UI: Drag and Drop Modifiers, Layout Updates

This patch implements the list panel system D7490 for modifiers.
It also moves modifier drawing to a callback in ModifierTypeInfo
in line with the extensible architecture refactoring goal T75724.

This adds a PanelRegister callback and utilities for registering
panels and subpanels. It also adds the callbacks for expansion saving
and drag and drop reordering described in D7490.

These utilities, callbacks, and other common UI elements shared
between modifiers live in MOD_ui_common.c.

Because modifier buttons are now in panels, we can make use of
subpanels for organization. The UI layouts also use the single
column layout style consistently used elsewhere in Blender.
Additionally, the mode-setting buttons are aligned and ordered
consistently with the outliner.

However, the large number of UI changes in this patch may mean
that additional polishing is required in master.

Thanks to William Reynish (@billreynish) who did a fair amount of the
layout work and to Julian Eisel (@Severin) for consistent help.

Differential Revision: https://developer.blender.org/D7498

1 files changed, 91 insertions, 1 deletions

diff --git a/source/blender/modifiers/intern/MOD_normal_edit.c b/source/blender/modifiers/intern/MOD_normal_edit.c
index 1521cfab356..c1901a97cda 100644
--- a/source/blender/modifiers/intern/MOD_normal_edit.c
+++ b/source/blender/modifiers/intern/MOD_normal_edit.c
@@ -27,17 +27,28 @@
 #include "BLI_bitmap.h"
 #include "BLI_math.h"
 
+#include "BLT_translation.h"
+
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
 #include "DNA_object_types.h"
+#include "DNA_screen_types.h"
 
+#include "BKE_context.h"
 #include "BKE_deform.h"
 #include "BKE_lib_id.h"
 #include "BKE_lib_query.h"
 #include "BKE_mesh.h"
+#include "BKE_screen.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+#include "RNA_access.h"
 
 #include "DEG_depsgraph_query.h"
 
+#include "MOD_ui_common.h"
 #include "MOD_util.h"
 
 static void generate_vert_coordinates(Mesh *mesh,
@@ -689,8 +700,86 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   return normalEditModifier_do((NormalEditModifierData *)md, ctx, ctx->object, mesh);
 }
 
+static void panel_draw(const bContext *C, Panel *panel)
+{
+  uiLayout *col;
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  PointerRNA ob_ptr;
+  modifier_panel_get_property_pointers(C, panel, &ob_ptr, &ptr);
+
+  uiLayoutSetPropSep(layout, true);
+
+  int mode = RNA_enum_get(&ptr, "mode");
+
+  uiItemR(layout, &ptr, "mode", UI_ITEM_R_EXPAND, NULL, ICON_NONE);
+  uiItemR(layout, &ptr, "target", 0, NULL, ICON_NONE);
+
+  col = uiLayoutColumn(layout, false);
+  uiLayoutSetActive(col, mode == MOD_NORMALEDIT_MODE_DIRECTIONAL);
+  uiItemR(col, &ptr, "use_direction_parallel", 0, NULL, ICON_NONE);
+
+  modifier_panel_end(layout, &ptr);
+}
+
+/* This panel could be open by default, but it isn't currently. */
+static void mix_mode_panel_draw(const bContext *C, Panel *panel)
+{
+  uiLayout *row;
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  PointerRNA ob_ptr;
+  modifier_panel_get_property_pointers(C, panel, &ob_ptr, &ptr);
+
+  uiLayoutSetPropSep(layout, true);
+
+  uiItemR(layout, &ptr, "mix_mode", 0, NULL, ICON_NONE);
+  uiItemR(layout, &ptr, "mix_factor", 0, NULL, ICON_NONE);
+
+  modifier_vgroup_ui(layout, &ptr, &ob_ptr, "vertex_group", "invert_vertex_group", NULL);
+
+  row = uiLayoutRow(layout, true);
+  uiItemR(row, &ptr, "mix_limit", 0, NULL, ICON_NONE);
+  uiItemR(row,
+          &ptr,
+          "no_polynors_fix",
+          0,
+          "",
+          (RNA_boolean_get(&ptr, "no_polynors_fix") ? ICON_LOCKED : ICON_UNLOCKED));
+}
+
+static void offset_panel_draw(const bContext *C, Panel *panel)
+{
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  modifier_panel_get_property_pointers(C, panel, NULL, &ptr);
+
+  int mode = RNA_enum_get(&ptr, "mode");
+  PointerRNA target_ptr = RNA_pointer_get(&ptr, "target");
+  bool needs_object_offset = (mode == MOD_NORMALEDIT_MODE_RADIAL &&
+                              RNA_pointer_is_null(&target_ptr)) ||
+                             (mode == MOD_NORMALEDIT_MODE_DIRECTIONAL &&
+                              RNA_boolean_get(&ptr, "use_direction_parallel"));
+
+  uiLayoutSetPropSep(layout, true);
+
+  uiLayoutSetActive(layout, needs_object_offset);
+  uiItemR(layout, &ptr, "offset", 0, NULL, ICON_NONE);
+}
+
+static void panelRegister(ARegionType *region_type)
+{
+  PanelType *panel_type = modifier_panel_register(
+      region_type, eModifierType_NormalEdit, panel_draw);
+  modifier_subpanel_register(region_type, "mix", "Mix", NULL, mix_mode_panel_draw, panel_type);
+  modifier_subpanel_register(region_type, "offset", "Offset", NULL, offset_panel_draw, panel_type);
+}
+
 ModifierTypeInfo modifierType_NormalEdit = {
-    /* name */ "Set Split Normals",
+    /* name */ "NormalEdit",
     /* structName */ "NormalEditModifierData",
     /* structSize */ sizeof(NormalEditModifierData),
     /* type */ eModifierTypeType_Constructive,
@@ -719,4 +808,5 @@ ModifierTypeInfo modifierType_NormalEdit = {
     /* foreachIDLink */ NULL,
     /* foreachTexLink */ NULL,
     /* freeRuntimeData */ NULL,
+    /* panelRegister */ panelRegister,
 };