4.2.2 MESH: rectangularly-connected mesh

The conventional suffix for a MESH file is .mesh.

The file syntax is

     [U][C][N][Z][4][u][v][n]MESH # Key word
     [Ndim]                 # Space dimension, present only if nMESH
     Nu Nv            # Mesh grid dimensions
                                  # Nu*Nv vertices, in format specified
                                  # by initial key word
     vertex(u=0,v=0)  vertex(1,0)  ... vertex(Nu-1,0)
     vertex(0,1) ...    vertex(Nu-1,1)
     ...
     vertex(0,Nv-1) ... vertex(Nu-1,Nv-1)

The key word is [U][C][N][Z][4][u][v][n]MESH. The optional prefix characters mean:

`U'

Each vertex includes a 3-component texture space parameter. The first two components are the usual S and T texture parameters for that vertex; the third should be specified as zero.

`C'

Each vertex (see Vertices above) includes a 4-component color.

`N'

Each vertex includes a surface normal vector.

`Z'

Of the 3 vertex position values, only the Z component is present; X and Y are omitted, and assumed to equal the mesh (u,v) coordinate so X ranges from 0 .. (Nu-1), Y from 0 .. (Nv-1) where Nu and Nv are the mesh dimensions – see below.

`4'

Vertices are 4D, each consists of 4 floating values. Z and 4 cannot both be present.

`u'

The mesh is wrapped in the u-direction, so the (0,v)'th vertex is connected to the (Nu-1,v)'th for all v.

`v'

The mesh is wrapped in the v-direction, so the (u,0)'th vertex is connected to the (u,Nv-1)'th for all u. Thus a u-wrapped or v-wrapped mesh is topologically a cylinder, while a uv-wrapped mesh is a torus.

`n'

Specifies a mesh whose vertices live in a higher dimensional space. The dimension follows the "MESH" keyword. Each vertex then has Ndim components.

Note that the order of prefix characters is significant; a colored, u-wrapped mesh is a CuMESH not a uCMESH.

Following the mesh header are integers Nu and Nv, the dimensions of the mesh.

Then follow Nu*Nv vertices, each in the form given by the header. They appear in v-major order, i.e. if we name each vertex by (u,v) then the vertices appear in the order

     (0,0) (1,0) (2,0) (3,0) ...  (Nu-1,0)
     (0,1) (1,1) (2,1) (3,1) ...  (Nu-1,1)
     ...
     (0,Nv-1)		...  (Nu-1,Nv-1)

A MESH BINARY format is accepted; See Binary format. The values of Nu and Nv are 32-bit integers; all other values are 32-bit floats.