Game Development Reference
In-Depth Information
is more like a performance motorbike, everything superfluous has been removed
and all that remains is raw power. This is excellent for an experienced OpenGL
programmer but a little intimidating for the beginner.
The versions of OpenGL available depend on the graphics cards drivers installed
on your system. Nearly every computer supports OpenGL 2.1 and a reasonably
recent graphics card will support OpenGL 3.x.
OpenGL ES
OpenGL ES is a modern version of OpenGL for embedded systems. It is quite
similar to recent versions of OpenGL but with a more restricted set of features.
It is used on high-end mobile phones such as the Android, BlackBerry, and
iPhone. It is also used in military hardware for heads-up displays on things like
warplanes.
OpenGL ES supports the programmable pipeline and has support for shaders.
WebGL
WebGL is currently still in development, but it is a version of OpenGL specifi-
cally made for use over the web. Using it will require a browser that supports the
HTML 5 canvas tag. It's hard to know at this stage if it is going to be something
that will take off. 3D for the web has been tried before and failed. For instance,
VRML (Virtual Reality Modeling Language) was similar to HTML but allowed
users to create 3D worlds; it had some academic popularity but never gained
traction with general users.
WebGL has some promising backers; a number of big name companies such as
Google, Apple, and Mozilla are in the WebGL working group and there are some
impressive demos. Currently the performance is very reasonable and it is likely to
compete with Flash if it matures.
OpenGL is a library that allows the programmer to send instructions to the
graphics card. The graphics card is a piece of specialized hardware to display 3D
data. Graphics cards are made up of a number of standard components includ-
ing the frame buffer, texture memory, and the GPU. The GPU, graphics pro-
cessing unit, controls how the vertices are processed and displayed on screen.
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