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SoTextureCombine.3coin2

Langue: en

Version: 383899 (fedora - 01/12/10)

Section: 3 (Bibliothèques de fonctions)

Sommaire

NAME
SYNOPSIS
Detailed Description
Member Enumeration Documentation
Constructor & Destructor Documentation
- SoTextureCombine::SoTextureCombine (void)Constructor.
- SoTextureCombine::~SoTextureCombine () [protected, virtual]Destructor.
Member Function Documentation
Author

NAME

SoTextureCombine -

The SoTextureCombine class is a node for setting texture combine functions.

This node is more or less an exact mapping of the OpenGL ARB_texture_env_combine extension (included in OpenGL in OpenGL v1.3). See http://oss.sgi.com/projects/ogl-sample/registry/ARB/texture_env_combine.txt for more information about this extension.

SYNOPSIS

#include <Inventor/nodes/SoTextureCombine.h>

Inherits SoNode.

Public Types

enum Source { PRIMARY_COLOR = SoTextureCombineElement::PRIMARY_COLOR, TEXTURE = SoTextureCombineElement::TEXTURE, CONSTANT = SoTextureCombineElement::CONSTANT, PREVIOUS = SoTextureCombineElement::PREVIOUS }

enum Operand { SRC_COLOR = SoTextureCombineElement::SRC_COLOR, ONE_MINUS_SRC_COLOR = SoTextureCombineElement::ONE_MINUS_SRC_COLOR, SRC_ALPHA = SoTextureCombineElement::SRC_ALPHA, ONE_MINUS_SRC_ALPHA = SoTextureCombineElement::ONE_MINUS_SRC_ALPHA }

enum Operation { REPLACE = SoTextureCombineElement::REPLACE, MODULATE = SoTextureCombineElement::MODULATE, ADD = SoTextureCombineElement::ADD, ADD_SIGNED = SoTextureCombineElement::ADD_SIGNED, SUBTRACT = SoTextureCombineElement::SUBTRACT, INTERPOLATE = SoTextureCombineElement::INTERPOLATE, DOT3_RGB = SoTextureCombineElement::DOT3_RGB, DOT3_RGBA = SoTextureCombineElement::DOT3_RGBA }

Public Member Functions

SoTextureCombine (void)

virtual void doAction (SoAction *action)

virtual void callback (SoCallbackAction *action)

virtual void GLRender (SoGLRenderAction *action)

virtual void pick (SoPickAction *action)

Static Public Member Functions

static void initClass (void)

Public Attributes

SoMFEnum rgbSource

SoMFEnum alphaSource

SoMFEnum rgbOperand

SoMFEnum alphaOperand

SoSFEnum rgbOperation

SoSFEnum alphaOperation

SoSFFloat rgbScale

SoSFFloat alphaScale

SoSFVec4f constantColor

Protected Member Functions

virtual ~SoTextureCombine ()

Detailed Description

The SoTextureCombine class is a node for setting texture combine functions.

Basically this node lets you specify up to three sources, and a function to combine those sources. In addition to the function, it's possible to apply simple operands on the sources. In the documentation below, the sources will be called Arg0, Arg1, and Arg2, just like in the ARB_texture_env_mode specification.

It's possible to specify both a color and an alpha operation.

This node has many fields, but usually it is sufficient to set only one or very few fields. The selected operation decides which values you need to set. One common example is to add a light map to textured geometry. A lightmap can look like this:

The example below just shows how to apply the lightmap to a cube, with one light source on each side of the cube. Usually the texture coordinates are calculated so that a spot light or a point light is simulated.

 
 
   Texture2 { filename "wood.jpg" }
   
   Switch {
     whichChild -3   # use to toggle lightmap on/off
     TextureUnit {
       unit 1
     }
     TextureCombine {
       rgbOperation ADD_SIGNED
       rgbSource [PREVIOUS, TEXTURE]
       rgbOperand [SRC_COLOR, SRC_COLOR ]
       alphaOperation REPLACE
       alphaSource [TEXTURE]
       alphaOperand [SRC_ALPHA]
     }
     Texture2 { filename "lightmap.jpg" }
     TextureUnit { unit 0 }
   }
   Cube { }
 
   .fi
 
 
 The scene above in a viewer:
 
   
 
 In addition to the functions you can set in rgbOperation (or alphaOperation), it's possible to create more complex texture functions by combining two textures that have already been combined. You can use the SoSceneTexture2 node to create those textures. Below is an example that shows how to implement Arg0*Arg1 + Arg2*Arg0, where Arg0 = texture1 RGB, Arg1 = texture2 RGB, Arg2 = texture 2 alpha:
 
 
 
 
   ShapeHints { vertexOrdering COUNTERCLOCKWISE shapeType SOLID }
 
   Separator {
     SceneTexture2 {
       size 256 256
       transparencyFunction NONE
       scene Separator {
         OrthographicCamera {
           height 2
           aspectRatio 1
           position 0 0 1
           viewportMapping LEAVE_ALONE
         }
         LightModel { model BASE_COLOR }
         Coordinate3 {
           point [ -1 -1 0, 1 -1 0, 1 1 0, -1 1 0 ] 
         }
         DEF texture1 Texture2 { filename "texture1.png" }
         TextureUnit { unit 1 }
         TextureCombine {
           rgbOperation MODULATE
           rgbSource [ PREVIOUS, TEXTURE ]
           rgbOperand [ SRC_COLOR, SRC_COLOR ]
           alphaOperation REPLACE
           alphaSource [TEXTURE]
           alphaOperand [ SRC_ALPHA ]
         }
         DEF texture2 Texture2 { filename "texture2_with_alpha.png" }
         TextureCoordinate2 {
           point [0 0, 1 0, 1 1, 0 1]
         }
         FaceSet { numVertices 4 }
       }
     }
     TextureUnit { unit 1 }
     TextureCombine {
       rgbOperation ADD
       rgbSource [ PREVIOUS, TEXTURE ]
       rgbOperand [ SRC_COLOR, SRC_COLOR ]
       alphaOperation REPLACE
       alphaSource [TEXTURE]
       alphaOperand [ SRC_ALPHA ]
     }
     SceneTexture2 {
       size 256 256
       transparencyFunction NONE
       scene Separator {
         OrthographicCamera {
           height 2
           aspectRatio 1
           position 0 0 1
           viewportMapping LEAVE_ALONE
         }
         LightModel { model BASE_COLOR }
         Coordinate3 {
           point [ -1 -1 0, 1 -1 0, 1 1 0, -1 1 0 ] 
         }
         USE texture1
         TextureUnit { unit 1 }
         TextureCombine {
           rgbOperation MODULATE
           rgbSource [ PREVIOUS, TEXTURE ]
           rgbOperand [ SRC_COLOR, SRC_ALPHA ]
           alphaOperation REPLACE
           alphaSource [TEXTURE]
           alphaOperand [ SRC_ALPHA ]
         }
         USE texture2
         TextureCoordinate2 {
           point [0 0, 1 0, 1 1, 0 1]
         }
         FaceSet { numVertices 4 }
       }
     }
     # map resulting texture onto a Cube
     Cube { }
   }
   .fi
 
 
 It should be possible to create almost any kind of texture function using this scheme, at the cost of extra texture memory usage (the intermediate textures), of course.
 
 FILE FORMAT/DEFAULTS: 
 
     TextureCombine {
         rgbSource [  ]
         alphaSource [  ]
         rgbOperand [  ]
         alphaOperand [  ]
         rgbOperation MODULATE
         alphaOperation MODULATE
         rgbScale 1
         alphaScale 1
         constantColor 1 1 1 1
     }

Since:

Coin 2.3

Member Enumeration Documentation

enum SoTextureCombine::SourceFor enumerating combiner sources.

Enumerator:

PRIMARY_COLOR: Choose primary color as source.
TEXTURE: Choose texture as source.
CONSTANT: Choose the constantColor field as source.
PREVIOUS: Choose the previous unit's texture as source.

enum SoTextureCombine::OperandFor enumerating source operands.

Enumerator:

SRC_COLOR: Use the source color as operand.
ONE_MINUS_SRC_COLOR: Use one minus source color as operand.
SRC_ALPHA: Use the source alpha as operand.
ONE_MINUS_SRC_ALPHA: Use one minus source alpha as operand.

enum SoTextureCombine::OperationFor enumerating combiner operations/functions.

Enumerator:

REPLACE: dst = Arg0
MODULATE: dst = Arg0 * Arg1
ADD: dst = Arg0 + Arg1
ADD_SIGNED: dst = Arg0 + Arg1 - 0.5
SUBTRACT: dst = Arg0 - Arg1
INTERPOLATE: dst = Arg0 * (Arg2) + Arg1 * (1-Arg2)
DOT3_RGB: Dot product of Arg0 and Arg1
DOT3_RGBA: Dot product (including alpha) of Arg0 and Arg1

Constructor & Destructor Documentation

SoTextureCombine::SoTextureCombine (void)Constructor.

References ADD, ADD_SIGNED, CONSTANT, DOT3_RGB, DOT3_RGBA, INTERPOLATE, MODULATE, ONE_MINUS_SRC_ALPHA, ONE_MINUS_SRC_COLOR, PREVIOUS, PRIMARY_COLOR, REPLACE, SoField::setDefault(), SoMField::setNum(), SRC_ALPHA, SRC_COLOR, SUBTRACT, and TEXTURE.