This is a generic way to get matrix data to shaders without using
(old-school) uniforms. This is another step towards more compatibility
with how new APIs (Vulkan) do things to increase the odds for a Vulkan
port at some point.
This uses UBOs for building a buffer object of uniform data before
using that data to draw objects. This should reduce the CPU overhead by
reducing the amount of glUniform calls required for executing a single
draw call. This is especially useful if rendering is limited by the CPU
which should help performance for people with slower CPUs.
This fixes#910.
All transformations are now handled by shaders so there is nothing
special going on in the graphics API specific code anymore. Since model
uniform buffers require access to these matrices I moved the matrix
handling out of the graphics API code.
Mike Nelson