#include <cairo-xlib.h>
#include <gdk/gdkx.h>
#include <stdlib.h>
+#include <sys/time.h>
#include <math.h>
const double ground_friction = 0.1, ground_level = 400;
static void
model_init_grid (Model *model)
{
- const int num_ropes = 4;
- const int num_rope_objects = 4;
+ const int num_ropes = 10;
+ const int num_rope_objects = 10;
const int num_objects = num_ropes * num_rope_objects;
const int num_strings = num_ropes * (num_rope_objects - 1) +
(num_ropes - 1) * num_rope_objects;
- const int string_length = 30;
- const int rope_offset = 30;
+ const int string_length = 10;
+ const int rope_offset = 10;
double x, y;
int i, j, index, string_index;
}
}
+/* The square root in the distance computation for the string and
+ * stick constraints can be aproximated using Newton:
+ *
+ * distance =
+ * (model->sticks[i].length +
+ * (dx * dx + dy * dy) / model->sticks[i].length) / 2;
+ *
+ * This works really well, since the constraints aren't typically
+ * violated much. Thus, the distance is really close to the stick
+ * length, which then makes a good initial guess. However, the
+ * approximation seems to be slower that just calling sqrt()...
+ */
+
+static inline double
+estimate_distance (double dx, double dy, double r)
+{
+#ifdef APPROXIMATE_SQUARE_ROOTS
+ return (r + (dx * dx + dy * dy) / r) / 2;
+#else
+ return sqrt (dx * dx + dy * dy);
+#endif
+}
+
static void
model_constrain (Model *model, double step)
{
y = model->strings[i].a->position.y;
dx = model->strings[i].b->position.x - x;
dy = model->strings[i].b->position.y - y;
- distance = sqrt (dx * dx + dy * dy);
+ distance = estimate_distance (dx, dy, model->strings[i].length);
if (distance < model->strings[i].length)
continue;
fraction = (distance - model->strings[i].length) / distance / 2;
model->strings[i].b->position.y = y + dy * (1 - fraction);
}
-#if 1
/* Stick constraints. */
for (i = 0; i < model->num_sticks; i++) {
x = model->sticks[i].a->position.x;
y = model->sticks[i].a->position.y;
dx = model->sticks[i].b->position.x - x;
dy = model->sticks[i].b->position.y - y;
- distance = sqrt (dx * dx + dy * dy);
+ distance = estimate_distance (dx, dy, model->sticks[i].length);
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);
model->sticks[i].b->position.y = y + dy * (1 - fraction);
}
-#else
- /* Stick constraints, without square roots. */
- squared = stick_length * stick_length;
- for (i = 0; i < model->num_objects - 1; i++) {
- j = i + 1;
- x = model->objects[i].position.x;
- y = model->objects[i].position.y;
- dx = model->objects[j].position.x - x;
- dy = model->objects[j].position.y - y;
- fraction = squared / (dx * dx + dy * dy + squared) - 0.5;
- model->objects[i].position.x = x + dx * fraction;
- model->objects[i].position.y = y + dy * fraction;
- model->objects[j].position.x = x + dx * (1 - fraction);
- model->objects[j].position.y = y + dy * (1 - fraction);
- }
-#endif
}
static void
model_accumulate_forces (model);
model_integrate (model, delta_t);
- for (i = 0; i < 35; i++)
+ for (i = 0; i < 100; i++)
model_constrain (model, delta_t);
model->theta += delta_t;
static Color black = { 0, 0, 0 };
static Color white = { 1, 1, 1 };
+typedef struct _Closure Closure;
+struct _Closure {
+ GtkWidget *drawing_area;
+ GtkWidget *fps_label;
+ Model *model;
+ int frame_count;
+ int i;
+ struct timeval start;
+};
+
static gboolean
expose_event (GtkWidget *widget,
GdkEventExpose *event,
gpointer data)
{
- Model *model = data;
+ Closure *closure = data;
cairo_t *cr;
cr = gdk_cairo_create (widget->window);
cairo_set_source_rgb (cr, 1, 1, 1);
cairo_paint (cr);
- draw_constraints (cr, model, &red);
- draw_sticks (cr, model, &black);
- draw_strings (cr, model, &green);
- draw_offsets (cr, model, &blue);
- draw_objects (cr, model, &white);
+ draw_constraints (cr, closure->model, &red);
+ draw_sticks (cr, closure->model, &black);
+ draw_strings (cr, closure->model, &green);
+ draw_offsets (cr, closure->model, &blue);
+ draw_objects (cr, closure->model, &white);
cairo_destroy (cr);
GdkEventButton *event,
gpointer data)
{
- Model *model = data;
+ Closure *closure = data;
if (event->button != 1)
return TRUE;
- model->anchor_position.x = event->x;
- model->anchor_position.y = event->y;
- model->anchor_object = model_find_nearest (model, event->x, event->y);
+ closure->model->anchor_position.x = event->x;
+ closure->model->anchor_position.y = event->y;
+ closure->model->anchor_object = model_find_nearest (closure->model,
+ event->x, event->y);
return TRUE;
}
GdkEventButton *event,
gpointer data)
{
- Model *model = data;
+ Closure *closure = data;
if ((event->state & GDK_BUTTON1_MASK) == 0)
return TRUE;
- model->anchor_object = NULL;
+ closure->model->anchor_object = NULL;
return TRUE;
}
GdkEventMotion *event,
gpointer data)
{
- Model *model = data;
+ Closure *closure = data;
int x, y;
GdkModifierType state;
gdk_window_get_pointer (event->window, &x, &y, &state);
- model->anchor_position.x = x + 0.5;
- model->anchor_position.y = y + 0.5;
+ closure->model->anchor_position.x = x + 0.5;
+ closure->model->anchor_position.y = y + 0.5;
return TRUE;
}
static void
model_changed (GtkComboBox *combo, gpointer user_data)
{
- Model *model = user_data;
+ Closure *closure = user_data;
GtkTreeIter iter;
GtkTreeModel *tree_model;
ModelInitFunc init;
gtk_tree_model_get (tree_model, &iter, 0, &name, 1, &init, -1);
- model_fini (model);
- (*init) (model);
+ model_fini (closure->model);
+ (*init) (closure->model);
}
static GtkTreeModel *
}
static GtkWidget *
-create_model_combo (Model *model)
+create_model_combo (Closure *closure)
{
GtkWidget *hbox;
GtkWidget *combo, *label;
gtk_label_set_mnemonic_widget (GTK_LABEL (label), combo);
gtk_box_pack_start (GTK_BOX (hbox), combo, FALSE, FALSE, 0);
g_signal_connect (combo, "changed",
- G_CALLBACK (model_changed), model);
+ G_CALLBACK (model_changed), closure);
+
+ label = gtk_label_new ("Frames per second: 0");
+ gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
+
+ closure->fps_label = label;
return hbox;
}
-static GtkWidget *
-create_window (Model *model)
+static void
+create_window (Closure *closure)
{
GtkWidget *window;
GtkWidget *frame;
GtkWidget *model_combo;
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
- gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");
+ gtk_window_set_title (GTK_WINDOW (window), "Akamaru");
g_signal_connect (window, "destroy",
G_CALLBACK (gtk_main_quit), &window);
/* Signals used to handle backing pixmap */
g_signal_connect (da, "expose_event",
- G_CALLBACK (expose_event), model);
+ G_CALLBACK (expose_event), closure);
/* Event signals */
g_signal_connect (da, "motion_notify_event",
- G_CALLBACK (motion_notify_event), model);
+ G_CALLBACK (motion_notify_event), closure);
g_signal_connect (da, "button_press_event",
- G_CALLBACK (button_press_event), model);
+ G_CALLBACK (button_press_event), closure);
g_signal_connect (da, "button_release_event",
- G_CALLBACK (button_release_event), model);
+ G_CALLBACK (button_release_event), closure);
/* Ask to receive events the drawing area doesn't normally
* subscribe to
| GDK_POINTER_MOTION_MASK
| GDK_POINTER_MOTION_HINT_MASK);
- model_combo = create_model_combo (model);
+ model_combo = create_model_combo (closure);
gtk_box_pack_start (GTK_BOX (vbox), model_combo, FALSE, FALSE, 0);
- return da;
+ closure->drawing_area = da;
}
-typedef struct _Closure Closure;
-struct _Closure {
- GtkWidget *drawing_area;
- Model *model;
- int i;
-};
-
static gint
timeout_callback (gpointer data)
{
Closure *closure = data;
int i;
- for (i = 0; i < 3; i++)
- model_step (closure->model, 0.5);
+ model_step (closure->model, 1);
closure->i++;
if (closure->i == 1) {
gtk_widget_queue_draw (closure->drawing_area);
closure->i = 0;
+ closure->frame_count++;
+ }
+
+ if (closure->frame_count == 200) {
+ struct timeval end, elapsed;
+ double total;
+ char text[50];
+
+ closure->frame_count = 0;
+ gettimeofday (&end, NULL);
+ if (closure->start.tv_usec > end.tv_usec) {
+ end.tv_usec += 1000000;
+ end.tv_sec--;
+ }
+
+ elapsed.tv_usec = end.tv_usec - closure->start.tv_usec;
+ elapsed.tv_sec = end.tv_sec - closure->start.tv_sec;
+
+ total = elapsed.tv_sec + ((double) elapsed.tv_usec / 1e6);
+ if (total < 0) {
+ total = 0;
+ }
+ closure->start = end;
+ snprintf (text, sizeof text, "Frames per second: %.2f", 200 / total);
+ gtk_label_set_text (GTK_LABEL (closure->fps_label), text);
}
return TRUE;
gtk_init (&argc, &argv);
model_init_rope (&model);
- closure.drawing_area = create_window (&model);
+ create_window (&closure);
closure.i = 0;
gtk_widget_show_all (gtk_widget_get_toplevel (closure.drawing_area));
closure.model = &model;
- g_timeout_add (100, timeout_callback, &closure);
+ closure.frame_count = 0;
+ gettimeofday (&closure.start, NULL);
+ g_timeout_add (40, timeout_callback, &closure);
gtk_main ();
return 0;
projects / akamaru / commitdiff