Clarify rgb vs srgb behavior

index.bs

@@ -21,7 +21,7 @@ WPT Path Prefix: webxr
 Editor: Brandon Jones 87824, Google https://google.com/, bajones@google.com
 Former Editor: Nell Waliczek 93109, Amazon [Microsoft until 2018] https://amazon.com/, nhw@amazon.com
 Editor: Manish Goregaokar 109489, Google [Mozilla until 2020], manishearth@google.com
-Editor: Rik Cabanier 106988, Meta https://facebook.com, cabanier@fb.com
+Editor: Rik Cabanier 106988, Meta https://meta.com, cabanier@meta.com
 
 Abstract: This specification describes support for accessing virtual reality (VR) and augmented reality (AR) devices, including sensors and head-mounted displays, on the Web.
 
@@ -33,11 +33,14 @@ spec:infra;
     type:dfn; text:string
     type:dfn; text:tuple
     type:dfn; text:continue
-spec:permissions-1;
+spec:permissions;
     type:dfn; text:powerful feature
 spec:webidl;
     type:dfn; text:new
     type:interface; text:any
+spec:dom;
+    type:dfn; text:ancestor
+    type:dfn; text:descendant
 spec:webxr-ar-module-1;
     type:dfn; text:first-person observer view
 spec:html; type:interface; text:Navigator
@@ -80,8 +83,12 @@ spec: WebGL; urlPrefix: https://www.khronos.org/registry/webgl/specs/latest/1.0/
     type: dfn; text: webgl context lost flag; for: WebGLRenderingContext; url: webgl-context-lost-flag
     type: dfn; text: Fire a WebGL context event; url: fire-a-webgl-context-event
     type: dfn; text: invalidated; for: WebGLObject; url: #webgl-object-invalidated-flag
+    type: typedef; text: RGBA; url: #5.14
+    type: typedef; text: RGB; url: #5.14
 spec: WebGL 2.0; urlPrefix: https://www.khronos.org/registry/webgl/specs/latest/2.0/
     type: interface; text: WebGL2RenderingContext; url: WebGL2RenderingContext
+    type: typedef; text: SRGB8; url: #5.14
+    type: typedef; text: SRGB8_ALPHA8; url: #5.14
 spec: Orientation Sensor; urlPrefix: https://www.w3.org/TR/orientation-sensor/
     type: interface; text: AbsoluteOrientationSensor; url: absoluteorientationsensor
     type: interface; text: RelativeOrientationSensor; url: relativeorientationsensor
@@ -928,7 +935,7 @@ The <dfn attribute for="XRSession">onend</dfn> attribute is an [=Event handler I
 
 The <dfn attribute for="XRSession">oninputsourceschange</dfn> attribute is an [=Event handler IDL attribute=] for the {{inputsourceschange}} event type.
 
-The <dfn attribute for="XRSession">onselectstart</dfn> attribute is an [=Event handler IDL attribute=] for the {{selectstart}} event type.
+The <dfn attribute for="XRSession">onselectstart</dfn> attribute is an [=Event handler IDL attribute=] for the {{XRSession/selectstart}} event type.
 
 The <dfn attribute for="XRSession">onselectend</dfn> attribute is an [=Event handler IDL attribute=] for the {{selectend}} event type.
 
@@ -1890,7 +1897,7 @@ An [=XR input source=] is an <dfn>auxiliary input source</dfn> if it does not su
 When an [=XR input source=] |source| for {{XRSession}} |session| begins its [=primary action=] the UA MUST run the following steps:
 
   1. Let |frame| be a [=new=] {{XRFrame}} in the [=relevant realm=] of |session| with {{XRFrame/session}} |session| with [=XRFrame/time=] being the time the action occurred.
-  1. [=Queue a task=] to [=fire an input source event=] with name {{selectstart!!event}}, frame |frame|, and source |source|.
+  1. [=Queue a task=] to [=fire an input source event=] with name {{XRSession/selectstart!!event}}, frame |frame|, and source |source|.
 
 </div>
 
@@ -1968,7 +1975,7 @@ When a [=transient input source=] |source| for {{XRSession}} |session| begins it
   1. [=Queue a task=] to perform the following steps:
     1. Fire any `"pointerdown"` events produced by the [=XR input source=]'s action, if necessary.
     1. [=add input source|Add the XR input source=] to the [=list of active XR input sources=].
-    1. If the [=transient action=] is a [=primary action=], [=fire an input source event=] with name {{selectstart!!event}}, frame |frame|, and source |source|.
+    1. If the [=transient action=] is a [=primary action=], [=fire an input source event=] with name {{XRSession/selectstart!!event}}, frame |frame|, and source |source|.
 
 </div>
 
@@ -2173,6 +2180,13 @@ The buffers attached to an [=opaque framebuffer=] MUST be cleared to the values
 
 Note: Implementations may optimize away the required implicit clear operation of the [=opaque framebuffer=] as long as a guarantee can be made that the developer cannot gain access to buffer contents from another process. For instance, if the developer performs an explicit clear then the implicit clear is not needed.
 
+If an {{XRWebGLLayer}} is created with an {{XRWebGLLayerInit/alpha}} set to `true`, the {{XRWebGLLayer/framebuffer}} must be backed by a texture with the {{RGBA}} color format.
+If an {{XRWebGLLayer}} is created with an {{XRWebGLLayerInit/alpha}} set to `false`, the {{XRWebGLLayer/framebuffer}} must be backed by a texture with the {{RGB}} color format.
+
+However, the [=XR Compositor=] MUST treat the {{XRWebGLLayer/framebuffer}}'s backing's pixels as if they were in the {{SRGB8_ALPHA8}} or {{SRGB8}} {{XRLayerInit/colorFormat}}.
+
+NOTE: this means that the [=XR Compositor=] MUST not do any gamma conversion from linear {{RGBA}} or {{RGB}} when it processes the texture backing the {{XRWebGLLayer/framebuffer}}. Otherwise, the pixels in the final rendering will appear too bright which will not match the rendering on a regular 2D {{WebGLRenderingContext}} context.
+
 When an {{XRWebGLLayer}} is set as an [=immersive session=]'s {{XRRenderState/baseLayer}} the content of the [=opaque framebuffer=] is presented to the [=immersive XR device=] immediately after an [=XR animation frame=] completes, but only if at least one of the following has occurred since the previous [=XR animation frame=]:
 
   - The [=immersive session=]'s {{XRRenderState/baseLayer}} was changed.