Overview
The Gobo Light Filter is a filter placed in front of a light source that tints or blocks the emitted light.
A gobo filter (in white) in front of a spot light, in the Viewer.
A gobo filter in the GafferThree node parameters.
Object Parameters
The object parameters of a gobo filter.
Translate
Rotate
Scale
Define the filter's translation, rotation and scale, respectively. These parameters are ignored in the rendered image when Use Filter Coordinate System has been turned off in the Material parameters.
Material Parameters
The material parameters of a gobo filter.
Map
An image file that is used as a filter. The image should have been processed beforehand by tdlmake.
Density
A map opacity multiplier. A density of 0 makes the map completely transparent.
Invert
Turning this parameter on will invert the map colors.
Use Filter Coordinate System
Defines if the translation, rotation and scale specified in the Object Parameters will be applied to the filter.
Scale
The scale factors applied to the range of S and T values covered by the filter, respectively. Values between 0 and 1 will appear to enlarge the map since the whole filter will cover a smaller portion of the usual texture coordinate area (from 0 to 1).
Offset
Specify S and T offset values applied on the map, respectively.
S Wrap Mode
T Wrap Mode
Control how the area outside the filter coverage will appear. The available options are:
| Value | Description |
|---|---|
| clamp | Coordinates below 0 are set to 0, and coordinates above 1 are set to 1. This will effectively repeat the map's border pixel. |
| black | Coordinates below 0 and above 1 are mapped to a black color. |
| mirror | The area outside the 0 to 1 range use coordinates that are repeated in a mirror fashion - from 0 to 1, then 1 to 0, and so on. |
| periodic | The area outside the 0 to 1 range use the 0 to 1 range repeated over again. |
Wrap Modes |
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Note that the corner pixels of the map are not black, hence the checkerboard pattern on the Clamp image.