ofLight is an openGL light for 3D rendering. It contains four main lighting types:

Spot light : Light originates from a single point and spreads outward in a cone of variable diameter and length

Point light : Light comes from a single point and spreads outward evenly in all directions

Directional light : Light comes evenly from a given direction, as if coming from a plan of infinite size and distance from the lit object

Ambient light : Light from a fixed intensity and fixed source that affects all objects equally

Within ofLight, the following properties of each light type can be set individually:

XYZ orientation

XYZ position

RGB color

Light attenuation / falloff

Additionally, spot lights have variable control of cone length and diameter.

Spotlight with yellow diffuse reflection, narrow cone

Spotlight with yellow diffuse reflection, wide cone

ofLight and ofMaterial

GL lighting effects are dependent on both the light and the material being lit. ofLight interacts strongly with ofMaterial, which has five rendering parameters for materials being lit:

Specular color : the color of highlights on a material

Diffuse color : the color of the material when it is illuminated

Point light with blue specular reflection and red diffuse reflection

Ambient color : the color of the material when it is not illuminated

Spotlight with red diffuse reflection, no specular reflection, and blue ambient color

Emissive color : the color the material illuminated from within

Emissive green material coloring, no external lights

Shininess : the matte or shiny property of the material, which impacts how much specular light vs diffuse light reflects from a surface.

Point light with yellow diffuse and blue specular reflections, high matte

Point light with yellow diffuse and blue specular reflections, high shine

ofLight and cameras

If an ofLight is drawn within the context of a camera such as ofEasyCam, its position and orientation will be controlled by the camera and it will be oriented relative to the scene focus of the camera.

camera.begin();
//spotlight is drawn in the camera frame and oriented relative to the focus of the camera
spotlight.enable(); 
ofSphere(0,0,0,100);
spotlight.disable();
camera.end();

If an ofLight is drawn outside the camera, it will be drawn in the global frame and will affect all objects in the scene equally.

spotlight.enable(); //spotlight is in the global frame and not the camera frame
camera.begin();
ofSphere(0,0,0,100);
camera.end();
spotlight.disable();

(Examples made using LightsCamera example by Pete Werner https://github.com/petewerner/generative/tree/master/lights_camera)