Triangulator: shift on merge (#528)

* allow shift on merge * fixed more tests with proper uncertainty * fixed another test
elalish · Aug 14, 2023 · 8011fb6 · 8011fb6
1 parent 9290d42
commit 8011fb6
Show file tree

Hide file tree

Showing 2 changed files with 53 additions and 29 deletions.
diff --git a/src/polygon/src/polygon.cpp b/src/polygon/src/polygon.cpp
@@ -381,9 +381,15 @@ class Monotones {
   struct EdgePair {
     VertItr vWest, vEast, vMerge;
     PairItr nextPair;
-    bool westCertain, eastCertain, startCertain;
+    bool westCertain, eastCertain;
 
     int WestOf(VertItr vert, float precision) const {
+      if (vEast->pos.x + precision < vert->pos.x &&
+          vEast->right->pos.x + precision < vert->pos.x)
+        return 1;
+      if (vEast->pos.x - precision > vert->pos.x &&
+          vEast->right->pos.x - precision > vert->pos.x)
+        return -1;
       int westOf = CCW(vEast->right->pos, vEast->pos, vert->pos, precision);
       if (westOf == 0 && !vert->right->Processed())
         westOf =
@@ -394,6 +400,12 @@ class Monotones {
     }
 
     int EastOf(VertItr vert, float precision) const {
+      if (vWest->pos.x - precision > vert->pos.x &&
+          vWest->left->pos.x - precision > vert->pos.x)
+        return 1;
+      if (vWest->pos.x + precision < vert->pos.x &&
+          vWest->left->pos.x + precision < vert->pos.x)
+        return -1;
       int eastOf = CCW(vWest->pos, vWest->left->pos, vert->pos, precision);
       if (eastOf == 0 && !vert->right->Processed())
         eastOf = CCW(vWest->pos, vWest->left->pos, vert->right->pos, precision);
@@ -536,8 +548,13 @@ class Monotones {
           PRINT("End");
           CloseEnd(vert);
           return End;
-        } else if (westPair != activePairs_.end() &&
-                   std::next(westPair) == eastPair) {
+        } else if (!eastPair->westCertain || !westPair->eastCertain ||
+                   (westPair != activePairs_.end() &&
+                    std::next(westPair) == eastPair)) {
+          if (!eastPair->westCertain)
+            activePairs_.splice(std::next(westPair), activePairs_, eastPair);
+          if (!westPair->eastCertain)
+            activePairs_.splice(eastPair, activePairs_, westPair);
           // facing out
           PRINT("Merge");
           CloseEnd(vert);
@@ -747,8 +764,13 @@ class Monotones {
     }
     if (isHole) return true;
 
-    activePairs_.splice(activePairs_.end(), activePairs_, inputPair);
-    inputPair->eastCertain = true;
+    if (activePairs_.size() > 1) {
+      activePairs_.splice(activePairs_.end(), activePairs_, inputPair);
+      inputPair->eastCertain =
+          std::prev(inputPair)->WestOf(vert, precision_) > 0;
+    } else {
+      inputPair->eastCertain = true;
+    }
     return false;
   }
 
@@ -780,9 +802,15 @@ class Monotones {
     }
     if (isHole) return true;
 
-    if (inputPair != activePairs_.begin())
-      activePairs_.splice(activePairs_.begin(), activePairs_, inputPair);
-    inputPair->westCertain = true;
+    activePairs_.splice(activePairs_.begin(), activePairs_, inputPair);
+
+    const PairItr eastPair = std::next(inputPair);
+    if (eastPair != activePairs_.end()) {
+      inputPair->westCertain = eastPair->EastOf(vert, precision_) > 0;
+    } else {
+      inputPair->westCertain = true;
+    }
+
     return false;
   }
 
@@ -845,8 +873,8 @@ class Monotones {
       bool isHole = false;
       if (type == Start) {
         newPair = activePairs_.insert(
-            activePairs_.begin(), {vert, vert, monotones_.end(),
-                                   activePairs_.end(), false, false, false});
+            activePairs_.begin(),
+            {vert, vert, monotones_.end(), activePairs_.end(), false, false});
         SetVWest(newPair, vert);
         SetVEast(newPair, vert);
         const int hole = IsHole(vert);

diff --git a/test/polygon_test.cpp b/test/polygon_test.cpp
@@ -517,7 +517,7 @@ TEST(Polygon, Sliver7) {
   TestPoly(polys, 6);
 }
 
-TEST(Polygon, DISABLED_Sliver8) {
+TEST(Polygon, Sliver8) {
   Polygons polys;
   polys.push_back({
       {27.9279995, 4.9749999},    //
@@ -531,7 +531,7 @@ TEST(Polygon, DISABLED_Sliver8) {
   TestPoly(polys, 5);
 }
 
-TEST(Polygon, DISABLED_Sliver9) {
+TEST(Polygon, Sliver9) {
   Polygons polys;
   polys.push_back({
       {1.49183154, -0.4795963766194},  //
@@ -883,7 +883,7 @@ TEST(Polygon, Precision3) {
   TestPoly(polys, 3, 0.00068);
 };
 
-TEST(Polygon, DISABLED_Sweep) {
+TEST(Polygon, Sweep) {
   Polygons polys;
   polys.push_back({
       {0, 0.637057483},          //
@@ -3087,7 +3087,7 @@ TEST(Polygon, BigSponge) {
   TestPoly(polys, 1771);
 }
 
-TEST(Polygon, DISABLED_Woodgrain1) {
+TEST(Polygon, Woodgrain1) {
   Polygons polys;
   polys.push_back({
       {72.5, -50},   //
@@ -3108,24 +3108,20 @@ TEST(Polygon, DISABLED_Woodgrain1) {
   TestPoly(polys, 12, 0.00145);
 }
 
-TEST(Polygon, DISABLED_Woodgrain2) {
+TEST(Polygon, Woodgrain2) {
   Polygons polys;
   polys.push_back({
-      {-15.694437, 33.8253479},   //
-      {13.2702093, -3.28426218},  //
-      {53.4751701, -32.0106316},  //
-      {61.4174232, 44.4299698},   //
+      {22.7295628, -49.5001106},   //
+      {-21.1059895, -49.9855423},  //
+      {-35.0938339, 10.1798563},   //
+      {-72.5, -50},                //
+      {-12.7149582, -50},          //
   });
   polys.push_back({
-      {17.61759, 25.2365837},     //
-      {17.6270828, 25.2370052},   //
-      {17.1236248, 26.0772629},   //
-      {20.4602833, -7.37109232},  //
+      {-40.1850586, -49.9840584},  //
+      {-40.2071075, -49.9845123},  //
+      {-40.3756485, -49.9855652},  //
+      {-40.0327415, -19.857235},   //
   });
-  polys.push_back({
-      {44.9942932, 39.2275734},  //
-      {45.120945, 29.0997658},   //
-      {44.896656, 25.2351685},   //
-  });
-  TestPoly(polys, 13, 0.00145);
+  TestPoly(polys, 9, 0.00145);
 }