[Solved] Loading Images Inside a Thread

[workmad3]

If you really want to, create an invisible view and draw your images to it right after loading them to force them into OGL

[deps]

That's one way to do it.
I don't think I would need such a function anyway. Was just trying to think ahead a little.

[Laurent]

If you really want to, create an invisible view and draw your images to it right after loading them to force them into OGL

Calling Bind() would be enough

[workmad3]

If you really want to, create an invisible view and draw your images to it right after loading them to force them into OGL

Calling Bind() would be enough

Give me a break... I haven't actually looked beyond class names in the 2d api so far I may look into it some more if I ever get beyond my action system in SFML

[lzr]

Awesome, so I should expect everything to work upon the next release of SFML. And to think, I was about to change the loading code. Great work guys, my game is all finished. Hopefully the next version will come out soon so I can put it online. Is the new thread friendly image loading code in the SVN already?

[Laurent]

It's not on SVN yet, I first have to complete another major modification. But it should be done in a few days.

I'm also thinking about releasing version 1.3 soon.

[lzr]

I didn't see it in the Release log of SFML 1.3. Was this feature left out? I did program my own version that works, but it would great if it was in the official release.

[Laurent]

It's only a little internal optimization which doesn't have any impact on the public interface, that's why it's not in the change log. But it's done, you can now load an image inside a thread

[dewyatt]

This is a little old but..

I've read all of this but I'm still wondering if it's possible to load images in a thread and draw something indicating progress (like an sf::String with percent).
I think laurent said it isn't really possible.
But is it not possible even with a mutex?

Sorry, I'm new to multi-threading for the most part.
And could anyone provide a tiny bit of sample code for loading images in a thread?

[dewyatt]

Okay, I answered my own question.
I'll post the code in a sec in case it helps someone else.

[dewyatt]

Okay, I put it on the wiki.

Here's the source:
http://www.sfml-dev.org/wiki/en/sources/loadimagesinthread.cpp

Here's a little tutorial (sort of):
http://www.sfml-dev.org/wiki/en/tutorials/loadimagesinthread

[Laurent]

Nice, thanks

[dewyatt]

I'm happy to contribute.  

Updated the tutorial and code.
Also added a download.

[dabo]

great addition, thanks.

[opatut]

It's time to revive this thread...

I am currently trying to implement the same as mentioned above: a loading screen and a thread loading the images in background. My current problem is a segfault I get when loading an Image (sf::Image::LoadFromFile) from the thread into a boost::ptr_map.

GDB outputs the following:

Code: [Select]

#0  0x00007ffff4d08669 in glGetIntegerv () from /usr/lib/libGL.so.1
#1  0x00007ffff794cd83 in sf::Image::GetMaximumSize() ()
    from /usr/lib/libsfml-graphics.so.2.0
#2  0x00007ffff794ce38 in sf::Image::CreateTexture() ()
    from /usr/lib/libsfml-graphics.so.2.0
#3  0x00007ffff794d544 in sf::Image::LoadFromFile(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
    from /usr/lib/libsfml-graphics.so.2.0
#4 ...


This seems to be an OpenGL context error.
Did you change anything about loading images in different threads in SFML 2, Laurent? Or is it just my fault?

/edit: I try to do all this without a Mutex as it is not my intention to lock any thread. I just want them to run simultaneously. In the main thread I poll every tick whether the loading thread has finished, so I can continue my program. I do not need the synchronicity provided by a mutex and I want to avoid a deadlock.