GetRay

Introduction

The GetRay method can be used to get a Ray representing objects which the Cursor is over. This Ray can be used for complex object picking, and will work even when the Camera is rotated, unlike the WorldXAt and WorldYAt methods.

Code Example

The following code shows how the GetRay function can be used to get a Ray representing the Cursor's current position and direction of the camera. The following code is implemented in the CustomInitialize and CustomActivity of an otherwise empty screen.

void CustomInitialize()
{
    // Add a circle for reference:
    Circle circle = ShapeManager.AddCircle();
    circle.Radius = 64;

    // so we can see the cursor:
    FlatRedBallServices.Game.IsMouseVisible = true;
}

void CustomActivity(bool firstTimeCalled)
{
    var ray = GuiManager.Cursor.GetRay();

    FlatRedBall.Debugging.Debugger.Write(
        "Ray Position: " + ray.Position + "\n" +
        "Ray Direction: " + ray.Direction);

    // let's move the camera around too to make sure this works:
    const float velocity = 50;
    InputManager.Keyboard.ControlPositionedObject(Camera.Main, velocity);

}

GetRay.png

Community Code

Mouse world coordinates for a rotated Camera by Scott Dancer