Package com.jogamp.opengl.glu

Interface GLUtessellatorCallback

  • All Known Implementing Classes:
    GLUtessellatorCallbackAdapter
    public interface GLUtessellatorCallback
    GLUtessellatorCallback interface provides methods that the user will override to define the callbacks for a tessellation object.
    Author:
    Eric Veach, July 1994, Java Port: Pepijn Van Eeckhoudt, July 2003, Java Port: Nathan Parker Burg, August 2003

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void begin​(int type)
      The begin callback method is invoked like glBegin to indicate the start of a (triangle) primitive.
      void beginData​(int type, Object polygonData)
      The same as the begin callback method except that it takes an additional reference argument.
      void combine​(double[] coords, Object[] data, float[] weight, Object[] outData)
      The combine callback method is called to create a new vertex when the tessellation detects an intersection, or wishes to merge features.
      void combineData​(double[] coords, Object[] data, float[] weight, Object[] outData, Object polygonData)
      The same as the combine callback method except that it takes an additional reference argument.
      void edgeFlag​(boolean boundaryEdge)
      The edgeFlag callback method is similar to glEdgeFlag.
      void edgeFlagData​(boolean boundaryEdge, Object polygonData)
      The same as the edgeFlage callback method except that it takes an additional reference argument.
      void end()
      The end callback serves the same purpose as glEnd.
      void endData​(Object polygonData)
      The same as the end callback method except that it takes an additional reference argument.
      void error​(int errnum)
      The error callback method is called when an error is encountered.
      void errorData​(int errnum, Object polygonData)
      The same as the error callback method except that it takes an additional reference argument.
      void vertex​(Object vertexData)
      The vertex callback method is invoked between the begin and end callback methods.
      void vertexData​(Object vertexData, Object polygonData)
      The same as the vertex callback method except that it takes an additional reference argument.

    • Method Detail

      • begin

        void begin​(int type)
        The begin callback method is invoked like glBegin to indicate the start of a (triangle) primitive. The method takes a single argument of type int. If the GLU_TESS_BOUNDARY_ONLY property is set to GL_FALSE, then the argument is set to either GL_TRIANGLE_FAN, GL_TRIANGLE_STRIP, or GL_TRIANGLES. If the GLU_TESS_BOUNDARY_ONLY property is set to GL_TRUE, then the argument will be set to GL_LINE_LOOP.
        Parameters:
        type - Specifics the type of begin/end pair being defined. The following values are valid: GL_TRIANGLE_FAN, GL_TRIANGLE_STRIP, GL_TRIANGLES or GL_LINE_LOOP.
        See Also:
        gluTessCallback, end, begin

      • beginData

        void beginData​(int type,
               Object polygonData)
        The same as the begin callback method except that it takes an additional reference argument. This reference is identical to the opaque reference provided when gluTessBeginPolygon was called.
        Parameters:
        type - Specifics the type of begin/end pair being defined. The following values are valid: GL_TRIANGLE_FAN, GL_TRIANGLE_STRIP, GL_TRIANGLES or GL_LINE_LOOP.
        polygonData - Specifics a reference to user-defined data.
        See Also:
        gluTessCallback, endData, begin

      • edgeFlag

        void edgeFlag​(boolean boundaryEdge)
        The edgeFlag callback method is similar to glEdgeFlag. The method takes a single boolean boundaryEdge that indicates which edges lie on the polygon boundary. If the boundaryEdge is GL_TRUE, then each vertex that follows begins an edge that lies on the polygon boundary, that is, an edge that separates an interior region from an exterior one. If the boundaryEdge is GL_FALSE, then each vertex that follows begins an edge that lies in the polygon interior. The edge flag callback (if defined) is invoked before the first vertex callback.

        Since triangle fans and triangle strips do not support edge flags, the begin callback is not called with GL_TRIANGLE_FAN or GL_TRIANGLE_STRIP if a non-null edge flag callback is provided. (If the callback is initialized to null, there is no impact on performance). Instead, the fans and strips are converted to independent triangles.

        Parameters:
        boundaryEdge - Specifics which edges lie on the polygon boundary.
        See Also:
        gluTessCallback, edgeFlagData

      • edgeFlagData

        void edgeFlagData​(boolean boundaryEdge,
                  Object polygonData)
        The same as the edgeFlage callback method except that it takes an additional reference argument. This reference is identical to the opaque reference provided when gluTessBeginPolygon was called.
        Parameters:
        boundaryEdge - Specifics which edges lie on the polygon boundary.
        polygonData - Specifics a reference to user-defined data.
        See Also:
        gluTessCallback, edgeFlag

      • vertex

        void vertex​(Object vertexData)
        The vertex callback method is invoked between the begin and end callback methods. It is similar to glVertex3f, and it defines the vertices of the triangles created by the tessellation process. The method takes a reference as its only argument. This reference is identical to the opaque reference provided by the user when the vertex was described (see gluTessVertex).
        Parameters:
        vertexData - Specifics a reference to the vertices of the triangles created by the tessellation process.
        See Also:
        gluTessCallback, vertexData

      • vertexData

        void vertexData​(Object vertexData,
                Object polygonData)
        The same as the vertex callback method except that it takes an additional reference argument. This reference is identical to the opaque reference provided when gluTessBeginPolygon was called.
        Parameters:
        vertexData - Specifics a reference to the vertices of the triangles created by the tessellation process.
        polygonData - Specifics a reference to user-defined data.
        See Also:
        gluTessCallback, vertex

      • end

        void end()
        The end callback serves the same purpose as glEnd. It indicates the end of a primitive and it takes no arguments.
        See Also:
        gluTessCallback, begin, endData

      • endData

        void endData​(Object polygonData)
        The same as the end callback method except that it takes an additional reference argument. This reference is identical to the opaque reference provided when gluTessBeginPolygon was called.
        Parameters:
        polygonData - Specifics a reference to user-defined data.
        See Also:
        gluTessCallback, beginData, end

      • combine

        void combine​(double[] coords,
             Object[] data,
             float[] weight,
             Object[] outData)
        The combine callback method is called to create a new vertex when the tessellation detects an intersection, or wishes to merge features. The method takes four arguments: an array of three elements each of type double, an array of four references, an array of four elements each of type float, and a reference to a reference.

        The vertex is defined as a linear combination of up to four existing vertices, stored in data. The coefficients of the linear combination are given by weight; these weights always add up to 1. All vertex pointers are valid even when some of the weights are 0. coords gives the location of the new vertex.

        The user must allocate another vertex, interpolate parameters using data and weight, and return the new vertex pointer in outData. This handle is supplied during rendering callbacks. The user is responsible for freeing the memory some time after gluTessEndPolygon is called.

        For example, if the polygon lies in an arbitrary plane in 3-space, and a color is associated with each vertex, the GLU_TESS_COMBINE callback might look like this: 

               void myCombine(double[] coords, Object[] data,
                        float[] weight, Object[] outData)
         {
            MyVertex newVertex = new MyVertex();

            newVertex.x = coords[0];
            newVertex.y = coords[1];
            newVertex.z = coords[2];
            newVertex.r = weight[0]*data[0].r +
                          weight[1]*data[1].r +
                          weight[2]*data[2].r +
                          weight[3]*data[3].r;
            newVertex.g = weight[0]*data[0].g +
                          weight[1]*data[1].g +
                          weight[2]*data[2].g +
                          weight[3]*data[3].g;
            newVertex.b = weight[0]*data[0].b +
                          weight[1]*data[1].b +
                          weight[2]*data[2].b +
                          weight[3]*data[3].b;
            newVertex.a = weight[0]*data[0].a +
                          weight[1]*data[1].a +
                          weight[2]*data[2].a +
                          weight[3]*data[3].a;
            outData = newVertex;
         }
Parameters:
coords - Specifics the location of the new vertex.
data - Specifics the vertices used to create the new vertex.
weight - Specifics the weights used to create the new vertex.
outData - Reference user the put the coodinates of the new vertex.
See Also:
gluTessCallback, combineData