User's Manual

Back Patch Culling
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Face normals are used by default with the following primitive types:
• csPolySet
• csQuadSet
• csTriFanSet
• csTriSet
• csTriStripSet
If normals are not provided for a csGeoSet and the primitive normal mode is enabled,
the csGeoSet is never back patch culled.
Using Back Patch Culling
There are two steps you take to implement back patch culling:
• Enable back patch culling.
• Build back patch culling data.
Enabling Back Patch Culling
You enable back patch culling by setting csDrawAction::setBPCullMode() with one of
the following arguments:
• NONE—Disables back patch culling.
• DRAW_FRONT_FACING—Culls all primitives wholly on the back side of a
geometry.
• DRAW_BACK_FACING—Culls all primitives wholly on the front side of a
geometry.
csDrawAction::getBPCullMode() returns the back patch culling mode.
Once back patch culling is set, it is carried out whenever an apply() method is invoked
with a csDrawAction.