Overlay Engine: Refactor & Cleanup

This is the unification of all overlays into one overlay engine as described in T65347.

I went over all the code making it more future proof with less hacks and removing old / not relevent parts.

Goals / Acheivements:
- Remove internal shader usage (only drw shaders)
- Remove viewportSize and viewportSizeInv and put them in gloabl ubo
- Fixed some drawing issues: Missing probe option and Missing Alt+B clipping of some shader
- Remove old (legacy) shaders dependancy (not using view UBO).
- Less shader variation (less compilation time at first load and less patching needed for vulkan)
- removed some geom shaders when I could
- Remove static e_data (except shaders storage where it is OK)
- Clear the way to fix some anoying limitations (dithered transparency, background image compositing etc...)
- Wireframe drawing now uses the same batching capabilities as workbench & eevee (indirect drawing).
- Reduced complexity, removed ~3000 Lines of code in draw (also removed a lot of unused shader in GPU).
- Post AA to avoid complexity and cost of MSAA.

Remaining issues:
- ~~Armature edits, overlay toggles, (... others?) are not refreshing viewport after AA is complete~~
- FXAA is not the best for wires, maybe investigate SMAA
- Maybe do something more temporally stable for AA.
- ~~Paint overlays are not working with AA.~~
- ~~infront objects are difficult to select.~~
- ~~the infront wires sometimes goes through they solid counterpart (missing clear maybe?) (toggle overlays on-off when using infront+wireframe overlay in solid shading)~~

Note: I made some decision to change slightly the appearance of some objects to simplify their drawing. Namely the empty arrows end (which is now hollow/wire) and distance points of the cameras/spots being done by lines.

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D6296

1 files changed, 24 insertions, 0 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/paint_face_vert.glsl b/source/blender/draw/engines/overlay/shaders/paint_face_vert.glsl
new file mode 100644
index 00000000000..2b5d586bdd1
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/paint_face_vert.glsl
@@ -0,0 +1,24 @@
+
+in vec3 pos;
+in vec4 nor; /* select flag on the 4th component */
+
+void main()
+{
+  GPU_INTEL_VERTEX_SHADER_WORKAROUND
+
+  vec3 world_pos = point_object_to_world(pos);
+  gl_Position = point_world_to_ndc(world_pos);
+
+  bool is_select = (nor.w > 0.0);
+  bool is_hidden = (nor.w < 0.0);
+
+  /* Don't draw faces that are selected. */
+  if (is_hidden || is_select) {
+    gl_Position = vec4(-2.0, -2.0, -2.0, 1.0);
+  }
+  else {
+#ifdef USE_WORLD_CLIP_PLANES
+    world_clip_planes_calc_clip_distance(world_pos);
+#endif
+  }
+}