Okay, that makes it easier. Should this change be conditional based on the type of context created?
Courtney On Thu, Dec 5, 2013 at 8:52 AM, Brian Paul <bri...@vmware.com> wrote: > On 12/04/2013 03:46 PM, Courtney Goeltzenleuchter wrote: > >> It's come to my attention that Mesa's handling of GL_TEXTURE_BASE_LEVEL >> and GL_TEXTURE_MAX_LEVEL in glTexParameter and glGetTexParameter may be >> incorrect. The issue happens with the following sequence: >> >> glTexStorage2D(GL_TEXTURE_2D, 4, GL_RGBA8, 128, 128); >> >> glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 5); >> >> glGetTexParameter(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, &n); >> >> The key question is: What is the value of n? >> >> Right now, the Mesa driver will clamp the glTexParameter call to the >> range 0 .. 3 (as specified by the TexStorage call) and n = 3 after the >> GetTexParameter call. However, the value returned on the Intel Windows >> driver and NVIDIA's Linux driver return 5. This has apparently been >> discussed among Kronos members in bug: 9342 >> (https://cvs.khronos.org/bugzilla/show_bug.cgi?id=9342 >> <https://urldefense.proofpoint.com/v1/url?u=https: >> //cvs.khronos.org/bugzilla/show_bug.cgi?id%3D9342&k= >> oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ% >> 2BTLs8wadB%2BiIj9xpBY%3D%0A&m=SrPAWBW251dxCErQJNhB0m93E9Vb62 >> KGHxK3yiRBRuU%3D%0A&s=a0c086b7a31a804e3e786118fd1771 >> b53c85717a4cf0c8dea41b60e5acd0406b>) >> >> which I don't have visibility of. >> >> To match that behavior the texture object will likely need two BaseLevel >> and MaxLevel attributes. One that's clamped and used locally and the >> other that simply holds the set value as given by the application in the >> glTexParameter call. >> >> Thoughts? >> > > From reading the bug report, it sounds like the ARB decided that clamping > should be done when the texture is used, not when glTexParameter is called. > In the GL 4.3 spec I don't see any language about clamping in > glTexParameter either. > > We should be doing the use-time clamping already. So I think we just have > to remove the clamping step in glTexParameter. > > -Brian > > -- Courtney Goeltzenleuchter LunarG
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