Calculate convex hulls for scene nodes and use it for collision testing

PlatformPhysics.py

@@ -9,6 +9,7 @@ from UM.Math.AxisAlignedBox import AxisAlignedBox
 from UM.Application import Application
 
 from PlatformPhysicsOperation import PlatformPhysicsOperation
+from ConvexHullJob import ConvexHullJob
 
 import time
 import threading
@@ -19,7 +20,6 @@ class PlatformPhysics:
         self._controller = controller
         self._controller.getScene().sceneChanged.connect(self._onSceneChanged)
         self._build_volume = volume
-        self._signal_source = None
 
         self._change_timer = QTimer()
         self._change_timer.setInterval(100)
@@ -39,13 +39,47 @@ class PlatformPhysics:
             if not bbox or not bbox.isValid():
                 continue
 
+            # Mark the node as outside the build volume if the bounding box test fails.
             if self._build_volume.getBoundingBox().intersectsBox(bbox) != AxisAlignedBox.IntersectionResult.FullIntersection:
                 node._outside_buildarea = True
             else:
                 node._outside_buildarea = False
 
+            # Move the node upwards if the bottom is below the build platform.
+            move_vector = Vector()
             if not Float.fuzzyCompare(bbox.bottom, 0.0):
-                self._signal_source = node
+                move_vector.setY(-bbox.bottom)
-                op = PlatformPhysicsOperation(node, Vector(0, -bbox.bottom, 0))
+
-                Application.getInstance().getOperationStack().push(op)
+            # If there is no convex hull for the node, start calculating it and continue.
-                self._signal_source = None
+            if not hasattr(node, '_convex_hull'):
+                if not hasattr(node, '_convex_hull_job'):
+                    job = ConvexHullJob(node)
+                    job.start()
+                    node._convex_hull_job = job
+            else:
+                # Check for collisions between convex hulls
+                for other_node in BreadthFirstIterator(root):
+                    # Ignore root, ourselves and anything that is not a normal SceneNode.
+                    if other_node is root or type(other_node) is not SceneNode or other_node is node:
+                        continue
+
+                    # Ignore nodes that do not have the right properties set.
+                    if not hasattr(other_node, '_convex_hull') or not other_node.getBoundingBox():
+                        continue
+
+                    # Check to see if the bounding boxes intersect. If not, we can ignore the node as there is no way the hull intersects.
+                    if node.getBoundingBox().intersectsBox(other_node.getBoundingBox()) == AxisAlignedBox.IntersectionResult.NoIntersection:
+                        continue
+
+                    # Get the overlap distance for both convex hulls. If this returns None, there is no intersection.
+                    overlap = node._convex_hull.intersectsPolygon(other_node._convex_hull)
+                    if overlap is None:
+                        continue
+
+                    print(overlap)
+                    move_vector.setX(-overlap[0])
+                    move_vector.setZ(-overlap[1])
+
+            if move_vector != Vector():
+                op = PlatformPhysicsOperation(node, move_vector)
+                op.push()