vtkLight

Section: Visualization Toolkit Rendering Classes

Usage

vtkLight is a virtual light for 3D rendering. It provides methods to locate and point the light, turn it on and off, and set its brightness and color. In addition to the basic infinite distance point light source attributes, you also can specify the light attenuation values and cone angle. These attributes are only used if the light is a positional light. The default is a directional light (e.g. infinite point light source).

Lights have a type that describes how the light should move with respect to the camera. A Headlight is always located at the current camera position and shines on the camera's focal point. A CameraLight also moves with the camera, but may not be coincident to it. CameraLights are defined in a normalized coordinate space where the camera is located at (0, 0, 1), the camera is looking at (0, 0, 0), and up is (0, 1, 0). Finally, a SceneLight is part of the scene itself and does not move with the camera. (Renderers are responsible for moving the light based on its type.)

Lights have a transformation matrix that describes the space in which they are positioned. A light's world space position and focal point are defined by their local position and focal point, transformed by their transformation matrix (if it exists).

To create an instance of class vtkLight, simply invoke its constructor as follows

  obj = vtkLight

Methods

The class vtkLight has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtkLight class.