sotexture2(3)

NAME

SoTexture2

SYNOPSIS

#include <Inventor/nodes/SoTexture2.h>
Inherits SoNode.

Detailed Description

The SoTexture2 class is used to map a 2D texture onto subsequent geometry in the scenegraph.

Shape nodes within the scope of SoTexture2 nodes in the scenegraph (ie below the same SoSeparator and to the righthand side of the SoTexture2) will have the texture applied according to each shape type's individual characteristics. See the documentation of the various shape types
(SoFaceSet, SoCube, SoSphere, etc etc) for information about the specifics of how the textures will be applied.

For a simple usage example, see the class documentation for SoSFImage.

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/nodes/SoSeparator.h>
#include <Inventor/nodes/SoTexture2.h>
#include <Inventor/SoDB.h>
#include <Inventor/SoInput.h>
#include <Inventor/SoOutput.h>
int main(int argc, char ** argv)
{
if (argc < 2) return -1;
SoDB::init();
SoInput in;
if (!in.openFile(argv[1])) return -1;
SoSeparator * root = SoDB::readAll(&in);
if (!root) return -1;
root->ref();
SoSearchAction sa;
sa.setType(SoTexture2::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(SoTexture2::getClassTypeId())) {
SoTexture2 * tex = (SoTexture2*) p->getTail();
if (tex->filename.getValue().getLength()) {
SbName name = tex->filename.getValue().getString();
unsigned long key = (unsigned long) ((void*) name.getString());
void * tmp;
if (!namedict.find(key, tmp)) {
// new texture. just insert into list
(void) namedict.enter(key, tex);
}
else if (tmp != (void*) tex) { // replace with node found in dict
SoGroup * parent = (SoGroup*) p->getNodeFromTail(1);
int idx = p->getIndexFromTail(0);
parent->replaceChild(idx, (SoNode*) tmp);
}
}
}
}
sa.reset();
// output fixed scene to stdout
SoOutput out;
SoWriteAction wa(&out);
wa.apply(root);
root->unref();
}
When working with Inventor files, one often wants to embed external
texture image files into the Inventor files themselves. Here's a
minimal, stand-alone example which shows how that can be accomplished
by calling SoField::touch() on the SoTexture2::image fields before scenegraph export:

#include <Inventor/SoDB.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoTexture2.h>
#include <Inventor/actions/SoSearchAction.h>
#include <Inventor/actions/SoWriteAction.h>
int
main(void)
{
SoDB::init();
SoInput in;
SoSeparator * root = SoDB::readAll(&in);
if (!root) { exit(1); }
root->ref();
SoSearchAction searchaction;
searchaction.setType(SoTexture2::getClassTypeId());
searchaction.setSearchingAll(TRUE);
searchaction.setInterest(SoSearchAction::ALL);
searchaction.apply(root);
const SoPathList & pl = searchaction.getPaths();
for (int i=0; i < pl.getLength(); i++) {
SoFullPath * fp = (SoFullPath *)pl[i];
SoTexture2 * tex = (SoTexture2 *)fp->getTail();
assert(tex->getTypeId() == SoTexture2::getClassTypeId());
tex->image.touch();
}
SoWriteAction wa;
wa.apply(root);
root->unref();
return 0;
}
Run the example by piping the iv-file you want do texture-embedding on from stdin, e.g. like this:

$ ./test < input.iv
.fi
FILE FORMAT/DEFAULTS:

Texture2 {
filename ''
image 0 0 0
wrapS REPEAT
wrapT REPEAT
model MODULATE
blendColor 0 0 0
enableCompressedTexture FALSE
}
Public Types
enum Model { MODULATE = SoTextureImageElement::MODULATE, DECAL =
SoTextureImageElement::DECAL, BLEND =
SoTextureImageElement::BLEND, REPLACE =
SoTextureImageElement::REPLACE }
enum Wrap { REPEAT = SoTextureImageElement::REPEAT, CLAMP =
SoTextureImageElement::CLAMP }
Public Member Functions
virtual SoType getTypeId (void) const
SoTexture2 (void)
virtual void doAction (SoAction *action) virtual void GLRender (SoGLRenderAction *action) virtual void callback (SoCallbackAction *action) virtual void rayPick (SoRayPickAction *action)
Static Public Member Functions
static SoType getClassTypeId (void) static void initClass (void)
static SbBool readImage (const SbString &fname, int &w, int &h, int
&nc, unsigned char *&bytes)
Public Attributes
SoSFString filename
SoSFImage image
SoSFEnum wrapS
SoSFEnum wrapT
SoSFEnum model
SoSFColor blendColor
Protected Member Functions
virtual const SoFieldData * getFieldData (void) const virtual ~SoTexture2 ()
virtual SbBool readInstance (SoInput *in, unsigned short flags) virtual void notify (SoNotList *list)
int getReadStatus (void)
void setReadStatus (int s)
Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)
Friends
class SoFieldData

Member Enumeration Documentation

enum SoTexture2::Model
Texture mapping model, for deciding how to 'merge' the texturemap with the object it is mapped onto.
Enumerator:
MODULATE
Texture color is multiplied by the polygon color. The result
will be Phong shaded (if light model is PHONG).
DECAL Texture image overwrites polygon shading. Textured pixels will
not be Phong shaded. Has undefined behaviour for grayscale and
grayscale-alpha textures.
BLEND This model is normally used with monochrome textures (i.e.
textures with one or two components). The first component, the
intensity, is then used to blend between the shaded color of the polygon and the SoTexture2::blendColor.
REPLACE
Texture image overwrites polygon shading. Textured pixels will
not be Phong shaded. Supports grayscale and grayscale alpha
textures. This feature requires OpenGL 1.1. MODULATE will be
used if OpenGL version < 1.1 is detected.
Please note that using this texture model will make your Inventor files incompatible with older versions of Coin and Inventor. You need Coin >= 2.2 or TGS Inventor 4.0 to load Inventor files that uses the REPLACE
texture model.
Since:
Coin 2.2
TGS Inventor 4.0
enum SoTexture2::Wrap
Enumeration of wrapping strategies which can be used when the
texturemap doesn't cover the full extent of the geometry.
Enumerator:
REPEAT Repeat texture when coordinate is not between 0 and 1.
CLAMP Clamp coordinate between 0 and 1.

Constructor & Destructor Documentation

SoTexture2::SoTexture2 (void)
Constructor.
SoTexture2::~SoTexture2 () [protected, virtual]
Destructor. Frees up internal resources used to store texture image
data.
References SoNode::VRML1.

Member Function Documentation

SoType SoTexture2::getClassTypeId (void) [static]
This static method returns the SoType object associated with objects of this class.
Reimplemented from SoNode.
Referenced by SoFieldData::addField(), SoFieldData::getField(), and
SoFieldData::getIndex().
SoType SoTexture2::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
}
else if (node->getTypeId().isOfType(SoGroup::getClassTypeId())) {
SoGroup * group = (SoGroup *)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.
Implements SoBase.
const SoFieldData ** SoTexture2::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 SoNode.
const SoFieldData * SoTexture2::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 SoFieldContainer.
void SoTexture2::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 SoNode.
Referenced by SoNode::initClasses().
void SoTexture2::doAction (SoAction * action) [virtual]
This function performs the typical operation of a node for any action.
Reimplemented from SoNode.
Referenced by callback().
void SoTexture2::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 SoNode.
void SoTexture2::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.
References doAction().
void SoTexture2::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.
SbBool SoTexture2::readImage (const SbString & fname, int & w, int & h, int
& nc, unsigned char *& bytes) [static] Not implemented in Coin; should probably not have been public in the
original SGI Open Inventor API. We'll consider to implement it if
requested.
SbBool SoTexture2::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.
References filename, SbString::getString(), SoSFString::getValue(),
SoReadError::post(), and setReadStatus().
void SoTexture2::notify (SoNotList * l) [protected, virtual]
Notifies all auditors for this instance when changes are made.
Reimplemented from SoNode.
int SoTexture2::getReadStatus (void) [protected]
Returns read status. 1 for success, 0 for failure.
void SoTexture2::setReadStatus (int s) [protected]
Sets read status.
See also:
getReadStatus()
References SoNotList::getLastField(), and image.
Referenced by readInstance().

Member Data Documentation

SoSFString SoTexture2::filename
Texture filename, referring to a file on disk in a supported image
bitmap format.
By default contains an empty string, which means the texture will be
fetched from SoTexture2::image and not from disk. (Specify either this field or use SoTexture2::image, not both.)
For reading texture image files from disk, Coin uses the 'simage'
library from Systems in Motion. This library must be installed for it
to be possible to load any image files at all.
The set of image formats you can actually read with the simage library depends on how the simage library was built, as simage is again
dependent on a few other low-level file import/export libraries (for
instance for JPEG, GIF, TIFF and PNG support). To make sure all wanted formats are supported, you should build the simage library yourself.
The set of image formats guaranteed to be supported by simage is Targa (.tga), PIC (.pic), SGI RGB (.rgb, .bw) and XWD (.xwd).
For more information about the simage library, including download and
build instructions, see the Coin www-pages.
Referenced by readInstance().
SoSFImage SoTexture2::image
Inline image data. Defaults to contain an empty image.
See documentation of the SoSFImage class for a very detailed description of how the format specification for the image data is layed out, and what different image formats for color textures, semitransparent textures, grayscale textures, etc etc, are supported.
Referenced by setReadStatus().
SoSFEnum SoTexture2::wrapS
Wrapping strategy for the S coordinate when the texturemap is narrower than the object to map onto.
Default value is SoTexture2::REPEAT.
SoSFEnum SoTexture2::wrapT
Wrapping strategy for the T coordinate when the texturemap is shorter
than the object to map onto.
Default value is SoTexture2::REPEAT.
SoSFEnum SoTexture2::model
Texturemapping model for how the texturemap is 'merged' with the
polygon primitives it is applied to. Default value is
SoTexture2::MODULATE.
SoSFColor SoTexture2::blendColor
Blend color. Used when SoTexture2::model is SoTexture2::BLEND.
Default color value is [0, 0, 0], black, which means no contribution to the blending is made.

Author

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