It's somewhat scary to see new graphics APIs being introduced.<p>The fragmentation of OpenGL is enough of a headache, but at least it offers some semblance of "write once, run anywhere." The introduction of Mantle and Metal, plus the longstanding existence of Direct3d, makes me worry that OpenGL will get no love. And then we'll have to write our graphics code, three, four, or goodness knows how many times.<p>I know: It's not realistic to expect "write once, run anywhere" for any app that pushes the capabilities of the GPU. But what about devs like me (of whom there are many) that aren't trying to achieve AAA graphics, but just want the very basics? For us, "write once, run anywhere" is very attractive and <i>should</i> be possible. I can do everything I want with GL 2.1, I don't need to push a massive number of polys, I don't need a huge textures, and I don't need advanced lighting.