DirectX Blues

["Neil" <dreaded.neil@phreaker.net>]

I'm having a few problems with my DirectX program. I was wondering if
someone could please help me with a few questions:
1. How do I check Windows messages to see when the program becomes avtive
(i.e. not minimized). I've read "just look for the WM_ACTIVATE message, so
I tried toggling a "BOOL Active" every time I get that message, but it
doesn't seem to work.
2. Can I safely assume that the screen's pitch as stored in the surface
descreption after locking a surface will remain constant? I.e. Can I get it
once and save it, or do I have to check it every frame?
3. How do I align my page-flips with the monitor's refresh? Is this done
automatically? Can I continue calculating something else while I wait?
4. Why does the following code not work? I'm using page-flipping, but the
screen is still flashing psychedellically and exhibiting massive tearing. I
can see pixels I've drawn over as semi-transparent just as though I were
writing directly to the screen even though I'm pretty sure I'm not; I know
I'm not trying to.

<errant code snippet, language = C>
inline void DrawScreen(BOOL Active, game_t *Game, trig_t *Trig, vec2_it
ScreenSize, int ScreenBits, LPDIRECTDRAW lpdd, LPDIRECTDRAWSURFACE
*lpddsPrimary, LPDIRECTDRAWSURFACE *lpddsBack, DDSURFACEDESC *ddsdBack) {
	HRESULT hResult; //for checking return value
	byte *ScreenBuffer; //pointer to back buffer
	int ScreenPitch; //stores the memory difference between vertical pixels

	if(Active) { //not minimized or otherwise hidden (Cant get this to do
anything or even work, how can I tell when my program is minimized /
fullscreen?)
		if(SUCCEEDED(hResult = IDirectDrawSurface_Lock(*lpddsBack, NULL,
ddsdBack, DDLOCK_SURFACEMEMORYPTR | DDLOCK_WAIT, NULL))) { //optain pointer
to back video memory
			ScreenBuffer = ddsdBack->lpSurface; //assign the back buffer memory
location to ScreenBuffer
			ScreenPitch = ddsdBack->lPitch; //take out of loop? This won't change,
will it?
			memset(ScreenBuffer, 0, ScreenPitch * ScreenSize.y * ScreenBits);
//clear the screen (DELETE THIS LATER)
			GameDraw(Game, Trig, ScreenBuffer, ScreenSize, ScreenPitch); //call the
function that draws to the screen
			IDirectDrawSurface_Unlock(*lpddsBack, ddsdBack->lpSurface); //release
the pointer to video memory
			//IDirectDraw_WaitForVerticalBlank(lpdd, DDWAITVB_BLOCKBEGIN, NULL);
//wait for monitor retrace (Doesn't seem to do anything but slow the
program down?)
			IDirectDrawSurface_Flip(*lpddsPrimary, NULL, DDFLIP_WAIT); //flip pages
		}
		else if(hResult == DDERR_SURFACELOST) { //if the surface memory was lost
(i.e. while inactive)
			IDirectDrawSurface_Restore(*lpddsPrimary); //try to restore it for next
time (todo: if this works, do the graphics (there is now a blank frame
after re-activation)
		}
	}
}
</code snippet>

-- Neil Edelman
-- ICQ UIN: 705130
-- email: mailto:dreaded.neil@phreaker.net?subject=sig
-- home: http://members.xoom.com/dreadedneil
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-- "My air-to-air missile overrides your air traffic control clearance"
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