.shader files define shaders, which are an important part of the Id Tech 3 graphics system. Shaders are text scripts which can be edited with a text editor. The JK2 SDK also comes with a GUI shader editor called ShaderEd.
Basically speaking, a shader can be thought of as a dynamic texture. Using shaders, the following kinds of textures can be created:
- animated textures
- lit and glowing textures
- moving/scrolling textures
- sky textures
- transparent or semi-transparent textures (eg. grates, glass, force fields)
- vertical textures (eg. grass)
Shaders do not only affect the visual appearance of surfaces, but can also change the behaviour of surfaces. So for example, shaders are used to create liquids, and surfaces made out of different kinds of materials (eg. metal, sand, snow).
System shaders are special shaders which affect game rendering and gameplay. Some of these are described below. Further information about system shaders can be found here.
textures/system/clip - creates an invisible clipping surface (blocks player and NPC movement)
textures/system/physics_clip - creates an invisible clipping surface that also stops weapons and projectiles. Commonly used to give solidness to models.
textures/system/do_not_enter - blocks NPC movement, but not players. Used to stop enemies and other AI entering certain areas of the map
textures/system/cushion - if players fall on to this surface, they will not take fall damage
textures/system/origin - used to set the origin of func_rotating, func_train and func_static entities
textures/system/trigger - used to create trigger entitites
textures/system/caulk - a non-drawn surface, but behaves as if it is solid (eg. blocks VIS and light) and "seals" off the map from the void
textures/system/weatherzone - for creating a weatherzone entity, see Weather
textures/system/outside - designates an outside area for weather
textures/system/inside - designates an inside area (no weather)
The following surface materials work in Jedi Academy. A shader that assigned one of these materials will cause different footstep sound effects to play when the player walks on them, and in some cases effects such as puffs of snow, footprints, etc. (These appear to be hardcoded into the game source code.)
q3map_material Carpet q3map_material Dirt q3map_material Gravel q3map_material HollowMetal q3map_material LongGrass q3map_material Mud q3map_material Sand q3map_material ShortGrass q3map_material Snow q3map_material SolidMetal q3map_material SolidWood