r704@erker: lars | 2010-02-22 00:24:19 +0100

 make sure that the path generators never get stuck in in infinite loop caused by floating point inaccuracies
 define a maximum recursion depth (20) for the PushCutter algorithm (i.e. maximum precision = 1/(1^20) of bounding box width)


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@156 bbaffbd6-741e-11dd-a85d-61de82d9cad9

pycam/PathGenerators/DropCutter.py

@@ -48,8 +48,10 @@ class DropCutter:
 
         finished_plane = False
         self._boundary_warning_already_shown = False
+        last_outer_loop = False
 
         while not finished_plane:
+            last_inner_loop = False
             finished_line = False
             dims[0].set(dims[0].start)
             pa.new_scanline()
@@ -71,10 +73,9 @@ class DropCutter:
 
                 # make sure, that the we also handle the outmost border of the bounding box
                 if dims[0].check_bounds(tolerance=d0):
-                    # check if we are still within the strict limits
-                    if not dims[0].check_bounds():
-                        # we exceeded the maximum, but we are still within step width
+                    if not dims[0].check_bounds() and not last_inner_loop:
                         dims[0].set(dims[0].end)
+                        last_inner_loop = True
                 else:
                     finished_line = True
 
@@ -83,10 +84,9 @@ class DropCutter:
 
             # make sure, that the we also handle the outmost border of the bounding box
             if dims[1].check_bounds(tolerance=d1):
-                # check if we are still within the strict limits
-                if not dims[1].check_bounds():
-                    # we crossed the maximum, but we are still within step width
+                if not dims[1].check_bounds() and not last_outer_loop:
                     dims[1].set(dims[1].end)
+                    last_outer_loop = True
             else:
                 finished_plane = True
 

pycam/PathGenerators/PushCutter.py

@@ -144,6 +144,7 @@ class PushCutter:
         """
         # max_deviation_x = dx/accuracy
         accuracy = 20
+        max_depth = 20
         x = minx
         y = miny
 
@@ -151,10 +152,13 @@ class PushCutter:
         if dx > 0:
             depth_x = math.log(accuracy * (maxx-minx) / dx) / math.log(2)
             depth_x = max(math.ceil(int(depth_x)), 4)
+            depth_x = min(depth_x, max_depth)
         else:
             depth_y = math.log(accuracy * (maxy-miny) / dy) / math.log(2)
             depth_y = max(math.ceil(int(depth_y)), 4)
+            depth_y = min(depth_y, max_depth)
 
+        last_loop = False
         while (x <= maxx) and (y <= maxy):
             points = []
             self.pa.new_scanline()
@@ -174,11 +178,13 @@ class PushCutter:
 
             if dx > 0:
                 x += dx
-                if (x > maxx) and (x - dx < maxx):
+                if (x > maxx) and not last_loop:
+                    last_loop = True
                     x = maxx
             else:
                 y += dy
-                if (y > maxy) and (y - dy < maxy):
+                if (y > maxy) and not last_loop:
+                    last_loop = True
                     y = maxy
 
     def DropCutterTest(self, point, model):
@@ -215,6 +221,7 @@ class PushCutter:
         
         line = 0
 
+        last_loop = False
         while x<=maxx and y<=maxy:
             self.pa.new_scanline()
             if False:
@@ -361,15 +368,17 @@ class PushCutter:
             if dx != 0:
                 x += dx
                 # never skip the outermost bounding limit - reduce the step size if required
-                if (x > maxx) and (x - dx < maxx):
+                if (x > maxx) and not last_loop:
                     x = maxx
+                    last_loop = True
             else:
                 x = minx
             if dy != 0:
                 y += dy
                 # never skip the outermost bounding limit - reduce the step size if required
-                if (y > maxy) and (y - dy < maxy):
+                if (y > maxy) and not last_loop:
                     y = maxy
+                    last_loop = True
             else:
                 y = miny