I am trying to load a bitmap onto a backbuffer using LoadBitmap() and then blit the information on the backbuffer, to the primary buffer. However, It''s not working! When I compile, I get a blank screen! What am I doing wrong?! Here is the code:


#define WIN32_LEAN_AND_MEAN

//include important stuff
#include >windows.h< //brackets are inverted for HTML tag
#include >windowsx.h<
#include >mmsystem.h<
#include >memory.h<
#include >ddraw.h<

#include "bmpblit.h"


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

HWND window_handle = NULL;
HINSTANCE instance = NULL;

LPDIRECTDRAW lpdd = NULL;
LPDIRECTDRAW4 lpdd4 = NULL;
LPDIRECTDRAWSURFACE4 pbuff = NULL;
LPDIRECTDRAWSURFACE4 bbuff = NULL;
DDSURFACEDESC2 ddsd;
DDSCAPS2 ddscaps;


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


// 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

// 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 = "class";
winclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

// save hinstance in global
instance = hinstance;

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

// create the window
if (!(hwnd = CreateWindowEx(NULL, // extended style
"class", // class
"BlitBMP", // title
WS_POPUP / WS_VISIBLE,
0,0, // initial x,y
640,480, // initial width, height
NULL, // handle to parent 
NULL, // handle to menu
hinstance,// instance of this application
NULL))) // extra creation parms
return(0);


ShowCursor(FALSE);

// save main window handle
window_handle = hwnd;

// initialize game here
GameInit();

// 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
GameMain();

} // end while

// closedown game here
GameEnd();

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

} // end WinM

bool LoadBMP(LPDIRECTDRAWSURFACE4 surface, LPSTR filename, int bmpwidth, int bmpheight,
int surfacewidth, int surfaceheight)
{
HBITMAP hbm;
HDC imagedc;
HDC surfacedc;

hbm = (HBITMAP)LoadImage(NULL, filename, IMAGE_BITMAP, bmpwidth, 
bmpheight, LR_LOADFROMFILE/LR_CREATEDIBSECTION);

if(hbm == NULL)
return FALSE;

imagedc = CreateCompatibleDC(NULL);
SelectObject(imagedc, hbm);

if(FAILED(surface->GetDC(&surfacedc)))
return FALSE;


if(BitBlt(surfacedc, 0, 0, surfacewidth, surfaceheight, 
imagedc, 0, 0, SRCCOPY)== FALSE)
return FALSE;


if(surfacedc)
{
surface->ReleaseDC(surfacedc);
}
if(imagedc)
{
DeleteDC(imagedc);
}
if(hbm)
{
DeleteObject(hbm);
}
return TRUE;
}

int GameInit()
{
if(FAILED(DirectDrawCreate(NULL, &lpdd, NULL)))
return(0);

if(FAILED(lpdd->QueryInterface(IID_IDirectDraw4, 
(LPVOID *)&lpdd4)))
return(0);

if(FAILED(lpdd4->SetCooperativeLevel(window_handle, DDSCL_FULLSCREEN/
DDSCL_EXCLUSIVE/DDSCL_ALLOWREBOOT)))
return(0);

if(FAILED(lpdd4->SetDisplayMode(640, 480, 16, 0, 0)))
return(0);

memset(&ddsd, 0, sizeof(ddsd));
ddsd.dwSize = sizeof(ddsd);
ddsd.dwFlags = DDSD_CAPS/DDSD_BACKBUFFERCOUNT;
ddsd.dwBackBufferCount = 1;
ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE/
DDSCAPS_COMPLEX/
DDSCAPS_FLIP;

if(FAILED(lpdd4->CreateSurface(&ddsd, &pbuff, NULL)))
return(0);

ddsd.ddsCaps.dwCaps = DDSCAPS_BACKBUFFER;

if(FAILED(pbuff->GetAttachedSurface(&ddscaps, &bbuff)))
return(0);

LoadBMP(bbuff, "image.bmp", 640, 480, 640, 480);
}//end GameInit()

int GameMain()
{

if(KEYDOWN(VK_ESCAPE))
{
SendMessage(window_handle, WM_CLOSE, 0, 0);
}

RECT source;
RECT dest;

source.top =0;
source.left =0;
source.bottom =480;
source.right =640;

dest.top =0;
dest.left =0;
dest.bottom =480;
dest.right =640;

if(FAILED(pbuff->Blt(&dest, bbuff, 
&source, DDBLT_WAIT, NULL)))
return(0);


return(1);

}//end GameMain()

int GameEnd()
{
if(lpdd4)
{
lpdd4->Release();
lpdd4 = NULL;
}
if(pbuff)
{
pbuff->Release();
pbuff = NULL;
}
if(bbuff)
{
bbuff->Release();
bbuff = NULL;
}
return(1);
}

paulcoz

230

February 22, 2000 09:16 PM

Psychoprog you never give up do you?

I think you also need to load the bitmap''s palette with a DirectDraw util such as DDLoadPalette, then apply the palette to the appropriate buffer - correct me if this is wrong people I don''t use DirectX much.

You can find out how to do this in the DirectDraw samples in the DirectX SDK.

Paulcoz.

Melo

122

February 23, 2000 04:10 PM

He doesn't have a palette, 'cause his program works in 16bit col.

Edited by - Melo on 2/23/00 4:11:00 PM

lshadow

123

February 24, 2000 08:54 AM

Well you should probably clear the memory for the back buffer(ddsd), after you create the primary surface. Also you may want to check your return values from GameInit and GameMain(and return (1) from GameInit if all goes well). Also you should release the surfaces in reverse order. So release the back first, then the primary, and then the direct draw object.

At the moment that''s all I see. But if you check your return values and clear the ddsd before setting up the back buffer and everything is ok and you still have a problem, tell me!

Working on: DoP

PsYcHoPrOg

Author

115

February 24, 2000 09:04 AM

Okay, I changed the code a bit, and it still doesn''t work. I''ll give the functions here:


bool LoadBMP(LPDIRECTDRAWSURFACE4	surface, LPSTR filename)
{
	DDSURFACEDESC2		ddsd2;//to get the surface description
	DDSCAPS2			ddscaps2;//to get the surface Caps
	HBITMAP				hbm; //handle to the bitmap object
	HDC					imagedc; //Handle to the image dc
	HDC					surfacedc;//Handle to the surface dc

	//get the surface description
	if(FAILED(surface->GetSurfaceDesc(&ddsd2)))
		return FALSE;

	//get the surface caps
	if(FAILED(surface->GetCaps(&ddscaps2)))
		return FALSE;

	//load the bitmap into the handle of the object
	hbm = (HBITMAP)LoadImage(NULL, filename, IMAGE_BITMAP, 
							 ddsd2.dwWidth, ddsd2.dwHeight, 
							 LR_LOADFROMFILE/LR_CREATEDIBSECTION);

	//Check if the function worked
	if(hbm == NULL)
		return FALSE;

	//Put the object into the dc
	imagedc = CreateCompatibleDC(NULL);
	SelectObject(imagedc, hbm);

	//lock the surface
	if(FAILED(surface->GetDC(&surfacedc)))
		return FALSE;

	//blit the bitmap to the surface

	BitBlt(surfacedc, 0, 0, ddsd.dwWidth, ddsd.dwHeight, 
		   imagedc, 0, 0, SRCCOPY);

	//clean up everything

	if(surfacedc)
		surface->ReleaseDC(surfacedc);

	if(imagedc)
		DeleteDC(imagedc);

	if(hbm)
		DeleteObject(hbm);

}

int GameInit()
{
	if(FAILED(DirectDrawCreate(NULL, &lpdd, NULL)))
		return(0);
 
	if(FAILED(lpdd->QueryInterface(IID_IDirectDraw4, 
								  (LPVOID *)&lpdd4)))
		return(0);

	if(FAILED(lpdd4->SetCooperativeLevel(window_handle, DDSCL_FULLSCREEN/
										 DDSCL_EXCLUSIVE/DDSCL_ALLOWREBOOT)))
		return(0);

	if(FAILED(lpdd4->SetDisplayMode(640, 480, 16, 0, 0)))
		return(0);

	memset(&ddsd, 0, sizeof(ddsd));
	ddsd.dwSize = sizeof(ddsd);
	ddsd.dwFlags = DDSD_CAPS/DDSD_BACKBUFFERCOUNT;
	ddsd.dwBackBufferCount = 1;
	ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE/
						  DDSCAPS_COMPLEX/
						  DDSCAPS_FLIP;

	if(FAILED(lpdd4->CreateSurface(&ddsd, &pbuff, NULL)))
		return(0);

	ddsd.ddsCaps.dwCaps = DDSCAPS_BACKBUFFER;

	if(FAILED(pbuff->GetAttachedSurface(&ddscaps, &bbuff)))
		return(0);

	memset(&ddsd, 0, sizeof(ddsd));
	ddsd.dwSize = sizeof(ddsd);
	ddsd.dwFlags = DDSD_CAPS/DDSD_HEIGHT/DDSD_WIDTH;
	ddsd.dwWidth = 640;
	ddsd.dwHeight = 480;
	ddsd.ddsCaps.dwCaps = DDSCAPS_OFFSCREENPLAIN;

	if(FAILED(lpdd4->CreateSurface(&ddsd, &Bitmap, NULL)))
		return (0);

	LoadBMP(Bitmap, "image.bmp");
}//end GameInit()

int GameMain()
{

	if(KEYDOWN(VK_ESCAPE))
	{
		SendMessage(window_handle, WM_CLOSE, 0, 0);
	}
 
 
	if(FAILED(bbuff->BltFast(0, 0, Bitmap, NULL,
							 DDBLTFAST_WAIT)))
	return(0);

	if(FAILED(pbuff->Flip(NULL, DDFLIP_WAIT)))
	return(0);

 

	return(1);

}//end GameMain()

int GameEnd()
{
	if(lpdd4)
	{
		lpdd4->Release();
		lpdd4 = NULL;
	}
	if(pbuff)
	{
		pbuff->Release();
		pbuff = NULL;
	}
	if(bbuff)
	{
		bbuff->Release();
		bbuff = NULL;
	}
	return(1);
}

The problem is, when my program runs, I hear a tone and am forced to CTR-ALT-DEL out of it. After I do so, I see a little yellow arrow next to the line:


if(FAILED(BltFast(0, 0, Bitmap, DDBLTFAST_WAIT)))

and I also see a dialogue box that says:

classFirst-chance exception in Blitex.exe: 0xC0000005: Access Violation.

It also says this in the debug box at the bottom of the screen. I am using VC++ 6.0. Please help if you can. I really have no Idea what the problem is.

lshadow

123

February 24, 2000 01:38 PM

You still need to check the return value from:
LoadBmp(Bitmap,"image.bmp");

To make sure that the bitmap is loading.
If it is loading correctly, feel free to send me the code and I''ll be happy to figure it out for you.

Working on: DoP

frizb

122

February 24, 2000 10:58 PM

Also don''t forget to release the old lpdd after the call to Query Interface instead of letting it hang around until you''re done.

Still Learning...

Still Learning...

FalloutBoy

122

February 25, 2000 03:25 PM

Maybe you already know this, but have you tried taking some sample code that already works and changing little bits at a time until it does what you want it to do? That''s a helluva lot easier than trying to write the DirectX initialization from scratch.

Mike Weldon, a.k.a. FalloutBoymweldon@san.rr.com

PsYcHoPrOg

Author

115

February 26, 2000 10:15 AM

This is what I have been doing. However, I don''t know how to fix the error that I get from the debugger.

"Remember, I'm the monkey, and you're the cheese grater. So no fooling around."
-Grand Theft Auto, London

RMack

122

February 26, 2000 10:36 AM

[imagedc = CreateCompatibleDC(NULL);
SelectObject(imagedc, hbm);
if(FAILED(surface->GetDC(&surfacedc)))
return FALSE;

if(BitBlt(surfacedc, 0, 0, surfacewidth, surfaceheight,
imagedc, 0, 0, SRCCOPY)== FALSE)
return FALSE;
]

I think your problem is here (above). Call surface->GetDC() then create a Compatible DC from the DC surface->GetDC() returns, not from NULL.

- Ryan -

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