Use const auto & in a few for loops that were not doing it.

Could help with compiler optimizations and thus performance.

Author: ruevs

src/draw.cpp

@@ -71,7 +71,7 @@ void GraphicsWindow::Selection::Draw(bool isHovered, Canvas *canvas) {
         auto it = std::unique(refs.begin(), refs.end(),
                               [](Vector a, Vector b) { return a.Equals(b); });
         refs.erase(it, refs.end());
-        for(Vector p : refs) {
+        for(const Vector &p : refs) {
             canvas->DrawLine(topLeft, p, hcsEmphasis);
         }
     }

src/export.cpp

@@ -1196,7 +1196,7 @@ void SolveSpaceUI::ExportMeshAsVrmlTo(FILE *f, const Platform::Path &filename, S
         }
 
         // Output all the vertices.
-        for(auto sp : spl.l) {
+        for(const auto &sp : spl.l) {
             fprintf(f, "          %f %f %f,\n",
                     sp.p.x / SS.exportScale,
                     sp.p.y / SS.exportScale,

src/file.cpp

@@ -261,7 +261,7 @@ void SolveSpaceUI::SaveUsingTable(const Platform::Path &filename, int type) {
                     [](std::pair<EntityKey, EntityId> &a, std::pair<EntityKey, EntityId> &b) {
                         return a.second.v < b.second.v;
                     });
-                for(auto it : sorted) {
+                for(const auto &it : sorted) {
                     fprintf(fh, "    %d %08x %d\n",
                             it.second.v, it.first.input.v, it.first.copyNumber);
                 }

src/graphicswin.cpp

@@ -592,7 +592,7 @@ void GraphicsWindow::LoopOverPoints(const std::vector<Entity *> &entities,
     for(Constraint *c : constraints) {
         std::vector<Vector> refs;
         c->GetReferencePoints(camera, &refs);
-        for(Vector p : refs) {
+        for(const Vector &p : refs) {
             HandlePointForZoomToFit(p, pmax, pmin, wmin, usePerspective, camera);
         }
     }

src/render/render2d.cpp

@@ -354,7 +354,7 @@ void SurfaceRenderer::OutputInPaintOrder() {
             mp.Clear();
         }
 
-        for(auto eit : edges) {
+        for(const auto &eit : edges) {
             hStroke hcs = eit.first;
             const SEdgeList &el = eit.second;
 

src/srf/boolean.cpp

@@ -39,7 +39,7 @@ static void FindVertsOnCurve(List<SInter> *l, const SCurve *curve, SShell *sh) {
     Vector amax, amin;
     curve->GetAxisAlignedBounding(&amax, &amin);
 
-    for(auto sc : sh->curve) {
+    for(const auto &sc : sh->curve) {
         if(!sc.isExact) continue;
 
         Vector cmax, cmin;
@@ -157,7 +157,7 @@ SCurve SCurve::MakeCopySplitAgainst(SShell *agnstA, SShell *agnstB,
         // Now add any vertex that is on this segment
         const Vector lineStart     = prev.p;
         const Vector lineDirection = (p->p).Minus(prev.p);
-        for(auto vtx : vertpts) {
+        for(const auto &vtx : vertpts) {
             double t = (vtx.p.Minus(lineStart)).DivProjected(lineDirection);
             if((0.0 < t) && (t < 1.0)) {
                 il.Add(&vtx);