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Re: [Public WebGL] WEBGL_depth_texture unspecified case: sampling from an uninitialized depth texture



I think Chrome either initializes or clears all textures before use.
While you can't provide initial data for an ANGLE_depth_texture texture
you still should be able to attach it to an FBO and clear it.

(Ken: feel free to correct me based on actual implementation details. I'm
basing this from memory of some discussions I had with Greg.)

-Daniel



On 2013-09-26 3:05 PM, "Benoit Jacob" <bjacob@mozilla.com> wrote:

>
>Hi,
>
>WEBGL_depth_texture introduces a basic possibility that does not exist
>in the core WebGL spec: the possibility of an uninitialized texture.
>
>While uninitialized renderbuffers are only an implementation detail that
>doesn't have any existence at the level of the WebGL spec, uninitialized
>textures are different because they can be sampled from.
>
>The question is what should the spec mandate implementations to do when
>executing code like this:
>
>   CreateAndTexImage2DSomeUninitializedDepthTexture();
>   SetUpRenderingStateSamplingFromThatTexture();
>   Draw();
>
>
>It's not technically an INVALID_FRAMEBUFFER_OPERATION since the
>uninitialized texture here is one we are sampling from, not one we are
>rendering to. So should that be an INVALID_OPERATION?
>
>Note: I'm running into this while implementing support for
>WEBGL_depth_texture on clients supporting only ANGLE_depth_texture. I
>understand that Chrome already supports that. I would like to know what
>is Chrome's current behavior there.
>
>Thanks,
>Benoit
>
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