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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. More...
#include <Inventor/nodes/SoTextureCombine.h>
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 |
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) |
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 { }
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 { } }
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 }
For enumerating combiner operations/functions.
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.
SoTextureCombine::~SoTextureCombine | ( | ) | [protected, virtual] |
Destructor.
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).
Reimplemented from SoNode.
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 } 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 ** SoTextureCombine::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 * 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::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 SoTextureCombine::doAction | ( | SoAction * | action | ) | [virtual] |
This function performs the typical operation of a node for any action.
Reimplemented from SoNode.
References SoFieldContainer::get(), SoMField::getNum(), SoAction::getState(), SoSFFloat::getValue(), SoSFEnum::getValue(), SoSFVec4f::getValue(), SoMFEnum::getValues(), and SoFieldContainer::set().
Referenced by GLRender().
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.
References SoNode::callback().
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.
References doAction(), DOT3_RGB, DOT3_RGBA, SoGLRenderAction::getCacheContext(), SoSFEnum::getValue(), and SoDebugError::postWarning().
void SoTextureCombine::pick | ( | SoPickAction * | action | ) | [virtual] |
Action method for SoPickAction.
Does common processing for SoPickAction action instances.
Reimplemented from SoNode.
References SoNode::pick().
Copyright © 1998-2007 by Systems in Motion AS. All rights reserved.
Generated on Mon Feb 23 16:34:02 2009 for Coin by Doxygen. 1.5.8