OpenGL Core support (i.e. non fixed pipeline)

[Nasenbaer]

The maintainer of the Widelands build for Maemo noticed, that mobile devices like tablets don't support OpenGL, but do support OpenGL-ES. Therefore it would be cool, to have a possibility to use OpenGL-ES .

References:

Wiki article on OpenGL-ES at Maemo: http://wiki.maemo.org/OpenGL-ES
A patched libglew version for OpenGL-ES: https://launchpad.net/linaro-graphics-misc

[SirVer (sirver)]

imho it should be possible to restrict us to OpenGL-ES which should also
work under other OpenGL implementations.

[SirVer (sirver)]

Setting to incomplete for bug sweeping.

[Launchpad Janitor (janitor)]

[Expired for widelands because there has been no activity for 60 days.]

[SirVer (sirver)]

We should target Open GL ES 2 for now. We should then be well inside of Open GL 3 too for work stations.

[SirVer (sirver)]

I started work on this in the linked branch. It contains changes to move the terrain rendering to shaders - this is not quite GL ES, but it is very close.

The surface blitting code that we have still needs to be implemented in shaders as well, that is still to do.

[SirVer (sirver)]

I call this done for now. Likely there are still minor incompatibilities in the code and the shaders, but they need to be sorted out when we actually target something mobile and they should be very minor.

[GunChleoc (gunchleoc)]

Fixed in build19-rc1.