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Unigine::WorldOccluder Class

This class is used to create a box-shaped occluder that culls surfaces, bounds of which are currently hidden behind it. If any part of the bound of the object's surface is visible behind the occluder, the surface will not be culled. The objects' surfaces behind the occluder are not sent to the GPU, thereby saving performance.

The occluder itself is rendered by the CPU and stored in a separate buffer.

Notice
The front or back faces of the occluder are used to cull surfaces. See details here.

Usage

In order to enhance performance, occluders should be used wisely. The following notes will help you to decide whether to use the occluder or not:

  • Occluders can be highly effective in case of complex environments where there are many objects that occlude each other and are costly to render (they have a lot of polygons and/or heavy shaders).
  • Effective culling is possible if objects are not too large, since if any part of their surface is seen, it cannot be culled. In case objects are big and have a few surfaces, it is likely that an additional performance load of an occluder will not pay off.
  • In case the scene is filled with flat objects or a camera looks down on the scene from above (for example, in flight simulators), it is better not to use occluders at all or disable them.

See Also

Unigine::WorldOccluder Class

Members


static int type ()

WorldOccluder type.

Return value

WorldOccluder type identifier.

static Ptr< WorldOccluder > create (const NodePtr & node)

WorldOccluder constructor.

Arguments

  • const NodePtr & node - Node smart pointer.

static Ptr< WorldOccluder > create (const vec3 & xxx)

WorldOccluder constructor.

virtual Ptr< Node > getNode () const =0

Returns a node pointer.

Return value

Node pointer.

virtual void setBackFace (int back) =0

Updates the value indicating whether the back faces of the occluder box are used instead of front faces to occlude objects' surfaces. By default, the front faces are used.

Arguments

  • int back - 1 to use the back faces of the occluder to cull surfaces; 0 to use the front ones.

virtual int isBackFace () const =0

Returns the value indicating whether the back faces of the occluder box are used instead of front faces to occlude objects' surfaces. By default, the front faces are used.

Return value

1 if the back faces of the occluder are used to cull surfaces; otherwise, 0.

virtual void setSize (const vec3 & size) =0

Updates the current dimensions of the world occluder box.

Arguments

  • const vec3 & size - The occluder dimensions.

virtual vec3 getSize () const =0

Returns the current dimensions of the world occluder box.

Return value

The occluder dimensions.

virtual void setDistance (float distance) =0

Updates the distance between the camera and the bounding box of the occluder, at which the occluder becomes disabled (it isn't processed by the CPU, hence it isn't rendered). By default, the inf value is used.

Arguments

  • float distance - The distance in units.

virtual float getDistance () const =0

Returns the current distance between the camera and the bounding box of the occluder, at which the occluder becomes disabled (it isn't processed by the CPU, hence it isn't rendered). By default, the inf value is used.

Return value

The distance in units.
Last update: 2017-07-03