#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;
};
struct _Offset {
- Object *a, *b;
+ int num_objects;
+ Object **objects;
int dx, dy;
};
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;
}
}
- 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;
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;
}
}
- 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_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)
{
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;
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]);
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;
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);
cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
for (i = 0; i < model->num_offsets; i++) {
- cairo_move_to (cr,
- model->offsets[i].a->position.x,
- model->offsets[i].a->position.y);
- cairo_line_to (cr,
- model->offsets[i].b->position.x,
- model->offsets[i].b->position.y);
+ 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);
}
- cairo_stroke (cr);
}
static void
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);
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_offsets (cr, model, &blue);
+ draw_objects (cr, model, &white);
cairo_destroy (cr);
+}
+
+static gboolean
+expose_event (GtkWidget *widget,
+ GdkEventExpose *event,
+ gpointer data)
+{
+ Closure *closure = data;
+
+ draw_model (widget, closure->model);
return TRUE;
}
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;
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);
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;