glFinish is meant to ensure every aspect of the screen is fully-drawn
before continuing. This causes issues with certain chipsets (Intel
4-8k)
glFlush is more of a suggestion that CPU work is complete and the GPU
should complete its work in a "timely" fashion.
We add an additional glFinish call before getting a screenshot as this
will copy the actual data from the card buffer.
Fixes: lp:1775976
* https://bugs.launchpad.net/kicad/+bug/1775976
* Split and rewrite the preview window and canvas.
* Create a new class for handling the board information.
* Adds new render targets: openGL, legacy, and ray tracing.
* Render targets take full advantage of the new 3D plugins system and 3D cache
for a fast 3D model loading.
* Faster board loading.
* New OpenGL render is faster than the old one.
* New ray tracing render target with a post processing shader.
* Use of new 3D plugins (WRL, X3D, STEP and IGES) and 3D model caching.
* Preview of 3D model while browsing the file name.
* 3D preview of the footprint while adding / align 3D shapes.
* Render of 3D models according to attributes: Normal, Normal+Insert, Virtual.
* Pivot rotation centered in one point over the PCB board.
* Shortcuts keys improved for XYZ orientation..
* Animated camera.
Seth Hillbrand
Mrio Luzeiro
Cirilo Bernardo
Mario Luzeiro