Make lines update in real-time in the simulation-view too.

This approach does suffer from returning to exactly the same point, which can mess up the view.

part of CURA-11521

plugins/SimulationView/SimulationPass.py

@@ -143,6 +143,7 @@ class SimulationPass(RenderPass):
                 if self._layer_view.getCurrentLayer() > -1 and ((not self._layer_view._only_show_top_layers) or (not self._layer_view.getCompatibilityMode())):
                     start = 0
                     end = 0
+                    towards_next_vertex = 0
                     element_counts = layer_data.getElementCounts()
                     for layer in sorted(element_counts.keys()):
                         # In the current layer, we show just the indicated paths
@@ -162,12 +163,19 @@ class SimulationPass(RenderPass):
                                 if ratio <= 0.0001 or index + 1 == len(polygon.data):
                                     # in case there multiple polygons and polygon changes, the first point has the same value as the last point in the previous polygon
                                     head_position = pos_a + node.getWorldPosition()
+                                    self._layer_shader.setUniformValue("u_last_vertex", pos_a)
+                                    self._layer_shader.setUniformValue("u_next_vertex", pos_a)
+                                    self._layer_shader.setUniformValue("u_last_line_ratio", 1.0)
                                 else:
                                     pos_b = Vector(polygon.data[index + 1][0],
                                                    polygon.data[index + 1][1],
                                                    polygon.data[index + 1][2])
                                     vec = pos_a * (1.0 - ratio) + pos_b * ratio
                                     head_position = vec + node.getWorldPosition()
+                                    towards_next_vertex = 2
+                                    self._layer_shader.setUniformValue("u_last_vertex", pos_a)
+                                    self._layer_shader.setUniformValue("u_next_vertex", pos_b)
+                                    self._layer_shader.setUniformValue("u_last_line_ratio", ratio)
                                 break
                             break
                         if self._layer_view.getMinimumLayer() > layer:
@@ -176,7 +184,7 @@ class SimulationPass(RenderPass):
 
                     # Calculate the range of paths in the last layer
                     current_layer_start = end
-                    current_layer_end = end + int( self._layer_view.getCurrentPath()) * 2  # Because each point is used twice
+                    current_layer_end = end + towards_next_vertex + int( self._layer_view.getCurrentPath()) * 2  # Because each point is used twice
 
                     # This uses glDrawRangeElements internally to only draw a certain range of lines.
                     # All the layers but the current selected layer are rendered first

plugins/SimulationView/layers3d.shader

@@ -19,6 +19,10 @@ vertex41core =
 
     uniform highp mat4 u_normalMatrix;
 
+    uniform vec3 u_last_vertex;
+    uniform vec3 u_next_vertex;
+    uniform float u_last_line_ratio;
+
     in highp vec4 a_vertex;
     in lowp vec4 a_color;
     in lowp vec4 a_material_color;
@@ -134,6 +138,10 @@ vertex41core =
     void main()
     {
         vec4 v1_vertex = a_vertex;
+        if (v1_vertex.xyz == u_next_vertex)
+        {
+            v1_vertex.xyz = mix(u_last_vertex, u_next_vertex, u_last_line_ratio);
+        }
         v1_vertex.y -= a_line_dim.y / 2;  // half layer down
 
         vec4 world_space_vert = u_modelMatrix * v1_vertex;

plugins/SimulationView/layers3d_shadow.shader

@@ -10,6 +10,10 @@ vertex41core =
 
     uniform highp mat4 u_normalMatrix;
 
+    uniform vec3 u_last_vertex;
+    uniform vec3 u_next_vertex;
+    uniform float u_last_line_ratio;
+
     in highp vec4 a_vertex;
     in lowp vec4 a_color;
     in lowp vec4 a_grayColor;
@@ -35,6 +39,10 @@ vertex41core =
     void main()
     {
         vec4 v1_vertex = a_vertex;
+        if (v1_vertex.xyz == u_next_vertex)
+        {
+            v1_vertex.xyz = mix(u_last_vertex, u_next_vertex, u_last_line_ratio);
+        }
         v1_vertex.y -= a_line_dim.y / 2;  // half layer down
 
         vec4 world_space_vert = u_modelMatrix * v1_vertex;
@@ -274,6 +282,8 @@ u_viewMatrix = view_matrix
 u_projectionMatrix = projection_matrix
 u_normalMatrix = normal_matrix
 u_lightPosition = light_0_position
+u_lastVertex = last_vertex
+u_nextVertex = next_vertex
 
 [attributes]
 a_vertex = vertex