// SampleX15 - Rendering "glass"
// by Lord Trancos
// ---------------------------------------------------------------------------
//
// This sample only covers the transparency issue.
// You may get a better look adding reflections
// using a sphere or cube map.
//
// This sample does not need a z-buffer, but it uses
// it in order to show you that writing to z-buffer
// must be disabled in order to rendering glass correctly.
// (well, instead of that you can sort the triangles...)
// Remember to enable again z-writing (and culling) to
// render other non-glass objects in the scene.
//
// The best is render first non glass objects:
//
//  - BeginScene
//  - Enable culling and writing to z-buffer
//  - Render non glass objects
//  - Disable culling and writing to z-buffer
//  - Render glass objects
//  - EndScene
//
