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-rw-r--r--apps/plugins/puzzles/untangle.c1491
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diff --git a/apps/plugins/puzzles/untangle.c b/apps/plugins/puzzles/untangle.c
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+/*
+ * untangle.c: Game about planar graphs. You are given a graph
+ * represented by points and straight lines, with some lines
+ * crossing; your task is to drag the points into a configuration
+ * where none of the lines cross.
+ *
+ * Cloned from a Flash game called `Planarity', by John Tantalo.
+ * <http://home.cwru.edu/~jnt5/Planarity> at the time of writing
+ * this. The Flash game had a fixed set of levels; my added value,
+ * as usual, is automatic generation of random games to order.
+ */
+
+/*
+ * TODO:
+ *
+ * - This puzzle, perhaps uniquely among the collection, could use
+ * support for non-aspect-ratio-preserving resizes. This would
+ * require some sort of fairly large redesign, unfortunately (since
+ * it would invalidate the basic assumption that puzzles' size
+ * requirements are adequately expressed by a single scalar tile
+ * size), and probably complicate the rest of the puzzles' API as a
+ * result. So I'm not sure I really want to do it.
+ *
+ * - It would be nice if we could somehow auto-detect a real `long
+ * long' type on the host platform and use it in place of my
+ * hand-hacked int64s. It'd be faster and more reliable.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "rbassert.h"
+#include <ctype.h>
+#include <math.h>
+
+#include "puzzles.h"
+#include "tree234.h"
+
+#define CIRCLE_RADIUS 6
+#define DRAG_THRESHOLD (CIRCLE_RADIUS * 2)
+#define PREFERRED_TILESIZE 64
+
+#define FLASH_TIME 0.30F
+#define ANIM_TIME 0.13F
+#define SOLVEANIM_TIME 0.50F
+
+enum {
+ COL_SYSBACKGROUND,
+ COL_BACKGROUND,
+ COL_LINE,
+#ifdef SHOW_CROSSINGS
+ COL_CROSSEDLINE,
+#endif
+ COL_OUTLINE,
+ COL_POINT,
+ COL_DRAGPOINT,
+ COL_NEIGHBOUR,
+ COL_FLASH1,
+ COL_FLASH2,
+ NCOLOURS
+};
+
+typedef struct point {
+ /*
+ * Points are stored using rational coordinates, with the same
+ * denominator for both coordinates.
+ */
+ long x, y, d;
+} point;
+
+typedef struct edge {
+ /*
+ * This structure is implicitly associated with a particular
+ * point set, so all it has to do is to store two point
+ * indices. It is required to store them in the order (lower,
+ * higher), i.e. a < b always.
+ */
+ int a, b;
+} edge;
+
+struct game_params {
+ int n; /* number of points */
+};
+
+struct graph {
+ int refcount; /* for deallocation */
+ tree234 *edges; /* stores `edge' structures */
+};
+
+struct game_state {
+ game_params params;
+ int w, h; /* extent of coordinate system only */
+ point *pts;
+#ifdef SHOW_CROSSINGS
+ int *crosses; /* mark edges which are crossed */
+#endif
+ struct graph *graph;
+ int completed, cheated, just_solved;
+};
+
+static int edgecmpC(const void *av, const void *bv)
+{
+ const edge *a = (const edge *)av;
+ const edge *b = (const edge *)bv;
+
+ if (a->a < b->a)
+ return -1;
+ else if (a->a > b->a)
+ return +1;
+ else if (a->b < b->b)
+ return -1;
+ else if (a->b > b->b)
+ return +1;
+ return 0;
+}
+
+static int edgecmp(void *av, void *bv) { return edgecmpC(av, bv); }
+
+static game_params *default_params(void)
+{
+ game_params *ret = snew(game_params);
+
+ ret->n = 10;
+
+ return ret;
+}
+
+static int game_fetch_preset(int i, char **name, game_params **params)
+{
+ game_params *ret;
+ int n;
+ char buf[80];
+
+ switch (i) {
+ case 0: n = 6; break;
+ case 1: n = 10; break;
+ case 2: n = 15; break;
+ case 3: n = 20; break;
+ case 4: n = 25; break;
+ default: return FALSE;
+ }
+
+ sprintf(buf, "%d points", n);
+ *name = dupstr(buf);
+
+ *params = ret = snew(game_params);
+ ret->n = n;
+
+ return TRUE;
+}
+
+static void free_params(game_params *params)
+{
+ sfree(params);
+}
+
+static game_params *dup_params(const game_params *params)
+{
+ game_params *ret = snew(game_params);
+ *ret = *params; /* structure copy */
+ return ret;
+}
+
+static void decode_params(game_params *params, char const *string)
+{
+ params->n = atoi(string);
+}
+
+static char *encode_params(const game_params *params, int full)
+{
+ char buf[80];
+
+ sprintf(buf, "%d", params->n);
+
+ return dupstr(buf);
+}
+
+static config_item *game_configure(const game_params *params)
+{
+ config_item *ret;
+ char buf[80];
+
+ ret = snewn(3, config_item);
+
+ ret[0].name = "Number of points";
+ ret[0].type = C_STRING;
+ sprintf(buf, "%d", params->n);
+ ret[0].sval = dupstr(buf);
+ ret[0].ival = 0;
+
+ ret[1].name = NULL;
+ ret[1].type = C_END;
+ ret[1].sval = NULL;
+ ret[1].ival = 0;
+
+ return ret;
+}
+
+static game_params *custom_params(const config_item *cfg)
+{
+ game_params *ret = snew(game_params);
+
+ ret->n = atoi(cfg[0].sval);
+
+ return ret;
+}
+
+static char *validate_params(const game_params *params, int full)
+{
+ if (params->n < 4)
+ return "Number of points must be at least four";
+ return NULL;
+}
+
+/* ----------------------------------------------------------------------
+ * Small number of 64-bit integer arithmetic operations, to prevent
+ * integer overflow at the very core of cross().
+ */
+
+typedef struct {
+ long hi;
+ unsigned long lo;
+} int64;
+
+#define greater64(i,j) ( (i).hi>(j).hi || ((i).hi==(j).hi && (i).lo>(j).lo))
+#define sign64(i) ((i).hi < 0 ? -1 : (i).hi==0 && (i).lo==0 ? 0 : +1)
+
+static int64 mulu32to64(unsigned long x, unsigned long y)
+{
+ unsigned long a, b, c, d, t;
+ int64 ret;
+
+ a = (x & 0xFFFF) * (y & 0xFFFF);
+ b = (x & 0xFFFF) * (y >> 16);
+ c = (x >> 16) * (y & 0xFFFF);
+ d = (x >> 16) * (y >> 16);
+
+ ret.lo = a;
+ ret.hi = d + (b >> 16) + (c >> 16);
+ t = (b & 0xFFFF) << 16;
+ ret.lo += t;
+ if (ret.lo < t)
+ ret.hi++;
+ t = (c & 0xFFFF) << 16;
+ ret.lo += t;
+ if (ret.lo < t)
+ ret.hi++;
+
+#ifdef DIAGNOSTIC_VIA_LONGLONG
+ assert(((unsigned long long)ret.hi << 32) + ret.lo ==
+ (unsigned long long)x * y);
+#endif
+
+ return ret;
+}
+
+static int64 mul32to64(long x, long y)
+{
+ int sign = +1;
+ int64 ret;
+#ifdef DIAGNOSTIC_VIA_LONGLONG
+ long long realret = (long long)x * y;
+#endif
+
+ if (x < 0)
+ x = -x, sign = -sign;
+ if (y < 0)
+ y = -y, sign = -sign;
+
+ ret = mulu32to64(x, y);
+
+ if (sign < 0) {
+ ret.hi = -ret.hi;
+ ret.lo = -ret.lo;
+ if (ret.lo)
+ ret.hi--;
+ }
+
+#ifdef DIAGNOSTIC_VIA_LONGLONG
+ assert(((unsigned long long)ret.hi << 32) + ret.lo == realret);
+#endif
+
+ return ret;
+}
+
+static int64 dotprod64(long a, long b, long p, long q)
+{
+ int64 ab, pq;
+
+ ab = mul32to64(a, b);
+ pq = mul32to64(p, q);
+ ab.hi += pq.hi;
+ ab.lo += pq.lo;
+ if (ab.lo < pq.lo)
+ ab.hi++;
+ return ab;
+}
+
+/*
+ * Determine whether the line segments between a1 and a2, and
+ * between b1 and b2, intersect. We count it as an intersection if
+ * any of the endpoints lies _on_ the other line.
+ */
+static int cross(point a1, point a2, point b1, point b2)
+{
+ long b1x, b1y, b2x, b2y, px, py;
+ int64 d1, d2, d3;
+
+ /*
+ * The condition for crossing is that b1 and b2 are on opposite
+ * sides of the line a1-a2, and vice versa. We determine this
+ * by taking the dot product of b1-a1 with a vector
+ * perpendicular to a2-a1, and similarly with b2-a1, and seeing
+ * if they have different signs.
+ */
+
+ /*
+ * Construct the vector b1-a1. We don't have to worry too much
+ * about the denominator, because we're only going to check the
+ * sign of this vector; we just need to get the numerator
+ * right.
+ */
+ b1x = b1.x * a1.d - a1.x * b1.d;
+ b1y = b1.y * a1.d - a1.y * b1.d;
+ /* Now construct b2-a1, and a vector perpendicular to a2-a1,
+ * in the same way. */
+ b2x = b2.x * a1.d - a1.x * b2.d;
+ b2y = b2.y * a1.d - a1.y * b2.d;
+ px = a1.y * a2.d - a2.y * a1.d;
+ py = a2.x * a1.d - a1.x * a2.d;
+ /* Take the dot products. Here we resort to 64-bit arithmetic. */
+ d1 = dotprod64(b1x, px, b1y, py);
+ d2 = dotprod64(b2x, px, b2y, py);
+ /* If they have the same non-zero sign, the lines do not cross. */
+ if ((sign64(d1) > 0 && sign64(d2) > 0) ||
+ (sign64(d1) < 0 && sign64(d2) < 0))
+ return FALSE;
+
+ /*
+ * If the dot products are both exactly zero, then the two line
+ * segments are collinear. At this point the intersection
+ * condition becomes whether or not they overlap within their
+ * line.
+ */
+ if (sign64(d1) == 0 && sign64(d2) == 0) {
+ /* Construct the vector a2-a1. */
+ px = a2.x * a1.d - a1.x * a2.d;
+ py = a2.y * a1.d - a1.y * a2.d;
+ /* Determine the dot products of b1-a1 and b2-a1 with this. */
+ d1 = dotprod64(b1x, px, b1y, py);
+ d2 = dotprod64(b2x, px, b2y, py);
+ /* If they're both strictly negative, the lines do not cross. */
+ if (sign64(d1) < 0 && sign64(d2) < 0)
+ return FALSE;
+ /* Otherwise, take the dot product of a2-a1 with itself. If
+ * the other two dot products both exceed this, the lines do
+ * not cross. */
+ d3 = dotprod64(px, px, py, py);
+ if (greater64(d1, d3) && greater64(d2, d3))
+ return FALSE;
+ }
+
+ /*
+ * We've eliminated the only important special case, and we
+ * have determined that b1 and b2 are on opposite sides of the
+ * line a1-a2. Now do the same thing the other way round and
+ * we're done.
+ */
+ b1x = a1.x * b1.d - b1.x * a1.d;
+ b1y = a1.y * b1.d - b1.y * a1.d;
+ b2x = a2.x * b1.d - b1.x * a2.d;
+ b2y = a2.y * b1.d - b1.y * a2.d;
+ px = b1.y * b2.d - b2.y * b1.d;
+ py = b2.x * b1.d - b1.x * b2.d;
+ d1 = dotprod64(b1x, px, b1y, py);
+ d2 = dotprod64(b2x, px, b2y, py);
+ if ((sign64(d1) > 0 && sign64(d2) > 0) ||
+ (sign64(d1) < 0 && sign64(d2) < 0))
+ return FALSE;
+
+ /*
+ * The lines must cross.
+ */
+ return TRUE;
+}
+
+static unsigned long squarert(unsigned long n) {
+ unsigned long d, a, b, di;
+
+ d = n;
+ a = 0;
+ b = 1L << 30; /* largest available power of 4 */
+ do {
+ a >>= 1;
+ di = 2*a + b;
+ if (di <= d) {
+ d -= di;
+ a += b;
+ }
+ b >>= 2;
+ } while (b);
+
+ return a;
+}
+
+/*
+ * Our solutions are arranged on a square grid big enough that n
+ * points occupy about 1/POINTDENSITY of the grid.
+ */
+#define POINTDENSITY 3
+#define MAXDEGREE 4
+#define COORDLIMIT(n) squarert((n) * POINTDENSITY)
+
+static void addedge(tree234 *edges, int a, int b)
+{
+ edge *e = snew(edge);
+
+ assert(a != b);
+
+ e->a = min(a, b);
+ e->b = max(a, b);
+
+ add234(edges, e);
+}
+
+static int isedge(tree234 *edges, int a, int b)
+{
+ edge e;
+
+ assert(a != b);
+
+ e.a = min(a, b);
+ e.b = max(a, b);
+
+ return find234(edges, &e, NULL) != NULL;
+}
+
+typedef struct vertex {
+ int param;
+ int vindex;
+} vertex;
+
+static int vertcmpC(const void *av, const void *bv)
+{
+ const vertex *a = (vertex *)av;
+ const vertex *b = (vertex *)bv;
+
+ if (a->param < b->param)
+ return -1;
+ else if (a->param > b->param)
+ return +1;
+ else if (a->vindex < b->vindex)
+ return -1;
+ else if (a->vindex > b->vindex)
+ return +1;
+ return 0;
+}
+static int vertcmp(void *av, void *bv) { return vertcmpC(av, bv); }
+
+/*
+ * Construct point coordinates for n points arranged in a circle,
+ * within the bounding box (0,0) to (w,w).
+ */
+static void make_circle(point *pts, int n, int w)
+{
+ long d, r, c, i;
+
+ /*
+ * First, decide on a denominator. Although in principle it
+ * would be nice to set this really high so as to finely
+ * distinguish all the points on the circle, I'm going to set
+ * it at a fixed size to prevent integer overflow problems.
+ */
+ d = PREFERRED_TILESIZE;
+
+ /*
+ * Leave a little space outside the circle.
+ */
+ c = d * w / 2;
+ r = d * w * 3 / 7;
+
+ /*
+ * Place the points.
+ */
+ for (i = 0; i < n; i++) {
+ double angle = i * 2 * PI / n;
+ double x = r * sin(angle), y = - r * cos(angle);
+ pts[i].x = (long)(c + x + 0.5);
+ pts[i].y = (long)(c + y + 0.5);
+ pts[i].d = d;
+ }
+}
+
+static char *new_game_desc(const game_params *params, random_state *rs,
+ char **aux, int interactive)
+{
+ int n = params->n, i;
+ long w, h, j, k, m;
+ point *pts, *pts2;
+ long *tmp;
+ tree234 *edges, *vertices;
+ edge *e, *e2;
+ vertex *v, *vs, *vlist;
+ char *ret;
+
+ w = h = COORDLIMIT(n);
+
+ /*
+ * Choose n points from this grid.
+ */
+ pts = snewn(n, point);
+ tmp = snewn(w*h, long);
+ for (i = 0; i < w*h; i++)
+ tmp[i] = i;
+ shuffle(tmp, w*h, sizeof(*tmp), rs);
+ for (i = 0; i < n; i++) {
+ pts[i].x = tmp[i] % w;
+ pts[i].y = tmp[i] / w;
+ pts[i].d = 1;
+ }
+ sfree(tmp);
+
+ /*
+ * Now start adding edges between the points.
+ *
+ * At all times, we attempt to add an edge to the lowest-degree
+ * vertex we currently have, and we try the other vertices as
+ * candidate second endpoints in order of distance from this
+ * one. We stop as soon as we find an edge which
+ *
+ * (a) does not increase any vertex's degree beyond MAXDEGREE
+ * (b) does not cross any existing edges
+ * (c) does not intersect any actual point.
+ */
+ vs = snewn(n, vertex);
+ vertices = newtree234(vertcmp);
+ for (i = 0; i < n; i++) {
+ v = vs + i;
+ v->param = 0; /* in this tree, param is the degree */
+ v->vindex = i;
+ add234(vertices, v);
+ }
+ edges = newtree234(edgecmp);
+ vlist = snewn(n, vertex);
+ while (1) {
+ int added = FALSE;
+
+ for (i = 0; i < n; i++) {
+ v = index234(vertices, i);
+ j = v->vindex;
+
+ if (v->param >= MAXDEGREE)
+ break; /* nothing left to add! */
+
+ /*
+ * Sort the other vertices into order of their distance
+ * from this one. Don't bother looking below i, because
+ * we've already tried those edges the other way round.
+ * Also here we rule out target vertices with too high
+ * a degree, and (of course) ones to which we already
+ * have an edge.
+ */
+ m = 0;
+ for (k = i+1; k < n; k++) {
+ vertex *kv = index234(vertices, k);
+ int ki = kv->vindex;
+ int dx, dy;
+
+ if (kv->param >= MAXDEGREE || isedge(edges, ki, j))
+ continue;
+
+ vlist[m].vindex = ki;
+ dx = pts[ki].x - pts[j].x;
+ dy = pts[ki].y - pts[j].y;
+ vlist[m].param = dx*dx + dy*dy;
+ m++;
+ }
+
+ qsort(vlist, m, sizeof(*vlist), vertcmpC);
+
+ for (k = 0; k < m; k++) {
+ int p;
+ int ki = vlist[k].vindex;
+
+ /*
+ * Check to see whether this edge intersects any
+ * existing edge or point.
+ */
+ for (p = 0; p < n; p++)
+ if (p != ki && p != j && cross(pts[ki], pts[j],
+ pts[p], pts[p]))
+ break;
+ if (p < n)
+ continue;
+ for (p = 0; (e = index234(edges, p)) != NULL; p++)
+ if (e->a != ki && e->a != j &&
+ e->b != ki && e->b != j &&
+ cross(pts[ki], pts[j], pts[e->a], pts[e->b]))
+ break;
+ if (e)
+ continue;
+
+ /*
+ * We're done! Add this edge, modify the degrees of
+ * the two vertices involved, and break.
+ */
+ addedge(edges, j, ki);
+ added = TRUE;
+ del234(vertices, vs+j);
+ vs[j].param++;
+ add234(vertices, vs+j);
+ del234(vertices, vs+ki);
+ vs[ki].param++;
+ add234(vertices, vs+ki);
+ break;
+ }
+
+ if (k < m)
+ break;
+ }
+
+ if (!added)
+ break; /* we're done. */
+ }
+
+ /*
+ * That's our graph. Now shuffle the points, making sure that
+ * they come out with at least one crossed line when arranged
+ * in a circle (so that the puzzle isn't immediately solved!).
+ */
+ tmp = snewn(n, long);
+ for (i = 0; i < n; i++)
+ tmp[i] = i;
+ pts2 = snewn(n, point);
+ make_circle(pts2, n, w);
+ while (1) {
+ shuffle(tmp, n, sizeof(*tmp), rs);
+ for (i = 0; (e = index234(edges, i)) != NULL; i++) {
+ for (j = i+1; (e2 = index234(edges, j)) != NULL; j++) {
+ if (e2->a == e->a || e2->a == e->b ||
+ e2->b == e->a || e2->b == e->b)
+ continue;
+ if (cross(pts2[tmp[e2->a]], pts2[tmp[e2->b]],
+ pts2[tmp[e->a]], pts2[tmp[e->b]]))
+ break;
+ }
+ if (e2)
+ break;
+ }
+ if (e)
+ break; /* we've found a crossing */
+ }
+
+ /*
+ * We're done. Now encode the graph in a string format. Let's
+ * use a comma-separated list of dash-separated vertex number
+ * pairs, numbered from zero. We'll sort the list to prevent
+ * side channels.
+ */
+ ret = NULL;
+ {
+ char *sep;
+ char buf[80];
+ int retlen;
+ edge *ea;
+
+ retlen = 0;
+ m = count234(edges);
+ ea = snewn(m, edge);
+ for (i = 0; (e = index234(edges, i)) != NULL; i++) {
+ assert(i < m);
+ ea[i].a = min(tmp[e->a], tmp[e->b]);
+ ea[i].b = max(tmp[e->a], tmp[e->b]);
+ retlen += 1 + sprintf(buf, "%d-%d", ea[i].a, ea[i].b);
+ }
+ assert(i == m);
+ qsort(ea, m, sizeof(*ea), edgecmpC);
+
+ ret = snewn(retlen, char);
+ sep = "";
+ k = 0;
+
+ for (i = 0; i < m; i++) {
+ k += sprintf(ret + k, "%s%d-%d", sep, ea[i].a, ea[i].b);
+ sep = ",";
+ }
+ assert(k < retlen);
+
+ sfree(ea);
+ }
+
+ /*
+ * Encode the solution we started with as an aux_info string.
+ */
+ {
+ char buf[80];
+ char *auxstr;
+ int auxlen;
+
+ auxlen = 2; /* leading 'S' and trailing '\0' */
+ for (i = 0; i < n; i++) {
+ j = tmp[i];
+ pts2[j] = pts[i];
+ if (pts2[j].d & 1) {
+ pts2[j].x *= 2;
+ pts2[j].y *= 2;
+ pts2[j].d *= 2;
+ }
+ pts2[j].x += pts2[j].d / 2;
+ pts2[j].y += pts2[j].d / 2;
+ auxlen += sprintf(buf, ";P%d:%ld,%ld/%ld", i,
+ pts2[j].x, pts2[j].y, pts2[j].d);
+ }
+ k = 0;
+ auxstr = snewn(auxlen, char);
+ auxstr[k++] = 'S';
+ for (i = 0; i < n; i++)
+ k += sprintf(auxstr+k, ";P%d:%ld,%ld/%ld", i,
+ pts2[i].x, pts2[i].y, pts2[i].d);
+ assert(k < auxlen);
+ *aux = auxstr;
+ }
+ sfree(pts2);
+
+ sfree(tmp);
+ sfree(vlist);
+ freetree234(vertices);
+ sfree(vs);
+ while ((e = delpos234(edges, 0)) != NULL)
+ sfree(e);
+ freetree234(edges);
+ sfree(pts);
+
+ return ret;
+}
+
+static char *validate_desc(const game_params *params, const char *desc)
+{
+ int a, b;
+
+ while (*desc) {
+ a = atoi(desc);
+ if (a < 0 || a >= params->n)
+ return "Number out of range in game description";
+ while (*desc && isdigit((unsigned char)*desc)) desc++;
+ if (*desc != '-')
+ return "Expected '-' after number in game description";
+ desc++; /* eat dash */
+ b = atoi(desc);
+ if (b < 0 || b >= params->n)
+ return "Number out of range in game description";
+ while (*desc && isdigit((unsigned char)*desc)) desc++;
+ if (*desc) {
+ if (*desc != ',')
+ return "Expected ',' after number in game description";
+ desc++; /* eat comma */
+ }
+ }
+
+ return NULL;
+}
+
+static void mark_crossings(game_state *state)
+{
+ int ok = TRUE;
+ int i, j;
+ edge *e, *e2;
+
+#ifdef SHOW_CROSSINGS
+ for (i = 0; (e = index234(state->graph->edges, i)) != NULL; i++)
+ state->crosses[i] = FALSE;
+#endif
+
+ /*
+ * Check correctness: for every pair of edges, see whether they
+ * cross.
+ */
+ for (i = 0; (e = index234(state->graph->edges, i)) != NULL; i++) {
+ for (j = i+1; (e2 = index234(state->graph->edges, j)) != NULL; j++) {
+ if (e2->a == e->a || e2->a == e->b ||
+ e2->b == e->a || e2->b == e->b)
+ continue;
+ if (cross(state->pts[e2->a], state->pts[e2->b],
+ state->pts[e->a], state->pts[e->b])) {
+ ok = FALSE;
+#ifdef SHOW_CROSSINGS
+ state->crosses[i] = state->crosses[j] = TRUE;
+#else
+ goto done; /* multi-level break - sorry */
+#endif
+ }
+ }
+ }
+
+ /*
+ * e == NULL if we've gone through all the edge pairs
+ * without finding a crossing.
+ */
+#ifndef SHOW_CROSSINGS
+ done:
+#endif
+ if (ok)
+ state->completed = TRUE;
+}
+
+static game_state *new_game(midend *me, const game_params *params,
+ const char *desc)
+{
+ int n = params->n;
+ game_state *state = snew(game_state);
+ int a, b;
+
+ state->params = *params;
+ state->w = state->h = COORDLIMIT(n);
+ state->pts = snewn(n, point);
+ make_circle(state->pts, n, state->w);
+ state->graph = snew(struct graph);
+ state->graph->refcount = 1;
+ state->graph->edges = newtree234(edgecmp);
+ state->completed = state->cheated = state->just_solved = FALSE;
+
+ while (*desc) {
+ a = atoi(desc);
+ assert(a >= 0 && a < params->n);
+ while (*desc && isdigit((unsigned char)*desc)) desc++;
+ assert(*desc == '-');
+ desc++; /* eat dash */
+ b = atoi(desc);
+ assert(b >= 0 && b < params->n);
+ while (*desc && isdigit((unsigned char)*desc)) desc++;
+ if (*desc) {
+ assert(*desc == ',');
+ desc++; /* eat comma */
+ }
+ addedge(state->graph->edges, a, b);
+ }
+
+#ifdef SHOW_CROSSINGS
+ state->crosses = snewn(count234(state->graph->edges), int);
+ mark_crossings(state); /* sets up `crosses' and `completed' */
+#endif
+
+ return state;
+}
+
+static game_state *dup_game(const game_state *state)
+{
+ int n = state->params.n;
+ game_state *ret = snew(game_state);
+
+ ret->params = state->params;
+ ret->w = state->w;
+ ret->h = state->h;
+ ret->pts = snewn(n, point);
+ memcpy(ret->pts, state->pts, n * sizeof(point));
+ ret->graph = state->graph;
+ ret->graph->refcount++;
+ ret->completed = state->completed;
+ ret->cheated = state->cheated;
+ ret->just_solved = state->just_solved;
+#ifdef SHOW_CROSSINGS
+ ret->crosses = snewn(count234(ret->graph->edges), int);
+ memcpy(ret->crosses, state->crosses,
+ count234(ret->graph->edges) * sizeof(int));
+#endif
+
+ return ret;
+}
+
+static void free_game(game_state *state)
+{
+ if (--state->graph->refcount <= 0) {
+ edge *e;
+ while ((e = delpos234(state->graph->edges, 0)) != NULL)
+ sfree(e);
+ freetree234(state->graph->edges);
+ sfree(state->graph);
+ }
+ sfree(state->pts);
+ sfree(state);
+}
+
+static char *solve_game(const game_state *state, const game_state *currstate,
+ const char *aux, char **error)
+{
+ int n = state->params.n;
+ int matrix[4];
+ point *pts;
+ int i, j, besti;
+ float bestd;
+ char buf[80], *ret;
+ int retlen, retsize;
+
+ if (!aux) {
+ *error = "Solution not known for this puzzle";
+ return NULL;
+ }
+
+ /*
+ * Decode the aux_info to get the original point positions.
+ */
+ pts = snewn(n, point);
+ aux++; /* eat 'S' */
+ for (i = 0; i < n; i++) {
+ int p, k;
+ long x, y, d;
+ int ret = sscanf(aux, ";P%d:%ld,%ld/%ld%n", &p, &x, &y, &d, &k);
+ if (ret != 4 || p != i) {
+ *error = "Internal error: aux_info badly formatted";
+ sfree(pts);
+ return NULL;
+ }
+ pts[i].x = x;
+ pts[i].y = y;
+ pts[i].d = d;
+ aux += k;
+ }
+
+ /*
+ * Now go through eight possible symmetries of the point set.
+ * For each one, work out the sum of the Euclidean distances
+ * between the points' current positions and their new ones.
+ *
+ * We're squaring distances here, which means we're at risk of
+ * integer overflow. Fortunately, there's no real need to be
+ * massively careful about rounding errors, since this is a
+ * non-essential bit of the code; so I'll just work in floats
+ * internally.
+ */
+ besti = -1;
+ bestd = 0.0F;
+
+ for (i = 0; i < 8; i++) {
+ float d;
+
+ matrix[0] = matrix[1] = matrix[2] = matrix[3] = 0;
+ matrix[i & 1] = (i & 2) ? +1 : -1;
+ matrix[3-(i&1)] = (i & 4) ? +1 : -1;
+
+ d = 0.0F;
+ for (j = 0; j < n; j++) {
+ float px = (float)pts[j].x / pts[j].d;
+ float py = (float)pts[j].y / pts[j].d;
+ float sx = (float)currstate->pts[j].x / currstate->pts[j].d;
+ float sy = (float)currstate->pts[j].y / currstate->pts[j].d;
+ float cx = (float)currstate->w / 2;
+ float cy = (float)currstate->h / 2;
+ float ox, oy, dx, dy;
+
+ px -= cx;
+ py -= cy;
+
+ ox = matrix[0] * px + matrix[1] * py;
+ oy = matrix[2] * px + matrix[3] * py;
+
+ ox += cx;
+ oy += cy;
+
+ dx = ox - sx;
+ dy = oy - sy;
+
+ d += dx*dx + dy*dy;
+ }
+
+ if (besti < 0 || bestd > d) {
+ besti = i;
+ bestd = d;
+ }
+ }
+
+ assert(besti >= 0);
+
+ /*
+ * Now we know which symmetry is closest to the points' current
+ * positions. Use it.
+ */
+ matrix[0] = matrix[1] = matrix[2] = matrix[3] = 0;
+ matrix[besti & 1] = (besti & 2) ? +1 : -1;
+ matrix[3-(besti&1)] = (besti & 4) ? +1 : -1;
+
+ retsize = 256;
+ ret = snewn(retsize, char);
+ retlen = 0;
+ ret[retlen++] = 'S';
+ ret[retlen] = '\0';
+
+ for (i = 0; i < n; i++) {
+ float px = (float)pts[i].x / pts[i].d;
+ float py = (float)pts[i].y / pts[i].d;
+ float cx = (float)currstate->w / 2;
+ float cy = (float)currstate->h / 2;
+ float ox, oy;
+ int extra;
+
+ px -= cx;
+ py -= cy;
+
+ ox = matrix[0] * px + matrix[1] * py;
+ oy = matrix[2] * px + matrix[3] * py;
+
+ ox += cx;
+ oy += cy;
+
+ /*
+ * Use a fixed denominator of 2, because we know the
+ * original points were on an integer grid offset by 1/2.
+ */
+ pts[i].d = 2;
+ ox *= pts[i].d;
+ oy *= pts[i].d;
+ pts[i].x = (long)(ox + 0.5F);
+ pts[i].y = (long)(oy + 0.5F);
+
+ extra = sprintf(buf, ";P%d:%ld,%ld/%ld", i,
+ pts[i].x, pts[i].y, pts[i].d);
+ if (retlen + extra >= retsize) {
+ retsize = retlen + extra + 256;
+ ret = sresize(ret, retsize, char);
+ }
+ strcpy(ret + retlen, buf);
+ retlen += extra;
+ }
+
+ sfree(pts);
+
+ return ret;
+}
+
+static int game_can_format_as_text_now(const game_params *params)
+{
+ return TRUE;
+}
+
+static char *game_text_format(const game_state *state)
+{
+ return NULL;
+}
+
+struct game_ui {
+ int dragpoint; /* point being dragged; -1 if none */
+ point newpoint; /* where it's been dragged to so far */
+ int just_dragged; /* reset in game_changed_state */
+ int just_moved; /* _set_ in game_changed_state */
+ float anim_length;
+};
+
+static game_ui *new_ui(const game_state *state)
+{
+ game_ui *ui = snew(game_ui);
+ ui->dragpoint = -1;
+ ui->just_moved = ui->just_dragged = FALSE;
+ return ui;
+}
+
+static void free_ui(game_ui *ui)
+{
+ sfree(ui);
+}
+
+static char *encode_ui(const game_ui *ui)
+{
+ return NULL;
+}
+
+static void decode_ui(game_ui *ui, const char *encoding)
+{
+}
+
+static void game_changed_state(game_ui *ui, const game_state *oldstate,
+ const game_state *newstate)
+{
+ ui->dragpoint = -1;
+ ui->just_moved = ui->just_dragged;
+ ui->just_dragged = FALSE;
+}
+
+struct game_drawstate {
+ long tilesize;
+ int bg, dragpoint;
+ long *x, *y;
+};
+
+static char *interpret_move(const game_state *state, game_ui *ui,
+ const game_drawstate *ds,
+ int x, int y, int button)
+{
+ int n = state->params.n;
+
+ if (IS_MOUSE_DOWN(button)) {
+ int i, best;
+ long bestd;
+
+ /*
+ * Begin drag. We drag the vertex _nearest_ to the pointer,
+ * just in case one is nearly on top of another and we want
+ * to drag the latter. However, we drag nothing at all if
+ * the nearest vertex is outside DRAG_THRESHOLD.
+ */
+ best = -1;
+ bestd = 0;
+
+ for (i = 0; i < n; i++) {
+ long px = state->pts[i].x * ds->tilesize / state->pts[i].d;
+ long py = state->pts[i].y * ds->tilesize / state->pts[i].d;
+ long dx = px - x;
+ long dy = py - y;
+ long d = dx*dx + dy*dy;
+
+ if (best == -1 || bestd > d) {
+ best = i;
+ bestd = d;
+ }
+ }
+
+ if (bestd <= DRAG_THRESHOLD * DRAG_THRESHOLD) {
+ ui->dragpoint = best;
+ ui->newpoint.x = x;
+ ui->newpoint.y = y;
+ ui->newpoint.d = ds->tilesize;
+ return "";
+ }
+
+ } else if (IS_MOUSE_DRAG(button) && ui->dragpoint >= 0) {
+ ui->newpoint.x = x;
+ ui->newpoint.y = y;
+ ui->newpoint.d = ds->tilesize;
+ return "";
+ } else if (IS_MOUSE_RELEASE(button) && ui->dragpoint >= 0) {
+ int p = ui->dragpoint;
+ char buf[80];
+
+ ui->dragpoint = -1; /* terminate drag, no matter what */
+
+ /*
+ * First, see if we're within range. The user can cancel a
+ * drag by dragging the point right off the window.
+ */
+ if (ui->newpoint.x < 0 ||
+ ui->newpoint.x >= (long)state->w*ui->newpoint.d ||
+ ui->newpoint.y < 0 ||
+ ui->newpoint.y >= (long)state->h*ui->newpoint.d)
+ return "";
+
+ /*
+ * We aren't cancelling the drag. Construct a move string
+ * indicating where this point is going to.
+ */
+ sprintf(buf, "P%d:%ld,%ld/%ld", p,
+ ui->newpoint.x, ui->newpoint.y, ui->newpoint.d);
+ ui->just_dragged = TRUE;
+ return dupstr(buf);
+ }
+
+ return NULL;
+}
+
+static game_state *execute_move(const game_state *state, const char *move)
+{
+ int n = state->params.n;
+ int p, k;
+ long x, y, d;
+ game_state *ret = dup_game(state);
+
+ ret->just_solved = FALSE;
+
+ while (*move) {
+ if (*move == 'S') {
+ move++;
+ if (*move == ';') move++;
+ ret->cheated = ret->just_solved = TRUE;
+ }
+ if (*move == 'P' &&
+ sscanf(move+1, "%d:%ld,%ld/%ld%n", &p, &x, &y, &d, &k) == 4 &&
+ p >= 0 && p < n && d > 0) {
+ ret->pts[p].x = x;
+ ret->pts[p].y = y;
+ ret->pts[p].d = d;
+
+ move += k+1;
+ if (*move == ';') move++;
+ } else {
+ free_game(ret);
+ return NULL;
+ }
+ }
+
+ mark_crossings(ret);
+
+ return ret;
+}
+
+/* ----------------------------------------------------------------------
+ * Drawing routines.
+ */
+
+static void game_compute_size(const game_params *params, int tilesize,
+ int *x, int *y)
+{
+ *x = *y = COORDLIMIT(params->n) * tilesize;
+}
+
+static void game_set_size(drawing *dr, game_drawstate *ds,
+ const game_params *params, int tilesize)
+{
+ ds->tilesize = tilesize;
+}
+
+static float *game_colours(frontend *fe, int *ncolours)
+{
+ float *ret = snewn(3 * NCOLOURS, float);
+
+ /*
+ * COL_BACKGROUND is what we use as the normal background colour.
+ * Unusually, though, it isn't colour #0: COL_SYSBACKGROUND, a bit
+ * darker, takes that place. This means that if the user resizes
+ * an Untangle window so as to change its aspect ratio, the
+ * still-square playable area will be distinguished from the dead
+ * space around it.
+ */
+ game_mkhighlight(fe, ret, COL_BACKGROUND, -1, COL_SYSBACKGROUND);
+
+ ret[COL_LINE * 3 + 0] = 0.0F;
+ ret[COL_LINE * 3 + 1] = 0.0F;
+ ret[COL_LINE * 3 + 2] = 0.0F;
+
+#ifdef SHOW_CROSSINGS
+ ret[COL_CROSSEDLINE * 3 + 0] = 1.0F;
+ ret[COL_CROSSEDLINE * 3 + 1] = 0.0F;
+ ret[COL_CROSSEDLINE * 3 + 2] = 0.0F;
+#endif
+
+ ret[COL_OUTLINE * 3 + 0] = 0.0F;
+ ret[COL_OUTLINE * 3 + 1] = 0.0F;
+ ret[COL_OUTLINE * 3 + 2] = 0.0F;
+
+ ret[COL_POINT * 3 + 0] = 0.0F;
+ ret[COL_POINT * 3 + 1] = 0.0F;
+ ret[COL_POINT * 3 + 2] = 1.0F;
+
+ ret[COL_DRAGPOINT * 3 + 0] = 1.0F;
+ ret[COL_DRAGPOINT * 3 + 1] = 1.0F;
+ ret[COL_DRAGPOINT * 3 + 2] = 1.0F;
+
+ ret[COL_NEIGHBOUR * 3 + 0] = 1.0F;
+ ret[COL_NEIGHBOUR * 3 + 1] = 0.0F;
+ ret[COL_NEIGHBOUR * 3 + 2] = 0.0F;
+
+ ret[COL_FLASH1 * 3 + 0] = 0.5F;
+ ret[COL_FLASH1 * 3 + 1] = 0.5F;
+ ret[COL_FLASH1 * 3 + 2] = 0.5F;
+
+ ret[COL_FLASH2 * 3 + 0] = 1.0F;
+ ret[COL_FLASH2 * 3 + 1] = 1.0F;
+ ret[COL_FLASH2 * 3 + 2] = 1.0F;
+
+ *ncolours = NCOLOURS;
+ return ret;
+}
+
+static game_drawstate *game_new_drawstate(drawing *dr, const game_state *state)
+{
+ struct game_drawstate *ds = snew(struct game_drawstate);
+ int i;
+
+ ds->tilesize = 0;
+ ds->x = snewn(state->params.n, long);
+ ds->y = snewn(state->params.n, long);
+ for (i = 0; i < state->params.n; i++)
+ ds->x[i] = ds->y[i] = -1;
+ ds->bg = -1;
+ ds->dragpoint = -1;
+
+ return ds;
+}
+
+static void game_free_drawstate(drawing *dr, game_drawstate *ds)
+{
+ sfree(ds->y);
+ sfree(ds->x);
+ sfree(ds);
+}
+
+static point mix(point a, point b, float distance)
+{
+ point ret;
+
+ ret.d = a.d * b.d;
+ ret.x = (long)(a.x * b.d + distance * (b.x * a.d - a.x * b.d));
+ ret.y = (long)(a.y * b.d + distance * (b.y * a.d - a.y * b.d));
+
+ return ret;
+}
+
+static void game_redraw(drawing *dr, game_drawstate *ds,
+ const game_state *oldstate, const game_state *state,
+ int dir, const game_ui *ui,
+ float animtime, float flashtime)
+{
+ int w, h;
+ edge *e;
+ int i, j;
+ int bg, points_moved;
+
+ /*
+ * There's no terribly sensible way to do partial redraws of
+ * this game, so I'm going to have to resort to redrawing the
+ * whole thing every time.
+ */
+
+ if (flashtime == 0)
+ bg = COL_BACKGROUND;
+ else if ((int)(flashtime * 4 / FLASH_TIME) % 2 == 0)
+ bg = COL_FLASH1;
+ else
+ bg = COL_FLASH2;
+
+ /*
+ * To prevent excessive spinning on redraw during a completion
+ * flash, we first check to see if _either_ the flash
+ * background colour has changed _or_ at least one point has
+ * moved _or_ a drag has begun or ended, and abandon the redraw
+ * if neither is the case.
+ *
+ * Also in this loop we work out the coordinates of all the
+ * points for this redraw.
+ */
+ points_moved = FALSE;
+ for (i = 0; i < state->params.n; i++) {
+ point p = state->pts[i];
+ long x, y;
+
+ if (ui->dragpoint == i)
+ p = ui->newpoint;
+
+ if (oldstate)
+ p = mix(oldstate->pts[i], p, animtime / ui->anim_length);
+
+ x = p.x * ds->tilesize / p.d;
+ y = p.y * ds->tilesize / p.d;
+
+ if (ds->x[i] != x || ds->y[i] != y)
+ points_moved = TRUE;
+
+ ds->x[i] = x;
+ ds->y[i] = y;
+ }
+
+ if (ds->bg == bg && ds->dragpoint == ui->dragpoint && !points_moved)
+ return; /* nothing to do */
+
+ ds->dragpoint = ui->dragpoint;
+ ds->bg = bg;
+
+ game_compute_size(&state->params, ds->tilesize, &w, &h);
+ draw_rect(dr, 0, 0, w, h, bg);
+
+ /*
+ * Draw the edges.
+ */
+
+ for (i = 0; (e = index234(state->graph->edges, i)) != NULL; i++) {
+ draw_line(dr, ds->x[e->a], ds->y[e->a], ds->x[e->b], ds->y[e->b],
+#ifdef SHOW_CROSSINGS
+ (oldstate?oldstate:state)->crosses[i] ?
+ COL_CROSSEDLINE :
+#endif
+ COL_LINE);
+ }
+
+ /*
+ * Draw the points.
+ *
+ * When dragging, we should not only vary the colours, but
+ * leave the point being dragged until last.
+ */
+ for (j = 0; j < 3; j++) {
+ int thisc = (j == 0 ? COL_POINT :
+ j == 1 ? COL_NEIGHBOUR : COL_DRAGPOINT);
+ for (i = 0; i < state->params.n; i++) {
+ int c;
+
+ if (ui->dragpoint == i) {
+ c = COL_DRAGPOINT;
+ } else if (ui->dragpoint >= 0 &&
+ isedge(state->graph->edges, ui->dragpoint, i)) {
+ c = COL_NEIGHBOUR;
+ } else {
+ c = COL_POINT;
+ }
+
+ if (c == thisc) {
+#ifdef VERTEX_NUMBERS
+ draw_circle(dr, ds->x[i], ds->y[i], DRAG_THRESHOLD, bg, bg);
+ {
+ char buf[80];
+ sprintf(buf, "%d", i);
+ draw_text(dr, ds->x[i], ds->y[i], FONT_VARIABLE,
+ DRAG_THRESHOLD*3/2,
+ ALIGN_VCENTRE|ALIGN_HCENTRE, c, buf);
+ }
+#else
+ draw_circle(dr, ds->x[i], ds->y[i], CIRCLE_RADIUS,
+ c, COL_OUTLINE);
+#endif
+ }
+ }
+ }
+
+ draw_update(dr, 0, 0, w, h);
+}
+
+static float game_anim_length(const game_state *oldstate,
+ const game_state *newstate, int dir, game_ui *ui)
+{
+ if (ui->just_moved)
+ return 0.0F;
+ if ((dir < 0 ? oldstate : newstate)->just_solved)
+ ui->anim_length = SOLVEANIM_TIME;
+ else
+ ui->anim_length = ANIM_TIME;
+ return ui->anim_length;
+}
+
+static float game_flash_length(const game_state *oldstate,
+ const game_state *newstate, int dir, game_ui *ui)
+{
+ if (!oldstate->completed && newstate->completed &&
+ !oldstate->cheated && !newstate->cheated)
+ return FLASH_TIME;
+ return 0.0F;
+}
+
+static int game_status(const game_state *state)
+{
+ return state->completed ? +1 : 0;
+}
+
+static int game_timing_state(const game_state *state, game_ui *ui)
+{
+ return TRUE;
+}
+
+static void game_print_size(const game_params *params, float *x, float *y)
+{
+}
+
+static void game_print(drawing *dr, const game_state *state, int tilesize)
+{
+}
+
+#ifdef COMBINED
+#define thegame untangle
+#endif
+
+const struct game thegame = {
+ "Untangle", "games.untangle", "untangle",
+ default_params,
+ game_fetch_preset,
+ decode_params,
+ encode_params,
+ free_params,
+ dup_params,
+ TRUE, game_configure, custom_params,
+ validate_params,
+ new_game_desc,
+ validate_desc,
+ new_game,
+ dup_game,
+ free_game,
+ TRUE, solve_game,
+ FALSE, game_can_format_as_text_now, game_text_format,
+ new_ui,
+ free_ui,
+ encode_ui,
+ decode_ui,
+ game_changed_state,
+ interpret_move,
+ execute_move,
+ PREFERRED_TILESIZE, game_compute_size, game_set_size,
+ game_colours,
+ game_new_drawstate,
+ game_free_drawstate,
+ game_redraw,
+ game_anim_length,
+ game_flash_length,
+ game_status,
+ FALSE, FALSE, game_print_size, game_print,
+ FALSE, /* wants_statusbar */
+ FALSE, game_timing_state,
+ SOLVE_ANIMATES, /* flags */
+};
generated by cgit v1.1 at 2026-04-25 14:26:07 +0000