> Not quite. You can render the z value to a texture, but that is done in the pixelshader and do not touch the hardware z-buffer used for z-fail/z-pass tests. It is this hardware z-buffer that is inaccessible, as it shares it memory with the stencil buffer which is used for stencil tests. Hence the proprietary format.
This was true for Direct3D 9 but 10+ allow you to bind the depth/stencil buffer as a texture, although there is the caveat that you can't have it simultaneously bound as a texture and as a render target.
This was true for Direct3D 9 but 10+ allow you to bind the depth/stencil buffer as a texture, although there is the caveat that you can't have it simultaneously bound as a texture and as a render target.
See "Reading the Depth-Stencil Buffer as a Texture" on this page: http://msdn.microsoft.com/en-us/library/windows/desktop/bb20...