Rational behind this change is that displayWidth and displayHeight are
X specific API calls in kwinglobals. For the future it's easier to only
rely on functionality which goes through the EffectsHandler API which
allows easier adjustments in KWin core.
displayWidth() and displayHeight() are only used to get the size or the
complete rect of all screens. This is also provided by:
effects->virtualScreenGeometry() or
effects->virtualScreenSize()
REVIEW: 116021
As all effects have always been compiled into the same .so file it's
questionable whether resolving the effects through a library is useful
at all. By linking against the built-in effects we gain the following
advantages:
* don't have to load/unload the KLibrary
* don't have to resolve the create, supported and enabled functions
* no version check required
* no dependency resolving (effects don't use it)
* remove the KWIN_EFFECT macros from the effects
All the effects are now registered in an effects_builtins file which
maps the name to a factory method and supported or enabled by default
methods.
During loading the effects we first check whether there is a built-in
effect by the given name and make a shortcut to create it through that.
If that's not possible the normal plugin loading is used.
Completely unscientific testing [1] showed an improvement of almost 10
msec during loading all the effects I use.
[1] QElapsedTimer around the loading code, start kwin five times, take
average.
REVIEW: 115073
We need to use the varying_in/out variables, the code was a little
bit too modern.
At the same time remove the identity matrix and replace it by mat4(1.0).
Note: the shader should probably go into glsl files as they are not
really generated.
* this effect is way cheaper than blur, don't cache it
* use its own atom
* also pass the matrix in the x property
* remove remnants of the cache
* do just a single pass
* get rid of config ui remnants
* a copy of the blur shader to become a copy of the background contrast effect
* contrastshader actually doing the light modification
* don't expand/shrink the area
