Structure that describes basic entities per face for solid or surface mesh representations. More...
Detailed Description
Structure that describes basic entities per face for solid or surface mesh representations.
- Version
- 2.0
In the context of solid or surface mesh representations, an entity can be a triangle, a fan, or a strip, with all declinations described for the the A3DTess3DData structure.
The m_uiStyleIndexesSize member has these values:
- 0 indicates that there are no graphics (in this case, all graphics are inherited from the owner (parent) of the A3DTess3DData).
- 1 indicates that one graphic is associated with the face.
- Greater than 1 indicates that the number of graphics is linked to the number of entities in the m_puiSizesTriangulated member.
- Wireframe representation
The following A3DTessFaceData members are for wireframe faces:
- m_uiStartWire : The starting index for the wire in the array of point indexes of the A3DTess3DData.
- m_puiSizesWires : Array of the number of indexes for each wire edge of the face, where the number of indexes is OR'd with the relevant flags kA3DTessFaceDataWireIsNotDrawn and/or kA3DTessFaceDataWireIsClosing. In an A3DTessFaceData structure, the size of a wire edge is limited to 16383 (0x3FFF) points. When both flags are set, they have the value 0xC000.
Consider an example of an A3DTessFaceData structure in which both loops describe closed wire edges:
- First loop consists of two wire edges:
- First edge has 16 points.
- Second edge has 32 points.
- Second loop consists of one edge having 18 points.
For this example, the m_puiSizesWires array has these entries: [0x0010, 0x4020, 0x4012]. The second and third array entries are the number of edges OR'd with the kA3DTessFaceDataWireIsNotDrawn (0x4000). Notice that the indexes for each edge's extremity are always stored. Therefore, the tenth point of the first edge is followed by the first point of the second edge.
- Solid representation
The following A3DTessFaceData members are for solid representations:
- m_usUsedEntitiesFlags (see Bitmasks for Specifying Tessellation Types): This flag specifies how to interpret the array m_puiSizesTriangulated.
- m_uiStartTriangulated : Starting index for the triangulated data in the array of point indexes of the A3DTess3DData.
- m_puiSizesTriangulated : Array of the number of indexes for each triangulated entity of the face.
The triangulated data sizes are stored following the order of values in Bitmasks for Specifying Tessellation Types. Thus, the triangles are stored before triangle fans and before textured triangles. - For triangle types, the m_puiSizesTriangulated member specifies the number of triangles.
- For triangle fan and strips types, the m_puiSizesTriangulated member specifies the number of fans or strips followed by the number of points for each of them.
Consider an example of an A3DTessFaceData structure that describes five triangles, two fans of 5 and 7 points respectively, and one strip of 11 indexes. For this example, set m_usUsedEntitiesFlags to kA3DTessFaceDataTriangle & kA3DTessFaceDataTriangleFan & kA3DTessFaceDataTriangleStripe . In this case, m_puiSizesTriangulated will be [5,2,5,7,1,11].
In case of the tessellation type kA3DTessFaceData*OneNormal (i.e., one of the bitmasks specifying a tessellation type with one normal), the number of points can bear the flag kA3DTessFaceDataNormalSingle, modifying the way of reading normals information. In such a case, you must use kA3DTessFaceDataNormalSingle to characterize status and kA3DTessFaceDataNormalMask to access the real value.
The following A3DTessFaceData members also apply to solid representations:
- m_pucRGBAVertices : Colors stored directly on vertices. Either there is no color on vertices or every vertex must bear a color. Therefore, m_uiRGBAVerticesSize is either 0 or equal to the number of point indexes as calculated from m_puiSizesTriangulated. (In the previous example, m_uiRGBAVerticesSize is 38 = 5*3 + 5 + 7 + 11).
- m_bIsRGBA : If true, the color scheme is RGBa; otherwise, it is RGB.
- m_usBehaviour : This member denotes the graphics behavior for this A3DTessFaceData towards owning entity in the tree, as described in Bit Field for Behavior on Graphics. For face behavior, kA3DGraphicsShow and kA3DGraphicsRemoved are not currently supported.
- m_uiTextureCoordIndexesSize : Number of texture coordinate indexes (see Bitmasks for Specifying Tessellation Types).
Field Documentation
A3DBool A3DTessFaceData::m_bIsRGBA |
A value of true specifies that the array is made of RGBA. A value of false indicates that it is made of RGB.
A3DUns8* A3DTessFaceData::m_pucRGBAVertices |
See explanations above.
A3DUns32* A3DTessFaceData::m_puiSizesTriangulated |
See explanations above.
A3DUns32* A3DTessFaceData::m_puiSizesWires |
See explanations above.
A3DUns32* A3DTessFaceData::m_puiStyleIndexes |
Array of display styles. See explanations above.
A3DUns32 A3DTessFaceData::m_uiRGBAVerticesSize |
Size of next array.
A3DUns32 A3DTessFaceData::m_uiSizesTriangulatedSize |
Size of next array.
A3DUns32 A3DTessFaceData::m_uiSizesWiresSize |
Size of next array.
A3DUns32 A3DTessFaceData::m_uiStartTriangulated |
See explanations above.
A3DUns32 A3DTessFaceData::m_uiStartWire |
See explanations above.
A3DUns32 A3DTessFaceData::m_uiStyleIndexesSize |
Size of next array.
A3DUns32 A3DTessFaceData::m_uiTextureCoordIndexesSize |
See explanations above.
A3DUns16 A3DTessFaceData::m_usBehaviour |
See explanations above.
A3DUns16 A3DTessFaceData::m_usStructSize |
Reserved; must be initialized with A3D_INITIALIZE_DATA.
A3DUns16 A3DTessFaceData::m_usUsedEntitiesFlags |
Bit field containing list of used entities in current face tessellation. See explanations above.