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
SoMaterial (void)
virtual void doAction (SoAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void callback (SoCallbackAction *action)
Static Public Member Functions
static void initClass (void)
Public Attributes
SoMFColor ambientColor
SoMFColor diffuseColor
SoMFColor specularColor
SoMFColor emissiveColor
SoMFFloat shininess
SoMFFloat transparency
Protected Member Functions
virtual ~SoMaterial ()
virtual void notify (SoNotList *list)
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 { }
.fi
(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 ]
}
}
.fi
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
void SoMaterial::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 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
Generated automatically by Doxygen for Coin from the source code.