Changeset 3320 in orxonox.OLD for orxonox/branches/parenting/src/curve.cc

Timestamp:

Jan 3, 2005, 12:23:41 PM (21 years ago)

Author:

bensch

Message:

orxonox/branches/parenting: curve-optimizations. Now calculation should be about 5 times faster. especially for long tracks.

File:

• orxonox/branches/parenting/src/curve.cc (modified) (5 diffs)

orxonox/branches/parenting/src/curve.cc

@@ -24 +24 @@
 #include "curve.h"
 
-
+#include <math.h>
+#include <stdio.h>
 
 /**
@@ -39 +40 @@
   currentNode->next = 0; // not sure if this really points to NULL!!
   currentNode->number = (++nodeCount);
+  this->rebuild();
   return;
 }
@@ -77 +79 @@
 
 /**
+   \brief Rebuilds a Curve
+*/
+void BezierCurve::rebuild(void)
+{
+  PathNode* tmpNode = firstNode;
+
+  int k=0;
+  int binCoef = 1;
+  while(tmpNode)
+    {
+      if (k+1 < nodeCount-k)
+        binCoef *=(nodeCount-k)/(k+1);
+      else
+        binCoef /= (k+1)/(nodeCount-k);
+      ++k;
+      tmpNode->factor = binCoef;
+      tmpNode = tmpNode->next;
+    }
+}
+
+/**
    \brief calculates the Position on the curve
    \param t The position on the Curve (0<=t<=1)
@@ -85 +108 @@
   if (nodeCount <=4)
     {
-      //      if (verbose >= 1)
+      //    if (verbose >= 1)
       //      printf ("Please define at least 4 nodes, until now you have only defined %i.\n", nodeCount);
       return Vector(0,0,0);
     }
   PathNode* tmpNode = firstNode;
-    
   Vector ret = Vector(0.0,0.0,0.0);
-  double factor;
-  int k=0;
-  while(tmpNode!=0)
+  float factor = 1.0*pow(1.0-t,nodeCount);
+  while(tmpNode)
     {
-      k++;
-      factor = ncr (nodeCount, k);
-      
-      for (int j=0; j<nodeCount-k; j++)
-        factor*=(1-t);
-      for (int j=0; j<k; j++)
-        factor*=t;
-      ret.x += factor * tmpNode->position.x;
-      ret.y += factor * tmpNode->position.y;
-      ret.z += factor * tmpNode->position.z;
-      
+      factor *= t/(1.0-t); // same as pow but much faster.
+      ret.x += tmpNode->factor * factor * tmpNode->position.x;
+      ret.y += tmpNode->factor * factor * tmpNode->position.y;
+      ret.z += tmpNode->factor * factor * tmpNode->position.z;
+
       tmpNode = tmpNode->next;
-
     }
   return ret;
@@ -160 +174 @@
   return curvePoint;
 }
-
-/**
-   \brief ncr-calculator, did not find an other method
-   \todo a c++ variante to do this
-*/
-int ncr(int n, int i)
-{
-  int ret = 1;
-  for (int k=1; k<=n; k++)
-    ret*=k;
-  for (int k=1; k<=i; k++)
-    ret/=k;
-  for (int k=1; k<=n-i; k++)
-    ret/=k;
-
-  return ret;
-}
-