For example, if your scene graph contains an SoTexture2 SoTexture2 SoTexture2 node followed by an SoSphere SoSphere SoSphere node, the texture is applied to the sphere using default texture coordinates. The texture covers the entire surface of the sphere, wrapping counterclockwise from the back of the sphere (see Figure 7.12, “ Default Texture Mapping for SoSphere ”). The texture wraps around and connects to itself. A visible seam can result if the texture is nonrepeating.

Figure 7.12.  Default Texture Mapping for SoSphere

	Tip: Increasing the complexity of a simple shape improves the appearance of a texture on it.

When a texture is applied to an SoCube SoCube SoCube using the default texture coordinates, the entire texture is applied to each face. On the front, back, right, and left sides of the cube, the texture is applied right-side up. On the top, the texture appears right-side up if you tilt the cube toward you. On the bottom, the texture appears right-side up if you tilt the cube away from you (see Figure 7.13, “ Default Texture Mapping for SoCube ”).

Figure 7.13.  Default Texture Mapping for SoCube

When a texture is applied to an SoCylinder SoCylinder SoCylinder using the default texture coordinates, the texture wraps around the sides in a counterclockwise direction, beginning at the -z axis. A circle cut from the center of the texture square is applied to the top and bottom of the cylinder. When you look at the cylinder from the +z axis, the texture on the top appears right-side up when the cylinder tips towards you. The texture on the bottom appears right-side up when the cylinder tips away from you (see Figure 7.14, “ Default Texture Mapping for SoCylinder ”).

Figure 7.14.  Default Texture Mapping for SoCylinder

When a texture is applied to anSoCone SoCone SoCone using the default texture coordinates, the texture wraps counterclockwise around the sides of the cone, starting at the back of the cone. The texture wraps around and connects to itself. A visible seam can result if the texture is nonrepeating. A circle cut from the center of the texture square is applied to the bottom of the cone just as it is applied to the bottom of a cylinder (see Figure 7.15, “ Default Texture Mapping for SoCone ”).

	Tip: Increasing the complexity of a textured cone is especially important because of the way the texture is mapped near the tip of the cone.

Figure 7.15.  Default Texture Mapping for SoCone

When a texture is applied to a NURBS surface using the default texture coordinates, the edges of the texture square are stretched to fit the NURBS patch (see Figure 7.16, “ Default Texture Mapping for SoNurbsSurface ”). A surface can be made up of many patches, like the teapot. If the NURBS surface is trimmed, so is the texture.

Figure 7.16.  Default Texture Mapping for SoNurbsSurface

When a texture is applied to the front of an SoText3 SoText3 SoText3 surface using the default texture coordinates, texture coordinate (0,0) is at the text's origin. The distance from 0.0 to 1.0 in s and t texture coordinates is equal to the font size. For the sides of an SoText3 SoText3 SoText3 surface, using default texture mapping, the s coordinate extends forward along the text profile, starting with texture coordinate 0.0 at the back of the letter and increasing to the front. A font-size distance along the profile is a texture coordinate distance of 1.0. The t coordinates extend around the outline of the character clockwise in a similar fashion. (See Figure 7.17, “ Default Texture Mapping for SoText3 ”.)

Figure 7.17.  Default Texture Mapping for SoText3

SoTextureCoordinatePlane SoTextureCoordinatePlane SoTextureCoordinatePlane , probably the most commonly used texture-coordinate function, projects a texture plane onto a shape object, as shown in Figure B.14, “ Plate 14 ”. You define an s and a t direction, which are used to define a plane for the texture. The texture coordinate (s) is then defined by the following equation, where coord is a coordinate in the object:

The fields for SoTextureCoordinatePlane SoTextureCoordinatePlane SoTextureCoordinatePlane are as follows:

The length of the direction vector equals the repeat interval of the texture (see Example 7.4, “ Using SoTextureCoordinatePlane ”).

Example 7.4, “ Using SoTextureCoordinatePlane ” shows the use ofSoTextureCoordinatePlane SoTextureCoordinatePlane SoTextureCoordinatePlane (see Figure 7.18, “ SoTextureCoordinatePlane with Different Repeat Frequencies”). It draws three texture-mapped spheres, each with a different repeat frequency as defined by the fields of the SoTextureCoordinatePlane SoTextureCoordinatePlane SoTextureCoordinatePlane node.

Figure 7.18.  SoTextureCoordinatePlane with Different Repeat Frequencies

#include <Inventor/nodes/SoMaterial.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/nodes/SoSphere.h>
#include <Inventor/nodes/SoTexture2.h>
#include <Inventor/nodes/SoTexture2Transform.h>
#include <Inventor/nodes/SoTextureCoordinatePlane.h>
#include <Inventor/nodes/SoTranslation.h>

#include <Inventor/Xt/SoXt.h>
#include <Inventor/Xt/viewers/SoXtExaminerViewer.h>

main(int , char **argv)
{
   Widget myWindow = SoXt::init(argv[0]);
   if(myWindow == NULL) exit(1);

   SoSeparator *root = new SoSeparator;
   root->ref();

   // Choose a texture.
   SoTexture2 *faceTexture = new SoTexture2;
   root->addChild(faceTexture);
   faceTexture->filename.setValue("sillyFace.rgb");
   // Make the diffuse color pure white
   SoMaterial *myMaterial = new SoMaterial;
   myMaterial->diffuseColor.setValue(1,1,1);
   root->addChild(myMaterial);

   // This texture2Transform centers the texture about (0,0,0) 
   SoTexture2Transform *myTexXf = new SoTexture2Transform;
   myTexXf->translation.setValue(.5,.5);
   root->addChild(myTexXf);

   // Define a texture coordinate plane node.  This one will 
   // repeat with a frequency of two times per unit length.
   // Add a sphere for it to affect.
   SoTextureCoordinatePlane *texPlane1 = new
             SoTextureCoordinatePlane;
   texPlane1->directionS.setValue(SbVec3f(2,0,0));
   texPlane1->directionT.setValue(SbVec3f(0,2,0));
   root->addChild(texPlane1);
   root->addChild(new SoSphere);

   // A translation node for spacing the three spheres.
   SoTranslation *myTranslation = new SoTranslation;
   myTranslation->translation.setValue(2.5,0,0);

   // Create a second sphere with a repeat frequency of 1.
   SoTextureCoordinatePlane *texPlane2 = new
            SoTextureCoordinatePlane;
   texPlane2->directionS.setValue(SbVec3f(1,0,0));
   texPlane2->directionT.setValue(SbVec3f(0,1,0));
   root->addChild(myTranslation);
   root->addChild(texPlane2);
   root->addChild(new SoSphere);

   // The third sphere has a repeat frequency of .5
   SoTextureCoordinatePlane *texPlane3 = new
            SoTextureCoordinatePlane;
   texPlane3->directionS.setValue(SbVec3f(.5,0,0));
   texPlane3->directionT.setValue(SbVec3f(0,.5,0));
   root->addChild(myTranslation);
   root->addChild(texPlane3);
   root->addChild(new SoSphere);

   SoXtExaminerViewer *myViewer = new SoXtExaminerViewer(myWindow);
   myViewer->setSceneGraph(root);
   myViewer->setTitle("Texture Coordinate Plane");
   myViewer->show();
   
   SoXt::show(myWindow);
   SoXt::mainLoop();
}
                          

using OIV.Inventor.Nodes;
using OIV.Inventor.Win;
using OIV.Inventor.Win.Viewers;
using OIV.Inventor;

namespace _07_3_TextureFunction
{
    public partial class MainForm : Form
    {
        SoWinExaminerViewer myViewer;

        public MainForm()
        {
            InitializeComponent();
            CreateSample();
        }

        public void CreateSample()
        {
            SoSeparator root = new SoSeparator();

            // Choose a texture.
            SoTexture2 faceTexture = new SoTexture2();
            root.AddChild(faceTexture);
            faceTexture.filename.SetValue("../../../../../data/sillyFace.png");

            // Make the diffuse color pure white
            SoMaterial myMaterial = new SoMaterial();
            myMaterial.diffuseColor.SetValue(1, 1, 1);
            root.AddChild(myMaterial);

            // This texture2Transform centers the texture about (0,0,0) 
            SoTexture2Transform myTexXf = new SoTexture2Transform();
            myTexXf.translation.SetValue(.5f, .5f);
            root.AddChild(myTexXf);

            // Define a texture coordinate plane node.  This one will 
            // repeat with a frequency of two times per unit length.
            // Add a sphere for it to affect.
            SoTextureCoordinatePlane texPlane1 = new SoTextureCoordinatePlane();
            texPlane1.directionS.SetValue(new SbVec3f(2, 0, 0));
            texPlane1.directionT.SetValue(new SbVec3f(0, 2, 0));
            root.AddChild(texPlane1);
            root.AddChild(new SoSphere());

            // A translation node for spacing the three spheres.
            SoTranslation myTranslation = new SoTranslation();
            myTranslation.translation.SetValue(2.5f, 0f, 0f);

            // Create a second sphere with a repeat frequency of 1.
            SoTextureCoordinatePlane texPlane2 = new SoTextureCoordinatePlane();
            texPlane2.directionS.SetValue(new SbVec3f(1, 0, 0));
            texPlane2.directionT.SetValue(new SbVec3f(0, 1, 0));
            root.AddChild(myTranslation);
            root.AddChild(texPlane2);
            root.AddChild(new SoSphere());

            // The third sphere has a repeat frequency of .5
            SoTextureCoordinatePlane texPlane3 = new SoTextureCoordinatePlane();
            texPlane3.directionS.SetValue(new SbVec3f(.5f, 0f, 0f));
            texPlane3.directionT.SetValue(new SbVec3f(0f, .5f, 0f));
            root.AddChild(myTranslation);
            root.AddChild(texPlane3);
            root.AddChild(new SoSphere());

            myViewer = new SoWinExaminerViewer(this, "", true, 
                SoWinFullViewer.BuildFlags.BUILD_ALL, SoWinViewer.Types.BROWSER);
            myViewer.SetSceneGraph(root);
            myViewer.SetTitle("Texture Coordinate Plane");

            // In Inventor 2.1, if the machine does not have hardware texture
            // mapping, we must override the default drawStyle to display textures.
            myViewer.SetDrawStyle(SoWinViewer.DrawTypes.STILL,
                           SoWinViewer.DrawStyles.VIEW_AS_IS);
        }
    }
}
                        

import tools.*;

import com.openinventor.inventor.awt.*;
import com.openinventor.inventor.nodes.*;
import com.openinventor.inventor.*;
import com.openinventor.util.Scene.DrawStyle;

import java.awt.*;

public class Main extends DemoInventor
{

  public static void main(String[] args)
  {
    Main applet = new Main();
    applet.isAnApplet = false;
    applet.start();
    demoMain(applet, "Texture Coordinate Plane");
  }

  public void start()
  {
    super.start();

    // Choose a texture.
    SoTexture2 faceTexture = new SoTexture2();
    faceTexture.filename.setValue(m_prefix + "../../../../data/textures/rgb/sillyFace.rgb");

    // Make the diffuse color pure white
    SoMaterial myMaterial = new SoMaterial();
    myMaterial.diffuseColor.setValue(1, 1, 1);

    // This texture2Transform centers the texture about (0,0,0)
    SoTexture2Transform myTexXf = new SoTexture2Transform();
    myTexXf.translation.setValue(.5f, .5f);

    // Define a texture coordinate plane node. This one will
    // repeat with a frequency of two times per unit length.
    // Add a sphere for it to affect.
    SoTextureCoordinatePlane texPlane1 = new SoTextureCoordinatePlane();
    texPlane1.directionS.setValue(new SbVec3f(2, 0, 0));
    texPlane1.directionT.setValue(new SbVec3f(0, 2, 0));

    // A translation node for spacing the three spheres.
    SoTranslation myTranslation = new SoTranslation();
    myTranslation.translation.setValue(2.5f, 0, 0);

    // Create a second sphere with a repeat frequency of 1.
    SoTextureCoordinatePlane texPlane2 = new SoTextureCoordinatePlane();
    texPlane2.directionS.setValue(new SbVec3f(1, 0, 0));
    texPlane2.directionT.setValue(new SbVec3f(0, 1, 0));

    // The third sphere has a repeat frequency of .5
    SoTextureCoordinatePlane texPlane3 = new SoTextureCoordinatePlane();
    texPlane3.directionS.setValue(new SbVec3f(.5f, 0, 0));
    texPlane3.directionT.setValue(new SbVec3f(0, .5f, 0));

    SoSeparator root = new SoSeparator();
    { // Assemble scene graph
      root.addChild(faceTexture);
      root.addChild(myMaterial);
      root.addChild(myTexXf);
      root.addChild(texPlane1);
      root.addChild(new SoSphere());
      root.addChild(myTranslation);
      root.addChild(texPlane2);
      root.addChild(new SoSphere());
      root.addChild(myTranslation);
      root.addChild(texPlane3);
      root.addChild(new SoSphere());
    }

    SwSimpleViewer myViewer = new SwSimpleViewer();
    myViewer.setSceneGraph(root);

    // In Inventor 2.1, if the machine does not have hardware texture
    // mapping, we must override the default drawStyle to display textures.
    myViewer.getArea().setDrawStyle(SwActiveArea.STILL, DrawStyle.VIEW_AS_IS);

    setLayout(new BorderLayout());
    add(myViewer, BorderLayout.CENTER);
  }
}
                        

The SoTextureCoordinateEnvironment SoTextureCoordinateEnvironment SoTextureCoordinateEnvironment node specifies that subsequent objects should reflect their environment, just as a shiny round Christmas ornament reflects its surroundings. For best results, the texture map specified should be a spherical reflection map. See the OpenGL Programming Guide, Chapter 9, for tips on how to create a spherical reflection map.

When SoTextureCoordinateEnvironment SoTextureCoordinateEnvironment SoTextureCoordinateEnvironment is used, a calculation is made at each vertex of the polygon to determine where a vector from the viewpoint to the vertex would be reflected. This reflection point defines the texture coordinate for that point on the polygon. See Figure B.16, “ Plate 16 ” and Figure B.17, “ Plate 17 ”.

Because of the way environment mapping is implemented in OpenGL, environment maps are accurate only if the camera does not move relative to the environment being reflected.