Provided by: libcoin80-doc_3.1.4~abc9f50-4ubuntu2_all bug

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
       virtual SoType getTypeId (void) const
           Returns the type identification of an object derived from a class inheriting SoBase.
           This is used for run-time type checking and 'downward' casting.
       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 SoType getClassTypeId (void)
       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 const SoFieldData * getFieldData (void) const
       virtual ~SoTextureCombine ()

   Static Protected Member Functions
       static const SoFieldData ** getFieldDataPtr (void)

   Additional Inherited Members

Detailed Description

       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.

       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

       ยท 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 { }
       }

       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::Source
       For 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::Operand
       For 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::Operation
       For 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.

   SoTextureCombine::~SoTextureCombine () [protected],  [virtual]
       Destructor.

Member Function Documentation

   SoType SoTextureCombine::getClassTypeId (void) [static]
       SoTextureCombine::rgbSource

       The color sources. This field is empty by default, but you can insert up to three values
       [Arg0, Arg1, Arg2]. When the field contains less than three values, the default [TEXTURE,
       PREVIOUS, CONSTANT], will be used for missing values.

       For texture unit 0, PREVIOUS maps to PRIMARY_COLOR,

       SoTextureCombine::alphaSource

       The alpha sources. This field is empty by default, but you can insert up to three values
       [Arg0, Arg1, Arg2]. When the field contains less than three values, the default [TEXTURE,
       PREVIOUS, CONSTANT], will be used for missing values.

       For texture unit 0, PREVIOUS maps to PRIMARY_COLOR,

       SoTextureCombine::rgbOperand

       The color operands. This field is empty by default, but you can insert up to three values.
       When the field contains less than three values, the default [SRC_COLOR, SRC_COLOR,
       SRC_COLOR] will be used for missing values.

       SoTextureCombine::alphaOperand

       The alpha operands. This field is empty by default, but you can insert up to three values.
       When the field contains less than three values, the default [SRC_ALPHA, SRC_ALPHA,
       SRC_ALPHA] will be used for missing values. Please not that only SRC_ALPHA and
       ONE_MINUS_SRC_ALPHA are valid operands for alpha operations.

       SoTextureCombine::rgbOperation

       The color operation. Default value is MODULATE.

       SoTextureCombine::alphaOperation

       The alpha operation. Default value is MODULATE.

       SoTextureCombine::rgbScale

       Scale color result by this value. Supported values are 1, 2, and 4.

       SoTextureCombine::alphaScale

       Scale alpha result by this value. Supported values are 1, 2, and 4.

       SoTextureCombine::constantColor

       The constant color (when CONSTANT is used as source). Default value is (1,1,1,1).

   SoType SoTextureCombine::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
         }
       }

       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 * SoTextureCombine::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 SoTextureCombine::doAction (SoAction *action) [virtual]
       This function performs the typical operation of a node for any action.

       Reimplemented from SoNode.

   void SoTextureCombine::callback (SoCallbackAction *action) [virtual]
       Action method for SoCallbackAction.

       Simply updates the state according to how the node behaves for the render action, so the
       application programmer can use the SoCallbackAction for extracting information about the
       scene graph.

       Reimplemented from SoNode.

   void SoTextureCombine::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.

   void SoTextureCombine::pick (SoPickAction *action) [virtual]
       Action method for SoPickAction.

       Does common processing for SoPickAction action instances.

       Reimplemented from SoNode.

Author

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