Class SoLevelOfSimplification

  • All Implemented Interfaces:

    public class SoLevelOfSimplification
    extends SoLOD
    Level-of-detail switching node designed for grouping simplified versions of the same shape. This group node is used to group the results of simplifying a shape, such that every child represents the same model but with a different number of primitives. Since it is derived from SoLOD, it can behave as a distance-based level-of-detail node; however, it also responds to the decimation percentage element. It records what percentage decimation each child is, and then chooses the appropriate child based on the DecimationPercentage and DecimationType elements.

    You should specify N percentages for N+1 children. If the DecimationType is HIGHEST or LOWEST, then the LevelOfSimplification node will automatically choose the first or last child, respectively. If the DecimationType is PERCENTAGE, then the node will choose child "i" based on the decimation percentage element value such that:

       percentages[i-1] <= DecimationPercentage < percentages[i]
    If the DecimationType is AUTOMATIC, then the child is chosen based on the range value in the usual SoLOD manner, but no child greater than the value of the DecimationPercentage element will be chosen.

    This node also has a field for recording how many triangles the full detail child contains. This allows this node to answer an SoGetPrimitiveCountAction without traversing its children. This is a benefit when some children contain WWWInline , a common occurrence. If the children contain some non-triangle primitives, then the field should be -1 which will force the node to traverse its children during SoGetPrimitiveCountAction.

    File format/default:

    LevelOfSimplification {

      percentages []
      numTriangles -1
      center 0 0 0
      range [ ]

    Action behavior:

    SoGLRenderAction, SoRayPickAction, SoCallbackAction
    Only the child with the appropriate level of detail is traversed.

    A child is chosen in the same way as in GLRender. If the numTriangles field is greater than 0, the percentage value for this child is multiplied by the numTriangles value and this value is added to the PrimitiveCount without traversing the child. If numTriangles is less than or equal to 0, then the child is traversed to get the count.

    Other actions

    Implemented as for SoGroup

    SoGetPrimitiveCountAction, SoLOD, SoOctreeOrdering, SoRenderList, SoValueOrdering SoLevelOfDetail

    • Field Detail

      • percentages

        public final SoMFFloat percentages
        Percentage decimation for each child. Should be numbers between 0.0 and 1.0, with 1.0 representing full detail and 0.0 representing bounding box detail.
      • numTriangles

        public final SoSFInt32 numTriangles
        Number of triangles in highest (1.0) case. Can be -1 if unknown or if children contain primitives other than triangles.
    • Constructor Detail

      • SoLevelOfSimplification

        public SoLevelOfSimplification​(int nChildren)
        Constructor that takes approximate number of children.
      • SoLevelOfSimplification

        public SoLevelOfSimplification()
        Creates level-of-simplification node with default settings.