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Home: Autodesk FBX SDK Progammer's Guide

 

Using layers to control how a model is rendered

Using layers to control how a model is rendered

Using layer 0 to store a normal to each face

 

Applying Textures and Materials to Meshes > Using layers to control how a model is rendered > 

Layers contain materials, textures, UV, and other layer elements

There are many types of layer element: textures (texture files), normals, UV coordinates, specular materials, diffuse materials, and so forth.

For each of these layer element types, you may have more than one element. For example, if the element type is textures, you may have more than one texture file; or if the element type is normals, you may have more than one normal.

To support multiple elements of each type, a layer element contains an array of elements. What is stored in each element of the array depends upon the layer element type. This array is called DirectArray. DirectArray is actually a lookup table, indexed by element number

If you need an additional level of indirection to the elements of a DirectArray, you can use IndexArray, an array of index numbers to DirectArray

For example, in the CubeCreator tutorial program, here is how we use the DirectArray and IndexArray for normals:

• We need normals to specify which way each polygon (face) of the cube is facing.
• We need to store six normals (representing Up, Down, Left, Right, Front, and Back): so the DirectArray for this element type must have six array elements.
• We must apply the same normal to all four vertices of each cube face. So we use a 24-element IndexArray to map the six normals to the 24 vertices.