If texture can be uploaded to GL using glTexImage2D normally, but
cannot be read back using glReadPixels, we still can accelerate it,
but we cannot create pixmap with FBO using this texture type. So,
add a flag to avoid such creations.
This allow us to accelerate 8-bit glyph masks on GL ES 2.0, because those
masks are used only as textures, and in next stages are rendered on RGBA
surfaces normally, so, we do not need to call glReadPixels on them.
This is needed for correctly working fonts on GL ES 2.0, due to inability
to use GL_RED and texture swizzle. We should use GL_ALPHA there, and
with this format we cannot have a complete framebuffer. But completed
framebuffer, according to testing, is not required for fonts anyway.
Also it fixes all 8-bit formats for GLES2.
Fixes#1362Fixes#1411
Signed-off-by: Konstantin Pugin <ria.freelander@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Acked-by: Michel Dänzer <mdaenzer@redhat.com>
Acked-by: Martin Roukala <martin.roukala@mupuf.org>
e573d4ca03