SoVRMLPixelTexture Class Reference
[VRML97 nodes]

Texture node. More...

#include <Inventor/VRMLnodes/SoVRMLPixelTexture.h>

Inheritance diagram for SoVRMLPixelTexture:

Public Member Functions
virtual SoType	getTypeId () const
	SoVRMLPixelTexture ()
Static Public Member Functions
static SoType	getClassTypeId ()
Public Attributes
SoSFImage	image

Detailed Description

Texture node.

See the VRML97 Specification, below.

NOTE: This class does not exist in Open Inventor 10.0 and later.

If the texture image's width or height is not a power of 2, or the image's width or height is greater than the maximum supported by OpenGL, then the image will be automatically scaled up or down to the next power of 2 or the maximum texture size. For maximum speed, point-sampling is used to do the scale; if you want more accurate resampling, pre-filter images to a power of 2 smaller than the maximum texture size (use the OpenGL glGetIntegerv(GL_MAX_TEXTURE_SIZE...) call to determine maximum texture for a specific OpenGL implementation).

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.

Performance Note: Automatic scaling of texture images to a power of 2 is a very convenient feature for prototyping, but it does take additional time the first time the texture node is traversed for rendering. For large images, or a large number of images, this can make the application seem slow while starting up or loading a new data file. Avoid this effect by either pre-scaling the image or by storing it as a sub-image in a "power of 2" image (then provide explicit texture coordinates such that only the sub-image is used).

VRML97 SPECIFICATION

This section may reference portions of the VRML97 specification that are not present in this help file. The complete VRML97 spec is available at http://www.web3d.org .

The SoVRMLPixelTexture node defines a 2D image-based texture map as an explicit array of pixel values and parameters controlling tiling repetition of the texture onto geometry.

Texture maps are defined in a 2D coordinate system, (s,t), that ranges from 0.0 to 1.0 in both directions. The bottom edge of the pixel image corresponds to the S-axis of the texture map, and left edge of the pixel image corresponds to the T-axis of the texture map. The lower-left pixel of the pixel image corresponds to s=0, t=0, and the top-right pixel of the image corresponds to s=1, t=1.

Images may be one component (grayscale), two component (grayscale plus alpha opacity), three component (full RGB color), or four-component (full RGB color plus alpha opacity). An ideal VRML implementation will use the texture image to modify the diffuse color and transparency ( = 1 - alpha opacity) of an object's material (specified in an SoVRMLMaterial node), then perform any lighting calculations using the rest of the object's material properties with the modified diffuse color to produce the final image. The texture image modifies the diffuse color and transparency depending on how many components are in the image, as follows:

1. Diffuse color is multiplied by the grayscale values in the texture image.

2. Diffuse color is multiplied by the grayscale values in the texture image; material transparency is multiplied by transparency values in texture image.

3. RGB colors in the texture image replace the material's diffuse color.

4. RGB colors in the texture image replace the material's diffuse color; transparency values in the texture image replace the material's transparency.

Browsers may approximate this ideal behavior to increase performance. One common optimization is to calculate lighting only at each vertex and combining the texture image with the color computed from lighting (performing the texturing after lighting). Another common optimization is to perform no lighting calculations at all when texturing is enabled, displaying only the colors of the texture image.

See "Concepts - Lighting Model" for details on the VRML lighting equations.

See the "Field Reference - SFImage" specification for details on how to specify an image.

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-to-1 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-to-1 range. The repeatT field is analogous to the repeatS field.

FILE FORMAT/DEFAULT

image	0 0 0
repeatS	TRUE
repeatT	TRUE
metadata	NULL

ACTION BEHAVIOR

SoGLRenderAction

SoCallbackAction

SoTextureImageElement

EVENTS

eventIn

SoSFImage	set_image
SoSFNode	set_metadata

eventOut

SoSFImage	image_changed
SoSFNode	metadata_changed

Deprecated:: Deprecated since Open Inventor 9500
The VRML API is no longer supported. See section http://oivdoc95.vsg3d.com/content/compatibility-notes-4#Deprecation of the Reference Manual.

Constructor & Destructor Documentation

SoVRMLPixelTexture::SoVRMLPixelTexture ( )

Constructor.

Member Function Documentation

static SoType SoVRMLPixelTexture::getClassTypeId ( ) [static]

Returns the type identifier for this class.

Reimplemented from SoVRMLTexture.

virtual SoType SoVRMLPixelTexture::getTypeId ( ) const [virtual]

Returns the type identifier for this specific instance.

Reimplemented from SoVRMLTexture.

Member Data Documentation

SoSFImage SoVRMLPixelTexture::image

The texture map.

Inventor/VRMLnodes/SoVRMLPixelTexture.h

SoVRMLPixelTexture Class Reference [VRML97 nodes]

Public Member Functions

Static Public Member Functions

Public Attributes