Created a base class for examples taken from gles2 book. It encapsulates the ...

Created a base class for examples taken from gles2 book. It encapsulates the well-defined pattern followed by the examples to eliminate duplicated code. Once we finalize this CL, I will go ahead and change all demos to use this base class.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=36542

[vangelis, 2010-01-19 18:00:48]

Looks fine but out of curiosity, is there a good reason to template the
functions?  Couldn't those be passed as arguments to the constructor for
example?  The only arg that I see value in templating is UserData.

http://codereview.chromium.org/543110/diff/1/2
File gpu/demos/gles2_book/example.h (right):

http://codereview.chromium.org/543110/diff/1/2#newcode23
gpu/demos/gles2_book/example.h:23: // They all use one ESContext that holds a
refernce to a custom UserData.
typo:reference

http://codereview.chromium.org/543110/diff/1/2#newcode40
gpu/demos/gles2_book/example.h:40: memset(&user_data_, 0, sizeof(HTUserData));
HTUserData -> UserData

[alokp, 2010-01-19 18:08:05]

There are a couple of reasons I made the callback functions as templates. Most
importantly it will be easier if you want to use HelloTriangle from two or more
places, say stand-alone and pepper. In that case I will just move the
HelloTriangle typedef to a header file that can be shared. Otherwise I will have
to create a factory function that instantiates the class with correct
function-pointer arguments. Does it make sense?

http://codereview.chromium.org/543110/diff/1/2
File gpu/demos/gles2_book/example.h (right):

http://codereview.chromium.org/543110/diff/1/2#newcode23
gpu/demos/gles2_book/example.h:23: // They all use one ESContext that holds a
refernce to a custom UserData.
On 2010/01/19 18:00:48, vangelis wrote:
> typo:reference
> 

Done.

http://codereview.chromium.org/543110/diff/1/2#newcode40
gpu/demos/gles2_book/example.h:40: memset(&user_data_, 0, sizeof(HTUserData));
oops. good catch!

[vangelis, 2010-01-19 20:36:38]

LGTM