Extensible 3D (X3D)
Part 1: Architecture and base components
11 Rendering component
11.1 IntroductionThe name of this component is "Rendering". This name shall be used when referring to this component in the COMPONENT statement (see 7.2.5.4 Component statement).
This clause describes the Rendering component of this document. This includes fundamental rendering primitives such as TriangleSet and PointSet nodes, and geometric properties nodes that define how coordinate indices, colors, normals and texture coordinates are specified. Table 11.1 provides links to the major topics in this clause.
11.2 ConceptsThe following nodes represent the fundamental visual objects common to polygonal rendering systems:
Most complex geometries, such as those found in the 13 Geometry3D component and 14 Geometry2D component, can be implemented as a combination of these nodes. The Rendering component provides these nodes as basic services for building arbitrary geometry types.
All of the rendering primitive nodes are descendants of the X3DGeometryNode type.
Several geometry nodes contain Coordinate, Color or ColorRGBA, Normal, and TextureCoordinate as geometric property node types. The geometric property node types are defined as individual node types so that instancing and sharing is possible between different geometry nodes. The TextureCoordinate node type is defined in 18 Texturing component.
Colour in X3D is specified using the RGB colour model in which the three components of colour specifications are red, green, and blue ranging in value from 0 to 1. This colour model results in a colour specification of (0,0,0) representing black and (1,1,1) representing white. Colour may also be specified using the RGBA colour model in which a fourth alpha component specifies a value ranging from 0 (fully transparent) to 1 (fully opaque). See [FOLEY] for more information on the RGB colour model.
Coordinates in X3D are specified as an (x, y, z) triplet in a right-handed, rectangular coordinate system.
Normals define perpendicular directions from a piece of geometry and are used to perform lighting calculations. They may either be specified as part of the content or computed directly from the geometry by the X3D browser. When specified as part of the content, each normal vector shall have unit length.
It is not possible to automatically calculate normal vectors for line and point geometry nodes (IndexedLineSet, LineSet, PointSet). Therefore, the following rules apply when rendering these nodes:
Emissive colors are the primary means of rendering these nodes. The emissiveColor and emissiveTexture fields typically control glowing effects.
If the Material node is used together with unlit points and lines, geometry shall be rendered as unlit and only the emissiveColor is used.
Note: The emissiveTexture of Material node is ignored in this case. Using the Material.emissiveColor is a special rule, only to provide compatibility with X3D 3, which is why it is deliberately limited, and does not provide any way to use Material.emissiveTexture or any PhysicalMaterial feature on unlit point and lines.
If the normal field contains a Normal node, points and lines shall be rendered using the same lighting equations as the other geometry and can be lit.
If the normal information is not provided (the normal field remains NULL), points and lines shall be rendered using the "unlit" lighting equations, following 17.2.2.4 Unlit lighting model. Authors are advised to use UnlitMaterial to customize the look of unlit points and lines.
If any other material node is used together with unlit points and lines, the geometry shall be rendered as white unlit.
In the absence of the normal field, rendering of the points and lines can be customized using textures, Color, ColorRGBA and UnlitMaterial nodes.
Certain geometry nodes have several fields that provide information about the rendering of the geometry. These fields specify the vertex ordering, if the shape is solid, if the shape contains convex faces, and at what angle a crease appears between faces, and are named ccw, solid, convex and creaseAngle, respectively.
The ccw field defines the ordering of the vertex coordinates of the geometry with respect to user-given or automatically generated normal vectors used in the lighting model equations. If ccw is TRUE, the normals shall follow the right hand rule; the orientation of each normal with respect to the vertices (taken in order) shall be such that the vertices appear to be oriented in a counterclockwise order when the vertices are viewed (in the local coordinate system of the Shape) from the opposite direction as the normal. If ccw is FALSE, the normals shall be oriented in the opposite direction. If normals are not generated but are supplied using a Normal node, and the orientation of the normals does not match the setting of the ccw field, results are undefined.
The solid field determines whether one or both sides of each polygon shall be displayed. If solid is FALSE, each polygon shall be visible regardless of the viewing direction ( i.e., no backface culling shall be done, and two sided lighting shall be performed to illuminate both sides of lit surfaces). If solid is TRUE, the visibility of each polygon shall be determined as follows: Let V be the position of the viewer in the local coordinate system of the geometry. Let N be the geometric normal vector of the polygon, and let P be any point (besides the local origin) in the plane defined by the polygon's vertices. Then if ( V dot N) - ( N dot P) is greater than zero, the polygon shall be visible; if it is less than or equal to zero, the polygon shall be invisible (back face culled).
The convex field indicates whether all polygons in the shape are convex (TRUE). A polygon is convex if it is planar, does not intersect itself, and all of the interior angles at its vertices are less than 180 degrees. Non planar and self intersecting polygons may produce undefined results even if the convex field is FALSE.
The creaseAngle field affects how default normals are generated. If the angle between the geometric normals of two adjacent faces is less than the crease angle, normals shall be calculated so that the faces are shaded smoothly across the edge; otherwise, normals shall be calculated so that a lighting discontinuity across the edge is produced. Crease angles shall be greater than or equal to 0.0 angle base units.
EXAMPLE A crease angle of 0.5 angle base units means that an edge between two adjacent polygonal faces will be smooth shaded if the geometric normals of the two faces form an angle that is less than 0.5 angle base units. Otherwise, the faces will appear faceted.
The 3D graphics rendering pipeline uses an implicit step of trimming objects that are partially in the view frustum called clipping. In addition to these implied bounds, it is also possible to provide an additional clipping of the geometry through the provision of additional clip plane definitions.
A clip plane is defined as a plane that generates two half-spaces. The affected geometry in the half-space that is defined as being outside the plane is removed from the rendered image as a result of a clipping operation.
Clip planes may be defined at any level of the transformation hierarchy. The clip plane definitions are accumulated from the root of the scene graph down to the individual leaf nodes that are rendered. Clipping occurs against the intersection of the half-spaces resulting from the current list of transformed clip plane definitions. Since the clip planes are collected during the traversal of the scene graph, specifying both local and globally scoped planes is possible.
Figure 11.1 illustrates four objects affected by a horizontal clip plane and a vertical clip plane.
A ClipPlane node affects only objects that are in the same transformation hierarchy as the node. Each plane is transformed according to the parent transformation hierarchy but is not further transformed by the children it affects.
Clip planes shall affect nodes derived from X3DBackgroundNode.
Many renderers only support a limited number of clip plane definitions (typically, six). If, while traversing from the root of the scene to a particular leaf, more than the number of supported clip planes are specified, the clip plane definitions closest to the leaf are discarded first ( i.e., the clip planes that are closer to the root of the scene graph are considered most important).
11.3 Abstract types
X3DColorNode : X3DGeometricPropertyNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This is the base node type for color specifications in X3D.
X3DComposedGeometryNode : X3DGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
}
This is the base node type for all composed 3D geometry in X3D.
A composed geometry node type defines an abstract type that composes geometry from a set of nodes that define individual components. Composed geometry may have color, coordinates, normal and texture coordinates supplied. The rendered output of the combination of these is dependent on the concrete node definition. However, in general, the following rules shall be applied for all nodes:
If the attrib field is not empty it shall contain a list of per-vertex attribute information for programmable shaders as specified in 32.2.2.4 Per-vertex attributes.
If the fogCoord field is not empty, it shall contain a list of per-vertex depth values for calculating fog depth as specified in 24.2.2.5 Fog colour calculation.
Further information about texCoord field handling is described in IndexedFaceSet.
X3DCoordinateNode : X3DGeometricPropertyNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This is the base node type for all coordinate node types in X3D. All coordinates are specified in nodes derived from this abstract node type.
X3DGeometricPropertyNode : X3DNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This is the base node type for all geometric property node types defined in X3D
X3DGeometryNode : X3DNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This is the base node type for all geometry in X3D.
X3DNormalNode : X3DGeometricPropertyNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This is the base node type for all normal node types in X3D. All normals are specified in nodes derived from this abstract node type.
11.4 Node referenceClipPlane : X3DChildNode {
SFBool [in,out] enabled TRUE
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFVec4f [in,out] plane 0 1 0 0 [-1,1]
}
The ClipPlane node specifies a single plane equation used to
clip the geometry. The plane field specifies a four-component plane
equation that describes the inside and outside half space,
a*x+b*y+c*z+d = 0. The first three
components are a normalized vector describing the direction of the plane's
normal direction. The fourth component is distance from local origin.
The inside half-space is clipped, i.e., not rendered.
Color : X3DColorNode {
MFColor [in,out] color [NULL] [0,1]
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This node defines a set of RGB colours to be used in the fields of another node.
Color nodes are only used to specify multiple colours for a single geometric shape, such as colours for the faces or vertices of an IndexedFaceSet. A material node is used to specify the overall material parameters of lit geometry. If both a material node and a Color node are specified for a geometric shape, the colours shall replace the main color component of the material.
The main color is defined as:
This definition of main color here is consistent with the definition of main texture used in case of Gouraud shading. See 17.2.2.8 Gouraud shading.
RGB or RGBA textures are mixed with colors. Details on lighting equations can be found in 17.2.2 Lighting model.
ColorRGBA : X3DColorNode {
MFColorRGBA [in,out] color [NULL] [0,1]
SFNode [in,out] metadata NULL [X3DMetadataObject]
}
This node defines a set of RGBA colours to be used in the fields of another node.
RGBA color nodes are only used to specify multiple colours with alpha for a single geometric shape, such as colours for the faces or vertices of an IndexedFaceSet. A material node is used to specify the overall material parameters of lit geometry. If both a material node and a ColorRGBA node are specified for a geometric shape, the colours shall replace the main color and transparency components of the material.
The main color is defined as:
This definition of main color here is consistent with the definition of main texture used in case of Gouraud shading is used. See 17.2.2.8 Gouraud shading.
RGB or RGBA textures are mixed with colors. Details on lighting equations can be found in 17.2.2 Lighting model.
Coordinate : X3DCoordinateNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
MFVec3f [in,out] point [] (-∞,∞)
}
This node defines a set of 3D coordinates to be used in the coord field of vertex-based geometry nodes including:
CoordinateDouble : X3DCoordinateNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
MFVec3d [in,out] point [] (-∞,∞)
}
CoordinateDouble is a node type derived from X3DCoordinateNode that allows the definition of 3D coordinates in double precision floating point values.
IndexedLineSet : X3DGeometryNode {
MFInt32 [in] set_colorIndex
MFInt32 [in] set_coordIndex
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
MFInt32 [] colorIndex [] [0,∞) or -1
SFBool [] colorPerVertex TRUE
MFInt32 [] coordIndex [] [0,∞) or -1
}
The IndexedLineSet node represents a 3D geometry formed by constructing polylines from 3D vertices specified in the coord field. IndexedLineSet uses the indices in its coordIndex field to specify the polylines by connecting vertices from the coord field. An index of "-1" indicates that the current polyline has ended and the next one begins. The last polyline may be (but does not have to be) followed by a "-1". IndexedLineSet is specified in the local coordinate system and is affected by the transformations of its ancestors.
The coord field specifies the 3D vertices of the line set and contains a X3DCoordinateNode node.
Lines do not participate in collision detection. The width and style of lines are determined by the line properties specified in an associated Appearance node. If no line properties are specified, the default values for fields of the LineProperties node shall be used (see 12.4.3 LineProperties).
If the color field is not NULL, it shall contain a node derived from X3DColorNode. The colours are applied to the line(s) as follows:
Lines can be lit (if the normal vectors are provided), textured and affected by per-vertex colors. See 11.2.2.5 Points and lines rendering section.
IndexedTriangleFanSet : X3DComposedGeometryNode {
MFInt32 [in] set_index [] [0,∞) or -1
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
MFInt32 [] index [] [0,∞) or -1
}
An IndexedTriangleFanSet represents a 3D shape composed of triangles that form a fan shape around the first vertex declared in each fan as depicted in Figure11.2. IndexedTriangleFanSet uses the indices in its index field to specify the triangle fans by connecting vertices from the coord field. An index of "-1" indicates that the current fan has ended and the next one begins. The last fan may be (but does not have to be) followed by a "-1".Each fan shall have at least three non-coincident vertices.
The IndexedTriangleFanSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color, ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal and texCoord fields, the values are applied in the same manner as the values from the coord field and there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not provided, normals shall be generated as follows:
The solid field determines whether the IndexedTriangleFanSet is visible when viewed from the inside. 11.2.3 Common geometry fields provides a complete description of the solid field.
IndexedTriangleSet : X3DComposedGeometryNode {
MFInt32 [in] set_index [] [0,∞)
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
MFInt32 [] index [] [0,∞)
}
The IndexedTriangleSet node represents a 3D shape composed of a collection of individual triangles as depicted in Figure11.3. IndexedTriangleSet uses the indices in its index field to specify the vertices of each triangle from the coord field. Each triangle is formed from a set of three vertices of the X3DCoordinateNode identified by three consecutive indices from the index field. If the index field does not contain a multiple of three coordinate values, the remaining vertices shall be ignored.
The IndexedTriangleSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color, ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal and texCoord fields, the values are applied in the same manner as the values from the coord field and there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not supplied, normals shall be generated as follows:
The solid field determines whether the IndexedTriangleSet is visible when viewed from the backside. 11.2.3 Common geometry fields provides a complete description of the solid field.
IndexedTriangleStripSet : X3DComposedGeometryNode {
MFInt32 [in] set_index [] [0,∞) or −1
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
MFInt32 [] index [] [0,∞) or −1
}
An IndexedTriangleStripSet represents a 3D shape composed of strips of triangles as depicted in Figure 11.3. IndexedTriangleStripSet uses the indices in its index field to specify the triangle strips by connecting vertices from the coord field. An index of "−1" indicates that the current strip has ended and the next one begins. The last strip may be (but does not have to be) followed by a "−1". Each strip shall have at least three non-coincident vertices.
The IndexedTriangleStripSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color, ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal and texCoord fields, the values are applied in the same manner as the values from the coord field and there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not supplied, normals shall be generated as follows:
The ccw field describes the ordering of the vertex coordinates in the initial triangle, and alternates for subsequent triangles.
The solid field determines whether the IndexedTriangleStripSet is visible when viewed from the inside. 11.2.3 Common geometry fields provides a complete description of the solid field.
LineSet : X3DGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
MFInt32 [in,out] vertexCount [] [2,∞)
}
The LineSet node represents a 3D geometry formed by constructing polylines from 3D vertices specified in the coord field.
The color field specifies the colour of the line set at each vertex and contains a node derived from X3DColorNode. A description of the color field is provided in the color node. If the color field is NULL and there is a material defined for the Appearance affecting this LineSet, the emissiveColor of the material shall be used to draw the lines. Details on lighting equations as they affect LineSet nodes are described in 17 Lighting component
The coord field specifies the 3D vertices of the line set and contains an X3DCoordinateNode.
The vertexCount field describes how many vertices are to be used in each polyline from the coordinate field. Coordinates are assigned to each line by taking vertexCount[n] vertices from the coordinate field. Each value of the vertexCount array shall be greater than or equal to two. It shall be an error to have a value less than two.
Lines do not participate in collision detection. The width and style of lines are determined by the line properties specified in an associated Appearance node. If no line properties are specified, the default values for the fields of the LineProperties node shall be used (see 12.4.3 LineProperties).
Lines can be lit (if the normal vectors are provided), textured and affected by per-vertex colors. See 11.2.2.5 Points and lines rendering section.
Normal : X3DNormalNode {
SFNode [in,out] metadata NULL [X3DMetadataObject]
MFVec3f [in,out] vector [] [-1,1]
}
This node defines a set of 3D direction vectors to be used for the normal field of some geometry nodes (EXAMPLE IndexedFaceSet, IndexedLineSet, LineSet, PointSet, and ElevationGrid). The term 'normal' is common usage to indicate direction vectors, even though the direction vectors might not necessarily indicate perpendicularity. This node contains one multiple-valued field that contains the normal vectors. Normals shall be of unit length.
PointSet : X3DGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
}
The PointSet node specifies a set of 3D points, in the local coordinate system, with associated colours at each point. The coord field specifies an X3DCoordinateNode. The results are undefined if the coord field specifies any other type of node. PointSet uses the coordinates in order. If the coord field is NULL, the point set is considered empty.
PointSet nodes are not lit, not texture-mapped, nor do they participate in collision detection. The size of each point is implementation-dependent.
If the color field is not NULL, it shall specify a node derived from X3DColorNode that contains at least the number of points contained in the coord node. The results are undefined if the color field specifies any other type of node. Colours shall be applied to each point in order. The results are undefined if the number of values in the X3DColorNode node is less than the number of values specified in the X3DCoordinateNode node.
Points can be lit (if the normal vectors are provided), textured and affected by per-vertex colors. See 11.2.2.5 Points and lines rendering section.
TriangleFanSet : X3DComposedGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
MFInt32 [in,out] fanCount [] [3,∞)
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
}
A TriangleFanSet represents a 3D shape composed of triangles that form a fan shape around the first vertex declared in each fan.
The fanCount field describes how many vertices are to be used in each fan from the coordinate field. Coordinates are assigned to each strip by taking fanCount[n] vertices from the coordinate field. Each value of the fanCount array shall be greater than or equal to three. It shall be an error to have a value less than three.
Figure 11.2 displays a TriangleFanSet containing a single fan showing the ordering of the vertices for that fan.
The TriangleFanSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color/ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal, and texCoord fields, there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not provided, for each fan, the normal shall be generated as follows: if normalPerVertex is TRUE, the normal shall be the average of all triangles within that fan sharing that vertex. For the vertex of the fan, the normal shall be the average of the contributions of all of the individual face normals. If normalPerVertex is FALSE, the normal shall be generated for the current triangle based on the ccw field.
The solid field determines whether the TriangleFanSet is visible when viewed from the inside. 11.2.3 Common geometry fields provides a complete description of the solid field.
TriangleSet : X3DComposedGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
}
The TriangleSet node represents a 3D shape that represents a collection of individual triangles.
The coord field contains an X3DCoordinateNode that defines the 3D vertices that define the triangle. Each triangle is formed from a consecutive set of three vertices of the X3DCoordinateNode node. If the X3DCoordinateNode node does not contain a multiple of three coordinate values, the remaining vertices shall be ignored.
Figure 11.3 depicts a TriangleSet node with several triangles. The ordering of the vertices is also shown.
The TriangleSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color/ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal, and texCoord fields, there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not supplied, the normal shall be generated as perpendicular to the face for either version of normalPerVertex.
The solid field determines whether the TriangleSet is visible when viewed from the backside. 11.2.3 Common geometry fields provides a complete description of the solid field.
TriangleStripSet : X3DComposedGeometryNode {
MFNode [in,out] attrib [] [X3DVertexAttributeNode]
SFNode [in,out] color NULL [X3DColorNode]
SFNode [in,out] coord NULL [X3DCoordinateNode]
SFNode [in,out] fogCoord NULL [FogCoordinate]
SFNode [in,out] metadata NULL [X3DMetadataObject]
SFNode [in,out] normal NULL [X3DNormalNode]
MFInt32 [in,out] stripCount [] [3,∞)
SFNode [in,out] texCoord NULL [X3DTextureCoordinateNode]
SFBool [] ccw TRUE
SFBool [] colorPerVertex TRUE
SFBool [] normalPerVertex TRUE
SFBool [] solid TRUE
}
A TriangleStripSet represents a 3D shape composed of strips of triangles.
The ccw field describes the ordering of the vertex coordinates in the initial triangle, and alternates for subsequent triangles.
The stripCount field describes how many vertices are to be used in each
strip from the coordinate field. Coordinates are assigned to each strip by taking
stripCount[i] vertices from the coordinate field, where i is a
sequential index of stripCount. Each value of the stripCount
array shall be greater than or equal to three. It shall be an error to have
a value less than three. Figure 11.4 depicts
a TriangleStripSet with a single triangle strip.
The TriangleStripSet node is specified in the local coordinate system and is affected by the transformations of its ancestors. Descriptions of the color, coord, normal, and texCoord fields are provided in the Color/ColorRGBA, Coordinate, Normal, and TextureCoordinate nodes, respectively. If values are provided for the color, normal, and texCoord fields, there shall be at least as many values as are present in the coord field. The value of the colorPerVertex field is ignored and always treated as TRUE. If the normal field is not provided, for each strip, the normal shall be generated as follows: if normalPerVertex is TRUE, the normal shall be the average of all triangles within that strip sharing that vertex. If normalPerVertex is FALSE, the normal shall be generated for the triangle based on the ccw field.
The solid field determines whether the TriangleStripSet is visible when viewed from the inside. 11.2.3 Common geometry fields provides a complete description of the solid field.
11.5 Support levelsThe Rendering component provides three levels of support as specified in Table 11.2.
Table 11.2 — Rendering component support levels
| Level | Prerequisites | Nodes/Features | Support |
|---|---|---|---|
| 1 | Core 1 Grouping 1 |
||
| X3DComposedGeometryNode (abstract) | n/a | ||
| X3DGeometricPropertyNode (abstract) | n/a | ||
| X3DGeometryNode (abstract) | n/a | ||
| X3DColorNode (abstract) | n/a | ||
| X3DCoordinateNode (abstract) | n/a | ||
| Color | All fields fully supported. | ||
| ColorRGBA | Alpha value optionally supported. | ||
| Coordinate | All fields fully supported. | ||
| CoordinateDouble | All fields fully supported. | ||
| IndexedLineSet | set_colorIndex optionally supported. set_coordIndex optionally supported. normal optionally supported. | ||
| LineSet | normal optionally supported. | ||
| PointSet | normal optionally supported. | ||
| 2 | Core 1 Grouping 1 |
||
| All Level 1 Rendering nodes | All fields as supported in Level 1. | ||
| X3DNormalNode (abstract) | n/a | ||
| Normal | All fields fully supported. | ||
| 3 | Core 1 Grouping 1 |
||
| All Level 2 Rendering nodes | All fields fully supported except for ColorRGBA supported as in Level 2. | ||
| IndexedTriangleFanSet | All fields fully supported. | ||
| IndexedTriangleSet | All fields fully supported. | ||
| IndexedTriangleStripSet | All fields fully supported. | ||
| TriangleFanSet | All fields fully supported. | ||
| TriangleSet | All fields fully supported. | ||
| TriangleStripSet | All fields fully supported. | ||
| 4 | Core 1 Grouping 1 |
||
| All Level 3 Rendering nodes | All fields as supported in Level 3. | ||
| ColorRGBA | Alpha value fully supported. | ||
| 5 | Core 1 Grouping 1 |
||
| All Level 4 Rendering nodes | All fields as supported in Level 4. | ||
| ClipPlane | All fields fully supported. |
