File trackballs-off_by_one.diff of Package trackballs

Matrix3D is a [3][3] array.

--- src/glHelp.cc
+++ src/glHelp.cc
@@ -762,7 +762,7 @@
 void useMatrix(Matrix3d A,const double B[3],double C[3]) {
   int i,k;
   for(i=0;i<3;i++) {
-    C[i] = A[i][3];
+    C[i] = A[i][2];
     for(k=0;k<3;k++)
       C[i] += A[i][k] * B[k];
   }