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 SbBool onoff) [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 (SbBool enable) 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_t maxage)
[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 short
flags) [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 (int status) [protected] Sets the
read status.
Author
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