Package org.apache.commons.geometry.io.euclidean.threed.obj

Class ObjWriter.MeshBuffer

  • Enclosing class:
    ObjWriter
    public final class ObjWriter.MeshBuffer
extends java.lang.Object
    Class used to produce OBJ mesh content from sequences of facets. As facets are added to the buffer their vertices and normals are converted to OBJ vertex and normal definition strings. Vertices and normals that produce equal definition strings are shared among all of the facets in the buffer. This process converts the facet sequence into a compact mesh suitable for writing as OBJ file content.

    Ideally, no vertices or normals would be duplicated in an OBJ file. However, when working with very large geometries it may not be desirable to store values in memory before writing to the output. This is where the batchSize property comes into play. The batchSize represents the maximum number of faces that the buffer will store before automatically flushing its contents to the output and resetting its state. This reduces the amount of memory used by the buffer at the cost of increasing the likelihood of duplicate vertices and/or normals in the output.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int batchSize
      Maximum number of faces that will be stored in the buffer before automatically flushing.
      private java.util.Map<java.lang.Integer,​java.lang.Integer> faceToNormalMap
      Map of local face indices to their local normal index.
      private java.util.List<int[]> faceVertices
      List of local face vertex indices.
      private java.util.Map<java.lang.String,​java.lang.Integer> normalMap
      Map of vertex normals to their local index.
      private java.util.Map<java.lang.String,​java.lang.Integer> vertexMap
      Map of vertex definition strings to their local index.

    • Constructor Summary

      Constructors 
      Constructor Description
      MeshBuffer​(int batchSize)
      Construct a new mesh buffer instance with the given batch size.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(PlaneConvexSubset boundary)
      Add a boundary to this buffer.
      void add​(FacetDefinition facet)
      Add a facet to this buffer.
      private void addFace​(java.util.List<Vector3D> vertices, Vector3D normal)
      Add a face to the buffer.
      int addNormal​(Vector3D normal)
      Add a normal to the buffer.
      private int addToMap​(Vector3D vec, java.util.Map<java.lang.String,​java.lang.Integer> map)
      Convert the given vector to on OBJ definition string and add it to the map if not yet present.
      int addVertex​(Vector3D vertex)
      Add a vertex to the buffer.
      void flush()
      Flush the buffer content to the output and reset its state.
      private void reset()
      Reset the buffer state.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • batchSize

        private final int batchSize
        Maximum number of faces that will be stored in the buffer before automatically flushing.

      • vertexMap

        private final java.util.Map<java.lang.String,​java.lang.Integer> vertexMap
        Map of vertex definition strings to their local index.

      • normalMap

        private final java.util.Map<java.lang.String,​java.lang.Integer> normalMap
        Map of vertex normals to their local index.

      • faceVertices

        private final java.util.List<int[]> faceVertices
        List of local face vertex indices.

      • faceToNormalMap

        private final java.util.Map<java.lang.Integer,​java.lang.Integer> faceToNormalMap
        Map of local face indices to their local normal index.

    • Constructor Detail

      • MeshBuffer

        MeshBuffer​(int batchSize)
        Construct a new mesh buffer instance with the given batch size.
        Parameters:
        batchSize - batch size; set to -1 to indicate an unlimited size

    • Method Detail

      • add

        public void add​(FacetDefinition facet)
        Add a facet to this buffer. If batchSize is greater than -1 and the number of currently stored faces is greater than or equal to batchSize, then the buffer content is written to the output and the buffer state is reset.
        Parameters:
        facet - facet to add
        Throws:
        java.io.UncheckedIOException - if an I/O error occurs

      • add

        public void add​(PlaneConvexSubset boundary)
        Add a boundary to this buffer. If batchSize is greater than -1 and the number of currently stored faces is greater than or equal to batchSize, then the buffer content is written to the output and the buffer state is reset.
        Parameters:
        boundary - boundary to add
        Throws:
        java.lang.IllegalArgumentException - if the boundary is infinite
        java.io.UncheckedIOException - if an I/O error occurs

      • addVertex

        public int addVertex​(Vector3D vertex)
        Add a vertex to the buffer.
        Parameters:
        vertex - vertex to add
        Returns:
        the index of the vertex in the buffer

      • addNormal

        public int addNormal​(Vector3D normal)
        Add a normal to the buffer.
        Parameters:
        normal - normal to add
        Returns:
        the index of the normal in the buffer

      • flush

        public void flush()
        Flush the buffer content to the output and reset its state.
        Throws:
        java.io.UncheckedIOException - if an I/O error occurs

      • addToMap

        private int addToMap​(Vector3D vec,
                     java.util.Map<java.lang.String,​java.lang.Integer> map)
        Convert the given vector to on OBJ definition string and add it to the map if not yet present. The mapped index of the vector is returned.
        Parameters:
        vec - vector to add
        map - map to add the vector to
        Returns:
        the index the vector entry is mapped to

      • addFace

        private void addFace​(java.util.List<Vector3D> vertices,
                     Vector3D normal)
        Add a face to the buffer. If batchSize is greater than -1 and the number of currently stored faces is greater than or equal to batchSize, then the buffer content is written to the output and the buffer state is reset.
        Parameters:
        vertices - face vertices
        normal - face normal; may be null
        Throws:
        java.io.UncheckedIOException - if an I/O error occurs

      • reset

        private void reset()
        Reset the buffer state.