advanced-user-manual4-en.md

Advanced User Manual 4: Multiple Lights

In previous manuals, we only added a directional light to the scene (otherwise all models will be dark). Now we will add more lights to the scene.

Types

Ash Engine supports four types of light sources, and up to eight for each type of light source:

Type	Class Name	Attribute
Ambient Light	AmbientLight	Color, Intensity
Directional Light	DirectionalLight	Color, Intensity, Direction
Point Light	PointLight	Color, Intensity, Position, Attenuation
Spot Light	SpotLight	Color, Intensity, Position, Direction, Cut-offs, Attenuation

Example

The following code shows how to add multiple lights to the scene and set their color and intensity:

int main(int argc, char *argv[]) {
    initApplication();

    QApplication a(argc, argv);

    // Step 1: Create an OpenGLWindow
    OpenGLWindow* window = new OpenGLWindow;
    window->resize(800, 600);

    // Step 2: Create an OpenGLRenderer for the window
    OpenGLRenderer* renderer = new OpenGLRenderer;
    window->setRenderer(renderer);

    // Step 3: Create a scene
    Scene* scene = new Scene;
    window->setScene(new OpenGLScene(scene));

    // Step 4: Customize your scene
    scene->addGridline(new Gridline);
    scene->camera()->moveForward(500.0f);

    Model* cubeModel = ModelLoader::loadCubeModel();
    cubeModel->setScaling(QVector3D(5, 5, 5));
    scene->addModel(cubeModel);

    DirectionalLight* directionalLight = new DirectionalLight(QVector3D(1, 1, 1), QVector3D(-2, -4, -3));
    directionalLight->setIntensity(0.6f);
    scene->addLight(directionalLight);

    PointLight* pointLight1 = new PointLight(QVector3D(1, 0.5, 0), QVector3D(5, 0, 0));
    pointLight1->setIntensity(1.2f);
    scene->addLight(pointLight1);

    PointLight* pointLight2 = new PointLight(QVector3D(0, 0.5, 1), QVector3D(0, 5, 0));
    pointLight2->setIntensity(1.2f);
    scene->addLight(pointLight2);

    PointLight* pointLight3 = new PointLight(QVector3D(0, 1, 0.5), QVector3D(0, 0, 5));
    pointLight3->setIntensity(1.2f);
    scene->addLight(pointLight3);

    window->show();

    return a.exec();
}

Replace the main function in src/AshEngine.cpp with the above code, recompile and execute, you can get the following results: