SFML Light System - Let There Be Light

[fatum]

Currently I'm trying to use LTBL in my project like this:

Code: [Select]

private:
ltbl::LightSystem *ls;
ltbl::Light_Point *testLight;


Code: [Select]

World::World(sf::RenderWindow &rwin)
{
ls = new ltbl::LightSystem(AABB(Vec2f(0.0f, 0.0f), Vec2f(static_cast<float>(screenWidth), static_cast<float>(screenHeight))), &rwin, "res/images/lightFin.png", "res/shaders/lightAttenuationShader.frag");

testLight = new ltbl::Light_Point();
testLight->SetCenter(Vec2f(400.0f, 400.0f));
testLight->SetRadius(500.05f);
testLight->m_size = 30.f;
testLight->m_spreadAngle = 2.f * static_cast<float>(M_PI);
testLight->m_softSpreadAngle = 0.f;
testLight->CalculateAABB();

ls->AddLight(testLight);
}

void World::draw(sf::RenderWindow &rwin)
{
rwin.setView(vw_main);
//Drawing logic (background, player, etc)
ls->RenderLights();
ls->RenderLightTexture();
}

However, there haven't been any changes to my scene after adding all of the necessary functions.  How could I further troubleshoot this?  Thanks for any help!

[Estivo]

Hi, guys. I have to edit blend functions in LTBL to made more realistic darkness.  I had problems with white spot so I changed two lines in RenderLightTexture. In Game



Function

void LightSystem::RenderLightTexture()
   {
      Vec2f viewSize(m_viewAABB.GetDims());

      // Translate by negative camera coordinates. glLoadIdentity will not work, probably
      // because SFML stores view transformations in the projection matrix
      glTranslatef(m_viewAABB.GetLowerBound().x, m_viewAABB.GetLowerBound().y, 0.0f);

      m_compositionTexture.getTexture().bind(&m_compositionTexture.getTexture());

      // Set up color function to multiply the existing color with the render texture color
      //glBlendFunc(GL_DST_ALPHA, GL_ZERO); // Seperate allows you to set color and alpha functions seperately
        glBlendFunc(GL_DST_COLOR, GL_ONE);
      glBegin(GL_QUADS);
         glTexCoord2i(0, 0); glVertex2f(0.0f, 0.0f);
         glTexCoord2i(1, 0); glVertex2f(viewSize.x, 0.0f);
         glTexCoord2i(1, 1); glVertex2f(viewSize.x, viewSize.y);
         glTexCoord2i(0, 1); glVertex2f(0.0f, viewSize.y);
      glEnd();

      if(m_useBloom)
      {
         m_bloomTexture.getTexture().bind(&m_bloomTexture.getTexture());

         //glBlendFunc(GL_ONE, GL_ONE);
            glBlendFunc(GL_DST_COLOR, GL_SRC_COLOR);
         glBegin(GL_QUADS);
            glTexCoord2i(0, 0); glVertex2f(0.0f, 0.0f);
            glTexCoord2i(1, 0); glVertex2f(viewSize.x, 0.0f);
            glTexCoord2i(1, 1); glVertex2f(viewSize.x, viewSize.y);
            glTexCoord2i(0, 1); glVertex2f(0.0f, viewSize.y);
         glEnd();
      }

      // Reset blend function
      glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

      m_pWin->resetGLStates();
   }

I hope I help someone.

[eXpl0it3r]

That looks nice! Do you have some more specifics?

[Estivo]

More specifics about project? It's screen from my game "Zombienation". I write the game for WSoC Contest. It will be 2d top down shooter like old Dead Frontier, but it will be single player game. All graphics are placeholders. More screenshoots here -> http://warsztat.gd/projects/Zombienation

[Estivo]

Another modification that I made is load shader from memory. QT 5 doesn't allow to load id from file (don"t know why)

[jamesl22]

Hi,

I am trying to implement LTBL into my game engine but I am struggling. I cannot get lights to render in the scene. Here is my code:

Engine::LightSystem::LightSystem(sf::RenderWindow &Window)
{
    ls = new ltbl::LightSystem(AABB(Vec2f(0.0f, 0.0f), Vec2f(16384.0f, 16384.0f)), &Window, "data/lightFin.png", "data/shaders/lightAttenuationShader.frag");

    Light = new ltbl::Light_Point();
    Light->m_center = Vec2f(200.0f, 1000.0f);
    Light->m_radius = 64.0f;
    Light->m_size = 30.0f;
    Light->m_intensity = 1.0f;
    Light->m_spreadAngle = 2.0f * 3.14159f;
    Light->m_softSpreadAngle = 0.0f;
    Light->CalculateAABB();
    ls->AddLight(Light);
}

void Engine::LightSystem::RenderLights(sf::View &View)
{
    ls->SetView(View);
    // Calculate the lights
    ls->RenderLights();
    // Draw the lights
    ls->RenderLightTexture();
}
 

I have attached an image of the problem. You will notice that LTBL is rendering the dark texture over the top.

[Estivo]

Set light intensity to 2.f. for better effects you could modify two lines in blending mode .

[Nutomic]

I tried to integrate the ltbl version from https://github.com/hovatterz/light into my project, but I'm unable to really get it working.

No matter what I do, the area where shadows are is always the same size, and always in the same position (see attachment).

Does anyone know what I have to do to resize/move this area?

[Estivo]

I think your code look like that

app.draw(smth);
lightSystem.renderLights();
lightSystem.renderLightTexture();

but it have to look like this

app.setView(view);
app.draw(smth);
app.setView(app.getDefaultView());
lightSystem.setView(app.getdefaultView());
lightSystem.renderLights();
lightSystem.renderLightTexture();

[Nutomic]

I think your code look like that

app.draw(smth);
lightSystem.renderLights();
lightSystem.renderLightTexture();

but it have to look like this

app.setView(view);
app.draw(smth);
app.setView(app.getDefaultView());
lightSystem.setView(app.getdefaultView());
lightSystem.renderLights();
lightSystem.renderLightTexture();

That's exactly how my current code looks (I basically copied the example into my project), but doing this only makes the light texture that is shown completely black (the previous code shows light correctly).

[Estivo]

Show me your code.

[Nutomic]

Initialization:

        ltbl::LightSystem mLightSystem(qdt::AABB(Vec2f(0, 0), Vec2f(800, 600)), &mWindow);
        // Create a light
        ltbl::Light* mLight = new ltbl::Light();
        mLight->center = Vec2f(200.0f, 200.0f);
        mLight->radius = 500.0f;
        mLight->size = 30.0f;
        mLight->softSpreadAngle = 0.0f;
        mLight->CalculateAABB();

        mLightSystem.AddLight(mLight);

        // Create a hull by loading it from a file
        ltbl::ConvexHull* testHull = new ltbl::ConvexHull();

        testHull->LoadShape("data/testShape.txt");

        // Pre-calculate certain aspects
        testHull->CalculateNormals();
        testHull->GenerateAABB();

        testHull->SetWorldCenter(Vec2f(0, 0));

        mLightSystem.AddConvexHull(testHull);

        // Create a hull by loading it from a file
        ltbl::ConvexHull* testHull2 = new ltbl::ConvexHull();

        testHull2->LoadShape("data/testShape.txt");

        // Pre-calculate certain aspects
        testHull2->CalculateNormals();
        testHull2->GenerateAABB();

        testHull2->SetWorldCenter(Vec2f(300.0f, 300.0f));

        mLightSystem.AddConvexHull(testHull2);

Rendering:

        mWindow.clear();

        mWorldView.setCenter(mPlayer->getPosition());

        // Render world and dynamic stuff.
        mWindow.setView(mWorldView);
        mWindow.draw(mWorld);

        // Update light
        mLight->center.x = mPlayer->getPosition().x;
        mLight->center.y = mPlayer->getPosition().y;
        mLight->UpdateTreeStatus();

        mWindow.setView(mWindow.getDefaultView());
        mLightSystem.view = mWindow.getDefaultView();
         mLightSystem.RenderLights();
        mLightSystem.RenderLightTexture();

        // Render GUI.
        mWindow.drawGUI();
        mWindow.draw(mCrosshair);

        mWindow.display();

As I said, I just took the example and copied it in there.

[Estivo]

I saw different sample.

mLightSystem.view = mWindow.getDefaultView();

to

mLightSystem.setView(mWindow.getDefaultView());

should solve problem You hardly set up view. setView function make some more than setting up view

   void LightSystem::SetView(const sf::View &view)
   {
      sf::Vector2f viewSize(view.getSize());
      m_viewAABB.SetDims(Vec2f(viewSize.x, viewSize.y));
      sf::Vector2f viewCenter(view.getCenter());

      // Flipped
      m_viewAABB.SetCenter(Vec2f(viewCenter.x, viewCenter.y));
   }

[Nutomic]

The thing is, the github version does not have setView, only a public member view.

I would try the version in the op, but gcc doesn't like the absolute include paths.

So I guess I'll try and reach the dev of this version and see if he can help.

[Estivo]

Ah I see now. You're using older version. http://sourceforge.net/projects/letthebelight/ here you have 1.5.1 that I'm using in Zombination