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, 18 insertions, 0 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/extra_loose_point_frag.glsl b/source/blender/draw/engines/overlay/shaders/extra_loose_point_frag.glsl
new file mode 100644
index 00000000000..8784b6cd73a
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/extra_loose_point_frag.glsl
@@ -0,0 +1,18 @@
+
+in vec4 finalColor;
+
+out vec4 fragColor;
+
+void main()
+{
+  vec2 centered = abs(gl_PointCoord - vec2(0.5));
+  float dist = max(centered.x, centered.y);
+
+  float fac = dist * dist * 4.0;
+  fragColor = mix(colorEditMeshMiddle, finalColor, 0.45 + fac * 0.65);
+
+  /* Make the effect more like a fresnel by offsetting
+   * the depth and creating mini-spheres.
+   * Disabled as it has performance impact. */
+  // gl_FragDepth = gl_FragCoord.z + 1e-6 * fac;
+}
\ No newline at end of file