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1

SFML development / I created fast sin() / cos() which could replace slower std::sin()/cos()

« on: March 06, 2021, 09:00:39 pm »

Hi

I was thinking I might be able to provide some code to SFML ... possibly ... .
It's this: There are sin() and cos() functions at least in 3 modules:

Transformable.hpp
rotate.hpp
view.hpp

And there something like this:

float angle = m_rotation * 3.141592654f / 180.f;
float cosine = static_cast<float>(std::cos(angle));
float sine = static_cast<float>(std::sin(angle));
 

sin() and cos() are significantly slower than multiplication and division so I was thinking if I could find an approximation function which gives the same result/accuracy as sin/cos but is faster. Now I finished working on that and my function fastSin(float angle) is more than 80% faster than std::sin() (and I can do the same for cos()). The good thing is that it is basically as accurate as std::sin(). So calling for example std::sin(0.2866) and fastSin(0.2866) gives the same result, it is just > 80% faster (so about 2 times faster).
(actually in testing it was 82% -340%  faster depending on how many sin() calls in a row).

I know this is not super critical, as those functions with sin/cos (like the getTransform()) are not likely to be called hundreds of thousands of times per second. But if this is any useful I am ready to provide the code for it.

By the way, I studied mathematics in an university and actually my final thesis was just about this: approximating functions (like sin()) by polynomial functions.

Any thoughts?

2

Window / SFML with MFC - sf::RenderWindow resize/update issue

« on: March 02, 2021, 11:27:24 am »

I use SFML with MFC. I want to keep the ball I draw at the same position/size when resizing the window. I read that I have to use setView() to set the new view according to the new CView window size. I tried it but it did not work directly like instructed on the websites. Then I investigated and got it working with this version (all related code here):

// When I create the window I initialize SFML window in CView class:
sf::RenderWindow sfmlWindow(GetSafeHwnd());
// ...
// Then when I get a WM_SIZE windows message, I do this in its OnSize() handler:
sf::Event event;
while (sfmlWindow.pollEvent(event));
sf::FloatRect visibleArea(0, 0, sfmlWindow.getSize().x, sfmlWindow.getSize().y);
sf::View newView{ visibleArea };
sfmlWindow.setView(newView);
 

I am happy it finally works (took me long time to figure it out ), but... is this really how it should be done (the correct way)?

I have couple of questions:
1) Why do I need to poll all the events in order the RenderWindow to update its size? Also, I was thinking that should the RenderWindow automatically do this update when I resize the window - why it does not change its m_size variable automatically when I resize? sfmlWindow.getSize() will not get updated to the new size if I do not flush the events with the while loop above it. Because I did some reseach: If I do not do that while() loop to poll all the events, the RenderWindow m_size will not get updated to the new size, and I am guessing this is why the sf::view does not get the correct values for the newView.

2) If I always need to empty the sf event queue (like I do above), what is the correct way to do it and where/in which function(s)? Does this issue also occur with other events like mouse events? So if my MFC CView gets a mouse event do I have to first flush the SFML event queue in order the SFML to be in a correct state?

3

General / Error installing/compiling with VS2015 community

« on: January 17, 2016, 02:55:47 pm »

****** UPDATE: please note this problem seems to be due to VC++ problem which seems to be "broken" somehow on my machine currently, so this post can be ignored until I fix it ***********

SOLVED (VS SETTINGS ISSUE): IF YOU WANT TO KNOW THE REASON, ITS IN THE LAST POST.

********************************************************************************


Hello,
I followed the instructions from the SFML documentation to install SFML to my Visual Studio 2015 community but I keep getting these errors:

1>------ Build started: Project: SfmlConcoleTemp, Configuration: Debug x64 ------
1>  main.cpp
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\config.hpp(163): error C2061: syntax error: identifier 'sf'
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\config.hpp(163): error C2059: syntax error: ';'
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\config.hpp(164): error C2449: found '{' at file scope (missing function header?)
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\config.hpp(190): error C2059: syntax error: '}'
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\system\clock.hpp(35): error C2061: syntax error: identifier 'sf'
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\system\clock.hpp(35): error C2059: syntax error: ';'
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\system\clock.hpp(36): error C2449: found '{' at file scope (missing function header?)
1>e:\important\programming\c++\temp\sfmlconcoletemp\sfmlconcoletemp\include\sfml\system\clock.hpp(84): error C2059: syntax error: '}'
1>c:\program files (x86)\microsoft visual studio 14.0\vc\include\vcruntime.h(294): error C2146: syntax error: missing ')' before identifier '_StackCookie'
...

I put my SMFL folder to: H:\SFML   and then I also tried to put it on the same project where the project is but it does not help.

The project recognizes #include <SFML\Graphics.hpp> ... it does not give any red marks when I put it in main.cpp so the project can see  SFML\Graphics.hpp.

I have done it in couple of ways (I also followed the youtube instructions at watch?v=2JVpmWwMo0o ) but I get the same error. Is there some setting in VS2015 default project which are not compatible with SFML? I tried Windows version and console version but I get the same errors.

I downloaded SFML-2.3.2-windows-vc14-64-bit and have Windows 10 compiled with 64bit projects.

Does the binary SFML-2.3.2-windows-vc14-64-bit work out of the box or I have to compile it somehow?

Thank you.