@Robert_U , sorry my instructions for recreating the issue were incomplete, I tested it now. Regarding my last post, first of all the attached .zip did not contain an .elf file but a .dff file. But it is a correct file, and enough for showing the problem.
To see whe glitches I'm talking about take these steps:
0.9) Use a computer that ONLY has Intel HD 4000/4600 GPU enabled (since selecting that in Dolphin won't necessarily disable the discrete GPU, AFAIK).
1) Download the latest developement version of Dolphin, Win x64 version from " Dolphin Emulator - Download " (tested today with 4.0-1871).
2) Extract the program, create an empty text file of name portable.txt in the program folder (the same that includes Dolphin.exe). This will save all the settings inside that folder (instead of global user folder).
3) Download the zipped .dff I posted earlier, unzip to location of your choice.
4) Launch Dolphin.
5) Select Config. On first page uncheck Enable Dual Core (fifo-player crashes with dual core, irrelevant for this issue).
6) Select Graphics. On first page select Backend: D3D (GPU should be Intel(R) HD Graphics 4X00, not Microsoft Basic Render Driver).
7) Select File/Open... , open the .dff file downloaded in 3).
This should open an output window for the recorded (3) frames that cycle rapidly. The picture is mainly black, since the frames don't include texture information for the black parts.
The glitches should here be seen as _bright white dots on some objects, especially in the lower right part of the screen_. The dots seem to form some wireframe lines.
The glitches can be fixed, if you change the backend (selected in 6)) to OpenGL. Also, they can't be seen, if you open the same file on a PC, that has a discrete GPU (AMD or NVIDIA), regardless if you choose D3D or OpenGL. And importantly, the glitches disappear, if you make the described change in the source code (change ">>7" to ">=128 ? 1 : 0", works for D3D but causes OpenGL to crash), see the initial post. So the glitches seem to only apper, after the graphics output is sent to Intel GPU's drivers when using D3D backend (which leads us here).
I'm happy to provide further information, and will provide all the information you asked for about my settings, altough this has been confirmed by other users. The computer works fine otherwise.
My system config is (shortened)
CPU: Intel i5-4670S
GPU: Intel HD 4600, driver version 10.18.10.3621
OS: Windows 8.1 Pro with Media Center 64-bit, latest updates installed (as of 16 Jun 2014).
Display: Samsung UE46F7007 LCD TV
Dolphin running in portable mode and/or global mode.
My DxDiag-report: https://dl.dropboxusercontent.com/u/23618751/Dolphin4.0.1288_glitch/DxDiag.txt
Thanks again for looking into this. I'm already grateful, I really am. Please reply if you can or can not reproduce the issue with these instructions. And thank you for your understanding, I am not a programmer, so I don't have the insight of all the relevant aspects.