Blender Git Loki

Cleanup: extract reproject functions

Merge branch 'blender2.8' into greasepencil-object

Fix segment fault when using eraser

The cache must be marked as dirty after any change operation, and the eraser change the strokes

Fix UI panel problem in properties tab

Cleanup: More unused include files, reorganization and name changes

Cleanup: Remove unused include files

Merge branch 'blender2.8' into greasepencil-object

Create a cache to drawing objects

Due speciall requirements for 2D drawing, the GP objects must be drawn after be sorteed by zdepth value.

We cannot use a simple GPU zdepth because this override the current layer/strokes order and the artists need to keep these controls as primary sorting method instead of GPU zdepth.

Create a shading group by stroke

As the drawing order is very important in 2D, each stroke must use its own shading group and don't share with others or the drawing order is missing and the layer system does not work.

Disable zdepth write for strokes

After some analysis, the strokes must work without affect the zdepth buffer or the layer system will not work.

The 2D artist agree that layer system must be the main zdepth order and not the GPU checking.

Cleanup: Create several separated functions

Enable again write depth pass for strokes only

Remove write zdepth to avoid z-fighting

The strokes don't need to write the depth buffer

Merge branch 'blender2.8' into greasepencil-object

Cleanup: Change some xray strings and parameter names

Cleanup: Remove unused code

THis code has been ported to new shaders

Implement Xray mode for strokes

Now support 3 modes: Front, 3D space and Back.

Still some problems with zfighting with layers that need to be fixed

Use zdepth of the position in geometry shader

Merge branch 'blender2.8' into greasepencil-object

Add more control for debug lines

Now the debug lines are only visible when code is 668