Coin Logo http://www.sim.no/
http://www.coin3d.org/

SoTexture2 Class Reference
[Node Classes]

#include <Inventor/nodes/SoTexture2.h>

Inherits SoTexture.

List of all members.


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
  

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
SoSFBool enableCompressedTexture

Protected Member Functions

virtual const SoFieldDatagetFieldData (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)

Member Enumeration Documentation

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

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.


Member Function Documentation

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.

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()


Member Data Documentation

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.

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, semi-transparent textures, grayscale textures, etc etc, are supported.

Wrapping strategy for the S coordinate when the texturemap is narrower than the object to map onto.

Default value is SoTexture2::REPEAT.

Wrapping strategy for the T coordinate when the texturemap is shorter than the object to map onto.

Default value is SoTexture2::REPEAT.

Texturemapping model for how the texturemap is "merged" with the polygon primitives it is applied to. Default value is SoTexture2::MODULATE.

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.

Hint to Coin that compressed textures should be used if this is supported by the graphics hardware and OpenGL drivers. Using compressed textures usually reduces texture memory usage for a texture by 4-6 times.

Since:
Coin 2.4.2

TGS Inventor 4.0


The documentation for this class was generated from the following files:

Copyright © 1998-2008 by Kongsberg SIM. All rights reserved.

Generated on Sat Nov 8 00:38:24 2008 for Coin by Doxygen 1.5.6.