The std::string generation with its malloc and free requirement
was a noticeable overhead. Also switch to an ordered_map to
avoid the std::hash call. As those maps usually have a size of
two elements, the lookup time shall not matter.
While convenient as a std::array, it's also quite a large set of data as
well (32KB). It being an array also means data cannot be std::moved. Any
situation where the code is being set or relocated means that a full
copy of that 32KB data must be done.
If we use a std::vector we do need to allocate on the heap, however, it
does allow us to std::move the data we have within the std::vector into
another std::vector instance, eliminating the need to always copy the
program data (as std::move in this case would just transfer the pointers
and bare necessities over to the new vector instance).
Namespaces all OpenGL code under the OpenGL namespace.
Prevents polluting the global namespace and allows clear distinction
between other renderers' code in the future.
All tested games that use a single texture show no regression.
Only Texture2D textures are supported right now, each shader gets its own "tex_fs/vs/gs" sampler array to maintain independent textures between shader stages, the textures themselves are reused if possible.