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NAME
SoMaterial -
The SoMaterial class is a node type for setting up material values for scene geometry.
After traversing an SoMaterial node, subsequent shape nodes with geometry in the scene
graph will use values from the material 'pool' of the traversal state set up from nodes of
this type.
SYNOPSIS
#include <Inventor/nodes/SoMaterial.h>
Inherits SoNode.
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.
SoMaterial (void)
virtual void doAction (SoAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void callback (SoCallbackAction *action)
Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass (void)
Public Attributes
SoMFColor ambientColor
SoMFColor diffuseColor
SoMFColor specularColor
SoMFColor emissiveColor
SoMFFloat shininess
SoMFFloat transparency
Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoMaterial ()
virtual void notify (SoNotList *list)
Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)
Additional Inherited Members
Detailed Description
The SoMaterial class is a node type for setting up material values for scene geometry.
After traversing an SoMaterial node, subsequent shape nodes with geometry in the scene
graph will use values from the material 'pool' of the traversal state set up from nodes of
this type.
For detailed information on the various components, see the OpenGL color model, presented
in the chapter 'Colors and Coloring' (chapter 2.13 in the OpenGL 1.4 specification).
Note that values from a material node will replace the previous values from the traversal
state, they will not accumulate. That's the case even when e.g. material changes are
implicit in an iv-file, as illustrated by the following example:
Also note that support for multiple values in ambientColor, emissiveColor, specularColor
and shininess was obsoleted in Open Inventor 2.1. The reason for this design change was
performance driven, since it's relatively slow to change the OpenGL material properties.
Changing the diffuse color value is fast though, so it's still possible to have multiple
diffuseColor and transparency values.
#Inventor V2.1 ascii
Material { ambientColor 1 0 0 }
Cone { }
Translation { translation 5 0 0 }
Material { }
Sphere { }
(The SoSphere will not 'inherit' the SoMaterial::ambientColor from the first SoMaterial
node, even though it is not explicitly set in the second material node. The default value
of SoMaterial::ambientColor will be used.)
Note that nodes imported as part of a VRML V1.0 file has a special case, where the fields
SoMaterial::ambientColor, SoMaterial::diffuseColor and SoMaterial::specularColor contains
zero values, and SoMaterial::emissiveColor contains one or more values. The values in
SoMaterial::emissiveColor should then be treated as precalculated lighting, and the other
fields should be ignored.
You can detect this case by checking the values of the material elements when the scene
graph is traversed using an SoCallbackAction. SoDiffuseColorElement,
SoAmbientColorElement, and SoSpecularColorElement will contain one value with a completely
black color (0.0f, 0.0f, 0.0f), SoShininessElement will contain one value of 0.0f, and
SoEmissiveColorElement will contain one or more values. It is done like this to make
rendering work correctly on systems that do not test for this specific case.
You should only check for this case when you're traversing a VRML V1.0 file scene graph,
of course. See SoNode::getNodeType() for information about how nodes can be tested for
whether or not they have been imported or otherwise set up as of VRML1 type versus
Inventor type.
When the scene graph is rendered using an SoGLRenderAction, the elements will be set
differently to optimize rendering. The SoDiffuseColorElement will be set to the values in
SoMaterial::emissiveColor, and the light model will be set to SoLightModel::BASE_COLOR.
The SoMaterial::transparency values will always be treated normally.
Here is a very simple usage example:
#Inventor V2.1 ascii
Separator {
Coordinate3 {
point [ 0 0 0, 1 0 0, 1 1 0 ]
}
Material {
diffuseColor [ 1 0 0, 1 1 0, 0 0 1 ]
}
MaterialBinding {
value PER_VERTEX
}
IndexedFaceSet {
coordIndex [ 0, 1, 2, -1 ]
}
}
FILE FORMAT/DEFAULTS:
Material {
ambientColor 0.2 0.2 0.2
diffuseColor 0.8 0.8 0.8
specularColor 0 0 0
emissiveColor 0 0 0
shininess 0.2
transparency 0
}
See Also:
SoMaterialBinding, SoBaseColor, SoPackedColor
Constructor & Destructor Documentation
SoMaterial::SoMaterial (void)
Constructor.
SoMaterial::~SoMaterial () [protected], [virtual]
Destructor.
Member Function Documentation
SoType SoMaterial::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 * SoMaterial::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 SoMaterial::doAction (SoAction *action) [virtual]
This function performs the typical operation of a node for any action.
Reimplemented from SoNode.
void SoMaterial::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 SoMaterial::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 SoMaterial::notify (SoNotList *l) [protected], [virtual]
Notifies all auditors for this instance when changes are made.
Reimplemented from SoNode.
Member Data Documentation
SoMFColor SoMaterial::ambientColor
Ambient material part color values. Will by default contain a single color value of [0.2,
0.2, 0.2] (ie dark gray).
The ambient part of the material is not influenced by any lightsources, and should be
thought of conceptually as the constant, but small contribution of light to a scene
'seeping in' from everywhere.
(Think of the ambient contribution in the context that there's always photons fizzing
around everywhere -- even in a black, lightsource-less room, for instance).
Only the first value in this field will be used. All other values will be ignored.
See Also:
SoEnvironment::ambientIntensity
SoMFColor SoMaterial::diffuseColor
Diffuse material part color values. This field is by default initialized to contain a
single color value of [0.8, 0.8, 0.8] (light gray).
The diffuse part is combined with the light emitted from the scene's light sources.
Traditional Open Inventor uses the same override bit for both diffuse color and
transparency. To get around this problem if you need to override one without the other,
set the environment variable 'COIN_SEPARATE_DIFFUSE_TRANSPARENCY_OVERRIDE'. This is a Coin
extension, and will not work on the other Open Inventor implementations.
SoMFColor SoMaterial::specularColor
Specular material part color values. Defaults to a single color value of [0, 0, 0]
(black).
Only the first value in this field will be used. All other values will be ignored.
SoMFColor SoMaterial::emissiveColor
The color of the light 'emitted' by the subsequent geometry, independent of lighting /
shading.
Defaults to contain a single color value of [0, 0, 0] (black, ie no contribution).
Only the first value in this field will be used. All other values will be ignored.
SoMFFloat SoMaterial::shininess
Shininess values. Decides how the light from light sources are distributed across the
geometry surfaces. Valid range is from 0.0 (which gives a dim appearance), to 1.0 (glossy-
looking surfaces).
Defaults to contain a single value of 0.2.
Only the first value in this field will be used. All other values will be ignored.
SoMFFloat SoMaterial::transparency
Transparency values. Valid range is from 0.0 (completely opaque, which is the default) to
1.0 (completely transparent, i.e. invisible).
Defaults to contain a single value of 0.0.
Traditional Open Inventor uses the same override bit for both transparency and diffuse
color. To get around this problem if you need to override one without the other, set the
environment variable 'COIN_SEPARATE_DIFFUSE_TRANSPARENCY_OVERRIDE'. This is a Coin
extension, and will not work on the other Open Inventor implementations.
Author
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