X-Git-Url: https://git.cworth.org/git?a=blobdiff_plain;f=akamaru.c;h=17c70e9303760518783a62668b22148b59ade159;hb=4d57fbbcfb5e364daab875ad1ff2a3f7fc2e1bb1;hp=af0a0f19bc66550ad0d94fd8970da51e1fa4c2d0;hpb=3d25488c0dcb5aada993d309c2bf3ffef8407425;p=akamaru

diff --git a/akamaru.c b/akamaru.c
index af0a0f1..17c70e9 100644
--- a/akamaru.c
+++ b/akamaru.c
@@ -26,10 +26,8 @@
 #include <sys/time.h>
 #include <math.h>
 
-const double ground_friction = 0.1, ground_level = 400;
-const double box_left = 200, box_top = 200, box_bottom = 210;
+const double ground_level = 500;
 const double elasticity = 0.7;
-const double edge_fuzz = 1;
 
 typedef struct _xy_pair Point;
 typedef struct _xy_pair Vector;
@@ -40,6 +38,7 @@ struct _xy_pair {
 typedef struct _Object Object;
 typedef struct _Stick Stick;
 typedef struct _String String;
+typedef struct _Spring Spring;
 typedef struct _Polygon Polygon;
 typedef struct _Offset Offset;
 typedef struct _Model Model;
@@ -66,10 +65,16 @@ struct _String {
 };
 
 struct _Offset {
-  Object *a, *b;
+  int num_objects;
+  Object **objects;
   int dx, dy;
 };
 
+struct _Spring {
+  Object *a, *b;
+  int length;
+};
+
 struct _Polygon {
   int num_points;
   Point *points;
@@ -86,6 +91,8 @@ struct _Model {
   String *strings;
   int num_offsets;
   Offset *offsets;
+  int num_springs;
+  Spring *springs;
   int num_polygons;
   Polygon *polygons;
   double k;
@@ -185,6 +192,7 @@ model_init_snake (Model *model)
     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;
+    model->objects[i].mass = 1;
 
     if (i + 1 < num_objects) {
       model->sticks[i * 2].a = &model->objects[i];
@@ -221,6 +229,7 @@ model_init_rope (Model *model)
     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;
+    model->objects[i].mass = 1;
 
     if (i + 1 < num_objects) {
       model->sticks[i].a = &model->objects[i];
@@ -249,10 +258,15 @@ model_init_curtain (Model *model)
   model->num_objects = num_objects;
   model->sticks = g_new (Stick, num_sticks);
   model->num_sticks = num_sticks;
-  model->offsets = g_new (Offset, num_ropes - 1);
-  model->num_offsets = num_ropes - 1;
+  model->offsets = g_new (Offset, 1);
+  model->num_offsets = 1;
   model_init_polygons (model);
 
+  model->offsets[0].num_objects = num_ropes;
+  model->offsets[0].objects = g_new (Object *, num_ropes);
+  model->offsets[0].dx = rope_offset;
+  model->offsets[0].dy = 0;
+
   for (i = 0; i < num_ropes; i++) {
     for (j = 0; j < num_rope_objects; j++) {
       x = 200 + i * rope_offset;
@@ -262,6 +276,7 @@ model_init_curtain (Model *model)
       model->objects[index].position.y = y;
       model->objects[index].previous_position.x = x;
       model->objects[index].previous_position.y = y;
+      model->objects[i].mass = 1;
 
       if (j + 1 < num_rope_objects) {
 	stick_index = i * (num_rope_objects - 1) + j;
@@ -271,12 +286,7 @@ model_init_curtain (Model *model)
       }
     }
 
-    if (i + 1 < num_ropes) {
-      model->offsets[i].a = &model->objects[i * num_rope_objects];
-      model->offsets[i].b = &model->objects[(i + 1) * num_rope_objects];
-      model->offsets[i].dx = rope_offset;
-      model->offsets[i].dy = 0;
-    }
+    model->offsets[0].objects[i] = &model->objects[i * num_rope_objects];
   }
 
   model->anchor_object = NULL;
@@ -300,10 +310,15 @@ model_init_grid (Model *model)
   model->num_objects = num_objects;
   model->strings = g_new (String, num_strings);
   model->num_strings = num_strings;
-  model->offsets = g_new (Offset, num_ropes - 1);
-  model->num_offsets = num_ropes - 1;
+  model->offsets = g_new (Offset, 1);
+  model->num_offsets = 1;
   model_init_polygons (model);
 
+  model->offsets[0].num_objects = num_ropes;
+  model->offsets[0].objects = g_new (Object *, num_ropes);
+  model->offsets[0].dx = rope_offset;
+  model->offsets[0].dy = 0;
+
   for (i = 0; i < num_ropes; i++) {
     for (j = 0; j < num_rope_objects; j++) {
       x = 200 + i * rope_offset;
@@ -313,6 +328,7 @@ model_init_grid (Model *model)
       model->objects[index].position.y = y;
       model->objects[index].previous_position.x = x;
       model->objects[index].previous_position.y = y;
+      model->objects[index].mass = 1;
 
       if (i + 1 < num_ropes) {
 	string_index = i * num_rope_objects + j;
@@ -330,17 +346,45 @@ model_init_grid (Model *model)
       }
     }
 
-    if (i + 1 < num_ropes) {
-      model->offsets[i].a = &model->objects[i * num_rope_objects];
-      model->offsets[i].b = &model->objects[(i + 1) * num_rope_objects];
-      model->offsets[i].dx = rope_offset;
-      model->offsets[i].dy = 0;
-    }
+    model->offsets[0].objects[i] = &model->objects[i * num_rope_objects];
   }
 
   model->anchor_object = NULL;
 }
 
+static void
+model_init_molecule (Model *model)
+{
+  const int num_objects = 8;
+  const int num_springs = num_objects * 2;
+  const int spring_length = 50;
+  int i;
+
+  memset (model, 0, sizeof *model);
+  model->objects = g_new (Object, num_objects);
+  model->num_objects = num_objects;
+  model->springs = g_new (Spring, num_springs);
+  model->num_springs = num_springs;
+  model->k = 0.2;
+
+  for (i = 0; i < num_objects; i++) {
+    model->objects[i].position.x = 200 + i * 20;
+    model->objects[i].position.y = 200;
+    model->objects[i].previous_position.x = 200 + i * 20;
+    model->objects[i].previous_position.y = 200;
+    model->objects[i].mass = 0;
+  }
+
+  for (i = 0; i < num_objects; i++) {
+    model->springs[i * 2].a = &model->objects[i];
+    model->springs[i * 2].b = &model->objects[(i + 1) % num_objects];
+    model->springs[i * 2].length = spring_length;
+    model->springs[i * 2 + 1].a = &model->objects[i];
+    model->springs[i * 2 + 1].b = &model->objects[(i + 2) % num_objects];
+    model->springs[i * 2 + 1].length = spring_length;
+  }
+}
+
 static void
 model_fini (Model *model)
 {
@@ -355,10 +399,27 @@ static void
 model_accumulate_forces (Model *model)
 {
   int i;
+  double x, y, dx, dy, distance, displacement;
+  Vector u;
 
   for (i = 0; i < model->num_objects; i++) {
     model->objects[i].force.x = 0;
-    model->objects[i].force.y = 3;
+    model->objects[i].force.y = 3 * model->objects[i].mass;
+  }
+
+  for (i = 0; i < model->num_springs; i++) {
+    x = model->springs[i].a->position.x;
+    y = model->springs[i].a->position.y;
+    dx = model->springs[i].b->position.x - x;
+    dy = model->springs[i].b->position.y - y;
+    distance = sqrt (dx * dx + dy * dy);
+    u.x = dx / distance;
+    u.y = dy / distance;
+    displacement = distance - model->springs[i].length;
+    model->springs[i].a->force.x += u.x * model->k * displacement;
+    model->springs[i].a->force.y += u.y * model->k * displacement;
+    model->springs[i].b->force.x -= u.x * model->k * displacement;
+    model->springs[i].b->force.y -= u.y * model->k * displacement;
   }
 }
 
@@ -375,9 +436,9 @@ model_integrate (Model *model, double step)
     y = o->position.y;
     
     o->position.x =
-      x + 0.9 * (x - o->previous_position.x) + o->force.x * step * step;
+      x + 0.8 * (x - o->previous_position.x) + o->force.x * step * step;
     o->position.y =
-      y + 0.9 * (y - o->previous_position.y) + o->force.y * step * step;
+      y + 0.8 * (y - o->previous_position.y) + o->force.y * step * step;
 
     o->previous_position.x = x;
     o->previous_position.y = y;
@@ -466,6 +527,28 @@ model_constrain_polygon (Model *model, Polygon *polygon)
   }
 }
 
+static void
+model_constrain_offset (Model *model, Offset *offset)
+{
+  double x, y;
+  int i;
+
+  x = 0;
+  y = 0;
+  for (i = 0; i < offset->num_objects; i++) {
+    x += offset->objects[i]->position.x;
+    y += offset->objects[i]->position.y;
+  }
+
+  x = x / offset->num_objects - offset->dx * (offset->num_objects - 1) / 2;
+  y = y / offset->num_objects - offset->dy * (offset->num_objects - 1) / 2;
+    
+  for (i = 0; i < offset->num_objects; i++) {
+    offset->objects[i]->position.x = x + offset->dx * i;
+    offset->objects[i]->position.y = y + offset->dy * i;
+  }
+}
+
 static void
 model_constrain (Model *model)
 {
@@ -480,16 +563,6 @@ model_constrain (Model *model)
     model->anchor_object->previous_position.y = model->anchor_position.y;
   }
 
-  /* Offset constraints. */
-  for (i = 0; i < model->num_offsets; i++) {
-    x = (model->offsets[i].a->position.x + model->offsets[i].b->position.x) / 2;
-    y = (model->offsets[i].a->position.y + model->offsets[i].b->position.y) / 2;
-    model->offsets[i].a->position.x = x - model->offsets[i].dx / 2;
-    model->offsets[i].a->position.y = y - model->offsets[i].dy / 2;
-    model->offsets[i].b->position.x = x + model->offsets[i].dx / 2;
-    model->offsets[i].b->position.y = y + model->offsets[i].dy / 2;
-  }
-
   /* String constraints. */
   for (i = 0; i < model->num_strings; i++) {
     x = model->strings[i].a->position.x;
@@ -520,6 +593,10 @@ model_constrain (Model *model)
     model->sticks[i].b->position.y = y + dy * (1 - fraction);
   }
 
+  /* Offset constraints. */
+  for (i = 0; i < model->num_offsets; i++)
+    model_constrain_offset (model, &model->offsets[i]);
+
   /* Polygon constraints. */
   for (i = 0; i < model->num_polygons; i++)
     model_constrain_polygon (model, &model->polygons[i]);
@@ -533,7 +610,7 @@ model_step (Model *model, double delta_t)
   model_accumulate_forces (model);
   model_integrate (model, delta_t);
 
-  for (i = 0; i < 100; i++)
+  for (i = 0; i < 500; i++)
     model_constrain (model);
 
   model->theta += delta_t;
@@ -628,7 +705,7 @@ draw_offsets (cairo_t *cr,
 	      Model   *model,
 	      Color   *color)
 {
-  int i;
+  int i, j;
 
   cairo_set_source_rgba (cr, color->red, color->green, color->blue, 0.5);
   cairo_new_path (cr);
@@ -637,12 +714,36 @@ draw_offsets (cairo_t *cr,
   cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
 
   for (i = 0; i < model->num_offsets; i++) {
+    for (j = 0; j < model->offsets[i].num_objects; j++) {
+      cairo_line_to (cr,
+		     model->offsets[i].objects[j]->position.x,
+		     model->offsets[i].objects[j]->position.y);
+    }
+    cairo_stroke (cr);
+  }
+
+}
+
+static void
+draw_springs (cairo_t *cr,
+	      Model   *model,
+	      Color   *color)
+{
+  int i;
+
+  cairo_set_source_rgba (cr, color->red, color->green, color->blue, 0.4);
+  cairo_new_path (cr);
+  cairo_set_line_width (cr, 2);
+  cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+  cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+
+  for (i = 0; i < model->num_springs; i++) {
     cairo_move_to (cr,
-		   model->offsets[i].a->position.x,
-		   model->offsets[i].a->position.y);
+		   model->springs[i].a->position.x,
+		   model->springs[i].a->position.y);
     cairo_line_to (cr,
-		   model->offsets[i].b->position.x,
-		   model->offsets[i].b->position.y);
+		   model->springs[i].b->position.x,
+		   model->springs[i].b->position.y);
   }
 
   cairo_stroke (cr);
@@ -672,7 +773,12 @@ draw_objects (cairo_t *cr, Model *model, Color *color)
 {
   int i;
 
+  cairo_set_source_rgba (cr, color->red, color->green, color->blue, 0.4);
   for (i = 0; i < model->num_objects; i++) {
+    cairo_arc (cr, model->objects[i].position.x,
+	       model->objects[i].position.y,
+	       3, 0, 2*M_PI);
+    cairo_fill (cr);
   }
 }
 
@@ -680,7 +786,6 @@ static Color blue = { 0, 0, 1 };
 static Color green = { 0, 1, 0 };
 static Color red = { 1, 0, 0 };
 static Color black = { 0, 0, 0 };
-static Color white = { 1, 1, 1 };
 
 typedef struct _Closure Closure;
 struct _Closure {
@@ -692,12 +797,9 @@ struct _Closure {
   struct timeval start;
 };
 
-static gboolean
-expose_event (GtkWidget      *widget,
-	      GdkEventExpose *event,
-	      gpointer	      data)
+static void
+draw_model (GtkWidget *widget, Model *model)
 {
-  Closure *closure = data;
   cairo_t *cr;
 
   cr = gdk_cairo_create (widget->window);
@@ -705,13 +807,24 @@ expose_event (GtkWidget      *widget,
   cairo_set_source_rgb (cr, 1, 1, 1);
   cairo_paint (cr);
 
-  draw_polygons (cr, closure->model, &blue);
-  draw_sticks (cr, closure->model, &black);
-  draw_strings (cr, closure->model, &green);
-  draw_offsets (cr, closure->model, &blue);
-  draw_objects (cr, closure->model, &white);
+  draw_polygons (cr, model, &blue);
+  draw_sticks (cr, model, &black);
+  draw_strings (cr, model, &green);
+  draw_springs (cr, model, &black);
+  draw_offsets (cr, model, &blue);
+  draw_objects (cr, model, &red);
 
   cairo_destroy (cr);
+}
+
+static gboolean
+expose_event (GtkWidget      *widget,
+	      GdkEventExpose *event,
+	      gpointer	      data)
+{
+  Closure *closure = data;
+
+  draw_model (widget, closure->model);
 
   return TRUE;
 }
@@ -759,7 +872,7 @@ motion_notify_event (GtkWidget	    *widget,
   GdkModifierType state;
 
   gdk_window_get_pointer (event->window, &x, &y, &state);
-
+  
   closure->model->anchor_position.x = x + 0.5;
   closure->model->anchor_position.y = y + 0.5;
 
@@ -797,7 +910,8 @@ create_model_store (void)
     { "Rope", model_init_rope },
     { "Snake", model_init_snake },
     { "Curtain", model_init_curtain },
-    { "Grid", model_init_grid }
+    { "Grid", model_init_grid },
+    { "Molecule", model_init_molecule }
   };
 
   GtkTreeIter iter;
@@ -884,7 +998,7 @@ create_window (Closure *closure)
       
   da = gtk_drawing_area_new ();
   /* set a minimum size */
-  gtk_widget_set_size_request (da, 600, 500);
+  gtk_widget_set_size_request (da, 200, 200);
 
   gtk_container_add (GTK_CONTAINER (frame), da);
 
@@ -973,7 +1087,7 @@ main (int argc, char *argv[])
   closure.model = &model;
   closure.frame_count = 0;
   gettimeofday (&closure.start, NULL);
-  g_timeout_add (50, timeout_callback, &closure);
+  g_timeout_add (100, timeout_callback, &closure);
   gtk_main ();
 
   return 0;