-/* -*- mode: c; c-basic-offset: 2 -*-
- * To compile:
- *
- * gcc -Wall -g $(pkg-config --cflags --libs gtk+-2.0 cairo) \
- * akamaru.c -o akamaru
- *
+/* -*- mode: c; c-basic-offset: 8 -*-
* See:
*
* http://en.wikipedia.org/wiki/Verlet_integration
*
* TODO:
*
- * - Add code to add boxes
- * - Add circle object
+ * - Add code to add boxes
+ * - Add circle object
+ * - Try out this idea: make constraint solver take mean of all
+ * corrections at the end instead of meaning as it goes.
*/
-#include <gtk/gtk.h>
-#include <cairo.h>
-#include <cairo-xlib.h>
-#include <gdk/gdkx.h>
+#include <glib.h>
#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
#include <math.h>
-const double ground_friction = 0.1, ground_level = 400;
-const double box_left = 200, box_top = 200, box_bottom = 210;
+#include "akamaru.h"
+
const double elasticity = 0.7;
-const double edge_fuzz = 1;
-
-typedef struct _xy_pair Point;
-typedef struct _xy_pair Vector;
-struct _xy_pair {
- double x, y;
-};
-
-typedef struct _Object Object;
-typedef struct _Stick Stick;
-typedef struct _Offset Offset;
-typedef struct _Model Model;
-
-struct _Object {
- Vector force;
-
- Point position;
- Point previous_position;
- Vector velocity;
-
- double mass;
- double theta;
-};
-
-struct _Stick {
- Object *a, *b;
- int length;
-};
-
-struct _Offset {
- Object *a, *b;
- int dx, dy;
-};
-
-struct _Model {
- int num_objects;
- Object *objects;
- int num_sticks;
- Stick *sticks;
- int num_offsets;
- Offset *offsets;
- double k;
- double friction;
-
- Object *anchor_object;
- Vector anchor_position;
-
- double theta;
-};
+const double friction = 8;
+const double gravity = 50;
-static void
-model_init_snake (Model *model)
+void
+object_init (Object *object, double x, double y, double mass)
{
- const int num_objects = 20;
- const int num_sticks = num_objects * 2 - 3;
- 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;
- model->num_offsets = 0;
-
- for (i = 0; i < num_objects; i++) {
- 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;
+ object->position.x = x;
+ object->position.y = y;
+ object->previous_position.x = x;
+ object->previous_position.y = y;
+ object->mass = mass;
}
-static void
-model_init_rope (Model *model)
+void
+spring_init (Spring *spring, Object *a, Object *b, double length)
{
- 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;
- }
- }
-
- model->anchor_object = NULL;
+ spring->a = a;
+ spring->b = b;
+ spring->length = length;
}
-static void
-model_init_curtain (Model *model)
+void
+stick_init (Stick *stick, Object *a, Object *b, double length)
{
- const int num_ropes = 5;
- const int num_rope_objects = 15;
- const int num_objects = num_ropes * num_rope_objects;
- const int num_sticks = num_ropes * (num_rope_objects - 1);
- const int stick_length = 10;
- const int rope_offset = 30;
- double x, y;
- int i, j, index, stick_index;
-
- model->objects = g_new (Object, num_objects);
- 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;
-
- for (i = 0; i < num_ropes; i++) {
- for (j = 0; j < num_rope_objects; j++) {
- x = 200 + i * rope_offset;
- y = 40 + j * stick_length;
- index = i * num_rope_objects + j;
- model->objects[index].position.x = x;
- model->objects[index].position.y = y;
- model->objects[index].previous_position.x = x;
- model->objects[index].previous_position.y = y;
-
- if (j + 1 < num_rope_objects) {
- stick_index = i * (num_rope_objects - 1) + j;
- model->sticks[stick_index].a = &model->objects[index];
- model->sticks[stick_index].b = &model->objects[index + 1];
- model->sticks[stick_index].length = stick_length;
- }
- }
-
- 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->anchor_object = NULL;
+ stick->a = a;
+ stick->b = b;
+ stick->length = length;
}
-static void
-model_fini (Model *model)
+void
+string_init (String *string, Object *a, Object *b, double length)
{
- g_free (model->objects);
- model->objects = NULL;
- model->num_objects = 0;
- g_free (model->sticks);
- model->sticks = NULL;
- model->sticks = 0;
- g_free (model->offsets);
- model->offsets = NULL;
- model->num_offsets = 0;
+ string->a = a;
+ string->b = b;
+ string->length = length;
}
-static void
-model_accumulate_forces (Model *model)
+void
+offset_spring_init (OffsetSpring *spring, Object *a, Object *b,
+ double dx, double dy)
{
- int i;
-
- for (i = 0; i < model->num_objects; i++) {
- model->objects[i].force.x = 0;
- model->objects[i].force.y = 3;
- }
+ spring->a = a;
+ spring->b = b;
+ spring->dx = dx;
+ spring->dy = dy;
}
-static void
-model_integrate (Model *model, double step)
+void
+spacer_init (Spacer *spacer, Object *a, Object *b, double length)
{
- double x, y;
- Object *o;
- int i;
-
- for (i = 0; i < model->num_objects; i++) {
- o = &model->objects[i];
- x = o->position.x;
- y = o->position.y;
-
- o->position.x =
- x + (x - o->previous_position.x) + o->force.x * step * step;
- o->position.y =
- y + (y - o->previous_position.y) + o->force.y * step * step;
-
- o->previous_position.x = x;
- o->previous_position.y = y;
- }
+ spacer->a = a;
+ spacer->b = b;
+ spacer->length = length;
}
-static void
-model_constrain (Model *model, double step)
+void
+anchor_init (Anchor *anchor, Object *object, double x, double y)
{
- double dx, dy, x, y, distance, fraction;
- int i;
-
- /* Anchor object constraint. */
- if (model->anchor_object != NULL) {
- model->anchor_object->position.x = model->anchor_position.x;
- model->anchor_object->position.y = model->anchor_position.y;
- model->anchor_object->previous_position.x = model->anchor_position.x;
- model->anchor_object->previous_position.y = model->anchor_position.y;
- }
-
- /* FIXME: this should be "is point inside box" test instead. Figure
- * out from previous_position which edge the point has passed
- * through and reflect in that. */
- for (i = 0; i < model->num_objects; i++) {
- x = model->objects[i].position.x;
- y = model->objects[i].position.y;
- if (box_top - edge_fuzz <= y &&
- model->objects[i].previous_position.y <= box_top + edge_fuzz &&
- x < box_left) {
- model->objects[i].position.y = box_top - (y - box_top) * elasticity;
- model->objects[i].previous_position.y =
- box_top - (model->objects[i].previous_position.y - box_top) * elasticity;
- }
- }
-
- /* Ground collision detection constraints. This puts a ground level
- * in to make sure the points don't fall off the screen. */
- for (i = 0; i < model->num_objects; i++) {
- x = model->objects[i].position.x;
- y = model->objects[i].position.y;
-
- if (model->objects[i].position.y > ground_level) {
- model->objects[i].position.y =
- ground_level - (model->objects[i].position.y - ground_level) * elasticity;
- model->objects[i].previous_position.y =
- ground_level - (model->objects[i].previous_position.y - ground_level) * elasticity;
-
- /* Friction on impact */
- model->objects[i].position.x =
- model->objects[i].position.x * (1 - ground_friction) +
- model->objects[i].previous_position.x * ground_friction;
- }
- }
-
- /* 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;
- }
-
-#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);
- 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
+ anchor->object = object;
+ anchor->x = x;
+ anchor->y = y;
}
-static void
-model_step (Model *model, double delta_t)
+void
+polygon_init (Polygon *p, int enclosing, int num_points, ...)
{
- int i;
-
- model_accumulate_forces (model);
- model_integrate (model, delta_t);
-
- for (i = 0; i < 5; i++)
- model_constrain (model, delta_t);
-
- model->theta += delta_t;
+ double dx, dy, length;
+ int i, j;
+ va_list ap;
+
+ /* Polygons are defined counter-clock-wise in a coordinate system
+ * with the y-axis pointing down. */
+
+ va_start (ap, num_points);
+ p->num_points = num_points;
+ p->points = g_new (Point, num_points);
+ p->enclosing = enclosing;
+
+ for (i = 0; i < num_points; i++) {
+ p->points[i].x = va_arg (ap, double);
+ p->points[i].y = va_arg (ap, double);
+ }
+ va_end (ap);
+
+ p->normals = g_new (Vector, p->num_points);
+ /* Compute outward pointing normals. p->normals[i] is the normal
+ * for the edged between p->points[i] and p->points[i + 1]. */
+ for (i = 0; i < p->num_points; i++) {
+ j = (i + 1) % p->num_points;
+ dx = p->points[j].x - p->points[i].x;
+ dy = p->points[j].y - p->points[i].y;
+ length = sqrt (dx * dx + dy * dy);
+ p->normals[i].x = -dy / length;
+ p->normals[i].y = dx / length;
+ }
}
-static double
-object_distance (Object *object, double x, double y)
+void
+polygon_init_diamond (Polygon *polygon, double x, double y)
{
- double dx, dy;
-
- dx = object->position.x - x;
- dy = object->position.y - y;
-
- return sqrt (dx*dx + dy*dy);
+ return polygon_init (polygon, FALSE, 5,
+ x, y,
+ x + 10, y + 40,
+ x + 90, y + 40,
+ x + 100, y,
+ x + 50, y - 20);
}
-static Object *
-model_find_nearest (Model *model, double x, double y)
+void
+polygon_init_rectangle (Polygon *polygon, double x0, double y0,
+ double x1, double y1)
{
- Object *object;
- double distance, min_distance;
- int i;
-
- for (i = 0; i < model->num_objects; i++) {
- distance = object_distance (&model->objects[i], x, y);
- if (i == 0 || distance < min_distance) {
- min_distance = distance;
- object = &model->objects[i];
- }
- }
-
- return object;
+ return polygon_init (polygon, FALSE, 4, x0, y0, x0, y1, x1, y1, x1, y0);
}
-typedef struct _Color Color;
-struct _Color {
- double red, green, blue;
-};
-
-static void
-draw_sticks (cairo_t *cr,
- Model *model,
- Color *color)
+void
+polygon_init_enclosing_rectangle (Polygon *polygon, double x0, double y0,
+ double x1, double y1)
{
- int i;
-
- cairo_set_source_rgba (cr, color->red, color->green, color->blue, 1);
- 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_sticks; i++) {
- cairo_move_to (cr,
- model->sticks[i].a->position.x,
- model->sticks[i].a->position.y);
- cairo_line_to (cr,
- model->sticks[i].b->position.x,
- model->sticks[i].b->position.y);
- }
-
- cairo_stroke (cr);
+ return polygon_init (polygon, TRUE, 4, x0, y0, x0, y1, x1, y1, x1, y0);
}
-static void
-draw_offsets (cairo_t *cr,
- Model *model,
- Color *color)
+void
+model_fini (Model *model)
{
- int i;
-
- cairo_set_source_rgba (cr, color->red, color->green, color->blue, 0.5);
- cairo_new_path (cr);
- cairo_set_line_width (cr, 4);
- cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
- 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);
- }
-
- cairo_stroke (cr);
+ int i;
+
+ g_free (model->objects);
+ g_free (model->sticks);
+ g_free (model->strings);
+ for (i = 0; i < model->num_offsets; i++)
+ g_free (model->offsets[i].objects);
+ g_free (model->springs);
+ g_free (model->offset_springs);
+ g_free (model->spacers);
+ for (i = 0; i < model->num_polygons; i++)
+ g_free (model->polygons[i].points);
+ g_free (model->polygons);
+
+ memset (model, 0, sizeof *model);
}
static void
-draw_constraints (cairo_t *cr,
- Model *model,
- Color *color)
+model_accumulate_forces (Model *model)
{
- cairo_set_source_rgba (cr, color->red, color->green, color->blue, 0.5);
-
- cairo_move_to (cr, 0, ground_level);
- cairo_line_to (cr, 1500, ground_level);
- cairo_line_to (cr, 1500, ground_level + 10);
- cairo_line_to (cr, 0, ground_level + 10);
- cairo_close_path (cr);
-
- cairo_move_to (cr, 0, box_top);
- cairo_line_to (cr, box_left, box_top);
- cairo_line_to (cr, box_left, box_bottom);
- cairo_line_to (cr, 0, box_bottom);
- cairo_close_path (cr);
-
- cairo_fill (cr);
+ int i;
+ double x, y, dx, dy, distance, displacement;
+ Point middle;
+ Vector u, v;
+
+ for (i = 0; i < model->num_objects; i++) {
+ /* Gravity */
+ model->objects[i].force.x = 0;
+ model->objects[i].force.y = gravity * model->objects[i].mass;
+
+ /* Friction */
+ v.x = model->objects[i].position.x - model->objects[i].previous_position.x;
+ v.y = model->objects[i].position.y - model->objects[i].previous_position.y;
+ model->objects[i].force.x -= v.x * friction;
+ model->objects[i].force.y -= v.y * friction;
+ }
+
+ 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;
+ }
+
+ for (i = 0; i < model->num_offset_springs; i++) {
+ middle.x =
+ (model->offset_springs[i].a->position.x +
+ model->offset_springs[i].b->position.x) / 2;
+ middle.y =
+ (model->offset_springs[i].a->position.y +
+ model->offset_springs[i].b->position.y) / 2;
+
+ x = middle.x - model->offset_springs[i].dx / 2;
+ y = middle.y - model->offset_springs[i].dy / 2;
+
+ dx = x - model->offset_springs[i].a->position.x;
+ dy = y - model->offset_springs[i].a->position.y;
+
+ model->offset_springs[i].a->force.x += dx * model->k;
+ model->offset_springs[i].a->force.y += dy * model->k;
+ model->offset_springs[i].b->force.x -= dx * model->k;
+ model->offset_springs[i].b->force.y -= dy * model->k;
+ }
+
+ for (i = 0; i < model->num_objects; i++) {
+ double f =
+ model->objects[i].force.x * model->objects[i].force.x +
+ model->objects[i].force.y * model->objects[i].force.y;
+
+ if (f > 100000000)
+ abort();
+ }
}
static void
-draw_objects (cairo_t *cr, Model *model, Color *color)
+model_integrate (Model *model, double step)
{
- int i;
-
- for (i = 0; i < model->num_objects; i++) {
- }
+ double x, y;
+ Object *o;
+ int i;
+
+ for (i = 0; i < model->num_objects; i++) {
+ o = &model->objects[i];
+ x = o->position.x;
+ y = o->position.y;
+
+ o->position.x =
+ x + (x - o->previous_position.x) + o->force.x * step * step;
+ o->position.y =
+ y + (y - o->previous_position.y) + o->force.y * step * step;
+
+ o->previous_position.x = x;
+ o->previous_position.y = y;
+ }
}
-static Color blue = { 0, 0, 1 };
-static Color red = { 1, 0, 0 };
-static Color black = { 0, 0, 0 };
-static Color white = { 1, 1, 1 };
+/* 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 gboolean
-expose_event (GtkWidget *widget,
- GdkEventExpose *event,
- gpointer data)
+static inline double
+estimate_distance (double dx, double dy, double r)
{
- Model *model = 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_offsets (cr, model, &blue);
- draw_objects (cr, model, &white);
-
- cairo_destroy (cr);
-
- return TRUE;
+#ifdef APPROXIMATE_SQUARE_ROOTS
+ return (r + (dx * dx + dy * dy) / r) / 2;
+#else
+ return sqrt (dx * dx + dy * dy);
+#endif
}
-static gboolean
-button_press_event (GtkWidget *widget,
- GdkEventButton *event,
- gpointer data)
+static int
+polygon_contains_point (Polygon *polygon, Point *point)
{
- Model *model = data;
+ int i;
+ double dx, dy;
- if (event->button != 1)
- return TRUE;
+ for (i = 0; i < polygon->num_points; i++) {
+ dx = point->x - polygon->points[i].x;
+ dy = point->y - polygon->points[i].y;
- model->anchor_position.x = event->x;
- model->anchor_position.y = event->y;
- model->anchor_object = model_find_nearest (model, event->x, event->y);
+ if (polygon->normals[i].x * dx + polygon->normals[i].y * dy >= 0)
+ return polygon->enclosing;
+ }
- return TRUE;
+ return !polygon->enclosing;
}
-static gboolean
-button_release_event (GtkWidget *widget,
- GdkEventButton *event,
- gpointer data)
+static void
+polygon_reflect_object (Polygon *polygon, Object *object)
{
- Model *model = data;
-
- if ((event->state & GDK_BUTTON1_MASK) == 0)
- return TRUE;
-
- model->anchor_object = NULL;
-
- return TRUE;
+ int i, edge;
+ double d, distance;
+ Vector *n;
+
+ distance = -1000;
+ for (i = 0; i < polygon->num_points; i++) {
+ d = polygon->normals[i].x * (object->position.x - polygon->points[i].x) +
+ polygon->normals[i].y * (object->position.y - polygon->points[i].y);
+
+ if (d > distance) {
+ distance = d;
+ edge = i;
+ n = &polygon->normals[i];
+ }
+ }
+
+ object->position.x -= (1 + elasticity) * distance * n->x;
+ object->position.y -= (1 + elasticity) * distance * n->y;
+
+ distance =
+ n->x * (object->previous_position.x - polygon->points[edge].x) +
+ n->y * (object->previous_position.y - polygon->points[edge].y);
+
+ object->previous_position.x -= (1 + elasticity) * distance * n->x;
+ object->previous_position.y -= (1 + elasticity) * distance * n->y;
}
-static gboolean
-motion_notify_event (GtkWidget *widget,
- GdkEventMotion *event,
- gpointer data)
+static void
+model_constrain_polygon (Model *model, Polygon *polygon)
{
- Model *model = data;
- int x, y;
- GdkModifierType state;
-
- gdk_window_get_pointer (event->window, &x, &y, &state);
+ int i;
- model->anchor_position.x = x + 0.5;
- model->anchor_position.y = y + 0.5;
-
- return TRUE;
+ for (i = 0; i < model->num_objects; i++) {
+ if (polygon_contains_point (polygon, &model->objects[i].position))
+ polygon_reflect_object (polygon, &model->objects[i]);
+ }
}
-typedef void (*ModelInitFunc) (Model *model);
-
static void
-model_changed (GtkComboBox *combo, gpointer user_data)
+model_constrain_anchor (Model *model, Anchor *anchor)
{
- Model *model = user_data;
- GtkTreeIter iter;
- GtkTreeModel *tree_model;
- ModelInitFunc init;
- char *name;
-
- tree_model = gtk_combo_box_get_model (combo);
- if (!gtk_combo_box_get_active_iter (combo, &iter))
- return;
-
- gtk_tree_model_get (tree_model, &iter, 0, &name, 1, &init, -1);
-
- model_fini (model);
- (*init) (model);
+ anchor->object->position.x = anchor->x;
+ anchor->object->position.y = anchor->y;
+ anchor->object->previous_position.x = anchor->x;
+ anchor->object->previous_position.y = anchor->y;
}
-static GtkTreeModel *
-create_model_store (void)
+static void
+model_constrain_offset (Model *model, Offset *offset)
{
- static struct {
- const char *name;
- ModelInitFunc init;
- } models[] = {
- { "Rope", model_init_rope },
- { "Snake", model_init_snake },
- { "Curtain", model_init_curtain }
- };
-
- GtkTreeIter iter;
- GtkTreeStore *store;
- gint i;
-
- store = gtk_tree_store_new (2, G_TYPE_STRING, G_TYPE_POINTER);
-
- for (i = 0; i < G_N_ELEMENTS(models); i++) {
- gtk_tree_store_append (store, &iter, NULL);
- gtk_tree_store_set (store, &iter,
- 0, models[i].name, 1, models[i].init, -1);
- }
-
- return GTK_TREE_MODEL (store);
-
+ 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 GtkWidget *
-create_model_combo (Model *model)
+static void
+model_constrain (Model *model)
{
- GtkWidget *hbox;
- GtkWidget *combo, *label;
- GtkTreeModel *store;
- GtkCellRenderer *renderer;
-
- hbox = gtk_hbox_new (FALSE, 8);
-
- label = gtk_label_new_with_mnemonic ("_Model:");
- gtk_box_pack_start (GTK_BOX (hbox), label, FALSE, FALSE, 0);
-
- store = create_model_store ();
- combo = gtk_combo_box_new_with_model (store);
- gtk_combo_box_set_active (GTK_COMBO_BOX (combo), 0);
- g_object_unref (store);
-
- renderer = gtk_cell_renderer_text_new ();
- gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (combo), renderer, TRUE);
- gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (combo), renderer,
- "text", 0,
- NULL);
-
- 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);
-
- return hbox;
+ double dx, dy, x, y, distance, fraction;
+ int i;
+
+ if (model->mouse_anchor.object != NULL)
+ model_constrain_anchor (model, &model->mouse_anchor);
+ for (i = 0; i < model->num_anchors; i++)
+ model_constrain_anchor (model, &model->anchors[i]);
+
+ /* String constraints. */
+ for (i = 0; i < model->num_strings; i++) {
+ x = model->strings[i].a->position.x;
+ y = model->strings[i].a->position.y;
+ dx = model->strings[i].b->position.x - x;
+ dy = model->strings[i].b->position.y - y;
+ 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].a->position.x = x + dx * fraction;
+ model->strings[i].a->position.y = y + dy * fraction;
+ model->strings[i].b->position.x = x + dx * (1 - fraction);
+ model->strings[i].b->position.y = y + dy * (1 - fraction);
+ }
+
+ /* Spacer constraints. */
+ for (i = 0; i < model->num_spacers; i++) {
+ x = model->spacers[i].a->position.x;
+ y = model->spacers[i].a->position.y;
+ dx = model->spacers[i].b->position.x - x;
+ dy = model->spacers[i].b->position.y - y;
+ distance = estimate_distance (dx, dy, model->spacers[i].length);
+ if (distance > model->spacers[i].length)
+ continue;
+ fraction = (distance - model->spacers[i].length) / distance / 2;
+ model->spacers[i].a->position.x = x + dx * fraction;
+ model->spacers[i].a->position.y = y + dy * fraction;
+ model->spacers[i].b->position.x = x + dx * (1 - fraction);
+ model->spacers[i].b->position.y = y + dy * (1 - fraction);
+ }
+
+ /* 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 = 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);
+ }
+
+ /* 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]);
}
-static GtkWidget *
-create_window (Model *model)
+void
+model_step (Model *model, double delta_t)
{
- GtkWidget *window;
- GtkWidget *frame;
- GtkWidget *vbox;
- GtkWidget *da;
- GtkWidget *model_combo;
-
- window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
- gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");
-
- g_signal_connect (window, "destroy",
- G_CALLBACK (gtk_main_quit), &window);
-
- gtk_container_set_border_width (GTK_CONTAINER (window), 8);
-
- vbox = gtk_vbox_new (FALSE, 8);
- gtk_container_set_border_width (GTK_CONTAINER (vbox), 8);
- gtk_container_add (GTK_CONTAINER (window), vbox);
-
- /*
- * Create the drawing area
- */
-
- frame = gtk_frame_new (NULL);
- gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);
- gtk_box_pack_start (GTK_BOX (vbox), frame, TRUE, TRUE, 0);
-
- da = gtk_drawing_area_new ();
- /* set a minimum size */
- gtk_widget_set_size_request (da, 600, 500);
-
- gtk_container_add (GTK_CONTAINER (frame), da);
-
- /* Signals used to handle backing pixmap */
-
- g_signal_connect (da, "expose_event",
- G_CALLBACK (expose_event), model);
-
- /* Event signals */
-
- g_signal_connect (da, "motion_notify_event",
- G_CALLBACK (motion_notify_event), model);
- g_signal_connect (da, "button_press_event",
- G_CALLBACK (button_press_event), model);
- g_signal_connect (da, "button_release_event",
- G_CALLBACK (button_release_event), model);
-
- /* Ask to receive events the drawing area doesn't normally
- * subscribe to
- */
- gtk_widget_set_events (da, gtk_widget_get_events (da)
- | GDK_LEAVE_NOTIFY_MASK
- | GDK_BUTTON_PRESS_MASK
- | GDK_BUTTON_RELEASE_MASK
- | GDK_POINTER_MOTION_MASK
- | GDK_POINTER_MOTION_HINT_MASK);
-
- model_combo = create_model_combo (model);
- gtk_box_pack_start (GTK_BOX (vbox), model_combo, FALSE, FALSE, 0);
-
- return da;
-}
+ int i;
-typedef struct _Closure Closure;
-struct _Closure {
- GtkWidget *drawing_area;
- Model *model;
- int i;
-};
+ model_accumulate_forces (model);
+ model_integrate (model, delta_t);
+ for (i = 0; i < 20; i++)
+ model_constrain (model);
-static gint
-timeout_callback (gpointer data)
-{
- Closure *closure = data;
- int i;
+ model->theta += delta_t;
+}
- for (i = 0; i < 3; i++)
- model_step (closure->model, 0.5);
+static double
+object_distance (Object *object, double x, double y)
+{
+ double dx, dy;
- closure->i++;
- if (closure->i == 1) {
- gtk_widget_queue_draw (closure->drawing_area);
- closure->i = 0;
- }
+ dx = object->position.x - x;
+ dy = object->position.y - y;
- return TRUE;
+ return sqrt (dx*dx + dy*dy);
}
-int
-main (int argc, char *argv[])
+Object *
+model_find_nearest (Model *model, double x, double y)
{
- Closure closure;
- Model model;
-
- gtk_init (&argc, &argv);
- model_init_rope (&model);
- closure.drawing_area = create_window (&model);
- closure.i = 0;
- gtk_widget_show_all (gtk_widget_get_toplevel (closure.drawing_area));
- closure.model = &model;
- g_timeout_add (100, timeout_callback, &closure);
- gtk_main ();
-
- return 0;
+ Object *object;
+ double distance, min_distance;
+ int i;
+
+ for (i = 0; i < model->num_objects; i++) {
+ distance = object_distance (&model->objects[i], x, y);
+ if (i == 0 || distance < min_distance) {
+ min_distance = distance;
+ object = &model->objects[i];
+ }
+ }
+
+ return object;
}
projects / akamaru / blobdiff