Class TAbstractNurbsSurfaceGeometryNode

This item has no description. Showing description inherited from TX3DNode.DirectEnumerateActive.

Enumerate all active child nodes of given node.

"Active nodes" are the ones affecting current look or collisions, e.g. from Switch node only one child will be enumerated. See Traverse for more precise definition.

"Direct" means that this enumerates only direct descendants, i.e. this is not recursive. See methods like Traverse or EnumerateNodes if you want recursive behavior.

This can enumerate both VRML1Children nodes and nodes within TSFNode and TMFNode fields.

Default implementation in this class enumerates all Children nodes of VRML 1.0. If you need to remove some children for VRML 1.0 (e.g. for Switch or LOD nodes) or add some children for VRML 2.0 you have to override this. You do not need to call inherited when overriding this — in fact, you should not, if you want to omit some nodes.

Stops and returns immediately if Func returns non-nil for some child.

This item has no description. Showing description inherited from TAbstractGeometryNode.Proxy.

Converts this node to another node class that may be better supported.

Typically, converts some complex geometry node (like Extrusion or Teapot) into more common node like IndexedFaceSet or IndexedTriangleSet. TShape class wraps this method into a more comfortable interface, that is TShape methods simply automatically convert geometry nodes to their proxy versions if needed.

In the base TAbstractGeometryNode class, returns Nil indicating that no conversion is known.

The resulting node's Name (if the result is not Nil) must be equal to our Name.

Some Proxy implementations (especially for VRML 1.0) will have to create new State (TX3DGraphTraverseState) instance along with a new geometry node. You should do this by copying the State into a new TX3DGraphTraverseState instance, and modyfying the State reference. Simply speaking, do

State := TX3DGraphTraverseState.CreateCopy(State);

You should not just modify the fields of the provided State instance. (Reasoning: some proxy methods rely on getting the original State, e.g. with original MaterialBinding, not the transformed state, to work correctly.)

You can modify State variable only when returning non-nil geometry.

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This item has no description. Showing description inherited from TAbstractGeometryNode.BoundingBox.

Calculate bounding box of this geometry node. They require State of this node during VRML traverse state — this is mainly for VRML 1.0 nodes, that depend on such state.

LocalBoundingBox gives a bounding box ignoring current transformation (or, equivalently, assuming like Transform = IdentityMatrix). Normal BoundingBox gives a bounding box taking current transformation into account.

Notes for descendants implementors:

The default implementations of these methods in TAbstractGeometryNode try to be smart and cover all common bases, so that you have to do as little work as possible to implement working descendant.

1. For nodes based on coordinates (when InternalCoord returns True), LocalBoundingBox and BoundingBox already have optimal and correct implementation in this class. Using Coord and CoordIndex, no other information is needed.

2. For other nodes, we first check ProxyGeometry and ProxyState. If ProxyGeometry is non-nil, we assume these came from Proxy call and we will use them to calculate bounding boxes, local and not local.

   So for nodes with Proxy overridden, you don't have to implement bounding box calculation, instead a ProxyGeometry will be created and provided here by the caller. This will work Ok if Proxy node will have bounding box calculation implemented.

   You can always override these methods, if you don't want to use proxy (for example, maybe there exists much faster method to calculate bounding box, or maybe tighter bounding box may be calculated directly).

3. For other nodes (not coordinate-based and without a proxy):

   The default implementation of LocalBoundingBox just calls BoundingBox with a specially modified State, such that Transform is identity.

   The default implementation of BoundingBox, in turn, just calls LocalBoundingBox and transforms this bounding box.

   So the default implementations call each other, and will loop infinitely... But if you override any one of them (local or not local), the other one will magically work.

   Note that the default implementation of LocalBoundingBox may be non-optimal as far as time is concerned, as we'll do useless multiplications by identity matrix. And the default implementation of BoundingBox may generate non-optimal bounding box, more direct approach (transforming each vertex) may give much tightier bounding box.

   So you only have to override one method — although if you want the best implementation, fastest and with the best tight bounding boxes, you may need to override both of them for some nodes.

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This item has no description. Showing description inherited from TAbstractGeometryNode.InternalCoord.

Return node's list of coordinates. Returns False if node is not based on coordinates. Returns True and sets ACoord if the node is based on coordinates. Even when returns True, it can set ACoord = Nil, which means that node is based on coordinates but they are empty right now (so for example bounding box may be considered empty).

In base TAbstractGeometryNode class this always returns False.

Override this for descendants that have some kind of "coord" field, then this should return True and set ACoord to coord.point field, assuming that coord is set and specifies Coordinate node. Override this even if coordinates affect the look indirectly, e.g. NURBS "controlPoint" fields also should be returned here. Otherwise should return True and set ACoord = Nil.

For VRML 1.0, coord may be taken from State, that's why we have to pass current traverse state here.

This item has no description. Showing description inherited from TAbstractGeometryNode.CoordField.

Node's "coord" field where you can place TCoordinateNode, or Nil if not available.

This gives you more possibilities than the InternalCoord and InternalCoordinates methods (as you can assign texCoord using this). However, it doesn't work for old VRML 1.0 (since they have coordinate information, but no "coord" field).

This item has no description. Showing description inherited from TAbstractGeometryNode.SolidField.

Is backface culling used. Nil if given geometry node doesn't have a field to control it.

Get the position of a point on the surface.

The returned position is in the local transformation space of this shape. This method is guaranteed to work the same, regardless if this node is part of any TX3DRootNode and TCastleSceneCore or not.

Parameters

U

First parameter of the parametric surface, in [0..1] range.

V

Second parameter of the parametric surface, in [0..1] range.

OutputNormal

Optional. If non-nil, will be set to the normal, that is, normalized direction in 3D that is orthogonal to the surface at this point.

Create node fields and events.

This item has no description. Showing description inherited from TX3DNode.ClassX3DType.

Node type name in VRML/X3D, for this class. Normal VRML/X3D node classes should override this to return something non-empty, and then X3DType automatically will return the same value.

Empty for classes that don't have a hardcoded VRML/X3D node name, like a special TX3DUnknownNode. Such special classes should override then X3DType to return actual non-empty name there.

You usually should call X3DType. The only use of this method is that it works on classes (it's "class function"), without needing at actual instance.

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Internal wrapper for property ControlPoint. This wrapper API may change, we advise to access simpler ControlPoint instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property TexCoord. This wrapper API may change, we advise to access simpler TexCoord instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property UTessellation. This wrapper API may change, we advise to access simpler UTessellation instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property VTessellation. This wrapper API may change, we advise to access simpler VTessellation instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property Weight. This wrapper API may change, we advise to access simpler Weight instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

Internal wrapper for property Solid. This wrapper API may change, we advise to access simpler Solid instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

Internal wrapper for property UClosed. This wrapper API may change, we advise to access simpler UClosed instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property UDimension. This wrapper API may change, we advise to access simpler UDimension instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property UKnot. This wrapper API may change, we advise to access simpler UKnot instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

Internal wrapper for property UOrder. This wrapper API may change, we advise to access simpler UOrder instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property VClosed. This wrapper API may change, we advise to access simpler VClosed instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property VDimension. This wrapper API may change, we advise to access simpler VDimension instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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Internal wrapper for property VKnot. This wrapper API may change, we advise to access simpler VKnot instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

Internal wrapper for property VOrder. This wrapper API may change, we advise to access simpler VOrder instead, if it is defined (TODO: for now, some field types do not have a simpler counterpart).

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