This simple example shows how to add a Line from the position (-1, -1, -1) to the position (1, 1, 1) as an augmented display in a GlScene, the line will be starting Blue and will finish transparent Red; the thickness of the line will be set to 1 pixel.

Coord startPos(-1, -1, -1);
Coord endPos(1, 1, 1);
Color startCol(0, 0, 255, 255);
Color endCol(255, 0, 0, 0);

// We create the line, the last parameter is the thickness of the line
 (note : you can't exceed 10)
GlLine* line = new GlLine(startPos, endPos, startCol, endCol, 1);

// Finally we add the line to the GlLayer, naming it "The famous
 tutorial line"
glMainLayer->addGlEntity(line, "The famous tutorial Line");	
		

Here is the screenshow of the result :

This example shows how to add a Box from the position (-1.5, -1.5, -1.5) to the position (1.5, 1.5, 1.5) as an augmented display in a GlLayer. The box will be blue and semi transparent (220, 220, 255, 80).

Coord topLeft(-1.5, -1.5, -1.5);
Coord bottomRight(1.5, 1.5, 1.5);
Color boxColor(220, 220, 255, 80);

// We create the box by giving the bounding box to the constructor
// (topLeft and bottomRight) and the color of the box.
GlBox *box = new GlBox(topLeft, bottomRight, boxColor);

// Finally we add the box to the GlLayer, naming it 
"Gl Tutorial 2 : Box"
glMainLayer->addGlEntity(box, "Gl Tutorial 2 : Box");
		

Here is the screenshot of the result :

This example shows how to add a Circle centered at the middle of the screen, of a radius of 256 pixels(The screenshot has been scaled). The circle will be light blue and will have 50 segments

//We firstly add a new GlLayer (with name "2D layer") in the scene and set layer to 2D mode
GlLayer *layer2D=new GlLayer("2D layer");
layer2D->set2DMode();
glScene->addLayer(layer2D);

//after, get the viewport to guess the center of the window
Vector<int, 4> viewport;
viewport = glScene->getViewport();

// This is the position of the center of the circle 
// (ScreenWidth / 2, ScreenHeight / 2, 1)
Coord circleCenter(viewport[2] / 2, viewport[3] / 2, 0);
Color circleColor(220, 220, 255, 255);

// We create the circle giving it's center position, it's color,
 it's radius and the number of segments
GlCircle* circle = new GlCircle(circleCenter, circleColor,
 256, 50);

// Finally we add the circle to the GlLayer.
layer2D->addGlEntity(circle, "Gl Tutorial 3 : Circle");
		

Here is the screenshot of the result (the screenshot has been shrinked so the radius is not of 256 pixels) :

This example shows how to use GlComposite to compose multiple effects in a scene. The scene will be composed of a sphere and 4 rectangles, to simulate an ArcBall

The circle will be positionned at the center of the screen. It will have a radius of 256 pixels and will be of a medium grey (128, 128, 128, 255).

The four squares will be positionned every 90° on the circle. They will also be in medium gray, and only wired

//We firstly add a new GlLayer (with name "2D layer") in the scene and set layer to 2D mode
GlLayer *layer2D=new GlLayer("2D layer");
layer2D->set2DMode();
glScene->addLayer(layer2D);

// Create a new composite to store the final Augmented display :
GlComposite *composite = new GlComposite();

// This is the medium grey color that will be applied to every Gl shape :
Color color(128, 128, 128, 255);

// We get the viewport for the circle :
Vector<int, 4> viewport;
viewport = glScene->getViewport();

// This is the position of the center of the circle 
// (ScreenWidth / 2, ScreenHeight / 2, 1)
Coord circleCenter(viewport[2] / 2, viewport[3] / 2, 0);

// We create the circle. It still have 50 segments
GlCircle* circle = new GlCircle(circleCenter, color, 256, 50);

// A 4 entries table for the squares
GlRect* rects[4];

Coord center, topLeft, bottomRight;

for(int i=0; i < 4; i++)
  {
    // We calculate the position of the center of each square
    center[0] = cos((double)i * 3.14/2.0) * 256;
    center[1] = sin((double)i * 3.14/2.0) * 256;
    center[2] = 0;
    center = center + circleCenter;

    // Then we find the position of the topLeft and the bottomRight corner
    topLeft     = center - Coord(16, 16, 0);
    bottomRight = center + Coord(16, 16, 0);

    rects[i] = new GlRect(bottomRight, topLeft, color, color);
  }

// We add the circle and the 4 squares to the composite
composite->addGlEntity(rects[0], "Gl Tutorial 4 : Rect1");
composite->addGlEntity(rects[1], "Gl Tutorial 4 : Rect2");
composite->addGlEntity(rects[2], "Gl Tutorial 4 : Rect3");
composite->addGlEntity(rects[3], "Gl Tutorial 4 : Rect4");
composite->addGlEntity(circle, "Gl Tutorial 4 : Circle");

// Finally we add the composite to the GlLayer
layer2D->addGlEntity(composite, "Composite");
	    

Here is a screenshot of the result :

This is very simple but you can do more simply : a GlLayer is composed with a GlComposite, so you can add rectangles and circle directly to the layer2D, like this :

// We add the circle and the 4 squares to the GlLayer
layer2D->addGlEntity(rects[0], "Gl Tutorial 4 : Rect1");
layer2D->addGlEntity(rects[1], "Gl Tutorial 4 : Rect2");
layer2D->addGlEntity(rects[2], "Gl Tutorial 4 : Rect3");
layer2D->addGlEntity(rects[3], "Gl Tutorial 4 : Rect4");
layer2D->addGlEntity(circle, "Gl Tutorial 4 : Circle");