From ba473756ffeecf489e94d2f87fd967ff9d689b01 Mon Sep 17 00:00:00 2001
From: josh <josh@bd8a9e45-a331-0410-811e-c64571078777>
Date: Thu, 21 Oct 2010 21:09:27 +0000
Subject: [PATCH] added chaos / iterative algorithm

git-svn-id: svn://anubis/misc/sierpinski-gtk@250 bd8a9e45-a331-0410-811e-c64571078777
---
 SierpinskiDA.cc   | 18 +++++++++++++++---
 sierpinski-gtk.cc |  5 +++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/SierpinskiDA.cc b/SierpinskiDA.cc
index 3ea1599..9313b14 100644
--- a/SierpinskiDA.cc
+++ b/SierpinskiDA.cc
@@ -1,4 +1,5 @@
 
+#include <stdlib.h>                 /* rand() */
 #include <GL/gl.h>
 #include <GL/glu.h>
 
@@ -32,11 +33,22 @@ void SierpinskiDA::regenerate(int npts)
 
     gl_begin();
     glNewList(m_dl, GL_COMPILE);
-    glBegin(GL_LINE_LOOP);
+    glBegin(GL_POINTS);
 
-    for (int i = 0; i < 4; i++)
+    double pt[3];
+    double r = rand() / RAND_MAX;
+    for (int i = 0; i < 3; i++)
     {
-        glVertex3fv(pts[i]);
+        pt[i] = pts[0][i] + r * pts[1][i] - pts[0][i];
+    }
+    for (int i = 0; i < npts; i++)
+    {
+        glVertex3dv(pt);
+        int pt_idx = rand() & 0x3;
+        for (int j = 0; j < 3; j++)
+        {
+            pt[j] = (pt[j] + pts[pt_idx][j]) / 2.0;
+        }
     }
 
     glEnd();
diff --git a/sierpinski-gtk.cc b/sierpinski-gtk.cc
index e1c2042..f536adb 100644
--- a/sierpinski-gtk.cc
+++ b/sierpinski-gtk.cc
@@ -1,4 +1,7 @@
 
+#include <time.h>                   /* time() */
+#include <stdlib.h>                 /* srand() */
+
 #include <iostream>
 
 #include <gtkmm/main.h>
@@ -33,6 +36,8 @@ int main(int argc, char * argv[])
         }
     }
 
+    srand(time(NULL));
+
     Gtk::Window mw;
     mw.set_default_size(400, 420);