CLIPPER_OFFSET_SCALE was made a power of two, the scaling functions

inside ClipperUtils are now using bit shifts instead of multiplication
by doubles, which makes the scaling precise.

Removed the scale parameter from all offset functions.

Modified the safety offset to calculate offset per polygon instead
of over all polygons at once. The old way was not safe and very slow,
sometimes this meant a kiss of death for supports for example.

1 files changed, 4 insertions, 4 deletions

diff --git a/xs/src/libslic3r/LayerRegion.cpp b/xs/src/libslic3r/LayerRegion.cpp
index 7c84629e2..52e384adf 100644
--- a/xs/src/libslic3r/LayerRegion.cpp
+++ b/xs/src/libslic3r/LayerRegion.cpp
@@ -91,9 +91,9 @@ LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollection*
     g.process();
 }
 
-//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS CLIPPER_OFFSET_SCALE, ClipperLib::jtMiter, 3.
-//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS CLIPPER_OFFSET_SCALE, ClipperLib::jtMiter, 1.5
-#define EXTERNAL_SURFACES_OFFSET_PARAMETERS CLIPPER_OFFSET_SCALE, ClipperLib::jtSquare, 0.
+//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtMiter, 3.
+//#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtMiter, 1.5
+#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtSquare, 0.
 
 void
 LayerRegion::process_external_surfaces(const Layer* lower_layer)
@@ -194,7 +194,7 @@ LayerRegion::process_external_surfaces(const Layer* lower_layer)
                         break;
                     }
                 // Grown by 3mm.
-                Polygons polys = offset(bridges[i].expolygon, float(margin), EXTERNAL_SURFACES_OFFSET_PARAMETERS);
+                Polygons polys = offset(to_polygons(bridges[i].expolygon), float(margin), EXTERNAL_SURFACES_OFFSET_PARAMETERS);
                 if (idx_island == -1) {
                     printf("Bridge did not fall into the source region!\r\n");
                 } else {