kwineffects.h is included in many files and not everyone needs the
RenderTarget and RenderViewport, so forward declare them to reduce the
amount of parsing work for the compiler.
The only purpose ScreenPaintData had was to pass around a copy of the viewport
projection matrix and the effectscreen, which can be handled in a simpler
way separately.
Instead of calling effects->renderTargetRect() and effects->renderTargetScale(),
pass the actually used render target and viewport in all the necessary methods.
This ensures that if an effect renders a screen with a modified scale or
projection matrix, the modified values get used instead of the "global" ones
If a window is made ready for painting with some delay, the item won't
schedule an update. To fix that, sync the item visibility state with
Window::readyForPainting(). When the item visibility changes, a repaint
will be scheduled.
BUG: 464955
While direct scanout happens, the damage of the SurfaceItem is reset, which
can cause the OpenGL texture to not be updated once direct scanout ends,
and leave the texture outdated until the surface is damaged again.
In order to fix that, make sure the texture is always fully updated after
the SurfaceItem has been used in direct scanout.
The main motivation behind this change is to share rendering code
between windows and the cursor, specifically the Item class which
requires a Scene.
Note that Scene subclasses are responsible for issuing
ItemRenderer::renderItem() calls. The main reason for that is the
current architecture of the effects system, specifically we need to call
some effects hooks before and after painting a window.
