The SceneGraph3D Description Language

Index

light

Derived from:

Node3D

Class name:

Light3D

Placement:

Anywhere

Description:

It adds a light source to the scene. The light source can be manipulated like any other node, including activation/deactivation and transformations. The light sources can be point lights, area lights (point lights with a non-zero radius) and spot lights, with or without attenuation or shadows. Lights also have a range of effect (and a near range for defining the closest-to-light distance for the shadow map) as well as an RGB color value which can be set to more than (1,1,1). Internally, illumination can withstand a 200% overexposure without being saturated, although the final result depends on the output buffer color accuracy. Shadows are enabled individually for each light source.

Special notes:

Attenuation and spotlight source type are not implemented yet.

Inherited attributes:

name, active

New attributes:

attribute	type	description
type	OPTION	The type of light source. This is ignored for the time being, as only positional lights are supported with a directed shadow map.
color	VEC3	The color of the light source. RGB values can be greater than 1.0.
shadows	BOOLEAN	True if the light casts shadows. False by default.
attenuation	BOOLEAN	True if the light is attenuated. False by default. Attenuation is linear and the light range is set by the range attribute (equal to the far shadow map clipping distance). Attenuation is not yet implemented.
range	FLOAT	The shadow map and attenuation (far) range. Default value is 100.0.
near_range	FLOAT	The shadow map near clipping distance. Default value is 1.0.
position	VEC3	The position of the light source, relative to the local coordinate system. This point is subject to transformations.
target	VEC3	The "look-at" point of the light source, relative to the local coordinate system. It is used for the spotlight type of sources and for the calculation of the shadow map frustum. This point is subject to transformations.
resolution	INT	The resolution of the shadow map (resolution x resolution square buffer). Default value is 512.
apperture	FLOAT	The side-to-side apperture of the light cone in degrees. used by spotlights and shadow maps. Default value is 90.0 degrees.
size	FLOAT	The diameter of the light source in world units. Affects the soft shadows. Default value is zero.
skipframes	INT	How many frames to skip before re-calculating the shadow map. This is a speed-up parameter. Normally, the shadow maps are calculated every frame, but if the scene/light position changes slowly or there are too many shadow mapped lights turned on, you might want to improve the frame rate by avoiding the redraw of the shadow maps in each frame. Default value is 0.
glow
glow_radius

Events:

event name	condition
-	-

Inherited events:

New messages:

attribute	value	description
follow	STRING	Follow the named node, if the name given is valid.
apperture	FLOAT	Change the apperture of the camera
focal_distance	FLOAT	Change the focal distance of the camera
focal_range	FLOAT	Change the focal range of the camera
near	FLOAT	Change the near clipping plane distance of the camera.
far	FLOAT	Change the far clipping plane distance of the camera.

Inherited messages:

Redefined messages:

Obsolete messages:

active, visible, hide, show, deactivate, enable, activate, disable

Example

<world ambient_occlusion="ssao" bloom="yes" shadows="disk" 
       ao_radius="6" ambient="0.3 0.3 0.3" defocus="yes">
  
    <camera name="first_person" apperture="50.0" 
            focal_distance ="30.0" focal_range="30.0"
            near="2.0" far="1000" follow="Myself" primary="true">
    </camera> 

    <transformation name="environment" scale="1.0,1.0,1.0" translation="0,0,-10">
        
        <object name="geom2" file="arena.obj"></object>
    
    </transformation>
 
    <user name="Myself" control="navigate" speed="2.0" turn="0.5"
          position="0,10,100" lookat="0,10,0" input="Console">
    </user>

    <input name="Console" type="mousekeyboard">
    </input>
</world>

Last update: 24 Feb. 2010