better animate rate (Marcelo Magallon)
diff --git a/progs/demos/pointblast.c b/progs/demos/pointblast.c
index 14e9cf3..715813f 100644
--- a/progs/demos/pointblast.c
+++ b/progs/demos/pointblast.c
@@ -79,7 +79,6 @@
 
 #define MEAN_VELOCITY 3.0
 #define GRAVITY 2.0
-#define TIME_DELTA 0.025  /* The speed of time. */
 
 /* Modeling units of ground extent in each X and Z direction. */
 #define EDGE 12
@@ -114,6 +113,13 @@
   float distance;
   int i;
 
+  static double t0 = -1.;
+  double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
+  if (t0 < 0.0)
+    t0 = t;
+  dt = t - t0;
+  t0 = t;
+
   motion = 0;
   for (i=0; i<numPoints; i++) {
     distance = pointVelocity[i][0] * theTime;
@@ -139,9 +145,9 @@
       pointTime[i] = 0.0;  /* Reset the particles sense of up time. */
     }
     motion = 1;
-    pointTime[i] += TIME_DELTA;
+    pointTime[i] += dt;
   }
-  theTime += TIME_DELTA;
+  theTime += dt;
   if (!motion && !spin) {
     if (repeat) {
       makePointList();
@@ -264,7 +270,7 @@
   case 0:
     makePointList();
     break;
-#if GL_ARB_point_parameters
+#ifdef GL_ARB_point_parameters
   case 1:
     glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, constant);
     break;
@@ -281,7 +287,7 @@
   case 5:
     blend = 0;
     break;
-#if GL_ARB_point_parameters
+#ifdef GL_ARB_point_parameters
   case 6:
     glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 1.0);
     break;