The class is not used by any effect any more and the
design of the ShaderEffect makes it hardly usable.
For most effects just rendering the windows with the Shader
attached to it makes more sense than rendering the complete
screen into a FBO and apply the shader on the off-screen texture.
The effect has been known to cause some problems for quite some time
and is not really useful. Therfore dropping the effect.
See discussion on kwin mailinglist:
http://lists.kde.org/?l=kwin&m=129597766829618&w=2
It now uses a GLShader for GLSL shaders and pushes it using the
ShaderManager.
It does not work with the nouveau driver plus GLES, but it works
with fglrx + desktop GL 2.x, so I assume it is a driver problem here.
It uses a generic vertex shader and because of that it needs to
mark all windows which are inverted as transformed.
There is currently a conflict with Lanczos (or thumbnails) and with
the desktop in cube effect.
When rendering opaque (RGB-only) windows the alpha ends up to be 0
with blending disabled. This breaks subsequent rendering steps which
require blenden (e.g. Lanczos). Therefore a uniform is used to ensure
that the alpha channel is set to 1.
Rotation is now only handled by the QMatrix4x4 m_rotationMatrix,
so no more need for display lists. Resulting in a cleaner code without
differences between OpenGL 1.x and 2.x/GLES.
The vertex buffer implementation uses the shader manager to decide
whether core painting should be used or not. Shader manager is only
used by shaders using vertex attributes instead of gl_Vertex etc.
This includes quite some refactoring. For the cube cap a VBO is used
instead of glLists and all the required transformations are moved into
paintCap() which makes paintScreen more clean.
Currently the mirroring of bottom texture is still missing and cylinder
and sphere caps are not yet ported to using VBO.
I wouldn't be surprised if it is broken for legacy GL atm.
CoverSwitch uses new concept of combining a custom fragment shader with the
built-in generic vertex shader. This shader is used to render the reflection
plane on top of the reflected windows.
The fragment shader uses two uniform colors for front and back and interpolates
between them based on the texcoords (which are not used for texture lookup).
The reflection plane vertices could be buffered.
ShaderManager supports a new concept to load just a fragment shader from file
and use a built-in shader for the vertex shader. This allows an effect to use
a custom fragment shader.
