Allow depth&&stencil result if depth||stencil requested.

kdashg · toji · commit 99b999118305 · 2020-03-23T19:29:13.000-07:00
We don't want to encourage !depth&amp;&amp;!stencil result if depth xor stencil.
diff --git a/index.bs b/index.bs
@@ -1778,8 +1778,8 @@ An <dfn>opaque framebuffer</dfn> functions identically to a standard {{WebGLFram
  - An [=opaque framebuffer=] MAY support antialiasing, even in WebGL 1.0.
  - An [=opaque framebuffer=]'s attachments cannot be inspected or changed. Calling {{framebufferTexture2D}}, {{framebufferRenderbuffer}}, {{deleteFramebuffer}}, or {{getFramebufferAttachmentParameter}} with an [=opaque framebuffer=] MUST generate an {{INVALID_OPERATION}} error.
  - An [=opaque framebuffer=] is considered incomplete outside of a {{XRSession/requestAnimationFrame()}} callback. When not in a {{XRSession/requestAnimationFrame()}} callback calls to {{checkFramebufferStatus}} MUST generate a {{FRAMEBUFFER_UNSUPPORTED}} error and attempts to clear, draw to, or read from the [=opaque framebuffer=] MUST generate an {{INVALID_FRAMEBUFFER_OPERATION}} error.
- - An [=opaque framebuffer=] initialized with {{XRWebGLLayerInit/depth}} <code>false</code> will not have an attached depth buffer.
- - An [=opaque framebuffer=] initialized with {{XRWebGLLayerInit/stencil}} <code>false</code> will not have an attached stencil buffer.
+ - An [=opaque framebuffer=] initialized with {{XRWebGLLayerInit/depth}} <code>true</code> will have an attached depth buffer.
+ - An [=opaque framebuffer=] initialized with {{XRWebGLLayerInit/stencil}} <code>true</code> will have an attached stencil buffer.
  - An [=opaque framebuffer=]'s color buffer will have an alpha channel if and only if {{XRWebGLLayerInit/alpha}} is <code>true</code>.
  - The [=XR Compositor=] will assume the [=opaque framebuffer=] contains colors with premultiplied alpha. This is true regardless of the {{WebGLContextAttributes|premultipliedAlpha}} value set in the {{XRWebGLLayer/context}}'s [=actual context parameters=].
 
