VIS
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* Mark small brushes that should not break VIS as detail (Detail brushes are opposed to Structural) | * Mark small brushes that should not break VIS as detail (Detail brushes are opposed to Structural) | ||
* Place hint brushes that will make additional portals for more accurate culling | * Place hint brushes that will make additional portals for more accurate culling | ||
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| + | == Console variables == | ||
| + | {{cvar|r_lockvisibility|disables visibility updates so you can walk around and inspect what is visible from locked position.}} | ||
| + | {{cvar|r_drawportals|draw portal surfaces in different colors.}} | ||
| + | {{cvar|r_novis|Disable visibility info (whole level will be drawn).}} | ||
| + | {{cvar|r_useportalculling|Improve framerate of r_novis by using portal culling. Still not as good as precompiled visibility data, but it helps on complex maps. A value of 2 will force portal culling even if VIS data is presented, which improves framerate on maps witout too much complexity but hurts on complex maps.}} | ||
==Tutorials== | ==Tutorials== | ||
Revision as of 09:01, 3 September 2012
Want to make one?
VIS stands for visibility. Its a name of map compilation phase, and data created during this phase and used for visibility checking. Vis can be estimated as a group of areas called portals with each portal having a link to all other postals visible from it. If entity standing in a portal that is visible from a portal of current eye position, it will get drawn.
Building the VIS
Vis portals is created during BSP stage, links are established during VIS stage.
Structural brushes will define a shape for portals to fill. It is sometimes called 'breaking VIS' because by nature it is breaking space for visible and not visible zones. All entities (including bmodels]) are meant to be changed/removed at any time, so they are always excluded from portals creation. The only entity that breaks VIS is func_group.
Leak
VIS requires map to be internally sealed. So it can know what part of the map is inside, and what is outside. When some inner part of the map is connected with void, map is leaked. When a leak occurs, the tools cannot know which part of the level is inside, and what part is outside, and portals cannot have visibility data generated. Most notable mistakes leading to leak:
- Small gaps between brushes leading to a void
- Detail brushes and entities being used as structural walls (they are not blocking VIS)
- Entities placed outside of map hull
When map compiler detects a leak, it will stop making portals and cast an error. Map editor will show the spot where leak was occured.
Optimizing VIS
It is important that portal tree should be balanced. It should be detailed enough to make accurate culling, and it should be small enough to have less RAM overhead and small processing time (VIS helps us to save some processing time, we should not allow it to take that time for its own processing). Optimizing portals is one of task map designer should care of:
- Mark small brushes that should not break VIS as detail (Detail brushes are opposed to Structural)
- Place hint brushes that will make additional portals for more accurate culling
Console variables
r_lockvisibility : disables visibility updates so you can walk around and inspect what is visible from locked position. r_drawportals : draw portal surfaces in different colors. r_novis : Disable visibility info (whole level will be drawn). r_useportalculling : Improve framerate of r_novis by using portal culling. Still not as good as precompiled visibility data, but it helps on complex maps. A value of 2 will force portal culling even if VIS data is presented, which improves framerate on maps witout too much complexity but hurts on complex maps.
