MENU

Lighting

The lighting calculation follows the standard Phong lighting model. The alpha channel of the image is used as the bump map. There are two types of lighting – specular lighting and diffuse lighting. Specular lighting is observed at smooth surfaces, while diffuse lighting is observed at rough surfaces. For a lighting primitive, exactly one light source must be specified as its child element. A light source can be a 'point light', a 'spot light', or a 'distant light'.

<feSpecularLighting> defines specular lighting...... CPFS
......in
......lighting-color="<color>": the color of the light source.
......surfaceScale="<number>": the height of the surface when the input alpha channel equals 1.
......specularConstant="<number>": ks in Phong lighting model.
......specularExponent="<number>": the 'brightness'/'shininess'.
......kernelUnitLength="<number> [number]": the intended distance in current filter units for dx and dy respectively, in the surface normal calculation formulas.

<feDiffuseLighting> defines diffuse lighting......CPFS
......in
......lighting-color="<color>": the color of the light source.
......surfaceScale="<number>": the height of the surface when the input alpha channel equals 1.
......diffuseConstant="<number>": kd in Phong lighting model.
......kernelUnitLength="<number> [number]": the intended distance in current filter units for dx and dy respectively, in the surface normal calculation formulas.

<fePointLight> defines a light source made up of a 'point light'......C
......x="<number>": the x location for the light source.
......y="<number>": the y location for the light source.
......z="<number>": the z location for the light source.

<feSpotLight> defines a light source made up of a 'spot light'......C
......x="<number>": the x location for the light source.
......y="<number>": the y location for the light source.
......z="<number>": the z location for the light source.
......pointsAtX="<number>": the x location of the pointed place.
......pointsAtY="<number>": the y location of the pointed place.
......pointsAtZ="<number>": the z location of the pointed place.
......specularExponent="<number>": the focus for the light source.
......limitingConeAngle="<number>": the angle in degrees between the spot light axis and the spot light cone.

<feDistantLight> defines a light source made up of a 'distant light'......C
......azimuth="<number>": angle in degrees for the light source on the XY plane from the x-axis.
......elevation="<number>": angle in degrees for the light source from the XY plane towards the z-axis.