Provided by: libcoin80-doc_3.1.4~abc9f50-4ubuntu2_all 
NAME
SoQuadMesh -
The SoQuadMesh class is used to render and optimize a quadrilateral mesh.
This node uses the coordinates in order, either from the state or from the
SoQuadMesh::vertexProperty node, to construct a quadrilateral mesh.
SYNOPSIS
#include <Inventor/nodes/SoQuadMesh.h>
Inherits SoNonIndexedShape.
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.
SoQuadMesh (void)
virtual void GLRender (SoGLRenderAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual SbBool generateDefaultNormals (SoState *state, SoNormalBundle *nb)
Static Public Member Functions
static SoType getClassTypeId (void)
static void initClass (void)
Public Attributes
SoSFInt32 verticesPerColumn
SoSFInt32 verticesPerRow
Protected Member Functions
virtual const SoFieldData * getFieldData (void) const
virtual ~SoQuadMesh ()
virtual void generatePrimitives (SoAction *action)
virtual void computeBBox (SoAction *action, SbBox3f &box, SbVec3f ¢er)
virtual SbBool generateDefaultNormals (SoState *, SoNormalCache *)
Static Protected Member Functions
static const SoFieldData ** getFieldDataPtr (void)
Additional Inherited Members
Detailed Description
The SoQuadMesh class is used to render and optimize a quadrilateral mesh.
This node uses the coordinates in order, either from the state or from the
SoQuadMesh::vertexProperty node, to construct a quadrilateral mesh.
The quads are generated in row major order, using the two fields
SoQuadMesh::verticesPerColumn and SoQuadMesh::verticesPerRow to specify the mesh. E.g. if
SoQuadMesh::verticesPerColumn is 3 and SoQuadMesh::verticesPerRow is 2, two quads will be
generated with the first one using (in order) coordinates 0, 1, 3 and 2, the second one
using coordinates 2, 3, 5 and 4 (you get three rows of vertices; the first row uses
vertices 0 and 1, the second row 2 and 3, and the third row 4 and 5).
Here's a quick and simple usage example code snippet:
// Vertices for the Quad mesh.
static float vertices[25][3] = {
// Row 1
{-11, 0, 1}, {0, 11, 1}, {11, 0, 1}, {0, -11, 1}, {-11, 0, 1},
// Row 2
{-9, 0, 1}, {0, 9, 1}, {9, 0, 1}, {0, -9, 1}, {-9, 0, 1},
// Row 3
{-9, 0, -1}, {0, 9, -1}, {9, 0, -1}, {0, -9, -1}, {-9, 0, -1},
// Row 4
{-11, 0, -1}, {0, 11, -1}, {11, 0, -1}, {0, -11, -1}, {-11, 0, -1},
// Row 5
{-11, 0, 1}, {0, 11, 1}, {11, 0, 1}, {0, -11, 1}, {-11, 0, 1}
};
// This function generate an object by using the SoQuadMesh node
// Return:
// SoSeparator *
static SoSeparator *
quadMesh(void)
{
SoSeparator * qm = new SoSeparator;
// Define coordinates
SoCoordinate3 * coords = new SoCoordinate3;
coords->point.setValues(0, 30, vertices);
qm->addChild(coords);
// QuadMesh
SoQuadMesh * mesh = new SoQuadMesh;
mesh->verticesPerRow = 5;
mesh->verticesPerColumn = 5;
qm->addChild(mesh);
return qm;
}
The quadmesh geometry resulting from this code looks like this:
Here is another example, this time making a 2x2 grid, with a texture:
#Inventor V2.1 ascii
Separator {
Complexity { textureQuality 0.01 }
Texture2 {
image 2 2 4 0xff0000ff 0x00ff00ff 0xffff00ff 0xff00ffff
}
Coordinate3 {
point [
0 2 0,
1 2 0,
2 2 0,
0 1 0,
1 1 0,
2 1 0,
0 0 0,
1 0 0,
2 0 0
]
}
QuadMesh {
verticesPerRow 3
verticesPerColumn 3
}
}
For SoQuadMesh, normals and materials can be bound PER_PART (per row), PER_FACE,
PER_VERTEX and OVERALL. The default material binding is OVERALL. The default normal
binding is PER_VERTEX.
A note about SoQuadMesh shading: the quads in the mesh are just passed on to OpenGL's
GL_QUAD primitive rendering. Under certain circumstances, this can lead to artifacts in
how your meshes are shaded. This is an inherent problem with drawing quads in meshes.
There is a work-around solution for the above mentioned problem that can be applied with
Coin: by setting the global environment variable COIN_QUADMESH_PRECISE_LIGHTING to '1',
the quads will be broken up in triangles before rendered, and shading will likely look
much better. Be aware that this technique causes rendering of the SoQuadMesh to slow down
by an approximate factor of 6.
The 'precise lighting' technique is currently limited to work only when SoQuadMesh
rendering is parameterized with 3D coordinates, a materialbinding that is not per vertex,
and if texture mapping is done is must be without using any of the
SoTextureCoordinateFunction subclass nodes.
FILE FORMAT/DEFAULTS:
QuadMesh {
vertexProperty NULL
startIndex 0
verticesPerColumn 1
verticesPerRow 1
}
See Also:
SoTriangleStripSet SoIndexedTriangleStripSet
Constructor & Destructor Documentation
SoQuadMesh::SoQuadMesh (void)
Constructor.
SoQuadMesh::~SoQuadMesh () [protected], [virtual]
Destructor.
Member Function Documentation
SoType SoQuadMesh::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.
Reimplemented from SoNonIndexedShape.
const SoFieldData * SoQuadMesh::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 SoNonIndexedShape.
void SoQuadMesh::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 SoShape.
void SoQuadMesh::getPrimitiveCount (SoGetPrimitiveCountAction *action) [virtual]
Action method for the SoGetPrimitiveCountAction.
Calculates the number of triangle, line segment and point primitives for the node and adds
these to the counters of the action.
Nodes influencing how geometry nodes calculates their primitive count also overrides this
method to change the relevant state variables.
Reimplemented from SoShape.
SbBool SoQuadMesh::generateDefaultNormals (SoState *state, SoNormalBundle *bundle) [virtual]
This API member is considered internal to the library, as it is not likely to be of
interest to the application programmer.
Subclasses should override this method to generate default normals using the
SoNormalBundle class. TRUE should be returned if normals were generated, FALSE otherwise.
Default method returns FALSE.
This function is an extension for Coin, and it is not available in the original SGI Open
Inventor v2.1 API.
Reimplemented from SoVertexShape.
void SoQuadMesh::generatePrimitives (SoAction *action) [protected], [virtual]
The method implements action behavior for shape nodes for SoCallbackAction. It is invoked
from SoShape::callback(). (Subclasses should not override SoNode::callback().)
The subclass implementations uses the convenience methods SoShape::beginShape(),
SoShape::shapeVertex(), and SoShape::endShape(), with SoDetail instances, to pass the
primitives making up the shape back to the caller.
Implements SoShape.
void SoQuadMesh::computeBBox (SoAction *action, SbBox3f &box, SbVec3f ¢er) [protected],
[virtual]
Implemented by SoShape subclasses to let the SoShape superclass know the exact size and
weighted center point of the shape's bounding box.
The bounding box and center point should be calculated and returned in the local
coordinate system.
The method implements action behavior for shape nodes for SoGetBoundingBoxAction. It is
invoked from SoShape::getBoundingBox(). (Subclasses should not override
SoNode::getBoundingBox().)
The box parameter sent in is guaranteed to be an empty box, while center is undefined upon
function entry.
Implements SoShape.
SbBool SoQuadMesh::generateDefaultNormals (SoState *state, SoNormalCache *cache) [protected],
[virtual]
This API member is considered internal to the library, as it is not likely to be of
interest to the application programmer.
Subclasses should override this method to generate default normals using the SoNormalCache
class. This is more effective than using SoNormalGenerator. Return TRUE if normals were
generated, FALSE otherwise.
Default method just returns FALSE.
This function is an extension for Coin, and it is not available in the original SGI Open
Inventor v2.1 API.
Reimplemented from SoVertexShape.
Member Data Documentation
SoSFInt32 SoQuadMesh::verticesPerColumn
Specifies to number of vertices in each column.
SoSFInt32 SoQuadMesh::verticesPerRow
Specifies the number of vertices in each row.
Author
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