From ea0fe26f0d55e530cd1920582da27f29d92914db Mon Sep 17 00:00:00 2001
From: =?utf8?q?Kristian=20H=C3=B8gsberg?= <krh@redhat.com>
Date: Fri, 19 May 2006 22:50:48 -0400
Subject: [PATCH] Different stick lengths, add back rope model.

---
 akamaru.c | 52 +++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 11 deletions(-)

diff --git a/akamaru.c b/akamaru.c
index b6a69b2..1c97fc5 100644
--- a/akamaru.c
+++ b/akamaru.c
@@ -11,8 +11,6 @@
  *
  * TODO:
  *
- *     - Fix box collision test
- *     - Add stick objects instead of hardcoding sticks
  *     - Add code to add boxes
  *     - Add circle object
  */
@@ -21,9 +19,9 @@
 #include <cairo.h>
 #include <cairo-xlib.h>
 #include <gdk/gdkx.h>
+#include <stdlib.h>
 #include <math.h>
 
-const double stick_length = 30;
 const double ground_friction = 0.1, ground_level = 400;
 const double box_left = 200, box_top = 200, box_bottom = 210;
 const double elasticity = 0.7;
@@ -52,6 +50,7 @@ struct _Object {
 
 struct _Stick {
   Object *a, *b;
+  int length;
 };
 
 struct _Model {
@@ -69,10 +68,10 @@ struct _Model {
 };
 
 static void
-model_init (Model *model)
+model_init_snake (Model *model)
 {
   const int num_objects = 20;
-  const int num_sticks = 40 - 3;
+  const int num_sticks = num_objects * 2 - 3;
   int i;
 
   model->objects = g_new (Object, num_objects);
@@ -81,18 +80,49 @@ model_init (Model *model)
   model->num_sticks = num_sticks;
 
   for (i = 0; i < num_objects; i++) {
-    model->objects[i].position.x = 200;
-    model->objects[i].position.y = i * stick_length + 40;
-    model->objects[i].previous_position.x = 200;
-    model->objects[i].previous_position.y = i * stick_length + 40;
+    model->objects[i].position.x = random() % 200 + 20;
+    model->objects[i].position.y = random() % 200 + 20;
+    model->objects[i].previous_position.x = random() % 200 + 20;
+    model->objects[i].previous_position.y = random() % 200 + 20;
 
     if (i + 1 < num_objects) {
       model->sticks[i * 2].a = &model->objects[i];
       model->sticks[i * 2].b = &model->objects[i + 1];
+      model->sticks[i * 2].length = random() % 20 + 20;
     }
     if (i + 2 < num_objects) {
       model->sticks[i * 2 + 1].a = &model->objects[i];
       model->sticks[i * 2 + 1].b = &model->objects[i + 2];
+      model->sticks[i * 2 + 1].length = random() % 20 + 20;
+    }
+  }
+
+  model->anchor_object = NULL;
+}
+
+static void
+model_init_rope (Model *model)
+{
+  const int num_objects = 20;
+  const int num_sticks = num_objects - 1;
+  const int stick_length = 20;
+  int i;
+
+  model->objects = g_new (Object, num_objects);
+  model->num_objects = num_objects;
+  model->sticks = g_new (Stick, num_sticks);
+  model->num_sticks = num_sticks;
+
+  for (i = 0; i < num_objects; i++) {
+    model->objects[i].position.x = 200;
+    model->objects[i].position.y = 40 + i * stick_length;
+    model->objects[i].previous_position.x = 200;
+    model->objects[i].previous_position.y = 40 + i * stick_length;
+
+    if (i + 1 < num_objects) {
+      model->sticks[i].a = &model->objects[i];
+      model->sticks[i].b = &model->objects[i + 1];
+      model->sticks[i].length = stick_length;
     }
   }
 
@@ -188,7 +218,7 @@ model_constrain (Model *model, double step)
     dx = model->sticks[i].b->position.x - x;
     dy = model->sticks[i].b->position.y - y;
     distance = sqrt (dx * dx + dy * dy);
-    fraction = (distance - stick_length) / distance / 2;
+    fraction = (distance - model->sticks[i].length) / distance / 2;
     model->sticks[i].a->position.x = x + dx * fraction;
     model->sticks[i].a->position.y = y + dy * fraction;
     model->sticks[i].b->position.x = x + dx * (1 - fraction);
@@ -561,7 +591,7 @@ main (int argc, char *argv[])
   Model model;
 
   gtk_init (&argc, &argv);
-  model_init (&model);
+  model_init_snake (&model);
   closure.drawing_area = create_window (&model);
   closure.i = 0;
   gtk_widget_show_all (gtk_widget_get_toplevel (closure.drawing_area));
-- 
2.43.0