C / C++ / MFC

9-May-02 21:29

After you check the case of some stuff there (struct name and function name), this code works as-is.

Measuring FPS

Coremn7-May-02 16:45

Coremn

7-May-02 16:45

Ok THis should be really easy, but as you all know frustration is the number one killer of compurter keyboards, so i've given up. Mad | :mad:

I have a loop that refreshes a OpenGl screen rendering contect.

What is the easiest and most reliable way to measure the the time taken to run through the loop I.E FPS. What time functions can I use to get the elapsed time in ms.
Thank you.

Paul M Watt7-May-02 16:54

Paul M Watt

7-May-02 16:54

The highest resolution timer that you can get is from a call to QueryPerformanceCounter. If you divide the result from this value by the result you get from QueryPerformanceFrequency, you will have a value in milliseconds.

Not all machines have access to a performance counter, therefore your next best choice is the multimedia counter. You can access this with a call to timeGetTime.

There is a really good timer function that is written inside of a set of DirectX utility classes in the SDK. It can be found in the samples/multimedia/Common/src folder and it is the dxutil.cpp file.
Also in the d3dutil.cpp file of the same directory there is some good code to generate the fps for a render sequence.

Good Luck!

Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!

Coremn7-May-02 18:41

Coremn

7-May-02 18:41

Thanks I am now using QueryPerformanceCounter
Works good. Max fps is 30 Smile | :)

Min 12

Mike Nordell9-May-02 21:33

9-May-02 21:33

kilowatt wrote:
Not all machines have access to a performance counter

Is this really true? I've heard it before, but I've actually never found a machine that lacks them.

What are they using? Why whouldn't they be available?

Please also note that the highest resolution "timer" you can get is the IA32 rdtsc instruction, though it's not strictly a "timer".

vijayaramaraju7-May-02 19:33

vijayaramaraju

7-May-02 19:33

you could also use the ZEN timer class which makes use of the timer chip on your motherboard.

you can take the code from Michael Abrash's Graphics Programming Black Book, Special Edition
or
Michael Abrash's Zen of Code Optimization

according to my knowledge thats as far as you can get since it is dependent on the clock frquency your hardware is using.

Best of luck.

Windows Media skins or Winamp skins on my SDI application!!!!

l a u r e n7-May-02 21:13

l a u r e n

7-May-02 21:13

vijayaramaraju wrote:
Michael Abrash's Graphics Programming Black Book, Special Edition
or
Michael Abrash's Zen of Code Optimization

both truly awesome books
Smile | :)

"... and so i said to him ... if it can't dance and you can't eat it either f**k it or throw it away"
8028finder.com

Kind7-May-02 16:16

Kind

7-May-02 16:16

I am currently working on the Window Media skins for my SDI application.
Skins can be Winamp skin also. Can someone advise me of this?
Confused | :confused:

Image constructor returns OutOfMemory status in GDI+

Softomatix7-May-02 15:59

Softomatix

7-May-02 15:59

Every time I try to create an image object with a JPEG file, i get OutOfMemory status. The documentation says that a constructor can throw this error for other reasons even though you may have plenty of free memory on your machine.
Anybody ran into this issue??

Thanks.

---
Softomatix
http://www.pardesiservices.com/Softomatix.asp

How to implement "Program Rollback"?

hex7-May-02 15:40

hex

7-May-02 15:40

hello,everyone:
help me . Is there anyone can tell me how to implement "Program Rollback"?
The key question is how to save the Program state at any time ,and how to restore the program state using C or C++. Cry | :((

Matt Gullett7-May-02 15:55

Matt Gullett

7-May-02 15:55

I think I understand what you are asking.

Program state is just a bunch of variables stored (most likely) in several places. Serialize them to a file with iostream or CArchive and then reverse the process. To some degree it depends on how exact you want the "rollback" to be. Do you want screen sizes, window positions, etc to be exactly the same? If this is the case then it will require some more work but it is basically the same process.

Typically in a MFC application you can use Document/View architecture. This can make "rollback" easy because all you have to do is serialize the data in your document class through a CArchive object (Serialize function).

In non MFC applications this can be accomplished with iostreams, standard FILE access, ado and any other way you want to accomplish it.

hex7-May-02 16:07

hex

7-May-02 16:07

thanks!
if i want to exactly save and restore the CPU registers' content in my C or C++ program ,when some error is detected ,then rollback to the previous saved CPU' state, how to do this?

Matt Gullett7-May-02 16:58

Matt Gullett

7-May-02 16:58

I am still not 100% sure what you are attempting to do, but I'll take a shot at it.

You can use inline assembler to access the register values directly. Simply put them in a memory location somewhere and put them back when you're done. I never was any good at assembler so I can't spit out any code quickly.

This probably isn't enough to restore your app to its previous state though as the other memory (not in registers) modified by the app would also need to be replaced. This includes stack and heap memory.

I don't think you can programmatically alter the stack in a safe way. You can overwrite the stack and possibly do what you want but I don't think its a good idea. The heap is a little bit easier, though. You would just need to implement your own memory allocators OR hook the windows ones. Either way, not a small task.

Niklas L8-May-02 1:28

Niklas L

8-May-02 1:28

I beleive what you're looking for is setjmp() and longjmp() defined in setjmp.h. These funstions will take a snapshot of your registers, and restore them when needed. They are well documented in MSDN with given examples.

KarstenK8-May-02 0:36

KarstenK

8-May-02 0:36

You must collect your Program state data and write it to a (temporary file). The name convention should allow changing (i.e. data1230-08052002.tmp") and write the name to the registry "Last state OK" key in your program section.;)

Mike Nordell9-May-02 21:34

Look at this horrible casting

9-May-02 21:34

There are just to many ways to do it to be able to liste them all.

Instead, I'll point you to the Memento pattern (from the GoF "Design Patterns").

NicholasCougar7-May-02 15:36

NicholasCougar

7-May-02 15:36

Hi,
Look at this nasty type casting. any one can help?

(AFX_PMSG)(AFX_PMSGW)(int (AFX_MSG_CALL CWnd::*)(LPCREEATESTRUCT))OnCreate

note:

typedef void (AFX_MSG_CALL CCmdTarget::*AFX_PMSG)(void);

These codes come from MessageMapping and Message Rounting.

Thank you.

Best regard.

I confess that I am a stubborn guy, but why not put things thoroughly, logically and systematically clean. One concrete prolem is worth a thousand unapplied abstractions.

Re: Look at this horrible casting

Tim Smith7-May-02 15:37

Tim Smith

7-May-02 15:37

What are you asking about?

But, in general you have to remember that the message map table just contains generic routine pointers. Thus, they have to be cast to the proper routine protocol when they are to be invoked.

Tim Smith

I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?

Re: Look at this horrible casting

NicholasCougar7-May-02 16:06

NicholasCougar

7-May-02 16:06

Can you explain the code for me in detail? I mean word by word.

Thank you.

Best regard.

I confess that I am a stubborn guy, but why not put things thoroughly, logically and systematically clean. One concrete prolem is worth a thousand unapplied abstractions.

Re: Look at this horrible casting

Mike Nordell9-May-02 21:40