diff --git a/include/osg/Transform b/include/osg/Transform index bacee23c4..e62b18233 100644 --- a/include/osg/Transform +++ b/include/osg/Transform @@ -11,9 +11,17 @@ namespace osg { /** Transform - is group which all children - are transformed by the the Transform's osg::Matrix. Typical uses - of the Transform is for positioning objects within a scene or - producing trakerball functionality or for animation. + * are transformed by the the Transform's osg::Matrix. Typical uses + * of the Transform is for positioning objects within a scene or + * producing trackball functionality or for animation. + * Note, if the transformation matrix scales the subgraph then the + * normals of the underlying geometry will need to be renormalized to + * be unit vectors once more. One can done transparently through OpenGL's + * use of either GL_NORMALIZE and GL_SCALE_NORMALIZE modes. Further + * background reading see the glNormalize documentation in the OpenGL Reference + * Guide (the blue book). To enable it in the OSG, you simple need to + * attach a local osg::StateSet to the osg::Transform, and set the appropriate + * mode to on via stateset->setMode(GL_NORMALIZE,osg::StateAttribute::ON);. */ class SG_EXPORT Transform : public Group { @@ -30,12 +38,12 @@ class SG_EXPORT Transform : public Group STATIC }; - /** Set the Transform Type, which can be DYNAMIC - the Marix - * value is updated duing the main loop, or STATIC - the Matrix - * is constant throughut the life of the main loop. STATIC + /** Set the Transform Type, which can be DYNAMIC - the Matrix + * value is updated during the main loop, or STATIC - the Matrix + * is constant throughout the life of the main loop. STATIC * Transforms can be optimized away is some instances, which - * can improve performanc so unless you plan to modify the - * Matrix explicity set the Matrix to STATIC. The default + * can improve performance so unless you plan to modify the + * Matrix explicitly set the Matrix to STATIC. The default * value is DYNAMIC.*/ inline void setType(Type type) { _type = type; }