The MeshDataTool is not used to generate geometry. But it is helpful for dynamically altering geometry, for example if you want to write a script to tessellate, simplify, or deform meshes.
The MeshDataTool is not as fast as altering arrays directly using ArrayMesh. However, it provides more information and tools to work with meshes than the ArrayMesh does. When the MeshDataTool is used, it calculates mesh data that is not available in ArrayMeshes such as faces and edges, which are necessary for certain mesh algorithms. If you do not need this extra information then it may be better to use an ArrayMesh.
MeshDataTool can only be used on Meshes that use the PrimitiveType
As an example, let's walk through the process of deforming the mesh generated in the ArrayMesh tutorial.
Assume the mesh is stored in an ArrayMesh named
mesh. We then initialize the MeshDataTool from
mesh by calling
create_from_surface(). If there is already data initialized in the MeshDataTool
create_from_surface() will clear it for you. Alternatively, you can call
before re-using the MeshDataTool
create_from_surface() uses the vertex arrays from the ArrayMesh to calculate two additional arrays,
one for edges and one for faces.
An edge is a connection between any two vertices. Each edge in the edge array contains a reference to the two vertices it is composed of, and up to two faces that it is contained within.
A face is a triangle made up of three vertices and three corresponding edges. Each face in the face array contains a reference to the three triangles and three edges it is composed of.
The vertex array contains edges, faces, normals, color, tangent, uv, uv2, bones, and weight information connected with each vertex.
To access information from these arrays you use a function of the form
What you choose to do with these functions is up to you. A common use case is to iterate over all vertices and transform them in some way:
commit_to_surface() adds a new surface to the ArrayMesh. So if you are dynamically
updating an existing ArrayMesh, first delete the existing surface before adding a new one.
Below is a complete example that creates a pulsing blob complete with new normals and vertex colors.