Check entity bounding box before hit testing edges.

src/draw.cpp

@@ -336,7 +336,7 @@ void GraphicsWindow::HitTestMakeSelection(Point2d mp) {
         }
 
         d = e->GetDistance(mp);
-        if(d < 10 && d < dmin) {
+        if(d < SELECTION_RADIUS && d < dmin) {
             s = {};
             s.entity = e->h;
             dmin = d;
@@ -348,7 +348,7 @@ void GraphicsWindow::HitTestMakeSelection(Point2d mp) {
         // Constraints
         for(i = 0; i < SK.constraint.n; i++) {
             d = SK.constraint.elem[i].GetDistance(mp);
-            if(d < 10 && d < dmin) {
+            if(d < SELECTION_RADIUS && d < dmin) {
                 s = {};
                 s.constraint = SK.constraint.elem[i].h;
                 dmin = d;

src/drawentity.cpp

@@ -152,6 +152,37 @@ SEdgeList *Entity::GetOrGenerateEdges() {
     return &edges;
 }
 
+BBox Entity::GetScreenBBox(bool *hasBBox) {
+    SBezierList *sbl = GetOrGenerateBezierCurves();
+
+    // We don't bother with bounding boxes for normals, workplanes, etc.
+    *hasBBox = (IsPoint() || sbl->l.n > 0);
+    if(!*hasBBox) return {};
+
+    BBox result = {};
+    if(IsPoint()) {
+        Vector proj = SS.GW.ProjectPoint3(PointGetNum());
+        result = BBox::From(proj, proj);
+    } else if(sbl->l.n > 0) {
+        Vector first = SS.GW.ProjectPoint3(sbl->l.elem[0].ctrl[0]);
+        result = BBox::From(first, first);
+        for(int i = 0; i < sbl->l.n; i++) {
+            SBezier *sb = &sbl->l.elem[i];
+            for(int i = 0; i <= sb->deg; i++) {
+                result.Include(SS.GW.ProjectPoint3(sb->ctrl[i]));
+            }
+        }
+    } else oops();
+
+    // Enlarge the bounding box to consider selection radius.
+    result.minp.x -= SELECTION_RADIUS;
+    result.minp.y -= SELECTION_RADIUS;
+    result.maxp.x += SELECTION_RADIUS;
+    result.maxp.y += SELECTION_RADIUS;
+
+    return result;
+}
+
 double Entity::GetDistance(Point2d mp) {
     dogd.drawing = false;
     dogd.mp = mp;
@@ -473,6 +504,15 @@ void Entity::GenerateBezierCurves(SBezierList *sbl) {
 }
 
 void Entity::DrawOrGetDistance(void) {
+    // If we're about to perform hit testing on an entity, consider
+    // whether the pointer is inside its bounding box first.
+    if(!dogd.drawing) {
+        bool hasBBox;
+        BBox box = GetScreenBBox(&hasBBox);
+        if(hasBBox && !box.Contains(dogd.mp))
+            return;
+    }
+
     if(!IsVisible()) return;
 
     switch(type) {

src/dsc.h

@@ -513,6 +513,7 @@ public:
 
     void Include(const Vector &v, double r = 0.0);
     bool Overlaps(BBox &b1);
+    bool Contains(const Point2d &p);
 };
 
 #endif

src/sketch.h

@@ -509,6 +509,7 @@ public:
 
     SBezierList *GetOrGenerateBezierCurves();
     SEdgeList *GetOrGenerateEdges();
+    BBox GetScreenBBox(bool *hasBBox);
 
     void Clear() {
         beziers.l.Clear();

src/ui.h

@@ -328,6 +328,8 @@ public:
     void EditControlDone(const char *s);
 };
 
+#define SELECTION_RADIUS 10.0
+
 class GraphicsWindow {
 public:
     void Init(void);

src/util.cpp

@@ -1047,3 +1047,7 @@ bool BBox::Overlaps(BBox &b1) {
 
     return fabs(t.x) < e.x && fabs(t.y) < e.y && fabs(t.z) < e.z;
 }
+
+bool BBox::Contains(const Point2d &p) {
+    return p.x >= minp.x && p.y >= minp.y && p.x <= maxp.x && p.y <= maxp.y;
+}