLE,
					 	    0,0,	  // initial x,y
						    SCREEN_WIDTH,SCREEN_HEIGHT,  // initial width, height
						    NULL,	  // handle to parent 
						    NULL,	  // handle to menu
						    hinstance,// instance of this application
						    NULL)))	// extra creation parms
return(0);

// save main window handle
main_window_handle = hwnd;

// initialize game here
Game_Init();

// enter main event loop
while(TRUE)
	{
    // test if there is a message in queue, if so get it
	if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
	   { 
	   // test if this is a quit
       if (msg.message == WM_QUIT)
           break;
	
	   // translate any accelerator keys
	   TranslateMessage(&msg);

	   // send the message to the window proc
	   DispatchMessage(&msg);
	   } // end if
    
       // main game processing goes here
       Game_Main();
       
	} // end while

// closedown game here
Game_Shutdown();

// return to Windows like this
return(msg.wParam);

} // end WinMain

///////////////////////////////////////////////////////////