better animate rate (Marcelo Magallon)
diff --git a/progs/demos/spectex.c b/progs/demos/spectex.c
index 9364245..cfa7f74 100644
--- a/progs/demos/spectex.c
+++ b/progs/demos/spectex.c
@@ -25,8 +25,8 @@
static GLUquadricObj *Quadric;
static GLuint Sphere;
static GLfloat LightPos[4] = {10.0, 10.0, 10.0, 1.0};
-static GLfloat Delta = 1.0;
-static GLint Mode = 0;
+static GLfloat Delta = 20.0;
+static GLint Mode = 4;
/*static GLfloat Blue[4] = {0.0, 0.0, 1.0, 1.0};*/
/*static GLfloat Gray[4] = {0.5, 0.5, 0.5, 1.0};*/
@@ -34,14 +34,18 @@
static GLfloat White[4] = {1.0, 1.0, 1.0, 1.0};
-
-static void Idle( void )
+static void
+Idle(void)
{
- LightPos[0] += Delta;
- if (LightPos[0]>15.0)
- Delta = -1.0;
- else if (LightPos[0]<-15.0)
- Delta = 1.0;
+ static double t0 = -1.;
+ double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;;
+ if (t0 < 0.0)
+ t0 = t;
+ dt = t - t0;
+ t0 = t;
+ LightPos[0] += Delta * dt;
+ if (LightPos[0]>15.0 || LightPos[0]<-15.0)
+ Delta = -Delta;
glutPostRedisplay();
}