//13.1 - The Random Color Program -Dirk Henkemans
#include <windows.h>
#include <cstdlib>
#include <ctime>
#include <ddraw.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT nMsg, WPARAM wParam,
							  LPARAM lParam);

LPDIRECTDRAW7 g_pdd; //the DirectDraw object
LPDIRECTDRAWSURFACE7 g_pddsprimary; //the primary surface
LPDIRECTDRAWSURFACE7 g_pddsback; //the back buffer
LPDIRECTDRAWSURFACE7 g_pddsone; //a temporary surface
DDSURFACEDESC2 ddsd; //used to store surface descriptions
DDSCAPS2 ddsc; //stores the capabilities of a surface
HRESULT hRet; //used to temporarily store the result of a function


int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPreInst,
				   LPSTR lpszCmdLine, int nCmdShow)
{
	HWND		hWnd;
	MSG			msg;
	WNDCLASSEX	wc;

	//fill the WNDCLASSEX structure with the appropriate values
	wc.cbSize = sizeof(WNDCLASSEX);
	wc.style = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc = WndProc;
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hInstance = hInst;
	wc.hIcon = LoadIcon(NULL, IDI_EXCLAMATION);
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wc.lpszMenuName = NULL;
	wc.lpszClassName = "RandomColor";
	wc.hIconSm = LoadIcon(NULL, IDI_EXCLAMATION);

	//register the new class
	RegisterClassEx(&wc);

	//create a window
	hWnd = CreateWindowEx(
		NULL,
		"RandomColor",
		"The Random Color Program",
		WS_VISIBLE,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		CW_USEDEFAULT,
		NULL,
		NULL,
		hInst,
		NULL
	);

	//event loop - handle all messages
	while(GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}

	//standard return value
	return (msg.wParam);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT nMsg, WPARAM wParam,
							  LPARAM lParam)
{
	
	//find out which message is being sent
	switch(nMsg)
	{
		case WM_CREATE:
			//create the timer (3 seconds)
			SetTimer(hWnd, 1, 3000, NULL);
			//create the DirectDraw object
			hRet = DirectDrawCreateEx(NULL, (void**)&g_pdd,IID_IDirectDraw7, NULL);
			if(hRet != DD_OK)
				MessageBox(hWnd, "DirectDrawCreateEx Failed", "Error", NULL);
			//Set the Cooperative Level
			hRet = g_pdd->SetCooperativeLevel(hWnd, DDSCL_FULLSCREEN | DDSCL_EXCLUSIVE);
			if(hRet != DD_OK)
				MessageBox(hWnd, "SetCooperativeLevel Failed", "Error", NULL);;
			//Set the display mode: 800x600 with 16 bits per pixel
			hRet = g_pdd->SetDisplayMode(800, 600, 16,0,0);
			if(hRet != DD_OK)
				MessageBox(hWnd, "SetDisplayMode Failed", "Error", NULL);;
			
			//prepare primary surface info
			ZeroMemory(&ddsd,sizeof(ddsd));
			ddsd.dwSize = sizeof(ddsd);
			ddsd.dwFlags = DDSD_CAPS | DDSD_BACKBUFFERCOUNT;
			ddsd.dwBackBufferCount = 1;
			ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE | DDSCAPS_FLIP | DDSCAPS_COMPLEX;
	
			//create the surface
			hRet = g_pdd->CreateSurface(&ddsd, &g_pddsprimary, NULL);
			if (hRet != DD_OK)
				MessageBox(hWnd, "CreateSurface Failed", "Error", NULL);
	
			//prepare the back buffer info
			ZeroMemory(&ddsc,sizeof(ddsc));
			ddsc.dwCaps = DDSCAPS_BACKBUFFER;
			
			//get a pointer to the back buffer
			hRet = g_pddsprimary->GetAttachedSurface(&ddsc,&g_pddsback);
			srand(time(0));
			break;
	
		case WM_TIMER: //when the timer goes off (only one)
			DDBLTFX ddbltfx;
			ZeroMemory(&ddbltfx,sizeof(ddbltfx));
			ddbltfx.dwSize = sizeof(ddbltfx);
			ddbltfx.dwFillColor = rand()%16;
			g_pddsback->Blt(NULL,NULL,NULL, DDBLT_COLORFILL, &ddbltfx);
			g_pddsprimary->Flip(NULL,0);
			break;

		case WM_DESTROY:
			//destroy the timer
			KillTimer(hWnd, 1);
			//end the program
			PostQuitMessage(0);
			break;
	
		default:
			//let Windows handle every other message
			return(DefWindowProc(hWnd, nMsg, wParam, lParam));
	}

	return 0;
}