Multi-Objects: CURVE_OT_select_similar

Implemented the following methods:
* SIMCURHAND_TYPE
* SIMCURHAND_RADIUS
* SIMCURHAND_WEIGHT
* SIMCURHAND_DIRECTION

Limits:
* DIRECTION does not support surfaces, because `BKE_nurb_bpoint_calc_normal`
  does not work with Nurbs of type `CU_CARDINAL`. This also didn't work prior
  to this patch, so we wait until surfaces are properly supported in EditMode.

* Also DIRECTION should take scaling into consideration. We need our own
  versions of BKE_nurb_bpoint_calc_normal/bezt.

* Threshold default is too large. Not sure if it's better to change the default
  or scale the threshold in code.

Differential Revision: https://developer.blender.org/D3846

Changes from committer (Dalai Felinto):
 * Moved nurb_bpoint_direction_worldspace_get/bezt to functions.
 * Comments hinting at the mode (direction) that require scaling to be
   taken into account - to be addressed by patch creator in a future
   patch.

1 files changed, 55 insertions, 0 deletions

diff --git a/source/blender/editors/util/select_utils.c b/source/blender/editors/util/select_utils.c
index dee49e11efb..92de124800b 100644
--- a/source/blender/editors/util/select_utils.c
+++ b/source/blender/editors/util/select_utils.c
@@ -23,9 +23,13 @@
  */
 
 #include "BLI_utildefines.h"
+#include "BLI_kdtree.h"
+#include "BLI_math.h"
 
 #include "ED_select_utils.h"
 
+#include "float.h"
+
 /** 1: select, 0: deselect, -1: pass. */
 int ED_select_op_action(const eSelectOp sel_op, const bool is_select, const bool is_inside)
 {
@@ -68,3 +72,54 @@ int ED_select_op_action_deselected(const eSelectOp sel_op, const bool is_select,
 	BLI_assert(!"invalid sel_op");
 	return -1;
 }
+
+int ED_select_similar_compare_float(const float delta, const float thresh, const int compare)
+{
+	switch (compare) {
+		case SIM_CMP_EQ:
+			return (fabsf(delta) < thresh + FLT_EPSILON);
+		case SIM_CMP_GT:
+			return ((delta + thresh) > -FLT_EPSILON);
+		case SIM_CMP_LT:
+			return ((delta - thresh) < FLT_EPSILON);
+		default:
+			BLI_assert(0);
+			return 0;
+	}
+}
+
+bool ED_select_similar_compare_float_tree(const KDTree *tree, const float length, const float thresh, const int compare)
+{
+	/* Length of the edge we want to compare against. */
+	float nearest_edge_length;
+
+	switch (compare) {
+		case SIM_CMP_EQ:
+			/* Compare to the edge closest to the current edge. */
+			nearest_edge_length = length;
+			break;
+		case SIM_CMP_GT:
+			/* Compare against the shortest edge. */
+			/* -FLT_MAX leads to some precision issues and the wrong edge being selected.
+			 * For example, in a tree with 1, 2 and 3, which is stored squared as 1, 4, 9, it returns as the nearest
+			 * length/node the "4" instead of "1". */
+			nearest_edge_length = -1.0f;
+			break;
+		case SIM_CMP_LT:
+			/* Compare against the longest edge. */
+			nearest_edge_length = FLT_MAX;
+			break;
+		default:
+			BLI_assert(0);
+			return false;
+	}
+
+	KDTreeNearest nearest;
+	float dummy[3] = {nearest_edge_length, 0.0f, 0.0f};
+	if (BLI_kdtree_find_nearest(tree, dummy, &nearest) != -1) {
+		float delta = length - nearest.co[0];
+		return ED_select_similar_compare_float(delta, thresh, compare);
+	}
+
+	return false;
+}