MeshBuffer

A triangle mesh kept in buffers, the same on the Lune and native runtimes, read from and saved to obj, glb, gltf, fbx.

What it is

A MeshBuffer holds a mesh's positions, normals, UVs, colours and triangles in buffers, with optional named groups (each object of a loaded file is a group). It works the same on the Lune runtime and the native one, where an EditableMesh exists only natively. A UV's V counts down from the top, like an image's rows. Only the file members end in Async; the rest never yield.

Making one


`new(positions, triangles, options)`	from a list of Vector3 and a flat list of 1-based vertex numbers, three a triangle; options may give Normals, UVs, Colors, Alphas and Groups, and what is left out is worked out (normals) or zero (UVs) or white (colours)
`FromTriangles(corners)`	from a corner buffer, 36 bytes a corner (Unions has the layout); equal corners become one vertex
`FromBuffer(bytes, format)`	from the bytes of a GLB, glTF, FBX, OBJ or Roblox .mesh file; the format ("glb", "gltf", "fbx", "obj" or "mesh") is told by content when left out
`LoadAsync(path)`	from such a file, the format from its ending
`FromPlace(root, options)`	from the plain Parts under an instance of a PlaceFile (Block, Wedge, CornerWedge, Cylinder and Ball, a Seat and a SpawnLocation counting as Parts too), in world space or relative to options.Origin; options may give Segments and Transparent. Gives the mesh and a table with Parts (how many were built) and Skipped (a count for each class left out: MeshParts, Unions, SpecialMeshes and the rest); stops the run when there is nothing to build

Loading stops the run with the reason when the file cannot be read.

Reading


`VertexCount, TriangleCount`	how many vertices and triangles
`GetInfo()`	the counts of vertices, triangles and groups, and Min, Max, Size and Center
`GetVertices()`	a copy of every vertex: Position, Normal, UV, Color and Alpha
`GetGroups()`	the groups in triangle order, each Name, FirstTriangle (from 1) and Triangles; {} when there are none
`ToTriangles()`	the triangles as a corner buffer, 36 bytes a corner, as EditableMesh's ReadTriangles gives them (Unions has the layout)

Changing

Normalize, Transform and SetColor give a new mesh and leave the first one as it was.


`Normalize(size)`	scaled evenly to fit the box (a number is a cube, a Vector3 the box) and centred on the origin
`Transform(cframe, scale)`	scaled (a number or per axis; negative mirrors), then moved by the CFrame; normals are rotated too
`SetColor(color, alpha)`	every vertex this colour (alpha 1 unless given)
`MeshBuffer.Merge(items)`	one mesh from several, each moved first by its Transform and Scale; an item is a MeshBuffer or a table with Mesh, Transform, Scale and Name
`MeshBuffer.EasyColorMerge(items)`	Merge for meshes of one colour each (an item may give Color): gives the mesh, with white colours and UVs into the atlas, and the atlas, a PixelImage with a 4 x 4 texel block a colour

Saving


`Encode(format, atlas)`	the file's bytes: "glb" (the default; an atlas PixelImage is embedded), "gltf" (text), "fbx" or "obj"
`SaveMeshWithAtlasAsync(path, atlas)`	writes a .glb, .gltf, .fbx or .obj file and the atlas as a PNG beside it named <name>.png

Native runtime only


`MeshBuffer.FromEditableMesh(mesh)`	a copy of an EditableMesh's triangles
`mesh:ToEditableMesh()`	a new EditableMesh with this mesh, which the caller owns

Both refuse on the Lune runtime, which has no EditableMesh.