Sculpt: Line gestures and Mask Line tool

This adds support for line gesture to SculptGestureContext and
implements a Mask Line tool, which affects everything to the right of a plane
defined by the straightline gesture.

For this to work, a new WM_gesture_straightline_oneshot_modal is needed
which only runs exec when the gesture is over.

Added as experimental as it does not have icon.

Reviewed By: Severin

Differential Revision: https://developer.blender.org/D8722

3 files changed, 77 insertions, 0 deletions

diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 80f330d91ca..8fba1ed342e 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -632,12 +632,16 @@ void WM_gesture_lasso_cancel(struct bContext *C, struct wmOperator *op);
 const int (*WM_gesture_lasso_path_to_array(struct bContext *C,
                                            struct wmOperator *op,
                                            int *mcoords_len))[2];
+
 int WM_gesture_straightline_invoke(struct bContext *C,
                                    struct wmOperator *op,
                                    const struct wmEvent *event);
 int WM_gesture_straightline_modal(struct bContext *C,
                                   struct wmOperator *op,
                                   const struct wmEvent *event);
+int WM_gesture_straightline_oneshot_modal(struct bContext *C,
+                                          struct wmOperator *op,
+                                          const struct wmEvent *event);
 void WM_gesture_straightline_cancel(struct bContext *C, struct wmOperator *op);
 
 /* Gesture manager API */
diff --git a/source/blender/windowmanager/intern/wm_gesture_ops.c b/source/blender/windowmanager/intern/wm_gesture_ops.c
index a38cbb920c4..25de76d4428 100644
--- a/source/blender/windowmanager/intern/wm_gesture_ops.c
+++ b/source/blender/windowmanager/intern/wm_gesture_ops.c
@@ -792,6 +792,16 @@ void WM_OT_lasso_gesture(wmOperatorType *ot)
 
 /* -------------------------------------------------------------------- */
 /** \name Straight Line Gesture
+ *
+ * Gesture defined by the start and end points of a line that is created between the posistion of
+ * the initial event and the position of the current event.
+ *
+ * Straight Line Gesture has two modal callbacks depending on the tool that is being implemented: a
+ * regular modal callback intended to update the data during the execution of the gesture and a
+ * oneshot callback that only updates the data once when the gesture finishes.
+ *
+ * It stores 4 values (xstart, ystart, xend, yend).
+ *
  * \{ */
 
 static bool gesture_straightline_apply(bContext *C, wmOperator *op)
@@ -841,6 +851,11 @@ int WM_gesture_straightline_invoke(bContext *C, wmOperator *op, const wmEvent *e
   return OPERATOR_RUNNING_MODAL;
 }
 
+/**
+ * This modal callback calls exec once per mouse move event while the gesture is active with the
+ * updated line start and end values, so it can be used for tools that have a real time preview
+ * (like a gradient updating in real time over the mesh).
+ */
 int WM_gesture_straightline_modal(bContext *C, wmOperator *op, const wmEvent *event)
 {
   wmGesture *gesture = op->customdata;
@@ -886,6 +901,63 @@ int WM_gesture_straightline_modal(bContext *C, wmOperator *op, const wmEvent *ev
   return OPERATOR_RUNNING_MODAL;
 }
 
+/**
+ * This modal oneshot callback only calls exec once after the gesture finishes without any updates
+ * during the gesture execution. Should be used for operations that are intended to be applied once
+ * without real time preview (like a trimming tool that only applies the bisect operation once
+ * after finishing the gesture as the bisect operation is too heavy to be computed in real time for
+ * a preview).
+ */
+int WM_gesture_straightline_oneshot_modal(bContext *C, wmOperator *op, const wmEvent *event)
+{
+  wmGesture *gesture = op->customdata;
+  wmWindow *win = CTX_wm_window(C);
+  rcti *rect = gesture->customdata;
+
+  if (event->type == MOUSEMOVE) {
+    if (gesture->is_active == false) {
+      rect->xmin = rect->xmax = event->x - gesture->winrct.xmin;
+      rect->ymin = rect->ymax = event->y - gesture->winrct.ymin;
+    }
+    else {
+      rect->xmax = event->x - gesture->winrct.xmin;
+      rect->ymax = event->y - gesture->winrct.ymin;
+    }
+
+    wm_gesture_tag_redraw(win);
+  }
+  else if (event->type == EVT_MODAL_MAP) {
+    switch (event->val) {
+      case GESTURE_MODAL_BEGIN:
+        if (gesture->is_active == false) {
+          gesture->is_active = true;
+          wm_gesture_tag_redraw(win);
+        }
+        break;
+      case GESTURE_MODAL_SELECT:
+      case GESTURE_MODAL_DESELECT:
+      case GESTURE_MODAL_IN:
+      case GESTURE_MODAL_OUT:
+        if (gesture->wait_for_input) {
+          gesture->modal_state = event->val;
+        }
+        if (gesture_straightline_apply(C, op)) {
+          gesture_modal_end(C, op);
+          return OPERATOR_FINISHED;
+        }
+        gesture_modal_end(C, op);
+        return OPERATOR_CANCELLED;
+
+      case GESTURE_MODAL_CANCEL:
+        gesture_modal_end(C, op);
+        return OPERATOR_CANCELLED;
+    }
+  }
+
+  gesture->is_active_prev = gesture->is_active;
+  return OPERATOR_RUNNING_MODAL;
+}
+
 void WM_gesture_straightline_cancel(bContext *C, wmOperator *op)
 {
   gesture_modal_end(C, op);
diff --git a/source/blender/windowmanager/intern/wm_operators.c b/source/blender/windowmanager/intern/wm_operators.c
index 2b01c8fe90e..0e4bb1cc33a 100644
--- a/source/blender/windowmanager/intern/wm_operators.c
+++ b/source/blender/windowmanager/intern/wm_operators.c
@@ -3904,6 +3904,7 @@ static void gesture_box_modal_keymap(wmKeyConfig *keyconf)
   WM_modalkeymap_assign(keymap, "PAINT_OT_mask_box_gesture");
   WM_modalkeymap_assign(keymap, "SCULPT_OT_face_set_box_gesture");
   WM_modalkeymap_assign(keymap, "SCULPT_OT_trim_box_gesture");
+  WM_modalkeymap_assign(keymap, "PAINT_OT_mask_line_gesture");
   WM_modalkeymap_assign(keymap, "VIEW2D_OT_zoom_border");
   WM_modalkeymap_assign(keymap, "VIEW3D_OT_clip_border");
   WM_modalkeymap_assign(keymap, "VIEW3D_OT_render_border");