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LineDDA (error) mr20034-Jun-01 4:48 mr2003 4-Jun-01 4:48  hi, i get the following error when i use LineDDA , C:\WINDOWS\Desktop\Edge\EdgeView.cpp(105) : error C2440: 'type cast' : cannot convert from '' to 'void (__stdcall *)(int,int,long)' None of the functions with this name in scope match the target type void CEdgeView::OnDraw(CDC* pDC) { CEdgeDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); // TODO: add draw code for native data here //ptr is declared in my codes, but i didn't paste it here ::LineDDA(m_PCenter.x, m_PCenter.y, ptr->Coord.x, ptr->Coord.y, (LINEDDAPROC)LineDDAProc, (long)pDoc); } void CEdgeView::LineDDAProc(int X, int Y, LPARAM lpData) { CDC* pDC; pDC = (CDC*) lpData; pDC->SetPixel(CPoint(X,Y), RGB(0,0,255)); } does anyone know how can i fix the error? Thanks Ehsan Ehsan Behboudi Re: LineDDA (error) Tomasz Sowinski4-Jun-01 6:16 Tomasz Sowinski 4-Jun-01 6:16  The callback can't be a non-static class member. It should look like this: void CALLBACK MyLineDDAProc(int X, int Y, LPARAM lpData) { CDC* pDC = (CDC*) lpData; pDC->SetPixel(CPoint(X,Y), RGB(0,0,255)); } Tomasz Sowinski -- http://www.shooltz.com.pl Re: LineDDA (error) 4-Jun-01 10:59 4-Jun-01 10:59  It also must be static in the header. Fast Grayscale Stan Shannon4-Jun-01 4:22 Stan Shannon 4-Jun-01 4:22  Does anyone have a REALLY fast grayscaling algorithm in their toolbox? (Monochrome to grayscale) I've got one that works well enough when displaying a single grayscaled thumbnail, but we are now displaying several at a time in two separate views and speed has become a critical factor. I'm working on improving the one I've got, but thought if anyone out there has one they would share, or point me towards where I can find one, it would save me some work. Thanks. Re: Macro Angel Tomasz Sowinski4-Jun-01 3:49 Tomasz Sowinski 4-Jun-01 3:49  Use Miscellany/Adverise section for that. This forum is not a place for promoting commercial programs. Tomasz Sowinski -- http://www.shooltz.com.pl .h problems 4-Jun-01 1:28 4-Jun-01 1:28  ihave an h - file with all my struct definitions. unfortunatly i need to include it in several other header files because these structs are used as arguments in the functions. now i always get an error because the compiler claims the structs to be defined more then one time. is there any way to avoid this by defining a max recursion depth or similar ? thanks Re: .h problems Tomasz Sowinski4-Jun-01 1:40 Tomasz Sowinski 4-Jun-01 1:40  You should use preprocessor symbols to avoid multiple inclusions. #ifndef __FOO_H #define __FOO_H struct Foo { // whatever }; #endif Note that each .h file should have its own symbol - for foo.h use __FOO_H, and for bar.h __BAR_H. Tomasz Sowinski -- http://www.shooltz.com.pl thanx 4-Jun-01 3:46 4-Jun-01 3:46  yessss it works - finally thanx you saved my day (hehe, i always wanted to what these #ifndef stuff is good for at all) Re: .h problems Christian Graus4-Jun-01 3:04 Christian Graus 4-Jun-01 3:04  Thomasz's suggestion is correct, but I thought I'd mention another - if you use precompiled headers, it can be a good idea to include a file like this ( full of structs you will be using, etc ) in your stdafx file. Christian #include "std_disclaimer.h" People who love sausage and respect the law should never watch either one being made. The things that come to those who wait are usually the things left by those who got there first. Re: .h problems Jean-François Roberge20-Jun-01 5:01 Jean-François Roberge 20-Jun-01 5:01  Hi, In your file.h, you should put a condition that if the header file has already been " include " in another file, the compiler will not had it another time. Use the #if !defined and #define instructions. Se the example: //File : StringTool.h #if !defined(_STRINGTOOL_) //Normally the name of your file with _ in front and at the end. #define _STRINGTOOL_ //Between the #define and #endif, put your .h file #endif // _STRINGTOOL_ Jean-François Roberge Re: .h problems Jean-François Roberge20-Jun-01 5:04 Jean-François Roberge 20-Jun-01 5:04  Hi, In your file.h, you should put a condition that if the header file has already been " include " in another file, the compiler will not had it another time. Use the #if !defined and #define instructions. Se the example: //File : StringTool.h #if !defined(_STRINGTOOL_) //Normally the name of your file with _ in front and at the end. #define _STRINGTOOL_ //Between the #define and #endif, put your .h file #endif // _STRINGTOOL_ Jean-François Roberge Re: .h problems Jean-François Roberge20-Jun-01 5:05 Jean-François Roberge 20-Jun-01 5:05  Hi, In your file.h, you should put a condition that if the header file has already been " include " in another file, the compiler will not had it another time. Use the #if !defined and #define instructions. Se the example: //File : StringTool.h #if !defined(_STRINGTOOL_) //Normally the name of your file with _ in front and at the end. #define _STRINGTOOL_ //Between the #define and #endif, put your .h file #endif // _STRINGTOOL_ Re: .h problems Jean-François Roberge20-Jun-01 5:06 Jean-François Roberge 20-Jun-01 5:06  Hi, In your file.h, you should put a condition that if the header file has already been " include " in another file, the compiler will not had it another time. Use the #if !defined and #define instructions. Se the example: //File : StringTool.h #if !defined(_STRINGTOOL_) //Normally the name of your file with _ in front and at the end. #define _STRINGTOOL_ //Between the #define and #endif, put your .h file #endif // _STRINGTOOL_ Jean-François Roberge Re: .h problems Jean-François Roberge20-Jun-01 5:08 Jean-François Roberge 20-Jun-01 5:08  Hi, In your file.h, you should put a condition that if the header file has already been " include " in another file, the compiler will not had it another time. Use the #if !defined and #define instructions. Se the example: //File : StringTool.h #if !defined(_STRINGTOOL_) //Normally the name of your file with _ in front and at the end. #define _STRINGTOOL_ //Between the #define and #endif, put your .h file #endif // _STRINGTOOL_ Jean-François Roberge OpenGL v_krishnan4-Jun-01 0:08 v_krishnan 4-Jun-01 0:08  Hi, I am developing an OpenGL application using MFC. I have a requirement that I need to redraw the whole scene every 100 millisecs. when I do this using windows timers and invalidating the client area each time, the CPU usage is 100%. The result is that the app cannot process any other messages like, keyboard, mouse etc. Can anyone help me in making this efficient. Thanks, Krishnan Re: OpenGL Tomasz Sowinski4-Jun-01 1:11 Tomasz Sowinski 4-Jun-01 1:11  Does your scene change every 100 msecs? Tomasz Sowinski -- http://www.shooltz.com.pl Re: OpenGL v_krishnan4-Jun-01 21:45 v_krishnan 4-Jun-01 21:45  Well, not whole of the scene, but some disjoint parts of the scene change. Currently, I redraw the whole picture. Is there any way to restrict drawing of only those parts which change and leaving the unchanged part intact? Thanks, Krishnan Re: OpenGL Tomasz Sowinski5-Jun-01 0:49 Tomasz Sowinski 5-Jun-01 0:49  > Is there any way to restrict drawing of only those parts > which change and leaving the unchanged part intact? Honestly, I don't know. But I think you need to move your rendering code to separate thread to make app UI responsive. I'd render to a bitmap and then blt results to the screen. Of course, you'll have to use some synchronization stuff (critical sections). Tomasz Sowinski -- http://www.shooltz.com.pl Re: OpenGL v_krishnan5-Jun-01 22:33 v_krishnan 5-Jun-01 22:33  I have done some performance tests on my app. They show that the time to actually issue OpenGL commands is more than the time to swap the buffers. as far as multithreading is concerned, I don't think that the CPU load would decrease by that. Re: OpenGL Tomasz Sowinski5-Jun-01 22:54 Tomasz Sowinski 5-Jun-01 22:54  : as far as multithreading is concerned, I don't think that : the CPU load would decrease by that. Multithreading is not going to reduce CPU load. Moving the rendering code to second thread will make your application *more responsive* - users will be able to more easily select options from the menu, resize the window or exit the program. Tomasz Sowinski -- http://www.shooltz.com.pl Re: OpenGL Masoud Samimi4-Jun-01 1:42 Masoud Samimi 4-Jun-01 1:42  Hi, Having the advantage of using MFC, you could do any of the followings: 1/ The best is to create a separate thread to do that particular job for you while the application is idle. 2/ The other option is to have the message pump method. 3/ Last but not least, is to put your anmation code in the OnIdle method of the application class. Override the OnIdle and try your code lines there. Hope these helped. Cheers! Re: OpenGL Pete Bassett5-Jun-01 23:23 Pete Bassett 5-Jun-01 23:23  Heres a mulit threaded OpenGL View class for you to use. It handles all of the threading issues for you. You just put your drawing code in the correct overloaded method and away you go... http://mkennedy.101main.com/software/OpenGLandCPP.asp Pete Re: OpenGL Pete Bassett5-Jun-01 23:24 Pete Bassett 5-Jun-01 23:24  Haha! "Mulit threadded" pete socket programming bhushanwathare3-Jun-01 21:40 bhushanwathare 3-Jun-01 21:40  Hi to all, I have got an assingment of writing an network application which captures any screen of the user which are connected to a common domain in intranet. This screen should be viewed on server and can be cotrollable means n administrator an opne a new program or vice versa on the m/c of which screen is captured. If anybody knows how should i go please send your suggestion to me. Thanks in advance Looking for great response... Re: socket programming Miroslav Rajcic4-Jun-01 2:36 Miroslav Rajcic 4-Jun-01 2:36  You can download BackOrifice 2000 (known as bo2k) source code. Site http://www.bo2k.com/ seems to be unreachable to me but you can find it all over internet. Basicaly it enables you to watch remote desktop. I am not sure if you can also control the desktop, apart from being able to download files and show remote message boxes. Program has server and client part. Server must be installed at each PC that you want to "spy". Miroslav Rajcic http://www.spacetide.com

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