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NAME

       SoVRMLImageTexture -

       The SoVRMLImageTexture class is used for mapping a texture file onto geometry.

       The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC
       14772-1:1997). It is copyright The Web3D Consortium, and is used by permission of the
       Consortium:

SYNOPSIS

       #include <Inventor/VRMLnodes/SoVRMLImageTexture.h>

       Inherits SoVRMLTexture.

   Public Member Functions
       SoVRMLImageTexture (void)
       void allowPrequalifyFile (SbBool enable)
       virtual void doAction (SoAction *action)
       virtual void GLRender (SoGLRenderAction *action)
       virtual void callback (SoCallbackAction *action)
       virtual void rayPick (SoRayPickAction *action)
       void setImage (const SbImage &image)
       const SbImage * getImage (void) const

   Static Public Member Functions
       static void initClass (void)
       static void setDelayFetchURL (const SbBool onoff)
       static void setPrequalifyFileCallBack (VRMLPrequalifyFileCallback *cb, void *closure)
       static void setImageDataMaxAge (const uint32_t maxage)

   Public Attributes
       SoMFString url

   Protected Member Functions
       virtual ~SoVRMLImageTexture ()
       virtual SbBool readInstance (SoInput *in, unsigned short flags)
       int getReadStatus (void) const
       void setReadStatus (int status)

Detailed Description

       The SoVRMLImageTexture class is used for mapping a texture file onto geometry.

       The detailed class documentation is taken verbatim from the VRML97 standard (ISO/IEC
       14772-1:1997). It is copyright The Web3D Consortium, and is used by permission of the
       Consortium:

         ImageTexture {
           exposedField MFString url     []
           field        SFBool   repeatS TRUE
           field        SFBool   repeatT TRUE
         }
         .fi

       The ImageTexture node defines a texture map by specifying an image file and general parameters for mapping to geometry. Texture maps are defined in a 2D coordinate system (s, t) that ranges from [0.0, 1.0] in both directions. The bottom edge of the image corresponds to the S-axis of the texture map, and left edge of the image corresponds to the T-axis of the texture map. The lower-left pixel of the image corresponds to s=0, t=0, and the top-right pixel of the image corresponds to s=1, t=1. These relationships are depicted in Figure 6.9.

         Figure 6.9

       The texture is read from the URL specified by the url field. When the url field contains no values ([]), texturing is disabled. Browsers shall support the JPEG and PNG image file formats. In addition, browsers may support other image formats (e.g. CGM) which can be rendered into a 2D image. Support for the GIF format is also recommended (including transparency).

       Details on the url field can be found in 4.5, VRML and the World Wide Web.

       See 4.6.11, Texture maps (<http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#4.6.11>), for a general description of texture maps.

       See 4.14, Lighting model (<http://www.web3d.org/x3d/specifications/vrml/ISO-IEC-14772-VRML97/part1/concepts.html#4.14>), for a description of lighting equations and the interaction between textures, materials, and geometry appearance.

       The repeatS and repeatT fields specify how the texture wraps in the S and T directions. If repeatS is TRUE (the default), the texture map is repeated outside the [0.0, 1.0] texture coordinate range in the S direction so that it fills the shape. If repeatS is FALSE, the texture coordinates are clamped in the S direction to lie within the [0.0, 1.0] range. The repeatT field is analogous to the repeatS field.

       The rest of this class documentation is not from the VRML97 standards documentation, but was written specifically for the Coin3D API documentation.

       One common flaw with many programs that has support for exporting VRML or Inventor files, is that the same texture file is exported several times, but as different nodes. This can cause excessive texture memory usage and slow rendering. Below is an example program that fixes this by replacing all instances of the same texture with a pointer to the first node:

         #include <Inventor/actions/SoSearchAction.h>
         #include <Inventor/actions/SoWriteAction.h>
         #include <Inventor/VRMLnodes/SoVRMLGroup.h>
         #include <Inventor/VRMLnodes/SoVRMLImageTexture.h>
         #include <Inventor/VRMLnodes/SoVRMLAppearance.h>
         #include <Inventor/SoDB.h>
         #include <Inventor/SoInput.h>
         #include <Inventor/SoOutput.h>
         #include <assert.h>

         int main(int argc, char ** argv)
         {
           if (argc < 2) return -1;
           SoDB::init();

           SoInput in;
           if (!in.openFile(argv[1])) return -1;

           if (!in.isFileVRML2()) return -1; // file is not a vrml2 file

           SoVRMLGroup * root = SoDB::readAllVRML(&in);

           if (!root) return -1;
           root->ref();

           SoSearchAction sa;
           sa.setType(SoVRMLImageTexture::getClassTypeId());
           sa.setInterest(SoSearchAction::ALL);
           sa.setSearchingAll(TRUE);
           sa.apply(root);
           SoPathList & pl = sa.getPaths();
           SbDict namedict;

           for (int i = 0; i < pl.getLength(); i++) {
             SoFullPath * p = (SoFullPath*) pl[i];
             if (p->getTail()->isOfType(SoVRMLImageTexture::getClassTypeId())) {
               SoVRMLImageTexture * tex = (SoVRMLImageTexture*) p->getTail();
               if (tex->url.getNum()) {
                 // FIXME: we only check the first name here. Should really check all of them
                 SbName name = tex->url[0].getString();
                 unsigned long key = (unsigned long) ((void*) name.getString());
                 void * tmp;
                 if (!namedict.find(key, tmp)) {
                   (void) namedict.enter(key, tex);
                 }
                 else if (tmp != (void*) tex) {
                   SoNode * parent = p->getNodeFromTail(1);
                   if (parent->isOfType(SoVRMLAppearance::getClassTypeId())) {
                     ((SoVRMLAppearance*)parent)->texture = (SoNode*) tmp;
                   }
                   else {
                     // not a valid VRML2 file. Print a warning or something.
                   }
                 }
               }
             }
           }
           sa.reset();
           SoOutput out;
           out.setHeaderString('#VRML V2.0 utf8');
           SoWriteAction wa(&out);
           wa.apply(root);
           root->unref();
         }

Constructor & Destructor Documentation

   SoVRMLImageTexture::SoVRMLImageTexture (void) Constructor.
   SoVRMLImageTexture::~SoVRMLImageTexture () [protected, virtual] Destructor.

Member Function Documentation

   void SoVRMLImageTexture::initClass (void) [static] Sets up initialization for data common to
       all instances of this class, like submitting necessary information to the Coin type
       system.
       Reimplemented from SoVRMLTexture.

   void SoVRMLImageTexture::setDelayFetchURL (const SbBoolonoff) [static] Sets whether the image
       loading is delayed until the first time the image is needed, or if the image is loaded
       immediately when the url field is changed/set. Default value is TRUE.
   void SoVRMLImageTexture::setPrequalifyFileCallBack (VRMLPrequalifyFileCallback *cb, void
       *closure) [static] Sets the prequalify callback for ImageTexture nodes. This is a callback
       that will be called when an image is about to be read.
   void SoVRMLImageTexture::allowPrequalifyFile (SbBoolenable) Enable prequalify file loading.
   void SoVRMLImageTexture::doAction (SoAction *action) [virtual] This function performs the
       typical operation of a node for any action.
       Reimplemented from SoNode.

   void SoVRMLImageTexture::GLRender (SoGLRenderAction *action) [virtual] Action method for the
       SoGLRenderAction.
       This is called during rendering traversals. Nodes influencing the rendering state in any
       way or who wants to throw geometry primitives at OpenGL overrides this method.

       Reimplemented from SoVRMLTexture.

   void SoVRMLImageTexture::callback (SoCallbackAction *action) [virtual] Action method for
       SoCallbackAction.
       Simply updates the state according to how the node behaves for the render action, so the
       application programmer can use the SoCallbackAction for extracting information about the
       scene graph.

       Reimplemented from SoNode.

   void SoVRMLImageTexture::rayPick (SoRayPickAction *action) [virtual] Action method for
       SoRayPickAction.
       Checks the ray specification of the action and tests for intersection with the data of the
       node.

       Nodes influencing relevant state variables for how picking is done also overrides this
       method.

       Reimplemented from SoNode.

   void SoVRMLImageTexture::setImage (const SbImage &image) Set the image data for this node. Can
       be used by the prequalify callback to set the data in the node.
   const SbImage * SoVRMLImageTexture::getImage (void) const Returns the texture image.
   void SoVRMLImageTexture::setImageDataMaxAge (const uint32_tmaxage) [static] This API member is
       considered internal to the library, as it is not likely to be of interest to the
       application programmer.
   SbBool SoVRMLImageTexture::readInstance (SoInput *in, unsigned shortflags) [protected,
       virtual] This method is mainly intended for internal use during file import operations.
       It reads a definition of an instance from the input stream in. The input stream state
       points to the start of a serialized / persistant representation of an instance of this
       class type.

       TRUE or FALSE is returned, depending on if the instantiation and configuration of the new
       object of this class type went ok or not. The import process should be robust and handle
       corrupted input streams by returning FALSE.

       flags is used internally during binary import when reading user extension nodes, group
       nodes or engines.

       Reimplemented from SoNode.

   int SoVRMLImageTexture::getReadStatus (void) const [protected] Returns the read status.
   void SoVRMLImageTexture::setReadStatus (intstatus) [protected] Sets the read status.

Author

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