Make sliver triangle tests work on the minimum altitude, not on

area.

[git-p4: depot-paths = "//depot/solvespace/": change = 1816]

mesh.cpp

@@ -67,8 +67,8 @@ void SMesh::Simplify(int start) {
     int i, j;
     for(i = start; i < l.n; i++) {
         STriangle *tr = &(l.elem[i]);
-        if((tr->Normal()).Magnitude() < LENGTH_EPS*LENGTH_EPS) {
-            tr->tag = 0;
+        if(tr->MinAltitude() < LENGTH_EPS) {
+            tr->tag = 1;
         } else {
             tr->tag = 0;
         }
@@ -171,7 +171,7 @@ void SMesh::Simplify(int start) {
 
         for(i = 0; i < convc - 2; i++) {
             STriangle tr = STriangle::From(meta, conv[0], conv[i+1], conv[i+2]);
-            if((tr.Normal()).Magnitude() > LENGTH_EPS*LENGTH_EPS) {
+            if(tr.MinAltitude() > LENGTH_EPS) {
                 tout[toutc++] = tr;
             }
         }

polygon.cpp

@@ -5,9 +5,17 @@ Vector STriangle::Normal(void) {
     return ab.Cross(bc);
 }
 
+double STriangle::MinAltitude(void) {
+    double altA = a.DistanceToLine(b, c.Minus(b)),
+           altB = b.DistanceToLine(c, a.Minus(c)),
+           altC = c.DistanceToLine(a, b.Minus(a));
+
+    return min(altA, min(altB, altC));
+}
+
 bool STriangle::ContainsPoint(Vector p) {
     Vector n = Normal();
-    if(n.Magnitude() < LENGTH_EPS*LENGTH_EPS) {
+    if(MinAltitude() < LENGTH_EPS) {
         // shouldn't happen; zero-area triangle
         return false;
     }

polygon.h

@@ -124,6 +124,7 @@ public:
     static STriangle From(STriMeta meta, Vector a, Vector b, Vector c);
     Vector Normal(void);
     void FlipNormal(void);
+    double MinAltitude(void);
     int WindingNumberForPoint(Vector p);
     bool ContainsPoint(Vector p);
     bool ContainsPointProjd(Vector n, Vector p);

solvespace.h

@@ -24,7 +24,7 @@ inline int WRAP(int v, int n) {
 #define ZERO(v) memset((v), 0, sizeof(*(v)))
 #define CO(v) (v).x, (v).y, (v).z
 
-#define LENGTH_EPS  (0.0000001)
+#define LENGTH_EPS  (1e-7)
 
 #define isforname(c) (isalnum(c) || (c) == '_' || (c) == '-' || (c) == '#')
 

util.cpp

@@ -269,10 +269,7 @@ Vector Vector::From(hParam x, hParam y, hParam z) {
 }
 
 bool Vector::Equals(Vector v) {
-    if(fabs(x - v.x) > LENGTH_EPS) return false;
-    if(fabs(y - v.y) > LENGTH_EPS) return false;
-    if(fabs(z - v.z) > LENGTH_EPS) return false;
-    return true;
+    return (this->Minus(v)).Magnitude() < LENGTH_EPS;
 }
 
 Vector Vector::Plus(Vector b) {

wishlist.txt

@@ -8,6 +8,7 @@ auto-generate circles and faces when lathing
 copy the section geometry to other end when sweeping
 cylindrical faces
 draw explicit edges
+symmetric about line segment
 
 
 long term