[Mesa-dev] Immutable textures and BGRA external format support

[kalyan kondapally]

>>Even APPLE_texture_format_BGRA8888
>>mentions that BGRA8_EXT is not accepted as an <internalformat>
>>parameter to TexImage* when the GL is OpenGL ES 3.0. With GLES3.0, I
>>am wondering if their is any way to use image data in BGRA format and
>>Immutable textures without swizzling the data to RGBA format ?

Correcting myself,
It's invalid to call TexImage after immutable texture is created.
APPLE_texture_format_BGRA888 doesn't mention that BGRA8_EXT is not
accepted with TexSubImage2D when GL is OpenGL ES 3.0. So,  adding
APPLE_texture_format_BGRA888 support in Mesa should resolve this or
any other ideas?

Thanks,
Kalyan

On Sat, Nov 22, 2014 at 10:33 PM, kalyan kondapally
<kondapallykalyancontribute at gmail.com> wrote:
> Hi,
>
> I am looking at Immutable textures usage with image data of BGRA
> format. According to Texture storage extension spec [1] if either
> EXT_texture_format_BGRA8888 or APPLE_texture_format_BGRA8888 are
> supported, glTexStorage2DEXT
> must accept BGRA8_EXT as internal format. EXT_texture_format_BGRA8888
> doesn't mention anything about BGRA8_EXT support. However,
> APPLE_texture_format_BGRA8888[3] mentions supports for BGRA8_EXT as an
> internal format with glTexStorage2DEXT and GL_BGRA_EXT as an external
> format for TexImage2D and TexSubImage2D
>
> glTexStorage2D is part of core in GLES3 but doesn't mention support
> for BGRA8 as an internal format. Even APPLE_texture_format_BGRA8888
> mentions that BGRA8_EXT is not accepted as an <internalformat>
> parameter to TexImage* when the GL is OpenGL ES 3.0. With GLES3.0, I
> am wondering if their is any way to use image data in BGRA format and
> Immutable textures without swizzling the data to RGBA format ?
>
> Relevant Discussion in Chromium side can be found here:
> https://code.google.com/p/chromium/issues/detail?id=407034
>
> Thanks for any pointers.
>
> Br,
> Kalyan
>
> 1)https://www.khronos.org/registry/gles/extensions/EXT/EXT_texture_storage.txt
> 2)https://www.khronos.org/registry/gles/extensions/EXT/EXT_texture_format_BGRA8888.txt
> 3)https://www.khronos.org/registry/gles/extensions/APPLE/APPLE_texture_format_BGRA8888.txt