GPencil: Merge GSoC curve edit mode

Differential Revision: https://developer.blender.org/D8660

This patch is the result of the GSoC 2020 "Editing Grease Pencil Strokes
Using Curves" project. It adds a submode to greasepencil edit mode that
allows for the transformation of greasepencil strokes using bezier
curves. More information about the project can be found
here: https://wiki.blender.org/wiki/User:Filedescriptor/GSoC_2020.

2 files changed, 9 insertions, 2 deletions

diff --git a/source/blender/draw/engines/overlay/shaders/edit_curve_handle_geom.glsl b/source/blender/draw/engines/overlay/shaders/edit_curve_handle_geom.glsl
index 9311542a79e..442f69aec7e 100644
--- a/source/blender/draw/engines/overlay/shaders/edit_curve_handle_geom.glsl
+++ b/source/blender/draw/engines/overlay/shaders/edit_curve_handle_geom.glsl
@@ -53,6 +53,9 @@ void main()
   bool edge_selected = (((vertFlag[1] | vertFlag[0]) & VERT_SELECTED) != 0);
   bool handle_selected = (showCurveHandles &&
                           (((vertFlag[1] | vertFlag[0]) & VERT_SELECTED_BEZT_HANDLE) != 0));
+  /* It reuses freestyle flag because the flag is 8 bits and all are already used and this
+   * flag is not used in this context. */
+  bool is_gpencil = ((vertFlag[1] & EDGE_FREESTYLE) != 0);
 
   /* If handle type is only selected and the edge is not selected, don't show. */
   if ((curveHandleDisplay != CURVE_HANDLE_ALL) && (!handle_selected)) {
@@ -61,6 +64,9 @@ void main()
     if ((!is_u_segment) && (color_id <= 4)) {
       return;
     }
+    if (is_gpencil) {
+      return;
+    }
   }
 
   vec4 inner_color;
diff --git a/source/blender/draw/engines/overlay/shaders/edit_curve_point_vert.glsl b/source/blender/draw/engines/overlay/shaders/edit_curve_point_vert.glsl
index a811fcca0d4..6b4edbfe578 100644
--- a/source/blender/draw/engines/overlay/shaders/edit_curve_point_vert.glsl
+++ b/source/blender/draw/engines/overlay/shaders/edit_curve_point_vert.glsl
@@ -17,16 +17,17 @@ void main()
 {
   GPU_INTEL_VERTEX_SHADER_WORKAROUND
 
+  /* Reuse the FREESTYLE flag to determine is GPencil. */
   if ((data & VERT_SELECTED) != 0) {
     if ((data & VERT_ACTIVE) != 0) {
       finalColor = colorEditMeshActive;
     }
     else {
-      finalColor = colorVertexSelect;
+      finalColor = ((data & EDGE_FREESTYLE) == 0) ? colorVertexSelect : colorGpencilVertexSelect;
     }
   }
   else {
-    finalColor = colorVertex;
+    finalColor = ((data & EDGE_FREESTYLE) == 0) ? colorVertex : colorGpencilVertex;
   }
 
   vec3 world_pos = point_object_to_world(pos);