Primitives are individual GPU draw calls comprising a Mesh.
Meshes typically have only a single Primitive, although various cases may require more. Each primitive may be assigned vertex attributes, morph target attributes, and a material. Any of these properties should be reused among multiple primitives where feasible.
Primitives cannot be moved independently of other primitives within the same mesh, except through the use of morph targets and skinning. If independent movement or other runtime behavior is necessary (like raycasting or collisions) prefer to assign each primitive to a different mesh. The number of GPU draw calls is typically not affected by grouping or ungrouping primitives to a mesh.
Each primitive may optionally be deformed by one or more morph targets, stored in a PrimitiveTarget.
const primitive = doc.createPrimitive() .setAttribute('POSITION', positionAccessor) .setAttribute('TEXCOORD_0', uvAccessor) .setMaterial(material); mesh.addPrimitive(primitive); node.setMesh(mesh);
Type of primitives to render. All valid values correspond to WebGL enums.
Adds a morph target to the primitive. All primitives in the same mesh must have the same number of targets.
Makes a copy of this property, with the same resources (by reference) as the original.
Copies all data from another property to this one. Child properties are copied by reference, unless a 'resolve' function is given to override that.
Removes both inbound references to and outbound references from this object. At the end of the process the object holds no references, and nothing holds references to it. A disposed object is not reusable.
Returns true if two properties are deeply equivalent, recursively comparing the attributes of the properties. For example, two Primitives are equivalent if they have accessors and materials with equivalent content — but not necessarily the same specific accessors and materials.
Returns a vertex attribute as an Accessor.
Returns default attributes for the property. Empty lists and maps should be initialized
to empty arrays and objects. Always invoke
super.getDefaults() and extend the result.
Returns a reference to the Extras object, containing application-specific data for this Property. Extras should be an Object, not a primitive value, for best portability.
Returns an Accessor with indices of vertices to be drawn.
Returns the material used to render the primitive.
Returns the GPU draw mode (
POINTS...) as a WebGL enum value.
Returns the name of this property. While names are not required to be unique, this is encouraged, and non-unique names will be overwritten in some tools. For custom data about a property, prefer to use Extras.
Returns true if the node has been permanently removed from the graph.
Lists all ExtensionProperty instances attached to this Property.
Returns a list of all properties that hold a reference to this property. For example, a material may hold references to various textures, but a texture does not hold references to the materials that use it.
It is often necessary to filter the results for a particular type: some resources, like Accessors, may be referenced by different types of properties. Most properties include the Root as a parent, which is usually not of interest.
const materials = texture .listParents() .filter((p) => p instanceof Material)
Lists all vertex attribute semantics associated with the primitive, excluding any semantics
used for morph targets. For example,
['POSITION', 'NORMAL', 'TEXCOORD_0']. Order will be
consistent with the order returned by .listAttributes().
Lists all morph targets associated with the primitive.
Removes a morph target from the primitive. All primitives in the same mesh must have the same number of targets.
Sets a vertex attribute to an Accessor. All attributes must have the same vertex count.
Updates the Extras object, containing application-specific data for this Property. Extras should be an Object, not a primitive value, for best portability.
Sets an Accessor with indices of vertices to be drawn. In
TRIANGLES draw mode,
each set of three indices define a triangle. The front face has a counter-clockwise (CCW)
Sets the material used to render the primitive.
Sets the GPU draw mode (
POINTS...) as a WebGL enum value.
Sets the name of this property. While names are not required to be unique, this is encouraged, and non-unique names will be overwritten in some tools. For custom data about a property, prefer to use Extras.