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, 52 insertions, 0 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/grid_vert.glsl b/source/blender/draw/engines/overlay/shaders/grid_vert.glsl
new file mode 100644
index 00000000000..496bb011c74
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/grid_vert.glsl
@@ -0,0 +1,52 @@
+
+/* Infinite grid
+ * Clément Foucault */
+
+uniform vec3 planeAxes;
+uniform float meshSize;
+
+uniform int gridFlag;
+
+#define cameraPos (ViewMatrixInverse[3].xyz)
+
+#define PLANE_XY (1 << 4)
+#define PLANE_XZ (1 << 5)
+#define PLANE_YZ (1 << 6)
+#define CLIP_Z_POS (1 << 7)
+#define CLIP_Z_NEG (1 << 8)
+
+in vec3 pos;
+
+out vec3 local_pos;
+
+void main()
+{
+  vec3 vert_pos;
+
+  /* Project camera pos to the needed plane */
+  if ((gridFlag & PLANE_XY) != 0) {
+    vert_pos = vec3(pos.x, pos.y, 0.0);
+  }
+  else if ((gridFlag & PLANE_XZ) != 0) {
+    vert_pos = vec3(pos.x, 0.0, pos.y);
+  }
+  else {
+    vert_pos = vec3(0.0, pos.x, pos.y);
+  }
+
+  local_pos = vert_pos;
+
+  vec3 real_pos = cameraPos * planeAxes + vert_pos * meshSize;
+
+  /* Used for additional Z axis */
+  if ((gridFlag & CLIP_Z_POS) != 0) {
+    real_pos.z = clamp(real_pos.z, 0.0, 1e30);
+    local_pos.z = clamp(local_pos.z, 0.0, 1.0);
+  }
+  if ((gridFlag & CLIP_Z_NEG) != 0) {
+    real_pos.z = clamp(real_pos.z, -1e30, 0.0);
+    local_pos.z = clamp(local_pos.z, -1.0, 0.0);
+  }
+
+  gl_Position = ViewProjectionMatrix * vec4(real_pos, 1.0);
+}