Finally properly fix the flashing on ARM Mali T880 GPU.
The flashing is caused by a 'full pipeline flush' (see DarkPhoton, https://www.opengl.org/discussion_boards/showthread.php/200754-Flashes-on-ARM-Mali?p=1291679&viewfull=1#post1291679 ). In order to combat it, first introduce the possibility that a single DistortedOutputSurface is backed up by more than one FBO. Then make DistortedScreen be derived from DistortedFramebuffer (which itself is derived from DistortedOutputSurface) and make it contain 3 FBOs, render to them in a circular queue fashion, and blit from a given FBO to the system FBO. The 'more than 1 intermediate FBO' queue prevents the pipeline flush....
Minor.
Port all the 'non-controversial' changes from order-independent-transparency branch.
Fixes ported from the 'OIT' branch:
- remove counting of transparent pixels- various fixes for the Mali GPU
SSBO: something is working already, although we still get the 4 bytes back from the shader in reverse order ( so '17'=0x00000011 written by the shader becomes '285212672 = 0x11000000' )
First try at the SSBO (doesn't work - reads in the application don't pick up changes in the shader; crashes.
Up library requirements to OpenGL ES 3.1 (needed for the upcoming GL_SHADER_STORAGE_BUFFER)
Change of API: move setting the EGL context back to the APP.
Reorganize the way we add and remove all Effects (do it through DistortedMaster and is POSTPROCES - adjust Bucket and SORT Nodes).
Buggy: removing effects does not work.
Progress with support for Effect classes. Last error in the library before it compiles!
Progress with support for Effect classes.