Overview | Package | Class | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## com.sun.j3d.utils.geometry
Class NormalGenerator

    java.lang.Object
      com.sun.j3d.utils.geometry.NormalGenerator

    public class NormalGenerator

extends java.lang.Object

The NormalGenerator utility will calculate and fill in the normals of a GeometryInfo object. The calculated normals are estimated based on an analysis of the indexed coordinate information. If your data isn't indexed, index lists will be created.

If two (or more) triangles in the model share the same coordinate index then the normal generator will attempt to generate one normal for the vertex, resulting in a "smooth" looking surface. If two coordinates don't have the same index then they will have two separate normals, even if they have the same position. This will result in a "crease" in your object. If you suspect that your data isn't properly indexed, call GeometryInfo.recomputeIndexes().

Of course, sometimes your model *has* a crease in it. That's what creaseAngle is. If two triangles' normals differ by more than creaseAngle, then the vertex will get two separate normals, creating a discontinuous crease in the model. This is perfect for the edge of a table or the corner of a cube, for instance.

Constructor Summary
`NormalGenerator()` Constructor.
`NormalGenerator(double radians)` Constructor.

Method Summary
`void` | `generateNormals(GeometryInfo geom)` Generate normals for the GeometryInfo object.
`double` | `getCreaseAngle()` Returns the current value of the crease angle, in radians.
`void` | `setCreaseAngle(double radians)` Set the crease angle.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### NormalGenerator

    public NormalGenerator(double radians)

  Constructor. Construct a NormalGenerator object with creaseAngle set to the given value.

### NormalGenerator

    public NormalGenerator()

  Constructor. Construct a NormalGenerator object with creaseAngle set to 44 degrees (0.767944871 radians).

Method Detail

### generateNormals

    public void generateNormals(GeometryInfo geom)

  Generate normals for the GeometryInfo object. If the GeometryInfo object didn't previously contain indexed data, indexes are made by collapsing identical positions into a single index. Any normal information previously contained in the GeometryInfo object is lost. Strips and Fans are converted into individual triangles for Normal generation, but are stitched back together if GeometryInfo.getGeometryArray() (or getIndexedGeometryArray()) is called without stripifying first.

### setCreaseAngle

    public void setCreaseAngle(double radians)

  Set the crease angle. If two triangles' normals differ by more than creaseAngle, then the vertex will get two separate normals, creating a discontinuous crease in the model. This is perfect for the edge of a table or the corner of a cube, for instance. Clamped to 0 <= creaseAngle <= PI. Optimizations are made for creaseAngle == 0 (facet normals) and creaseAngle == PI (smooth shading).

### getCreaseAngle

    public double getCreaseAngle()

  Returns the current value of the crease angle, in radians.

Overview | Package | Class | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

Copyright 1996-2008 Sun Microsystems, Inc. All Rights Reserved. Use is subject to license terms.