Oops: initialise that new 'has_incentre' flag to false, otherwise the
[sgt/puzzles] / loopy.c
diff --git a/loopy.c b/loopy.c
index 37c85d5..1b32635 100644 (file)
--- a/loopy.c
+++ b/loopy.c
@@ -839,8 +839,14 @@ static float *game_colours(frontend *fe, int *ncolours)
     ret[COL_FOREGROUND * 3 + 1] = 0.0F;
     ret[COL_FOREGROUND * 3 + 2] = 0.0F;
 
-    ret[COL_LINEUNKNOWN * 3 + 0] = 0.8F;
-    ret[COL_LINEUNKNOWN * 3 + 1] = 0.8F;
+    /*
+     * We want COL_LINEUNKNOWN to be a yellow which is a bit darker
+     * than the background. (I previously set it to 0.8,0.8,0, but
+     * found that this went badly with the 0.8,0.8,0.8 favoured as a
+     * background by the Java frontend.)
+     */
+    ret[COL_LINEUNKNOWN * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.9F;
+    ret[COL_LINEUNKNOWN * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.9F;
     ret[COL_LINEUNKNOWN * 3 + 2] = 0.0F;
 
     ret[COL_HIGHLIGHT * 3 + 0] = 1.0F;
@@ -1834,7 +1840,6 @@ static char *new_game_desc(game_params *params, random_state *rs,
     grid *g;
     game_state *state = snew(game_state);
     game_state *state_new;
-    int count = 0;
     params_generate_grid(params);
     state->game_grid = g = params->game_grid;
     g->refcount++;
@@ -1856,7 +1861,6 @@ static char *new_game_desc(game_params *params, random_state *rs,
      * preventing games smaller than 4x4 seems to stop this happening */
     do {
         add_full_clues(state, rs);
-        if (++count%100 == 0) printf("tried %d times to make a unique board\n", count);
     } while (!game_has_unique_soln(state, params->diff));
 
     state_new = remove_clues(state, rs, params->diff);
@@ -2432,6 +2436,13 @@ static int trivial_deductions(solver_state *sstate)
         if (state->clues[i] < 0)
             continue;
 
+        /*
+         * This code checks whether the numeric clue on a face is so
+         * large as to permit all its remaining LINE_UNKNOWNs to be
+         * filled in as LINE_YES, or alternatively so small as to
+         * permit them all to be filled in as LINE_NO.
+         */
+
         if (state->clues[i] < current_yes) {
             sstate->solver_status = SOLVER_MISTAKE;
             return DIFF_EASY;
@@ -2453,6 +2464,57 @@ static int trivial_deductions(solver_state *sstate)
             sstate->face_solved[i] = TRUE;
             continue;
         }
+
+        if (f->order - state->clues[i] == current_no + 1 &&
+            f->order - current_yes - current_no > 2) {
+            /*
+             * One small refinement to the above: we also look for any
+             * adjacent pair of LINE_UNKNOWNs around the face with
+             * some LINE_YES incident on it from elsewhere. If we find
+             * one, then we know that pair of LINE_UNKNOWNs can't
+             * _both_ be LINE_YES, and hence that pushes us one line
+             * closer to being able to determine all the rest.
+             */
+            int j, k, e1, e2, e, d;
+
+            for (j = 0; j < f->order; j++) {
+                e1 = f->edges[j] - g->edges;
+                e2 = f->edges[j+1 < f->order ? j+1 : 0] - g->edges;
+
+                if (g->edges[e1].dot1 == g->edges[e2].dot1 ||
+                    g->edges[e1].dot1 == g->edges[e2].dot2) {
+                    d = g->edges[e1].dot1 - g->dots;
+                } else {
+                    assert(g->edges[e1].dot2 == g->edges[e2].dot1 ||
+                           g->edges[e1].dot2 == g->edges[e2].dot2);
+                    d = g->edges[e1].dot2 - g->dots;
+                }
+
+                if (state->lines[e1] == LINE_UNKNOWN &&
+                    state->lines[e2] == LINE_UNKNOWN) {
+                    for (k = 0; k < g->dots[d].order; k++) {
+                        int e = g->dots[d].edges[k] - g->edges;
+                        if (state->lines[e] == LINE_YES)
+                            goto found;    /* multi-level break */
+                    }
+                }
+            }
+            continue;
+
+          found:
+            /*
+             * If we get here, we've found such a pair of edges, and
+             * they're e1 and e2.
+             */
+            for (j = 0; j < f->order; j++) {
+                e = f->edges[j] - g->edges;
+                if (state->lines[e] == LINE_UNKNOWN && e != e1 && e != e2) {
+                    int r = solver_set_line(sstate, e, LINE_YES);
+                    assert(r);
+                    diff = min(diff, DIFF_EASY);
+                }
+            }
+        }
     }
 
     check_caches(sstate);
@@ -3342,10 +3404,8 @@ static void grid_to_screen(const game_drawstate *ds, const grid *g,
 /* Returns (into x,y) position of centre of face for rendering the text clue.
  */
 static void face_text_pos(const game_drawstate *ds, const grid *g,
-                          const grid_face *f, int *xret, int *yret)
+                          grid_face *f, int *xret, int *yret)
 {
-    int x, y, x0, y0, x1, y1, xbest, ybest, i, shift;
-    long bestdist;
     int faceindex = f - g->faces;
 
     /*
@@ -3359,154 +3419,11 @@ static void face_text_pos(const game_drawstate *ds, const grid *g,
     }
 
     /*
-     * Otherwise, try to find the point in the polygon with the
-     * maximum distance to any edge or corner.
-     *
-     * Start by working out the face's bounding box, in grid
-     * coordinates.
+     * Otherwise, use the incentre computed by grid.c and convert it
+     * to screen coordinates.
      */
-    x0 = x1 = f->dots[0]->x;
-    y0 = y1 = f->dots[0]->y;
-    for (i = 1; i < f->order; i++) {
-        if (x0 > f->dots[i]->x) x0 = f->dots[i]->x;
-        if (x1 < f->dots[i]->x) x1 = f->dots[i]->x;
-        if (y0 > f->dots[i]->y) y0 = f->dots[i]->y;
-        if (y1 < f->dots[i]->y) y1 = f->dots[i]->y;
-    }
-
-    /*
-     * If the grid is at excessive resolution, decide on a scaling
-     * factor to bring it within reasonable bounds so we don't have to
-     * think too hard or suffer integer overflow.
-     */
-    shift = 0;
-    while (x1 - x0 > 128 || y1 - y0 > 128) {
-        shift++;
-        x0 >>= 1;
-        x1 >>= 1;
-        y0 >>= 1;
-        y1 >>= 1;
-    }
-
-    /*
-     * Now iterate over every point in that bounding box.
-     */
-    xbest = ybest = -1;
-    bestdist = -1;
-    for (y = y0; y <= y1; y++) {
-        for (x = x0; x <= x1; x++) {
-            /*
-             * First, disqualify the point if it's not inside the
-             * polygon, which we work out by counting the edges to the
-             * right of the point. (For tiebreaking purposes when
-             * edges start or end on our y-coordinate or go right
-             * through it, we consider our point to be offset by a
-             * small _positive_ epsilon in both the x- and
-             * y-direction.)
-             */
-            int in = 0;
-            for (i = 0; i < f->order; i++) {
-                int xs = f->edges[i]->dot1->x >> shift;
-                int xe = f->edges[i]->dot2->x >> shift;
-                int ys = f->edges[i]->dot1->y >> shift;
-                int ye = f->edges[i]->dot2->y >> shift;
-                if ((y >= ys && y < ye) || (y >= ye && y < ys)) {
-                    /*
-                     * The line goes past our y-position. Now we need
-                     * to know if its x-coordinate when it does so is
-                     * to our right.
-                     *
-                     * The x-coordinate in question is mathematically
-                     * (y - ys) * (xe - xs) / (ye - ys), and we want
-                     * to know whether (x - xs) >= that. Of course we
-                     * avoid the division, so we can work in integers;
-                     * to do this we must multiply both sides of the
-                     * inequality by ye - ys, which means we must
-                     * first check that's not negative.
-                     */
-                    int num = xe - xs, denom = ye - ys;
-                    if (denom < 0) {
-                        num = -num;
-                        denom = -denom;
-                    }
-                    if ((x - xs) * denom >= (y - ys) * num)
-                        in ^= 1;
-                }
-            }
-
-            if (in) {
-                long mindist = LONG_MAX;
-
-                /*
-                 * This point is inside the polygon, so now we check
-                 * its minimum distance to every edge and corner.
-                 * First the corners ...
-                 */
-                for (i = 0; i < f->order; i++) {
-                    int xp = f->dots[i]->x >> shift;
-                    int yp = f->dots[i]->y >> shift;
-                    int dx = x - xp, dy = y - yp;
-                    long dist = (long)dx*dx + (long)dy*dy;
-                    if (mindist > dist)
-                        mindist = dist;
-                }
-
-                /*
-                 * ... and now also check the perpendicular distance
-                 * to every edge, if the perpendicular lies between
-                 * the edge's endpoints.
-                 */
-                for (i = 0; i < f->order; i++) {
-                    int xs = f->edges[i]->dot1->x >> shift;
-                    int xe = f->edges[i]->dot2->x >> shift;
-                    int ys = f->edges[i]->dot1->y >> shift;
-                    int ye = f->edges[i]->dot2->y >> shift;
-
-                    /*
-                     * If s and e are our endpoints, and p our
-                     * candidate circle centre, the foot of a
-                     * perpendicular from p to the line se lies
-                     * between s and e if and only if (p-s).(e-s) lies
-                     * strictly between 0 and (e-s).(e-s).
-                     */
-                    int edx = xe - xs, edy = ye - ys;
-                    int pdx = x - xs, pdy = y - ys;
-                    long pde = (long)pdx * edx + (long)pdy * edy;
-                    long ede = (long)edx * edx + (long)edy * edy;
-                    if (0 < pde && pde < ede) {
-                        /*
-                         * Yes, the nearest point on this edge is
-                         * closer than either endpoint, so we must
-                         * take it into account by measuring the
-                         * perpendicular distance to the edge and
-                         * checking its square against mindist.
-                         */
-
-                        long pdre = (long)pdx * edy - (long)pdy * edx;
-                        long sqlen = pdre * pdre / ede;
-
-                        if (mindist > sqlen)
-                            mindist = sqlen;
-                    }
-                }
-
-                /*
-                 * Right. Now we know the biggest circle around this
-                 * point, so we can check it against bestdist.
-                 */
-                if (bestdist < mindist) {
-                    bestdist = mindist;
-                    xbest = x;
-                    ybest = y;
-                }
-            }
-        }
-    }
-
-    assert(bestdist >= 0);
-
-    /* convert to screen coordinates */
-    grid_to_screen(ds, g, xbest << shift, ybest << shift,
+    grid_find_incentre(f);
+    grid_to_screen(ds, g, f->ix, f->iy,
                    &ds->textx[faceindex], &ds->texty[faceindex]);
 
     *xret = ds->textx[faceindex];
@@ -3673,9 +3590,11 @@ static void game_redraw_in_rect(drawing *dr, game_drawstate *ds,
     draw_rect(dr, x, y, w, h, COL_BACKGROUND);
 
     for (i = 0; i < g->num_faces; i++) {
-        face_text_bbox(ds, g, &g->faces[i], &bx, &by, &bw, &bh);
-        if (boxes_intersect(x, y, w, h, bx, by, bw, bh))
-            game_redraw_clue(dr, ds, state, i);
+        if (state->clues[i] >= 0) {
+            face_text_bbox(ds, g, &g->faces[i], &bx, &by, &bw, &bh);
+            if (boxes_intersect(x, y, w, h, bx, by, bw, bh))
+                game_redraw_clue(dr, ds, state, i);
+        }
     }
     for (phase = 0; phase < NPHASES; phase++) {
         for (i = 0; i < g->num_edges; i++) {
@@ -3834,6 +3753,11 @@ static float game_flash_length(game_state *oldstate, game_state *newstate,
     return 0.0F;
 }
 
+static int game_is_solved(game_state *state)
+{
+    return state->solved;
+}
+
 static void game_print_size(game_params *params, float *x, float *y)
 {
     int pw, ph;
@@ -3960,6 +3884,7 @@ const struct game thegame = {
     game_redraw,
     game_anim_length,
     game_flash_length,
+    game_is_solved,
     TRUE, FALSE, game_print_size, game_print,
     FALSE /* wants_statusbar */,
     FALSE, game_timing_state,