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odd exception errors in D3D9

Started by jollyjeffers Feb 2, 2003 at 8:18 PM 2 replies 450+ views

Original Post

Feb 2, 2003 at 8:18 PM

hi, I''m having a rather odd problem with DirectX9 / C++.Net - I keep getting an exception from a piece of code and I cant find out how/why! I''ve done my utmost best to debug it - but even VStudio.Net isn''t being that helpful - the exception ("user breakpoint") breaks straight to dissasembly and the call stack just has the current (error) line and a previous line in dissasembly... I cant work out which line in my actual source code generates the error. However, by commenting out diff. lines I can find out roughly whats wrong. So I stick it in a try...catch block (to stop the unhandled exception), and it''s still thrown!! I dont get that! Here''s my code:

  try {
		LPRECT x = new RECT;
		x->top = 5;
		x->left = 5;
		x->bottom = 20;
		x->right = 200;
		char *pMsg = "blah";
		//pMsg = new char;

		//if (fCurrFPS < 10)

		//	fCurrFPS = -3.14159;

		//sprintf( pMsg, "Current Frame Rate: %d", (int)fCurrFPS );

		lpFont->DrawTextA(pMsg,-1, x, DT_TOP|DT_LEFT, D3DCOLOR_XRGB(255,0,0) );
		//delete pMsg;

	} catch ( ... ) {
		MessageBox(NULL, "EXCEPTION CAUGHT!!!!","Error",MB_OK);
	}

Basically, I''m trying to get D3D9 to draw some text to the screen including the frame rate info. i specifically DONT want to use the SDK frameworks, hence I''m using my own code drawing text works fine - the fonts exist okay, I can replace param-1 in the DrawTextA() line above with "Hello" and it''ll print just fine. any hints!?! cheers Jack

jollyjeffers

Feb 2, 2003 at 8:24 PM

oh, one more thing...

the unknown exception doesn''t appear for a good 20-30 seconds into execution!

which means the above code has to tick-over 1500+ times before it causes an error!

Jack

DrunkenHyena

Feb 2, 2003 at 11:10 PM

There are some issues with your code, but they''re C++ issues, not DirectX ones.

You dynamically allocate a RECT each time through your loop, but never seem to free it. Eventually it will fail and you''ll be dereferencing random memory.

Similarly the pMsg code that''s commented out, dynamically allocates a single char, then copies a long string over top (which trashes memory since your buffer is 1 char long).

At the top of your function, declare this:
RECT x;
char pMsg[80];

Then in your code:

x.top = 5;
x.left = 5;
x.bottom = 20;
x.right = 200;
sprintf( &pMsg, "Current Frame Rate: %d", (int)fCurrFPS);
lpFont->DrawTextA(&pMsg,-1, &x, DT_TOP|DT_LEFT, D3DCOLOR_XRGB(255,0,0) );

Stay Casual,

Ken
Drunken Hyena

jollyjeffers

Feb 3, 2003 at 11:24 AM

cheers, thought it might be something like that... it just really stumped me WHY i couldn''t trace the error

any ideas on that?

the final code I had to use was:


RECT rcText;
char *pMsg = new char[100];

rcText.top = 5;
rcText.left = 5;
rcText.bottom = 20;
rcText.right = 200;

sprintf( pMsg, "Current Frame Rate: %d", (int)fCurrFPS );
lpFont->Begin();
	lpFont->DrawTextA(pMsg,-1, &rcText, DT_TOP|DT_LEFT, D3DCOLOR_XRGB(255,0,0));
lpFont->End();
delete pMsg;

slightly different, but your code gave clashes with sprintf().

Jack

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