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SoTextureScalePolicy Class Reference
[Nodes]

#include <Inventor/nodes/SoTextureScalePolicy.h>

Inheritance diagram for SoTextureScalePolicy:

SoNode SoFieldContainer SoBase List of all members.

Detailed Description

The SoTextureScalePolicy class is a node for controlling the texture scale policy.

If a texture map is of size != 2^n, it must be scaled before OpenGL can handle it. This node enables you to control how/if textures are scaled before it is sent to OpenGL.

Also, if a texture map is bigger than the maximum OpenGL texture size (implementation and context dependent), it will be scaled down to the maximum size. You can avoid this by setting the texture policy to SoTextureScalePolicy::FRACTURE, in which case the texture will be split into several small subtextures before the geometry using the texture is rendered.

The SoTextureScalePolicy::FRACTURE policy is also very handy for using the Coin library's built-in handling of non-power-of-2 textures. This will then be done completely transparent to the application programmer, for maximum convenience. Below is a very simple example which demonstrates how to use it. The texture has dimensions 3x3, but no scaling (and thereby interpolation) will have to be done when SoTextureScalePolicy::FRACTURE is specified:

  #Inventor V2.1 ascii
  
  Separator {
     TextureScalePolicy { policy FRACTURE }
     Complexity { textureQuality 0.01 }  # don't generate smoothed mipmaps
     Texture2 { 
        image 3 3 4  # dimensions 3x3, RGBA (4-component) image
        0xff0000ff 0x00ff00ff 0x0000ffff  # red, green, blue
        0xffff00ff 0xff00ffff 0x00ffffff  # yellow, magenta, cyan
        0x222222ff 0x777777ff 0xccccccff  # dark, medium and light grey
     }
     Cube { }
  }
  

Be aware that this class is an extension for Coin, and it is not available in the original SGI Open Inventor v2.1 API.

Since:
Coin 2.0


Public Types

enum  Policy { USE_TEXTURE_QUALITY, SCALE_DOWN, SCALE_UP, FRACTURE }

Public Member Functions

virtual SoType getTypeId (void) const
 SoTextureScalePolicy (void)
virtual void GLRender (SoGLRenderAction *action)

Static Public Member Functions

SoType getClassTypeId (void)
void initClass (void)

Public Attributes

SoSFEnum policy
SoSFFloat quality

Protected Member Functions

virtual const SoFieldDatagetFieldData (void) const
virtual ~SoTextureScalePolicy ()

Static Protected Member Functions

const SoFieldData ** getFieldDataPtr (void)


Member Enumeration Documentation

enum SoTextureScalePolicy::Policy
 

Enumerates the available policy settings.

Enumeration values:
USE_TEXTURE_QUALITY  Uses the texture quality to decide whether to scale up or down.
SCALE_DOWN  Always scales down.
SCALE_UP  Always scales up.
FRACTURE  Splits the texture into several subtextures, and clips the geometry into each subtexture. This makes it possible to have textures with almost unlimted size (the only real limit is the amount on memory on the system, since the entire texture most fit into memory).

Be aware that the rendering is quite slow if you have lots of triangles.


Constructor & Destructor Documentation

SoTextureScalePolicy::SoTextureScalePolicy void   ) 
 

Constructor.

SoTextureScalePolicy::~SoTextureScalePolicy  )  [protected, virtual]
 

Destructor.


Member Function Documentation

SoType SoTextureScalePolicy::getClassTypeId void   )  [static]
 

This static method returns the SoType object associated with objects of this class.

Reimplemented from SoNode.

SoType SoTextureScalePolicy::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 ** SoTextureScalePolicy::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 * SoTextureScalePolicy::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 SoTextureScalePolicy::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.

void SoTextureScalePolicy::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.


Member Data Documentation

SoSFEnum SoTextureScalePolicy::policy
 

The policy setting. Default value is USE_TEXTURE_QUALITY.

SoSFFloat SoTextureScalePolicy::quality
 

The texture scale/resize quality. Default value is 0.5.


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

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Generated on Tue Jul 13 06:41:16 2004 for Coin by Doxygen. 1.3.4