Topics

1

General / sf::Text Won't Render After glBindVertexArray()

« on: November 22, 2015, 10:26:08 pm »

Hi there!

This is a question that probably has a really simple answer, as to what I've been reading it has to do with SFML having it's own VBO, VAO, or whatever it is, and I need to use the corresponding glDelete function with it, but I've tried a few different ways with no success.

The way my code is now, the text renders for a second and then goes blank the second that glBindVertexArray(VertexArrayID); is called.

Here is the relevant code:

void AMEngine::Render()
{
        MainWindow->pushGLStates();
        MainWindow->draw(sText);
        MainWindow->popGLStates();

       
        Shader::setShader(&shader, &transform);
       
        GLuint VertexArrayID;
        glGenVertexArrays(1, &VertexArrayID);
        glBindVertexArray(VertexArrayID);
        static const GLfloat g_vertex_buffer_data[] = {
                  - 1.0f, -1.0f, 0.0f,
                    1.0f, -1.0f, 0.0f,
                    0.0f, 1.0f, 0.0f,
                };
       
        // This will identify our vertex buffer
        GLuint vertexbuffer;
        // Generate 1 buffer, put the resulting identifier in vertexbuffer
        glGenBuffers(1, &vertexbuffer);
        // The following commands will talk about our 'vertexbuffer' buffer
        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
        // Give our vertices to OpenGL.
        glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
        glEnableVertexAttribArray(0);
        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
        glVertexAttribPointer(
                0,
                3,
                GL_FLOAT,
                GL_FALSE,
                0,
                (void*)0
                );
       
        glDrawArrays(GL_TRIANGLES, 0, 3);
        glDisableVertexAttribArray(0);
        glDeleteVertexArrays(1, &VertexArrayID);
       
}

Again I'm probably missing something simple as understanding what's going on is very difficult for me, so I apologize if it's simple.

2

Network / How Mature is the Network Module?

« on: November 02, 2015, 01:38:26 am »

This is really a general question. But basically I'm working on learning the fundamentals of a game engine implemented with SFML (purely to learn) and I wanted to know SFML's versatility with networking. Do you recommend using SFML's network module exclusively, or is there another more mature networking library that's lightweight and verbose?

I've only really experimented with networking a few times with a couple of different libraries, and it's not something I know a lot about, but I'm much more confident with it after working on a multiplayer game for some time now. Basically I'm looking for something that's both simple to work with yet expandable. SFML has exceeded my expectations with that, but I wanted to get some input from somebody who's worked with it.

3

General / Threads To Take Screenshots Seamlessly?

« on: October 30, 2015, 11:00:06 am »

Hi there! I'd been looking at a tutorial to make a simple screenshot function, and it had suggested to use threads so game performance wasn't impacted. Currently I'm using the C++11 threads. I was having a terrible time trying to get this to work, but found that you have to disable the OpenGL context when dealing with a window in another thread with the RenderWindow's setActive().

The problem with this, at least as I understand it, I have to wait for the function\thread to be done so I can set the window active again and therefore I suffer from the 1-2 second pause of taking a screenshot that I was trying to avoid because the capture() is slow (according to the SFML wiki)

Is there any way around this?

To give you an idea of what I have:

void AMEngine::ScreenCapture()
{
        sf::Image screenshot = MainWindow->capture();

        time_t epoch_time;
        struct tm tm_p;
        errno_t err;
        epoch_time = time(NULL);
        err = localtime_s(&tm_p, &epoch_time);

        //ToDo: Improve screenshot name formatting
        std::string screenshotName = std::to_string(
                tm_p.tm_mday) +
                "-" +
                std::to_string(tm_p.tm_mon) +
                "-" +
                std::to_string(tm_p.tm_year) +
                " " +
                std::to_string(tm_p.tm_hour) +
                std::to_string(tm_p.tm_min) +
                std::to_string(tm_p.tm_sec);

        screenshot.saveToFile("screenshots/" + screenshotName + ".png");

        MainWindow->display();
}

void AMEngine::Update()
{
        sf::Event event;
        while (MainWindow->pollEvent(event))
        {
                if (event.type == sf::Event::Closed)
                        m_bIsRunning = false;
                if (event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::Escape)
                        m_bIsRunning = false;

                if (event.type == sf::Event::KeyPressed && event.key.code == sf::Keyboard::F5)
                {
                        MainWindow->setActive(false);
                        std::thread tSC(&AMEngine::ScreenCapture, this);
                        tSC.join();
                        MainWindow->setActive(true);
                }

        }
}

Or is this a pipe dream?

I tried searching about screenshots with threads, but ironically, there's a thread on this forum called the Screenshot Thread. XD

4

General / Crash on Exit Passing RenderWindow to Class

« on: October 25, 2015, 05:49:54 am »

Hi there!

I've researched this issue and tried various things learning that the RenderWindow is non-copyable and all that fun stuff. But, I swear I see other programs doing this that don't have an issue, which I'm guessing I'm simply missing a step.

At the moment, I'm running under Debug mode with the debug libraries linked statically. Basically I have a Camera class with a function DrawHUD that works like so:

void Camera::DrawHUD(sf::RenderWindow &window)
{
        testText.setString("Hi! I'm a HUD!");
        window.pushGLStates();
        window.draw(testText);
        window.popGLStates();
}

Basically it all comes down to window.draw() is where it ultimately crashes. Well, that's sort of true, because it only crashes when the program exits, but only if that draw() is called from inside my class.

When it crashes it goes to the file crtexe.c and points to the lines here:

            if (has_cctor == 0)
                _cexit();

and then proceeds to give me the Unhandled Exception error with ntdll.dll.

It doesn't matter if I pass it as a pointer, and I can't pass it directly because RenderWindow is noncopyable to avoid duplicate windows. So am I just stupid, or?

For more code context, this is basically how it works:

Camera mainCamera;
//...
//WHILE LOOP HERE
mainCamera.DrawHUD(window);

Any ideas? By the way, that testText thing has all the other stuff setup in the class' constructor, but where I put that seemed to not make any difference anyway.