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, 47 insertions, 0 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/motion_path_line_geom.glsl b/source/blender/draw/engines/overlay/shaders/motion_path_line_geom.glsl
new file mode 100644
index 00000000000..95e5b08049e
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/motion_path_line_geom.glsl
@@ -0,0 +1,47 @@
+
+layout(lines) in;
+layout(triangle_strip, max_vertices = 4) out;
+
+uniform int lineThickness = 2;
+
+in vec4 finalColor_geom[];
+in vec2 ssPos[];
+
+out vec4 finalColor;
+
+vec2 compute_dir(vec2 v0, vec2 v1)
+{
+  vec2 dir = normalize(v1 - v0 + 1e-8);
+  dir = vec2(-dir.y, dir.x);
+  return dir;
+}
+
+void main(void)
+{
+  vec2 t;
+  vec2 edge_dir = compute_dir(ssPos[0], ssPos[1]) * sizeViewportInv.xy;
+
+  bool is_persp = (ProjectionMatrix[3][3] == 0.0);
+  float line_size = float(lineThickness) * sizePixel;
+
+#ifdef USE_WORLD_CLIP_PLANES
+  world_clip_planes_set_clip_distance(gl_in[0].gl_ClipDistance);
+#endif
+  finalColor = finalColor_geom[0];
+  t = edge_dir * (line_size * (is_persp ? gl_in[0].gl_Position.w : 1.0));
+  gl_Position = gl_in[0].gl_Position + vec4(t, 0.0, 0.0);
+  EmitVertex();
+  gl_Position = gl_in[0].gl_Position - vec4(t, 0.0, 0.0);
+  EmitVertex();
+
+#ifdef USE_WORLD_CLIP_PLANES
+  world_clip_planes_set_clip_distance(gl_in[1].gl_ClipDistance);
+#endif
+  finalColor = finalColor_geom[1];
+  t = edge_dir * (line_size * (is_persp ? gl_in[1].gl_Position.w : 1.0));
+  gl_Position = gl_in[1].gl_Position + vec4(t, 0.0, 0.0);
+  EmitVertex();
+  gl_Position = gl_in[1].gl_Position - vec4(t, 0.0, 0.0);
+  EmitVertex();
+  EndPrimitive();
+}