Avoids some nullptr-related errors and leads to simpler implementation,
as we need to only handle ImageReference and BufferImage types. All
other Image classes are implicitly convertible to ImageReference and
implicit conversion works only with references, not with pointers. The
usage might be clumsy at this point, as Trade::*Importer classes return
pointer to Trade::ImageData which then needs to be dereferenced.
Hopefully introducing C++14's std::optional (or equivalent) might help
solve that issue.
Also removed "convenience" overloads for setting e.g. 2D subdata of 3D
texture. The convenience overload doesn't cover all subdata cases (only
XY plane, not YZ or XZ ones) and overly complicates the implementation.
This can be done in the future in Image classes themselves.
* Not requiring ARB_texture_storage, as Texture::setStorage() has
already implemented fallback.
* Not requiring EXT_texture_rg for single-channel texture on ES2, as
this extension might not be available everywhere (unlike in ES3
desktop OpenGL, where Mesa 8/9 with OpenGL 2.1 supports it), fallback
to Luminance in GlyphCache and RGB in DistanceFieldGlyphCache,
because Luminance might not be renderable everywhere.
* Re-enabled building of Text library in all ES PKGBUILDs.
Solves another trivial choice (similar to the one with TextureFormat
etc. in 7de45c98b1), less typing and also
preparation for ARB_sampler_objects extension.
Advantages:
* The enums were large (600-800 lines) and they polluted the header,
now they are in separate files (except for BufferTexture, which has
the enum small enough to be left in the same file).
* Image classes now don't need to include OpenGL headers, as they were
needed only for the enum values. With advantage of C++11's forward
enum declarations there is no need to include the enum headers
anywhere in implementation, only when particular values are needed.
* The values are now less verbose:
AbstractTexture::InternalFormat::RGB8 // before
TextureFormat::RGB8 // now
* Resolved another "trivial choice" problem (thanks @JanDupal for
introducing this term to me): how to specify the format if there are
ten ways to do it (some being massively confusing):
Image2D::Format f = AbstractImage::Format::RGB; // too long...
Image2D::Format f = Image3D::Format::RGBA; // why 3D? this works?
Image2D::Format f = BufferImage1D::Format::RGBA; // wat?
It is even worse (and more verbose) with textures:
Texture2D::InternalFormat f =
CubeMapTextureArray::InternalFormat::RGB8; // this is allowed?
To have consistent naming this change was done also with
BufferTexture::InternalFormat (now BufferTextureFormat), although there
were no trivial choice issues and the enum isn't too large. But at least
it is now less typing.
Vladimír Vondruš