6.2.3 OVWRT_ATTR (a1, a2, ...)

A group of attributes ai which is used with the following rules when the scene graph is rendered:

When the scene graph is traverted, each scene graph node gets a structure with the currently active attributes from its parent, and a structure with overwrite attributes.

The scene graph nodes makes two copys of the active attributes struct. The first copy will be used when the primitives attached to the scene graph node itself get rendered, the second copy will be passed to the child scene nodes.

It also makes a copy of the overwrite attributes struct, which will be passed to the child scene nodes too.

Then happens the following:

• The attributes set with ATTRIBS (see 6.2.1) are applied to both copys of the active attributes struct.

• The attributes set with LOCAL_ATTR (see 6.2.2) are only applied to the copy which is used by the scene graph node itself when it renders its own primitives (i.e. this has no influence to the child scene nodes)

• Then the attributes set with OVWRT_ATTR are applied to both copys of the active attributes, and to the copy of the overwrite attributes struct.

• Then the scene graph node renders its own primitives with the first copy of the active attributes struct, afterwards it calls its child scene graph nodes with the second copy of the active attributes struct and the copy of the overwrite attributes struct.

The ai must be attribute type nodes.