DummyBackend
A Backend used for unit-testing, which renders nothing. By having a backend which doesn't actually render anything, unit tests which are not testing the actual display output do not need to create a window, or use OpenGL.
Functions
OpenGL is moe efficient when operations can be batched. So rather than call drawTexture multiple times (with the same texture, tint, and modelMatrix), batch them and call TextureBatch.draw instead.
In a JVM context, path is the path of a file (which may be a relative path). The textures are loaded immediately (unlike in a JS context, where there will be a delay).
A gradient fill. Each vertex of each triangle has a color.
If you need to use OpenGL while Glok is rendering a scene, you must perform these actions within a block. This saves the OpenGL state, runs the block, and then restores the state again.