Difference between revisions of "OCCL"

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==Introduction==
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{{IplSection
'''Occlusion''' is a feature in Vice City and San Andreas that helps make the game run smoother in certain parts of the game. Occlusion boxes disable models that are behind the box from rendering. The occlusions are controlled by the occlu.ipl file in Vice City and other files scattered around in San Andreas. Rockstar didn't use this feature efficiently and didn't improve this much from Vice City. Deleting all entries in the occlu section doesn't have a major affect on your games.
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| game        = {{Icon|VC}} {{Icon|SA}} {{Icon|4}}
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| description = Creates occlusion culling zones
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}}
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'''OCCL''' is a section in the [[item placement]] file in [[Vice City]], [[San Andreas]], and [[GTA IV]]. It is used to create [[wikipedia:Hidden surface determination|occlusion culling]] zones that helps make the game run smoother in certain parts of the world. Since it is wasteful to render models behind opaque models, these zones can disable the rendering of any models that are directly behind the zones.
  
==Details==
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== Format ==
'''Format of the occlu section of the IPL file:'''
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=== Vice City ===
direct mid x, direct mid y, bottom height z, width x, width y, height from bottom height to top,
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[[File:VC occlu.jpg|thumb|A map of Vice City's <code>occlu.ipl</code> areas]]
rotation
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{{Pre|
*'''direct mid x, direct mid y:''' The middle of the occlusion box in X and Y coordinates.<br>
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occl
*'''bottom height z:''' The bottom Z coordinate of the occlusion box.<br>
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MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation
*'''width x, width y:''' The width of the occlusion box in units of X and Y.<br>
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end
*'''height from bottom height to top:''' The difference in height from the top of the occlusion box to the bottom.<br>
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}}
*'''rotation:''' The rotation of the occlusion box in angles (probably radians, I'm not sure).<br>
 
Occlusion boxes can only be viewed through Moo Mapper v0.95 or higher.
 
  
==References==
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The section is used in the <code>occlu.ipl</code> file but it can be used in any IPL files.
[http://sodagirl.xmgfree.com/occlu.php Occlusion Tool (temp site)]
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{|class="wikitable center-col-1 center-col-2"
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!style="width: 3em;"|{{Icon|VC}}
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!style="width: 12em;"|Identifier
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!style="width: 6em;" |Type
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!Description
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|-
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|A,B ||MidX, MidY ||float[2] ||The X and Y coordinates of the center of the occlusion zone.
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|-
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|C ||BottomZ ||float ||The bottom Z coordinate of the occlusion zone.
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|-
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|D,E ||WidthX, WidthY ||float[2] ||The width of the occlusion zone in units.
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|-
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|F ||Height ||float ||The height of the zone &mdash; the difference between the top and the bottom of the zone.
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|-
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|G ||Rotation ||float ||The [[Angle|rotation]] of the occlusion zone in degrees.
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|}
  
[[Category:Map Formats]][[Category:GTA VC]][[Category:GTA SA]]
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=== San Andreas ===
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The section is used in <code>occluint.ipl</code>, <code>occluLA.ipl</code>, <code>occlusf.ipl</code>, and <code>occluveg.ipl</code> files.
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{{Pre|
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occl
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MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation, , ,
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end
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}}
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{|class="wikitable center-col-1 center-col-2"
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!style="width: 3em;"|{{Icon|SA}}
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!style="width: 12em;"|Identifier
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!style="width: 6em;" |Type
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!Description
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|-
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|A,B ||MidX, MidY ||float[2] ||The X and Y coordinates of the center of the occlusion zone.
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|-
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|C ||BottomZ ||float ||The bottom Z coordinate of the occlusion zone.
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|-
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|D,E ||WidthX, WidthY ||float[2] ||The width of the occlusion zone in units.
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|-
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|F ||Height ||float ||The height of the zone &mdash; the difference between the top and the bottom of the zone.
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|-
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|G ||Rotation ||float ||The [[Angle|rotation]] of the occlusion zone in degrees.
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|-
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|H,I || ||float ||
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|-
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|J || ||int ||
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|}
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== Issues ==
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When removing buildings from the world, you may see unexpected pop ups caused by existing occlusion zones. Deleting all the occlusion zones is the easiest solution. An example of this issue is the Liberty City project. Before this section was researched, the team experienced unexpected pop ups with models loading and unloading behind areas where Vice City's buildings used to be. Someone realized that the <code>occlu.ipl</code> was the problem and deleted every line in that file. The pop ups disappeared and the issue was resolved.
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== Statistics ==
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Total number of OCCL entries in:
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:Vice City: 344 (max 350)
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== Tools and scripts ==
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* [[KEd]] &ndash; by {{U|JernejL}}
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* {{GTAF|277798|Script pack for 3ds Max}} &ndash; by {{U|Deniska}}
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* {{GTAF|402942|&#91;IV&#93;&#91;Rel&#93;GTA-IV Scripts Centre}} &ndash; by {{U|Gforce}}
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{{N|4|SA|VC}}
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[[Category:Map Formats]]

Latest revision as of 18:40, 10 November 2016

OCCL (IPL section)
Short description:Creates occlusion culling zones
Supported games:Vice City San Andreas GTA IV
IPL Sections:
2DFX AUZO BLOK CARS CULL ENEX GRGE
INST JUMP LINK LODM MLO+ MULT OCCL
PATH PICK RTFX SLOW TCYC VNOD ZONE

OCCL is a section in the item placement file in Vice City, San Andreas, and GTA IV. It is used to create occlusion culling zones that helps make the game run smoother in certain parts of the world. Since it is wasteful to render models behind opaque models, these zones can disable the rendering of any models that are directly behind the zones.

Format

Vice City

A map of Vice City's occlu.ipl areas
occl
MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation
end

The section is used in the occlu.ipl file but it can be used in any IPL files.

Vice City Identifier Type Description
A,B MidX, MidY float[2] The X and Y coordinates of the center of the occlusion zone.
C BottomZ float The bottom Z coordinate of the occlusion zone.
D,E WidthX, WidthY float[2] The width of the occlusion zone in units.
F Height float The height of the zone — the difference between the top and the bottom of the zone.
G Rotation float The rotation of the occlusion zone in degrees.

San Andreas

The section is used in occluint.ipl, occluLA.ipl, occlusf.ipl, and occluveg.ipl files.

occl
MidX, MidY, BottomZ, WidthX, WidthY, Height, Rotation, , ,
end
San Andreas Identifier Type Description
A,B MidX, MidY float[2] The X and Y coordinates of the center of the occlusion zone.
C BottomZ float The bottom Z coordinate of the occlusion zone.
D,E WidthX, WidthY float[2] The width of the occlusion zone in units.
F Height float The height of the zone — the difference between the top and the bottom of the zone.
G Rotation float The rotation of the occlusion zone in degrees.
H,I float
J int

Issues

When removing buildings from the world, you may see unexpected pop ups caused by existing occlusion zones. Deleting all the occlusion zones is the easiest solution. An example of this issue is the Liberty City project. Before this section was researched, the team experienced unexpected pop ups with models loading and unloading behind areas where Vice City's buildings used to be. Someone realized that the occlu.ipl was the problem and deleted every line in that file. The pop ups disappeared and the issue was resolved.

Statistics

Total number of OCCL entries in:

Vice City: 344 (max 350)

Tools and scripts