SoVRMLImageTexture(3) The SoVRMLImageTexture class is used for mapping a texture file onto geometry.

SYNOPSIS


#include <Inventor/VRMLnodes/SoVRMLImageTexture.h>

Inherits SoVRMLTexture.

Public Member Functions


virtual SoType getTypeId (void) const

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 SoType getClassTypeId (void)

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 const SoFieldData * getFieldData (void) const

virtual ~SoVRMLImageTexture ()

virtual SbBool readInstance (SoInput *in, unsigned short flags)

int getReadStatus (void) const

void setReadStatus (int status)

Static Protected Member Functions


static const SoFieldData ** getFieldDataPtr (void)

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

SoType SoVRMLImageTexture::getClassTypeId (void) [static]

This static method returns the SoType object associated with objects of this class.

Reimplemented from SoVRMLTexture.

SoType SoVRMLImageTexture::getTypeId (void) const [virtual]

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and 'downward' casting.

Usage example: 

  void foo(SoNode * node)
  {
    if (node->getTypeId() == SoFile::getClassTypeId()) {
      SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
    }
  }

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Reimplemented from SoVRMLTexture.

const SoFieldData ** SoVRMLImageTexture::getFieldDataPtr (void) [static], [protected]

This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.

Reimplemented from SoVRMLTexture.

const SoFieldData * SoVRMLImageTexture::getFieldData (void) const [protected], [virtual]

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoVRMLTexture.

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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