Reduce vertices per tube by 1

Since the tubes are symmetrical, instead of using an extra vertex to flip the winding order, I just mirror all horizontal coordinates so that the triangles flip inside out.

plugins/SimulationView/layers3d.shader

@@ -198,17 +198,16 @@ geometry41core =
             EndPrimitive();
         } else {
             // All normal lines are rendered as 3d tubes.
-            myEmitVertex(v_vertex[0], v_color[0], g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[0].gl_Position + g_vertex_offset_horz));
-            myEmitVertex(v_vertex[0], v_color[0], g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[0].gl_Position + g_vertex_offset_horz));
-            myEmitVertex(v_vertex[1], v_color[1], g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[1].gl_Position + g_vertex_offset_horz));
-            myEmitVertex(v_vertex[0], v_color[0], g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[0].gl_Position + g_vertex_offset_vert));
-            myEmitVertex(v_vertex[1], v_color[1], g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[1].gl_Position + g_vertex_offset_vert));
             myEmitVertex(v_vertex[0], v_color[0], -g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[0].gl_Position - g_vertex_offset_horz));
             myEmitVertex(v_vertex[1], v_color[1], -g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[1].gl_Position - g_vertex_offset_horz));
-            myEmitVertex(v_vertex[0], v_color[0], -g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[0].gl_Position - g_vertex_offset_vert));
-            myEmitVertex(v_vertex[1], v_color[1], -g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[1].gl_Position - g_vertex_offset_vert));
+            myEmitVertex(v_vertex[0], v_color[0], g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[0].gl_Position + g_vertex_offset_vert));
+            myEmitVertex(v_vertex[1], v_color[1], g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[1].gl_Position + g_vertex_offset_vert));
             myEmitVertex(v_vertex[0], v_color[0], g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[0].gl_Position + g_vertex_offset_horz));
             myEmitVertex(v_vertex[1], v_color[1], g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[1].gl_Position + g_vertex_offset_horz));
+            myEmitVertex(v_vertex[0], v_color[0], -g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[0].gl_Position - g_vertex_offset_vert));
+            myEmitVertex(v_vertex[1], v_color[1], -g_vertex_normal_vert, u_viewProjectionMatrix * (gl_in[1].gl_Position - g_vertex_offset_vert));
+            myEmitVertex(v_vertex[0], v_color[0], -g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[0].gl_Position - g_vertex_offset_horz));
+            myEmitVertex(v_vertex[1], v_color[1], -g_vertex_normal_horz, u_viewProjectionMatrix * (gl_in[1].gl_Position - g_vertex_offset_horz));
 
             EndPrimitive();