Merge pull request #5153 from nortikin/viewer_curve_arrows

"Viewer Draw Curve": indicate curve direction

docs/nodes/viz/viewer_draw_curve.rst

@@ -55,6 +55,13 @@ The parameters of the node are (in this order):
 .. image:: https://user-images.githubusercontent.com/14288520/190168448-b0691bc4-392f-4f83-bb5b-926da7b64b8e.png
   :target: https://user-images.githubusercontent.com/14288520/190168448-b0691bc4-392f-4f83-bb5b-926da7b64b8e.png
 
+* **Display Arrows**, **Arrows Color**, **Arrows Line Width**. Control display
+  of small arrows which indicate the direction of curve (direction in which
+  curve's T parameter grows). Curve arrows are not shown by default.
+
+.. image:: ../../../docs/assets/nodes/viz/viewer_draw_curve_arrows.png
+   :target: ../../../docs/assets/nodes/viz/viewer_draw_curve_arrows.png
+
 -------------
 
 * **Display Control Points**, **Control Points Color**, **Control Points

nodes/curve/prepare_curves_net.py

@@ -161,8 +161,8 @@ def process(self):
                 new_u_curves.append(u_curves)
                 new_v_curves.append(v_curves)
                 new_pts.append(pts)
-                new_u_values.append(u_values)
-                new_v_values.append(v_values)
+                new_u_values.append(u_values.tolist())
+                new_v_values.append(v_values.tolist())
             if flat_output:
                 u_curves_out.extend(new_u_curves)
                 v_curves_out.extend(new_v_curves)

nodes/curve/refine_nurbs_curve.py

@@ -135,6 +135,9 @@ def process(self):
             curves_list = []
             new_knots_list = []
             for curve, new_knots, resolution, t_min, t_max in zip_long_repeat(*params):
+                curve = SvNurbsCurve.to_nurbs(curve)
+                if curve is None:
+                    raise Exception("Curve is not NURBS")
                 if not self.specify_segment:
                     t_min = t_max = None
 

nodes/viz/viewer_draw_curve.py

@@ -36,6 +36,18 @@ def draw_edges(shader, points, edges, line_width, color, is_smooth=False):
         batch.draw(shader)
         drawing.reset_line_width()
 
+def draw_arrows(shader, tips, pts1, pts2, line_width, color):
+    n = len(tips)
+    points = np.concatenate((tips, pts1, pts2))
+    edges = [(i, i+n) for i in range(n-1)]
+    edges.extend([(i, i+2*n) for i in range(n-1)])
+    drawing.set_line_width(line_width)
+    batch = batch_for_shader(shader, 'LINES', {"pos": points.tolist()}, indices=edges)
+    shader.bind()
+    shader.uniform_float('color', color)
+    batch.draw(shader)
+    drawing.reset_line_width()
+
 def draw_edges_colored(shader, points, edges, line_width, colors):
     drawing.set_line_width(line_width)
     batch = batch_for_shader(shader, 'LINES', {"pos": points, "color": colors}, indices=edges)
@@ -88,6 +100,9 @@ def draw_curves(context, args):
         if node.draw_verts and item.points is not None:
             draw_points(v_shader, item.points, node.verts_size, node.verts_color)
 
+        if node.draw_arrows and item.arrow_pts1 is not None and item.arrow_pts2 is not None:
+            draw_arrows(e_shader, item.np_points[1:], item.arrow_pts1, item.arrow_pts2, node.arrows_line_width, node.arrows_color)
+
     drawing.enable_blendmode()
 
 class SvBakeCurveOp(bpy.types.Operator, SvGenericNodeLocator):
@@ -153,6 +168,23 @@ class SvCurveViewerDrawNode(SverchCustomTreeNode, bpy.types.Node):
             min = 1, default = 2,
             update = updateNode)
 
+    draw_arrows : BoolProperty(
+            name = "Display arrows",
+            default = False,
+            update = updateNode)
+
+    arrows_line_width : IntProperty(
+            name = "Arrows Line Width",
+            min = 1, default = 1,
+            update = updateNode)
+
+    arrows_color : FloatVectorProperty(
+            name = "Arrows Color",
+            default = (0.5, 0.8, 1.0, 1.0),
+            size = 4, min = 0.0, max = 1.0,
+            subtype = 'COLOR',
+            update = updateNode)
+
     draw_control_points: BoolProperty(
         update=updateNode, name='Display control points', default=False)
 
@@ -243,6 +275,11 @@ def draw_buttons(self, context, layout):
         row.prop(self, 'line_color', text="")
         row.prop(self, 'line_width', text="px")
 
+        row = grid.row(align=True)
+        row.prop(self, 'draw_arrows', icon='EVENT_RIGHT_ARROW', text='')
+        row.prop(self, 'arrows_color', text='')
+        row.prop(self, 'arrows_line_width', text='px')
+
         row = grid.row(align=True)
         row.prop(self, 'draw_control_points', icon='DECORATE_KEYFRAME', text='')
         row.prop(self, 'control_points_color', text="")

utils/curve/bakery.py

@@ -37,11 +37,12 @@ def __init__(self, node, curve, resolution):
 
         logger = get_logger()
 
-        if node.draw_line or node.draw_verts or node.draw_comb or node.draw_curvature:
+        if node.draw_line or node.draw_verts or node.draw_comb or node.draw_curvature or node.draw_arrows:
             t_min, t_max = curve.get_u_bounds()
             ts = np.linspace(t_min, t_max, num=resolution)
             n = len(ts)
-            self.points = curve.evaluate_array(ts).tolist()
+            self.np_points = curve.evaluate_array(ts)
+            self.points = self.np_points.tolist()
         else:
             self.points = None
 
@@ -85,8 +86,8 @@ def __init__(self, node, curve, resolution):
             normals = curve.main_normal_array(ts, normalize=True)
             curvatures = self.curvatures[np.newaxis].T
             comb_normals = node.comb_scale * curvatures * normals
-            comb_points = self.points - comb_normals
-            self.comb_points = np.concatenate((self.points, comb_points)).tolist()
+            comb_points = self.np_points - comb_normals
+            self.comb_points = np.concatenate((self.np_points, comb_points)).tolist()
             comb_normal_edges = [(i, i+n) for i in range(n)]
             comb_tangent_edges = [(i, i+1) for i in range(n, 2*n-1)]
             self.comb_edges = comb_normal_edges + comb_tangent_edges
@@ -108,6 +109,27 @@ def __init__(self, node, curve, resolution):
             self.curvature_point_colors = None
             self.curvature_edge_colors = None
 
+        if node.draw_arrows:
+            n = len(self.points)
+            binormals = curve.binormal_array(ts[1:], normalize=True)
+            vectors = self.np_points[1:] - self.np_points[:-1]
+            vector_lens = np.linalg.norm(vectors, axis=1, keepdims=True)
+            mean_len = vector_lens.mean()
+            vectors /= vector_lens
+            is_zero = np.linalg.norm(binormals, axis=1) < 1e-4
+            z = np.array([0,0,1])
+            binormals[is_zero] = np.cross(z, vectors)[is_zero]
+            vectors *= mean_len
+            binormals *= mean_len
+            arrow_vecs1 = binormals - vectors
+            arrow_vecs2 = -binormals - vectors
+            tips = self.np_points[1:]
+            self.arrow_pts1 = tips + arrow_vecs1
+            self.arrow_pts2 = tips + arrow_vecs2
+        else:
+            self.arrow_pts1 = None
+            self.arrow_pts2 = None
+
     @property
     def nurbs_curve(self):
         if self._nurbs_curve is None:

utils/surface/bakery.py

@@ -97,6 +97,7 @@ def __init__(self):
             self.draw_nodes = False
             self.draw_comb = False
             self.draw_curvature = False
+            self.draw_arrows = False
 
     def __init__(self, node, surface, resolution_u, resolution_v):
         self.node = node

utils/surface/gordon.py

@@ -43,7 +43,8 @@ def adjust(t):
 
     result = segments[0]
     for segment in segments[1:]:
-        result = result.concatenate(segment)
+        if segment is not None:
+            result = result.concatenate(segment)
 
     return result