* 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.
* Older GLSL doesn't have texelFetch() and related things, working
around it by using classical texture() and normalized floating-point
coordinates. But that needs to have Texture::imageSize() passed,
which is not available in OpenGL ES, thus the user must specify it
explicitly there. On desktop OpenGL that parameter is ignored.
* Older GLSL doesn't have gl_VertexID, thus vertex buffer must be
created and vertex data passed expliticly.
* GLSL ES 2.0 doesn't have one-component texture format and
TextureFormat::Luminance probably isn't renderable anywhere, thus
TextureFormat::RGB should be used, although it is inefficient.
* Checking for framebuffer completeness, if not complete, nothing is
done.
* Re-eabled building of TextureTools 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