Added an extruded convex hull as a raft instead of a grey plane.

- New shader transparent_object.shader
- Raft thickness is calculated in BuildVolume and used in
  ConvexHullDecorator, notified by a Signal.
- Removed old grey plane from BuildVolume.
- Vertex data below build plane is no longer discarded (caused convex
  hulls that are too small).
- Uses new functions in MeshBuilder (update Uranium as well).

CURA-1707

cura/ConvexHullNode.py

@@ -4,16 +4,16 @@
 from UM.Scene.SceneNode import SceneNode
 from UM.Resources import Resources
 from UM.Math.Color import Color
-from UM.Math.Vector import Vector
 from UM.Mesh.MeshBuilder import MeshBuilder  # To create a mesh to display the convex hull with.
 
 from UM.View.GL.OpenGL import OpenGL
 
 class ConvexHullNode(SceneNode):
-    ##  Convex hull node is a special type of scene node that is used to display a 2D area, to indicate the
+    ##  Convex hull node is a special type of scene node that is used to display an area, to indicate the
     #   location an object uses on the buildplate. This area (or area's in case of one at a time printing) is
-    #   then displayed as a transparent shadow.
-    def __init__(self, node, hull, parent = None):
+    #   then displayed as a transparent shadow. If the adhesion type is set to raft, the area is extruded
+    #   to represent the raft as well.
+    def __init__(self, node, hull, thickness, parent = None):
         super().__init__(parent)
 
         self.setCalculateBoundingBox(False)
@@ -23,7 +23,7 @@ class ConvexHullNode(SceneNode):
         self._original_parent = parent
 
         # Color of the drawn convex hull
-        self._color = Color(35, 35, 35, 128)
+        self._color = Color(35, 35, 35, 192)
 
         # The y-coordinate of the convex hull mesh. Must not be 0, to prevent z-fighting.
         self._mesh_height = 0.1
@@ -34,11 +34,17 @@ class ConvexHullNode(SceneNode):
         self._onNodeDecoratorsChanged(self._node)
 
         self._convex_hull_head_mesh = None
-        self._hull = hull
 
+        self._hull = hull
+        self._thickness = thickness
         if self._hull:
-            hull_mesh = self.createHullMesh(self._hull.getPoints())
-            if hull_mesh:
+            hull_mesh_builder = MeshBuilder()
+
+            if hull_mesh_builder.addConvexPolygonExtrusion(
+                self._hull.getPoints()[::-1],  # bottom layer is reversed
+                self._mesh_height-thickness, self._mesh_height, color=self._color):
+
+                hull_mesh = hull_mesh_builder.build()
                 self.setMeshData(hull_mesh)
         convex_hull_head = self._node.callDecoration("getConvexHullHead")
         if convex_hull_head:
@@ -47,31 +53,17 @@ class ConvexHullNode(SceneNode):
     def getHull(self):
         return self._hull
 
-    ##  Actually create the mesh from the hullpoints
-    #   /param hull_points list of xy values
-    #   /return meshData
-    def createHullMesh(self, hull_points):
-        # Input checking.
-        if len(hull_points) < 3:
-            return None
-
-        mesh_builder = MeshBuilder()
-        point_first = Vector(hull_points[0][0], self._mesh_height, hull_points[0][1])
-        point_previous = Vector(hull_points[1][0], self._mesh_height, hull_points[1][1])
-        for point in hull_points[2:]:  # Add the faces in the order of a triangle fan.
-            point_new = Vector(point[0], self._mesh_height, point[1])
-            mesh_builder.addFace(point_first, point_previous, point_new, color = self._color)
-            point_previous = point_new  # Prepare point_previous for the next triangle.
-
-        return mesh_builder.build()
+    def getThickness(self):
+        return self._thickness
 
     def getWatchedNode(self):
         return self._node
 
     def render(self, renderer):
         if not self._shader:
-            self._shader = OpenGL.getInstance().createShaderProgram(Resources.getPath(Resources.Shaders, "default.shader"))
-            self._shader.setUniformValue("u_color", self._color)
+            self._shader = OpenGL.getInstance().createShaderProgram(Resources.getPath(Resources.Shaders, "transparent_object.shader"))
+            self._shader.setUniformValue("u_diffuseColor", self._color)
+            self._shader.setUniformValue("u_opacity", 0.6)
 
         if self.getParent():
             if self.getMeshData():
@@ -85,4 +77,5 @@ class ConvexHullNode(SceneNode):
         self._color = Color(35, 35, 35, 0.5)
 
         if not node:
-            return
+            return
+