Package com.openinventor.inventor.nodes

Class SoTexture3

  • All Implemented Interfaces:
    SafeDisposable
    public class SoTexture3
extends SoTexture
    3D texture mapping node. This property node defines a 3D texture map and parameters for that map. This map is used to apply a 3D texture to subsequent shapes as they are rendered.

    The texture can be read from the file(s) specified by the filenames field. Once the texture has been read, the images field contains the texture data. However, this field is marked so the image is not written out when the texture node is written to a file. To turn off texturing, set the first value of the filenames field to an empty string ("").

    Textures can also be specified in memory by setting the images field to contain the texture data. Doing so resets the filenames field to the empty string.

    Simply put, a 3D texture is a set of well-arranged 2D textures. Typically, 3D textures represent a set of image-slices of a given volume of data, and are used for mapping onto pieces of geometry. Note that this is different from direct volume rendering in that 3D textures need to be mapped onto a piece of geometry.

    OpenGL requires all images in a 3D texture to have the same dimensions, and each dimension (X, Y, and Z) needs to be a power of 2. Also, images must have the same number of components (grayscale, grayscale with transparency, RGB, or RGB with transparency).

    • Images that do not have the same number of components as the first image are recomputed to have the same number of components. At best, there is no loss of quality. At worst, the recomputed images may lose colors and/or transparency.
    • If the 2D texture image's width or height is greater than the maximum supported by OpenGL, then the image will be clipped at the maximum texture size.
    • If one or more of the dimensions is not a power of 2, the texture is enlarged (it is never shrunk) to fit the power-of-2 requirement. Note that, unlike 2D textures where a resized texture is actually rescaled, the 3D image is not rescaled. Instead, black pixels are added to the edge of the image.

    You should take this into account when setting texture coordinates. If your 3D image is not correctly dimensioned, you may want to consider either applying a ratio to your coordinates or adding an SoTexture3Transform node with the field scaleFactor set to compensate.

    • Images that have a different size from the first image are resized (clipped or augmented) to match the size of the first image (which itself may have been resized to satisfy the size requirements of OpenGL).
    • If the number of images (the depth of the 3D texture) is not a power of 2, an error is issued and the nearest power of 2 is chosen. If it is lower, some images are discarded; if it is higher, new images are created and filled with zeros.

    The quality of the texturing is affected by the textureQuality field of the SoComplexity node. The textureQuality field affects what kind of filtering is done to the texture when it must be minified or magnified. The mapping of a particular texture quality value to a particular OpenGL filtering technique is implementation dependent, and varies based on the texturing performance. If mipmap filtering is required, mipmaps are automatically created using the simple box filter.

    Transparency Texture images can contain transparency (alpha values less than 1) and modify the transparency of geometry in the scene. Also note that some image file formats, for example JPEG, do not support transparency information (alpha channel).

    LIMITATIONS

    3D textures are only supported by the following shapes:

    Only SoIndexedFaceSet shapes automatically compute texture coordinates if they are not specified either by a texture coordinate function (see SoTextureCoordinateFunction) or by explicit texture coordinates (see SoTextureCoordinate3).

    File format/default:

    Texture3 {

      filenames ""
      enableCompressedTexture false
      images 0 0 0 0
      wrapS REPEAT
      wrapT REPEAT
      wrapR REPEAT
      model MODULATE
      blendColor 0 0 0
      enableBorder false
      borderColor 0 0 0 1
      maxAnisotropy 1.0
      minFilter AUTO
      magFilter AUTO
      useAutoMipmap false
      internalFormat AUTO_INTERNAL_FORMAT
      layout VOLUME
    }

    Action behavior:

    SoGLRenderAction, SoCallbackAction
    Sets current texture in state. Sets: SoTextureImage3Element

    See Also:
    SoComplexity, SoMaterial, SoTextureCoordinate3, SoTextureCoordinateBinding, SoTextureCoordinateFunction

    • Field Detail

      • filenames

        public final SoMFFilePathString filenames
        Names of file(s) from which to read texture image(s).
        The standard image file formats are supported. See SoRasterImageRW for the list. If the filename is not an absolute path name, the list of directories maintained by SoInput is searched. If the texture is not found in any of those directories, then the file is searched for relative to the directory from which the SoTexture3 node was read. For example, if an SoTexture3 node with a filename of "../tofu.rgb" is read from /usr/people/bob/models/food.iv, then /usr/people/bob/tofu.rgb will be read (assuming tofu.rgb isn't found in the directories maintained by SoInput).

        All images must have the same dimensions and number of components. Depth (number of slices) is determined by the number of file names.

        Note that only 2D image file formats are currently supported. A 3D texture image can be read as a series of 2D image files.

      • images

        public final SoSFImage3 images
        Contains an in-memory representation of the texture map. It is either the contents of the file(s) read from filenames, an image read directly from an Open Inventor file, or an image set programmatically using the methods provided by SoSFImage3.

      • wrapT

        public final SoSFEnum<SoTexture.WrapType> wrapT
        Indicates what to do when texture coordinates in the T (vertical) direction lie outside the range 0-1. . Default is REPEAT.

      • wrapR

        public final SoSFEnum<SoTexture.WrapType> wrapR
        Indicates what to do when texture coordinates in the R (depth) direction lie outside the range 0-1. . Default is REPEAT.

      • layout

        public final SoSFEnum<SoTexture3.Layouts> layout
        Indicates whether the data layout is a volumetric texture VOLUME or an array of bi-dimensional textures ARRAY. . Default is VOLUME.

        Note that if you use a SoTexture3 with a SoShaderProgram, the layout value affects the type of sampler in GLSL: if the layout value is VOLUME, the sampler type is sampler3D; if the layout value is ARRAY, the sampler type is sampler2DArray.

        Since:
        Open Inventor 9.6

    • Constructor Detail

      • SoTexture3

        public SoTexture3()
        Creates a texture node with default settings.