From e9dd46f7950b2fce4672758f40e0d6065ba59c25 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sun, 28 Mar 2010 10:55:41 +0100
Subject: [PATCH] Cache meshes for S-bends

---
 src/SBend.cpp | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/SBend.cpp b/src/SBend.cpp
index 218834a..6b1695c 100644
--- a/src/SBend.cpp
+++ b/src/SBend.cpp
@@ -23,6 +23,8 @@
 #include "OpenGLHelper.hpp"
 
 #include <cassert>
+#include <map>
+
 #include <boost/lexical_cast.hpp>
 
 // Spline curves which start and finish in the same direction
@@ -60,16 +62,19 @@ private:
 
    BezierCurve<float> curve;
    IMeshPtr railMesh;
+
+   typedef tuple<int, int> Parameters;
+   typedef map<Parameters, IMeshPtr> MeshCache; 
+   static MeshCache meshCache;
 };
 
+SBend::MeshCache SBend::meshCache;
+
 SBend::SBend(track::Direction dir, int straight, int off)
    : straight(straight), offset(off),
      height(0.0f),
      axis(dir)
 {
-   debug() << "SBend axis=" << axis
-           << " straight=" << straight << " off=" << off;
-
    assert(straight > 0);
 
    const float pinch = static_cast<float>(straight) / 3.0f;
@@ -85,10 +90,15 @@ SBend::SBend(track::Direction dir, int straight, int off)
    Vector<float> p4 = makeVector(straightF, 0.0f, offsetF);
 
    curve = makeBezierCurve(p1, p2, p3, p4);
-   railMesh = makeBezierRailMesh(curve);
 
-   debug() << "f(0) = " << curve(0.0f)
-           << " f(1) = " << curve(1.0f);
+   Parameters parms = make_tuple(straight, offset * reflect);
+   MeshCache::iterator it = meshCache.find(parms);
+   if (it == meshCache.end()) {
+      railMesh = makeBezierRailMesh(curve);
+      meshCache[parms] = railMesh;
+   }
+   else
+      railMesh = (*it).second;
 }
 
 void SBend::setOrigin(int x, int y, float h)
-- 
2.39.2