Nodes

A Guerilla scene is a hierarchy of nodes, with Document being the root node of the hierarchy.

All classes of nodes are derived from the Node base class. Examples of node classes are:

• SceneGraphNode the base class for all 3d objects
• Primitive the class for rendering objects
• RenderGraph the class for rendergraphs
• RenderGraphNode the class for rendergraph nodes

Each node can contain children nodes, starting with Document which contains the whole scene.

Iterating through a node children

Use the children iterator:

-- List all Camera nodes directly in Document
for node in children (Document, "Camera") do
    print (node:getname ())
end

Iterating through the whole hierarcy

Use the children iterator again, with the recursive option turned to true:

-- List all Primitive nodes in Document, even in hierarchy
for node in children (Document, "Primitive", nil true) do
    print (node:getname ())
end

Picking a node from its name or its path

Nodes in hierarchy are identified by their path, which is the concatenation of the parent nodes names, separated by the '|' (pipe) character. For instance, "Perspective|Frustum" is the path to the Frustum node contained in the Perspective node.

Use the getchild method with the immediate child name:

-- Get the Perspective node in Document
local perspective = Document:getchild ("Perspective")

Or use the findchild method with the relative child path:

-- Get the Frustum node in Perspective
local frustum = Document:findchild ("Perspective|Frustum")

Guerilla also offers a simple and convenient way to retrieve a node using the '_' (underscore) function:

-- Get the Frustum node in Perspective
local frustum = _("Perspective|Frustum")
-- When using strings directly, you can omit the ():
local frustum = _"Perspective|Frustum"