From ce37b1cf72a11c54623226820e98651cb1833695 Mon Sep 17 00:00:00 2001
From: Jonathan Westhues <jwesthues@cq.cx>
Date: Wed, 7 Oct 2009 23:55:09 -0800
Subject: [PATCH] A better fix to the display mesh issue; instead of drawing
 the previous group, copy the previous group's mesh into ours, and draw ours.
 This makes other stuff that uses that mesh (like the export and analysis
 code) work properly.

[git-p4: depot-paths = "//depot/solvespace/": change = 2050]
---
 draw.cpp      | 11 +++-----
 groupmesh.cpp | 73 +++++++++++++++++++++++++++++++--------------------
 wishlist.txt  |  5 ++--
 3 files changed, 50 insertions(+), 39 deletions(-)

diff --git a/draw.cpp b/draw.cpp
index c811ab5..6992c9b 100644
--- a/draw.cpp
+++ b/draw.cpp
@@ -227,14 +227,9 @@ void GraphicsWindow::HitTestMakeSelection(Point2d mp) {
 
         // Faces, from the triangle mesh; these are lowest priority
         if(s.constraint.v == 0 && s.entity.v == 0 && showShaded && showFaces) {
-            SMesh *m;
-            Group *g  = SK.GetGroup(activeGroup),
-                  *pg = g->RunningMeshGroup();
-            if(pg && g->thisMesh.IsEmpty() && g->thisShell.IsEmpty()) {
-                m = &(pg->displayMesh);
-            } else {
-                m = &(g->displayMesh);
-            }
+            Group *g = SK.GetGroup(activeGroup);
+            SMesh *m = &(g->displayMesh);
+
             DWORD v = m->FirstIntersectionWith(mp);
             if(v) {
                 s.entity.v = v;
diff --git a/groupmesh.cpp b/groupmesh.cpp
index 0ffdbad..4d000ae 100644
--- a/groupmesh.cpp
+++ b/groupmesh.cpp
@@ -312,23 +312,50 @@ void Group::GenerateDisplayItems(void) {
     // to find the emphasized edges for a mesh), so we will run it only
     // if its inputs have changed.
     if(displayDirty) {
-        displayMesh.Clear();
-        runningShell.TriangulateInto(&displayMesh);
-        STriangle *tr;
-        for(tr = runningMesh.l.First(); tr; tr = runningMesh.l.NextAfter(tr)) {
-            STriangle trn = *tr;
-            Vector n = trn.Normal();
-            trn.an = n;
-            trn.bn = n;
-            trn.cn = n;
-            displayMesh.AddTriangle(&trn);
-        }
+        Group *pg = RunningMeshGroup();
+        if(pg && thisMesh.IsEmpty() && thisShell.IsEmpty()) {
+            // We don't contribute any new solid model in this group, so our
+            // display items are identical to the previous group's; which means
+            // that we can just display those, and stop ourselves from
+            // recalculating for those every time we get a change in this group.
+            //
+            // Note that this can end up recursing multiple times (if multiple
+            // groups that contribute no solid model exist in sequence), but
+            // that's okay.
+            pg->GenerateDisplayItems();
 
-        displayEdges.Clear();
+            displayMesh.Clear();
+            displayMesh.MakeFromCopyOf(&(pg->displayMesh));
 
-        if(SS.GW.showEdges) {
-            runningShell.MakeEdgesInto(&displayEdges);
-            runningMesh.MakeEmphasizedEdgesInto(&displayEdges);
+            displayEdges.Clear();
+            if(SS.GW.showEdges) {
+                SEdge *se;
+                SEdgeList *src = &(pg->displayEdges);
+                for(se = src->l.First(); se; se = src->l.NextAfter(se)) {
+                    displayEdges.l.Add(se);
+                }
+            }
+        } else {
+            // We do contribute new solid model, so we have to triangulate the
+            // shell, and edge-find the mesh.
+            displayMesh.Clear();
+            runningShell.TriangulateInto(&displayMesh);
+            STriangle *t;
+            for(t = runningMesh.l.First(); t; t = runningMesh.l.NextAfter(t)) {
+                STriangle trn = *t;
+                Vector n = trn.Normal();
+                trn.an = n;
+                trn.bn = n;
+                trn.cn = n;
+                displayMesh.AddTriangle(&trn);
+            }
+
+            displayEdges.Clear();
+
+            if(SS.GW.showEdges) {
+                runningShell.MakeEdgesInto(&displayEdges);
+                runningMesh.MakeEmphasizedEdgesInto(&displayEdges);
+            }
         }
 
         displayDirty = false;
@@ -397,20 +424,8 @@ void Group::Draw(void) {
     // can control this stuff independently, with show/hide solids, edges,
     // mesh, etc.
 
-    // If this changes then make sure to also do the face selection off the
-    // correct mesh, in draw.cpp.
-    Group *pg = RunningMeshGroup();
-    if(pg && thisMesh.IsEmpty() && thisShell.IsEmpty()) {
-        // We don't contribute any new solid model in this group, so our
-        // display items are identical to the previous group's; which means
-        // that we can just display those, and stop ourselves from
-        // recalculating for those every time we get a change in this group.
-        pg->GenerateDisplayItems();
-        pg->DrawDisplayItems(type);
-    } else {
-        GenerateDisplayItems();
-        DrawDisplayItems(type);
-    }
+    GenerateDisplayItems();
+    DrawDisplayItems(type);
 
     if(!SS.checkClosedContour) return;
 
diff --git a/wishlist.txt b/wishlist.txt
index 733f588..95630ab 100644
--- a/wishlist.txt
+++ b/wishlist.txt
@@ -1,13 +1,14 @@
 
 multi-drag
+copy and paste
+wireframe export
+import mirrored
 
 -----
 some kind of import
 filled contours for export
-wireframe export
 faster triangulation
 interpolating splines
-copy and paste
 loop detection
 IGES export
 incremental regen of entities