1 files changed, 72 insertions, 39 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl b/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl
index f5a3aa2c332..c77c89396af 100644
--- a/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl
+++ b/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl
@@ -57,6 +57,34 @@ bvec4 gather_edges(vec2 uv, uint ref)
   return notEqual(ids, uvec4(ref));
 }
 
+/* Clockwise */
+vec2 rotate_90(vec2 v)
+{
+  return vec2(v.y, -v.x);
+}
+vec2 rotate_180(vec2 v)
+{
+  return vec2(-v.x, -v.y);
+}
+vec2 rotate_270(vec2 v)
+{
+  return vec2(-v.y, v.x);
+}
+
+/* Counter-Clockwise */
+bvec4 rotate_90(bvec4 v)
+{
+  return v.yzwx;
+}
+bvec4 rotate_180(bvec4 v)
+{
+  return v.zwxy;
+}
+bvec4 rotate_270(bvec4 v)
+{
+  return v.wxyz;
+}
+
 /* Apply offset to line endpoint based on surrounding edges infos. */
 bool line_offset(bvec2 edges, vec2 ofs, inout vec2 line_point)
 {
@@ -79,6 +107,7 @@ bool line_offset(bvec2 edges, vec2 ofs, inout vec2 line_point)
 /* Use surrounding edges to approximate the outline direction to create smooth lines. */
 void straight_line_dir(bvec4 edges1, bvec4 edges2, out vec2 line_start, out vec2 line_end)
 {
+  /* Y_POS as reference. Other cases are rotated to match reference. */
   line_end = vec2(1.5, 0.5 + PROXIMITY_OFS);
   line_start = vec2(-line_end.x, line_end.y);
 
@@ -92,53 +121,50 @@ void straight_line_dir(bvec4 edges1, bvec4 edges2, out vec2 line_start, out vec2
   }
 }
 
-/* Compute line direction vector from the bottom left corner. */
-void diag_dir(bvec4 edges, out vec2 line_start, out vec2 line_end)
+vec2 diag_offset(bvec4 edges)
 {
-  /* TODO Improve diagonal antialiasing. */
+  /* X_NEG | Y_POS as reference. Other cases are rotated to match reference.
+   * So the line is comming from bottom left. */
   if (all(edges.wz)) {
-    line_start = vec2(-3.0, -0.5 + PROXIMITY_OFS);
-    line_end = vec2(3.0, 0.5 + PROXIMITY_OFS);
+    /* Horizontal line. */
+    return vec2(2.5, 0.5);
   }
   else if (all(not(edges.xw))) {
-    line_start = vec2(-0.5 - PROXIMITY_OFS, -3.0);
-    line_end = vec2(0.5 - PROXIMITY_OFS, 3.0);
+    /* Vertical line. */
+    return vec2(0.5, 2.5);
   }
   else if (edges.w) {
-    line_start = vec2(-1.0, -0.5 - PROXIMITY_OFS);
-    line_end = vec2(2.0, 0.5 - PROXIMITY_OFS);
+    /* Less horizontal Line. */
+    return vec2(2.5, 0.5);
   }
   else {
-    line_start = vec2(-0.6, -0.5 + PROXIMITY_OFS);
-    line_end = vec2(0.6 - PROXIMITY_OFS, 0.5);
+    /* Less vertical Line. */
+    return vec2(0.5, 2.5);
   }
 }
-/* Clockwise */
-vec2 rotate_90(vec2 v)
-{
-  return vec2(v.y, -v.x);
-}
-vec2 rotate_180(vec2 v)
-{
-  return vec2(-v.x, -v.y);
-}
-vec2 rotate_270(vec2 v)
-{
-  return vec2(-v.y, v.x);
-}
 
-/* Counter-Clockwise */
-bvec4 rotate_90(bvec4 v)
-{
-  return v.yzwx;
-}
-bvec4 rotate_180(bvec4 v)
-{
-  return v.zwxy;
-}
-bvec4 rotate_270(bvec4 v)
+/* Compute line direction vector from the bottom left corner. */
+void diag_dir(bvec4 edges1, bvec4 edges2, out vec2 line_start, out vec2 line_end)
 {
-  return v.wxyz;
+  /* Negate instead of rotating back the result of diag_offset. */
+  edges2 = not(edges2);
+  edges2 = rotate_180(edges2);
+  line_end = diag_offset(edges1);
+  line_end += diag_offset(edges2);
+
+  if (line_end.x == line_end.y) {
+    /* Perfect diagonal line. Push line start towards edge. */
+    line_start = vec2(-1.0, 1.0) * PROXIMITY_OFS * 0.4;
+  }
+  else if (line_end.x > line_end.y) {
+    /* Horizontal Line. Lower line start. */
+    line_start = vec2(0.0, PROXIMITY_OFS);
+  }
+  else {
+    /* Vertical Line. Push line start to the right. */
+    line_start = -vec2(PROXIMITY_OFS, 0.0);
+  }
+  line_end += line_start;
 }
 
 void main()
@@ -292,26 +318,33 @@ void main()
       /* Diagonal */
     case DIAG_XNEG_YPOS:
       extra_edges = gather_edges(uvs + ofs.xy * vec2(1.5), ref);
-      diag_dir(extra_edges, line_start, line_end);
+      extra_edges2 = gather_edges(uvs + ofs.xy * vec2(-1.5), ref);
+      diag_dir(extra_edges, extra_edges2, line_start, line_end);
       break;
     case DIAG_XPOS_YNEG:
       extra_edges = gather_edges(uvs - ofs.xy * vec2(1.5), ref);
+      extra_edges2 = gather_edges(uvs - ofs.xy * vec2(-1.5), ref);
       extra_edges = rotate_180(extra_edges);
-      diag_dir(extra_edges, line_start, line_end);
+      extra_edges2 = rotate_180(extra_edges2);
+      diag_dir(extra_edges, extra_edges2, line_start, line_end);
       line_start = rotate_180(line_start);
       line_end = rotate_180(line_end);
       break;
     case DIAG_XPOS_YPOS:
       extra_edges = gather_edges(uvs + ofs.xy * vec2(1.5, -1.5), ref);
+      extra_edges2 = gather_edges(uvs - ofs.xy * vec2(1.5, -1.5), ref);
       extra_edges = rotate_90(extra_edges);
-      diag_dir(extra_edges, line_start, line_end);
+      extra_edges2 = rotate_90(extra_edges2);
+      diag_dir(extra_edges, extra_edges2, line_start, line_end);
       line_start = rotate_90(line_start);
       line_end = rotate_90(line_end);
       break;
     case DIAG_XNEG_YNEG:
       extra_edges = gather_edges(uvs - ofs.xy * vec2(1.5, -1.5), ref);
+      extra_edges2 = gather_edges(uvs + ofs.xy * vec2(1.5, -1.5), ref);
       extra_edges = rotate_270(extra_edges);
-      diag_dir(extra_edges, line_start, line_end);
+      extra_edges2 = rotate_270(extra_edges2);
+      diag_dir(extra_edges, extra_edges2, line_start, line_end);
       line_start = rotate_270(line_start);
       line_end = rotate_270(line_end);
       break;