[Mesa-dev] [PATCH] mesa: Add ARB_texture_view to Mesa core
courtney at lunarg.com
Mon Nov 11 12:43:50 PST 2013
On Mon, Nov 11, 2013 at 11:15 AM, Ian Romanick <idr at freedesktop.org> wrote:
> On 11/05/2013 11:36 AM, Courtney Goeltzenleuchter wrote:
> > On Tue, Nov 5, 2013 at 12:22 PM, Ian Romanick <idr at freedesktop.org
> > <mailto:idr at freedesktop.org>> wrote:
> > On 11/05/2013 09:44 AM, Chris Forbes wrote:
> > >> So, you can create a GL_LUMINANCE view of a GL_LUMINANCE texture.
> > Hmm...
> > >
> > > My understanding is you can't actually, since views can only be
> > > created from immutable-format textures, and GL_LUMINANCE is not a
> > > sized internalformat, so it can't be used with TexStorage?
> > I was just using GL_LUMINANCE as shorthand for GL_LUMINANCE4,
> > GL_LUMINANCE8, GL_LUMINANCE12, and GL_LUMINANCE16. As far as I can
> > tell,
> > glGenTextures(1, &tex);
> > glBindTexture(GL_TEXTURE_2D, tex);
> > glTexStorage2D(GL_TEXTURE_2D,
> > 8,
> > GL_LUMINANCE8,
> > 1024, 1024);
> > is perfectly valid. Sayeth GL_ARB_texture_storage:
> > Accepted by the <internalformat> parameter of TexStorage* when
> > implemented on OpenGL ES:
> > ALPHA8_EXT 0x803C
> > LUMINANCE8_EXT 0x8040
> > LUMINANCE8_ALPHA8_EXT 0x8045
> > I guess that means GL_LUMINANCE4, GL_LUMINANCE12, and GL_LUMINANCE16
> > out. As are all GL_INTENSITY formats. There are still these three
> > legacy formats to handle.
> > So, if we support GL_ARB_texture_view in a compatibility profile,
> > glGenTextures(1, &view);
> > glTextureView(view,
> > GL_TEXTURE_2D,
> > tex,
> > GL_LUMINANCE8,
> > 1, 1, 1, 1);
> > is also valid.
> > Right?
> > The spec is pickier than that. For 8bit texels the allowed internal
> > formats are: R8UI, R8I, R8, R8_SNORM
> > I use the table specified in the ARB_texture_view to translate the
> > target internalFormat passed to glTextureView into a VIEW_CLASS.
> > GL_LUMINANCE8 does not have a valid VIEW_CLASS and could not match the
> > internal format of the source texture.
> I don't think it matters that GL_LUMINANCE8 is missing from the table or
> that it doesn't have a VIEW_CLASS. The GL_ARB_texture_view spec says
> (emphasis mine):
> The two textures' internal formats must be compatible according to
> Table 3.X.2 (Compatible internal formats for TextureView) if the
> internal format exists in that table and *the internal formats
> must be identical if not in that table*, or else an
> INVALID_OPERATION error is generated.
> In my above code example, the internal formats are identical. By my
> reading of the above quoted text, that code is legal. We should modify
> one of the texture_view tests to use these legacy formats, and try that
> test on NVIDIA with a compatibility profile.
Good point. I'll talk with Jon about testing that if we don't already.
> > That makes me wonder, should I be trying to map the target
> > internalformat into a driver internal format?
> > Courtney
> > --
> > Courtney Goeltzenleuchter
> > LunarG
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