uh Unreal Engine, its base code is mainly unchanged between platform, doesnt matter if its PPC or X86 etc, it still runs Open GL regardless,
so no im not confusing anything
the GAME engine is Id tech 5 for example
Call of Duty is running on a modified Id Tech 3,
Source Engine runs on a modified Id Tech 3 i believe if i remember right
Unreal Engine has to have support for Open GL and both code paths again PS3 / 360, Mac OS X / Windows
so no in reality the Engine thats take the basic model and texture information and display it while handling physics AI as well have the code paths already for Direct X and Open GL, otherwise you wouldnt see the games on all systems,
I know the difference in API as well,
Simple fact IS
Open GL ES 2.0 is the standard for ARM and Mobile Devices,
Open GL ES 1.0 and 2.0 were bastardised in the use of the PS3,
Open GL ES 1.0 and 2.0 from what i remember are used in the Wii and Wii U
only one console uses Direct X, yes current consoles are Power PC based, but then if its so different why do essentially Xbox code run perfectly fine on PC, anyone remember Dead Island where the 360 version was essentially used as the PC version and it got pulled, but worked just fine?
doesnt matter much all these code paths are there for the most part, It has to be, otherwise the engines couldnt be used, ARM is not PPC, PPC is not x86 but Unreal Engine works across all without issue same goes for many other game engines.
Essentially these APIs get called various names but essentially
Wii, Wii U, PS3, PS4, ARM, all make use of Open GL in some form or another, do to Open GL ES 2.0 and 4.1 offering programmable pipeline they can be customized, but in the end
OpenGL 4.1
Released on 26 July 2010[32]
Supported Cards: Nvidia GeForce 400 series, Nvidia GeForce 500 series, ATI Radeon HD 5000 series, AMD Radeon HD 6000 Series, AMD Radeon HD 7000 Series
This new version adds these additional features to the specification, many of which help bring it in line with those in Direct3D 11:
OpenGL Shading language (GLSL) 4.1
Full compatibility with OpenGL for Embedded Systems (OpenGL ES) 2.0 APIs
Reduced shaders compilation times with the ability to query and load a binary for shader program objects
The ability to bind programs individually to the five programmable stages (Vertex, Tessellation Control, Tessellation Evaluation, Geometry, and Fragment)
Improvements to the general 64-bit floating point supported added in OpenGL 4.0 (64-bit floating-point component input for vertex shader)
Essentially this means as of Open GL 4.1 support for Open GL ES 2.0 based APIs is possible on desktops Open GL is no on version 4.2 which supports Tessellation etc,
the API essentially now offers broader support across nearly every possible platform in one way or another
In terms of abilities Open GL ES 2.0 = Open GL 2.0
They were seperate however for a great deal of time, the newest revision change this, essentially their are many off shoots but its not unlike Direct X in terms of 9, 10 or 11 where different functionalities exist for different hardware. Considering again most GAME ENGINES have support for Open GL due to the other platforms its not that much different, and considering the Mac OSX game support is continuing to grow and makes use of the same API and functions Linux does, its not that big a stretch, the major issue is kernel support etc among various Linux builds which is why Valve is sticking to one distro right now and it just so happens to be the most popular Distro in use by consumers.
In reality Open GL is actually easier to code for, HOWEVER its harder for Hardware vendors to write a good performing DRIVER for it,
Essentially both APIs can accomplish the same thing each offers a different advantage.