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Solve function for Inertia, using what's essentially an approximate

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TSP algorithm.

[originally from svn r6289]
This commit is contained in:
Simon Tatham
2005-09-11 12:40:49 +00:00
parent 08c8cf370e
commit b25fcc3f26
2 changed files with 853 additions and 9 deletions
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848
inertia.c
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@ -32,6 +32,7 @@
#define UNDRAWN '?'
#define DIRECTIONS 8
#define DP1 (DIRECTIONS+1)
#define DX(dir) ( (dir) & 3 ? (((dir) & 7) > 4 ? -1 : +1) : 0 )
#define DY(dir) ( DX((dir)+6) )
@ -56,6 +57,7 @@ enum {
COL_MINE,
COL_GEM,
COL_WALL,
COL_HINT,
NCOLOURS
};
@ -63,6 +65,12 @@ struct game_params {
int w, h;
};
typedef struct soln {
int refcount;
int len;
unsigned char *list;
} soln;
struct game_state {
game_params p;
int px, py;
@ -70,6 +78,9 @@ struct game_state {
char *grid;
int distance_moved;
int dead;
int cheated;
int solnpos;
soln *soln;
};
static game_params *default_params(void)
@ -627,6 +638,10 @@ static game_state *new_game(midend *me, game_params *params, char *desc)
state->distance_moved = 0;
state->dead = FALSE;
state->cheated = FALSE;
state->solnpos = 0;
state->soln = NULL;
return state;
}
@ -643,20 +658,750 @@ static game_state *dup_game(game_state *state)
ret->distance_moved = state->distance_moved;
ret->dead = FALSE;
memcpy(ret->grid, state->grid, wh);
ret->cheated = state->cheated;
ret->soln = state->soln;
if (ret->soln)
ret->soln->refcount++;
ret->solnpos = state->solnpos;
return ret;
}
static void free_game(game_state *state)
{
if (state->soln && --state->soln->refcount == 0) {
sfree(state->soln->list);
sfree(state->soln);
}
sfree(state->grid);
sfree(state);
}
/*
* Internal function used by solver.
*/
static int move_goes_to(int w, int h, char *grid, int x, int y, int d)
{
int dr;
/*
* See where we'd get to if we made this move.
*/
dr = -1; /* placate optimiser */
while (1) {
if (AT(w, h, grid, x+DX(d), y+DY(d)) == WALL) {
dr = DIRECTIONS; /* hit a wall, so end up stationary */
break;
}
x += DX(d);
y += DY(d);
if (AT(w, h, grid, x, y) == STOP) {
dr = DIRECTIONS; /* hit a stop, so end up stationary */
break;
}
if (AT(w, h, grid, x, y) == GEM) {
dr = d; /* hit a gem, so we're still moving */
break;
}
if (AT(w, h, grid, x, y) == MINE)
return -1; /* hit a mine, so move is invalid */
}
assert(dr >= 0);
return (y*w+x)*DP1+dr;
}
static int compare_integers(const void *av, const void *bv)
{
const int *a = (const int *)av;
const int *b = (const int *)bv;
if (*a < *b)
return -1;
else if (*a > *b)
return +1;
else
return 0;
}
static char *solve_game(game_state *state, game_state *currstate,
char *aux, char **error)
{
return NULL;
int w = state->p.w, h = state->p.h, wh = w*h;
int *nodes, *nodeindex, *edges, *backedges, *edgei, *backedgei, *circuit;
int nedges;
int *dist, *dist2, *list;
int *unvisited;
int circuitlen, circuitsize;
int head, tail, pass, i, j, n, x, y, d, dd;
char *err, *soln, *p;
/*
* Solving Inertia is a question of first building up the graph
* of where you can get to from where, and secondly finding a
* tour of the graph which takes in every gem.
*
* This is of course a close cousin of the travelling salesman
* problem, which is NP-complete; so I rather doubt that any
* _optimal_ tour can be found in plausible time. Hence I'll
* restrict myself to merely finding a not-too-bad one.
*
* First construct the graph, by bfsing out move by move from
* the current player position. Graph vertices will be
* - every endpoint of a move (place the ball can be
* stationary)
* - every gem (place the ball can go through in motion).
* Vertices of this type have an associated direction, since
* if a gem can be collected by sliding through it in two
* different directions it doesn't follow that you can
* change direction at it.
*
* I'm going to refer to a non-directional vertex as
* (y*w+x)*DP1+DIRECTIONS, and a directional one as
* (y*w+x)*DP1+d.
*/
/*
* nodeindex[] maps node codes as shown above to numeric
* indices in the nodes[] array.
*/
nodeindex = snewn(DP1*wh, int);
for (i = 0; i < DP1*wh; i++)
nodeindex[i] = -1;
/*
* Do the bfs to find all the interesting graph nodes.
*/
nodes = snewn(DP1*wh, int);
head = tail = 0;
nodes[tail] = (currstate->py * w + currstate->px) * DP1 + DIRECTIONS;
nodeindex[nodes[0]] = tail;
tail++;
while (head < tail) {
int nc = nodes[head++], nnc;
d = nc % DP1;
/*
* Plot all possible moves from this node. If the node is
* directed, there's only one.
*/
for (dd = 0; dd < DIRECTIONS; dd++) {
x = nc / DP1;
y = x / w;
x %= w;
if (d < DIRECTIONS && d != dd)
continue;
nnc = move_goes_to(w, h, currstate->grid, x, y, dd);
if (nnc >= 0 && nnc != nc) {
if (nodeindex[nnc] < 0) {
nodes[tail] = nnc;
nodeindex[nnc] = tail;
tail++;
}
}
}
}
n = head;
/*
* Now we know how many nodes we have, allocate the edge array
* and go through setting up the edges.
*/
edges = snewn(DIRECTIONS*n, int);
edgei = snewn(n+1, int);
nedges = 0;
for (i = 0; i < n; i++) {
int nc = nodes[i];
edgei[i] = nedges;
d = nc % DP1;
x = nc / DP1;
y = x / w;
x %= w;
for (dd = 0; dd < DIRECTIONS; dd++) {
int nnc;
if (d >= DIRECTIONS || d == dd) {
nnc = move_goes_to(w, h, currstate->grid, x, y, dd);
if (nnc >= 0 && nnc != nc)
edges[nedges++] = nodeindex[nnc];
}
}
}
edgei[n] = nedges;
/*
* Now set up the backedges array.
*/
backedges = snewn(nedges, int);
backedgei = snewn(n+1, int);
for (i = j = 0; i < nedges; i++) {
while (j+1 < n && i >= edgei[j+1])
j++;
backedges[i] = edges[i] * n + j;
}
qsort(backedges, nedges, sizeof(int), compare_integers);
backedgei[0] = 0;
for (i = j = 0; i < nedges; i++) {
int k = backedges[i] / n;
backedges[i] %= n;
while (j < k)
backedgei[++j] = i;
}
backedgei[n] = nedges;
/*
* Set up the initial tour. At all times, our tour is a circuit
* of graph vertices (which may, and probably will often,
* repeat vertices). To begin with, it's got exactly one vertex
* in it, which is the player's current starting point.
*/
circuitsize = 256;
circuit = snewn(circuitsize, int);
circuitlen = 0;
circuit[circuitlen++] = 0; /* node index 0 is the starting posn */
/*
* Track which gems are as yet unvisited.
*/
unvisited = snewn(wh, int);
for (i = 0; i < wh; i++)
unvisited[i] = FALSE;
for (i = 0; i < wh; i++)
if (currstate->grid[i] == GEM)
unvisited[i] = TRUE;
/*
* Allocate space for doing bfses inside the main loop.
*/
dist = snewn(n, int);
dist2 = snewn(n, int);
list = snewn(n, int);
err = NULL;
soln = NULL;
/*
* Now enter the main loop, in each iteration of which we
* extend the tour to take in an as yet uncollected gem.
*/
while (1) {
int target, n1, n2, bestdist, extralen, targetpos;
#ifdef TSP_DIAGNOSTICS
printf("circuit is");
for (i = 0; i < circuitlen; i++) {
int nc = nodes[circuit[i]];
printf(" (%d,%d,%d)", nc/DP1%w, nc/(DP1*w), nc%DP1);
}
printf("\n");
printf("moves are ");
x = nodes[circuit[0]] / DP1 % w;
y = nodes[circuit[0]] / DP1 / w;
for (i = 1; i < circuitlen; i++) {
int x2, y2, dx, dy;
if (nodes[circuit[i]] % DP1 != DIRECTIONS)
continue;
x2 = nodes[circuit[i]] / DP1 % w;
y2 = nodes[circuit[i]] / DP1 / w;
dx = (x2 > x ? +1 : x2 < x ? -1 : 0);
dy = (y2 > y ? +1 : y2 < y ? -1 : 0);
for (d = 0; d < DIRECTIONS; d++)
if (DX(d) == dx && DY(d) == dy)
printf("%c", "89632147"[d]);
x = x2;
y = y2;
}
printf("\n");
#endif
/*
* First, start a pair of bfses at _every_ vertex currently
* in the tour, and extend them outwards to find the
* nearest as yet unreached gem vertex.
*
* This is largely a heuristic: we could pick _any_ doubly
* reachable node here and still get a valid tour as
* output. I hope that picking a nearby one will result in
* generally good tours.
*/
for (pass = 0; pass < 2; pass++) {
int *ep = (pass == 0 ? edges : backedges);
int *ei = (pass == 0 ? edgei : backedgei);
int *dp = (pass == 0 ? dist : dist2);
head = tail = 0;
for (i = 0; i < n; i++)
dp[i] = -1;
for (i = 0; i < circuitlen; i++) {
int ni = circuit[i];
if (dp[ni] < 0) {
dp[ni] = 0;
list[tail++] = ni;
}
}
while (head < tail) {
int ni = list[head++];
for (i = ei[ni]; i < ei[ni+1]; i++) {
int ti = ep[i];
if (ti >= 0 && dp[ti] < 0) {
dp[ti] = dp[ni] + 1;
list[tail++] = ti;
}
}
}
}
/* Now find the nearest unvisited gem. */
bestdist = -1;
target = -1;
for (i = 0; i < n; i++) {
if (unvisited[nodes[i] / DP1] &&
dist[i] >= 0 && dist2[i] >= 0) {
int thisdist = dist[i] + dist2[i];
if (bestdist < 0 || bestdist > thisdist) {
bestdist = thisdist;
target = i;
}
}
}
if (target < 0) {
/*
* If we get to here, we haven't found a gem we can get
* at all, which means we terminate this loop.
*/
break;
}
/*
* Now we have a graph vertex at list[tail-1] which is an
* unvisited gem. We want to add that vertex to our tour.
* So we run two more breadth-first searches: one starting
* from that vertex and following forward edges, and
* another starting from the same vertex and following
* backward edges. This allows us to determine, for each
* node on the current tour, how quickly we can get both to
* and from the target vertex from that node.
*/
#ifdef TSP_DIAGNOSTICS
printf("target node is %d (%d,%d,%d)\n", target, nodes[target]/DP1%w,
nodes[target]/DP1/w, nodes[target]%DP1);
#endif
for (pass = 0; pass < 2; pass++) {
int *ep = (pass == 0 ? edges : backedges);
int *ei = (pass == 0 ? edgei : backedgei);
int *dp = (pass == 0 ? dist : dist2);
for (i = 0; i < n; i++)
dp[i] = -1;
head = tail = 0;
dp[target] = 0;
list[tail++] = target;
while (head < tail) {
int ni = list[head++];
for (i = ei[ni]; i < ei[ni+1]; i++) {
int ti = ep[i];
if (ti >= 0 && dp[ti] < 0) {
dp[ti] = dp[ni] + 1;
/*printf("pass %d: set dist of vertex %d to %d (via %d)\n", pass, ti, dp[ti], ni);*/
list[tail++] = ti;
}
}
}
}
/*
* Now for every node n, dist[n] gives the length of the
* shortest path from the target vertex to n, and dist2[n]
* gives the length of the shortest path from n to the
* target vertex.
*
* Our next step is to search linearly along the tour to
* find the optimum place to insert a trip to the target
* vertex and back. Our two options are either
* (a) to find two adjacent vertices A,B in the tour and
* replace the edge A->B with the path A->target->B
* (b) to find a single vertex X in the tour and replace
* it with the complete round trip X->target->X.
* We do whichever takes the fewest moves.
*/
n1 = n2 = -1;
bestdist = -1;
for (i = 0; i < circuitlen; i++) {
int thisdist;
/*
* Try a round trip from vertex i.
*/
if (dist[circuit[i]] >= 0 &&
dist2[circuit[i]] >= 0) {
thisdist = dist[circuit[i]] + dist2[circuit[i]];
if (bestdist < 0 || thisdist < bestdist) {
bestdist = thisdist;
n1 = n2 = i;
}
}
/*
* Try a trip from vertex i via target to vertex i+1.
*/
if (i+1 < circuitlen &&
dist2[circuit[i]] >= 0 &&
dist[circuit[i+1]] >= 0) {
thisdist = dist2[circuit[i]] + dist[circuit[i+1]];
if (bestdist < 0 || thisdist < bestdist) {
bestdist = thisdist;
n1 = i;
n2 = i+1;
}
}
}
if (bestdist < 0) {
/*
* We couldn't find a round trip taking in this gem _at
* all_. Give up.
*/
err = "Unable to find a solution from this starting point";
break;
}
#ifdef TSP_DIAGNOSTICS
printf("insertion point: n1=%d, n2=%d, dist=%d\n", n1, n2, bestdist);
#endif
#ifdef TSP_DIAGNOSTICS
printf("circuit before lengthening is");
for (i = 0; i < circuitlen; i++) {
printf(" %d", circuit[i]);
}
printf("\n");
#endif
/*
* Now actually lengthen the tour to take in this round
* trip.
*/
extralen = dist2[circuit[n1]] + dist[circuit[n2]];
if (n1 != n2)
extralen--;
circuitlen += extralen;
if (circuitlen >= circuitsize) {
circuitsize = circuitlen + 256;
circuit = sresize(circuit, circuitsize, int);
}
memmove(circuit + n2 + extralen, circuit + n2,
(circuitlen - n2 - extralen) * sizeof(int));
n2 += extralen;
#ifdef TSP_DIAGNOSTICS
printf("circuit in middle of lengthening is");
for (i = 0; i < circuitlen; i++) {
printf(" %d", circuit[i]);
}
printf("\n");
#endif
/*
* Find the shortest-path routes to and from the target,
* and write them into the circuit.
*/
targetpos = n1 + dist2[circuit[n1]];
assert(targetpos - dist2[circuit[n1]] == n1);
assert(targetpos + dist[circuit[n2]] == n2);
for (pass = 0; pass < 2; pass++) {
int dir = (pass == 0 ? -1 : +1);
int *ep = (pass == 0 ? backedges : edges);
int *ei = (pass == 0 ? backedgei : edgei);
int *dp = (pass == 0 ? dist : dist2);
int nn = (pass == 0 ? n2 : n1);
int ni = circuit[nn], ti, dest = nn;
while (1) {
circuit[dest] = ni;
if (dp[ni] == 0)
break;
dest += dir;
ti = -1;
/*printf("pass %d: looking at vertex %d\n", pass, ni);*/
for (i = ei[ni]; i < ei[ni+1]; i++) {
ti = ep[i];
if (ti >= 0 && dp[ti] == dp[ni] - 1)
break;
}
assert(i < ei[ni+1] && ti >= 0);
ni = ti;
}
}
#ifdef TSP_DIAGNOSTICS
printf("circuit after lengthening is");
for (i = 0; i < circuitlen; i++) {
printf(" %d", circuit[i]);
}
printf("\n");
#endif
/*
* Finally, mark all gems that the new piece of circuit
* passes through as visited.
*/
for (i = n1; i <= n2; i++) {
int pos = nodes[circuit[i]] / DP1;
assert(pos >= 0 && pos < wh);
unvisited[pos] = FALSE;
}
}
#ifdef TSP_DIAGNOSTICS
printf("before reduction, moves are ");
x = nodes[circuit[0]] / DP1 % w;
y = nodes[circuit[0]] / DP1 / w;
for (i = 1; i < circuitlen; i++) {
int x2, y2, dx, dy;
if (nodes[circuit[i]] % DP1 != DIRECTIONS)
continue;
x2 = nodes[circuit[i]] / DP1 % w;
y2 = nodes[circuit[i]] / DP1 / w;
dx = (x2 > x ? +1 : x2 < x ? -1 : 0);
dy = (y2 > y ? +1 : y2 < y ? -1 : 0);
for (d = 0; d < DIRECTIONS; d++)
if (DX(d) == dx && DY(d) == dy)
printf("%c", "89632147"[d]);
x = x2;
y = y2;
}
printf("\n");
#endif
/*
* That's got a basic solution. Now optimise it by removing
* redundant sections of the circuit: it's entirely possible
* that a piece of circuit we carefully inserted at one stage
* to collect a gem has become pointless because the steps
* required to collect some _later_ gem necessarily passed
* through the same one.
*
* So first we go through and work out how many times each gem
* is collected. Then we look for maximal sections of circuit
* which are redundant in the sense that their removal would
* not reduce any gem's collection count to zero, and replace
* each one with a bfs-derived fastest path between their
* endpoints.
*/
while (1) {
int oldlen = circuitlen;
for (i = 0; i < wh; i++)
unvisited[i] = 0;
for (i = 0; i < circuitlen; i++) {
int xy = nodes[circuit[i]] / DP1;
if (currstate->grid[xy] == GEM)
unvisited[xy]++;
}
/*
* If there's any gem we didn't end up visiting at all,
* give up.
*/
for (i = 0; i < wh; i++) {
if (currstate->grid[i] == GEM && unvisited[i] == 0) {
err = "Unable to find a solution from this starting point";
break;
}
}
if (i < wh)
break;
for (i = j = 0; i < circuitlen; i++) {
int xy = nodes[circuit[i]] / DP1;
if (currstate->grid[xy] == GEM && unvisited[xy] > 1) {
unvisited[xy]--;
} else if (currstate->grid[xy] == GEM || i == circuitlen-1) {
/*
* circuit[i] collects a gem for the only time, or is
* the last node in the circuit. Therefore it cannot be
* removed; so we now want to replace the path from
* circuit[j] to circuit[i] with a bfs-shortest path.
*/
int k, dest, ni, ti, thisdist;
#ifdef TSP_DIAGNOSTICS
printf("optimising section from %d - %d\n", j, i);
#endif
for (k = 0; k < n; k++)
dist[k] = -1;
head = tail = 0;
dist[circuit[j]] = 0;
list[tail++] = circuit[j];
while (head < tail && dist[circuit[i]] < 0) {
int ni = list[head++];
for (k = edgei[ni]; k < edgei[ni+1]; k++) {
int ti = edges[k];
if (ti >= 0 && dist[ti] < 0) {
dist[ti] = dist[ni] + 1;
list[tail++] = ti;
}
}
}
thisdist = dist[circuit[i]];
assert(thisdist >= 0 && thisdist <= i-j);
memmove(circuit+j+thisdist, circuit+i,
(circuitlen - i) * sizeof(int));
circuitlen -= i-j;
i = j + thisdist;
circuitlen += i-j;
#ifdef TSP_DIAGNOSTICS
printf("new section runs from %d - %d\n", j, i);
#endif
dest = i;
assert(dest >= 0);
ni = circuit[i];
while (1) {
/* printf("dest=%d circuitlen=%d ni=%d dist[ni]=%d\n", dest, circuitlen, ni, dist[ni]); */
circuit[dest] = ni;
if (dist[ni] == 0)
break;
dest--;
ti = -1;
for (k = backedgei[ni]; k < backedgei[ni+1]; k++) {
ti = backedges[k];
if (ti >= 0 && dist[ti] == dist[ni] - 1)
break;
}
assert(k < backedgei[ni+1] && ti >= 0);
ni = ti;
}
/*
* Now re-increment the visit counts for the new
* path.
*/
while (++j < i) {
int xy = nodes[circuit[j]] / DP1;
if (currstate->grid[xy] == GEM)
unvisited[xy]++;
}
#ifdef TSP_DIAGNOSTICS
printf("during reduction, circuit is");
for (k = 0; k < circuitlen; k++) {
int nc = nodes[circuit[k]];
printf(" (%d,%d,%d)", nc/DP1%w, nc/(DP1*w), nc%DP1);
}
printf("\n");
printf("moves are ");
x = nodes[circuit[0]] / DP1 % w;
y = nodes[circuit[0]] / DP1 / w;
for (k = 1; k < circuitlen; k++) {
int x2, y2, dx, dy;
if (nodes[circuit[k]] % DP1 != DIRECTIONS)
continue;
x2 = nodes[circuit[k]] / DP1 % w;
y2 = nodes[circuit[k]] / DP1 / w;
dx = (x2 > x ? +1 : x2 < x ? -1 : 0);
dy = (y2 > y ? +1 : y2 < y ? -1 : 0);
for (d = 0; d < DIRECTIONS; d++)
if (DX(d) == dx && DY(d) == dy)
printf("%c", "89632147"[d]);
x = x2;
y = y2;
}
printf("\n");
#endif
}
}
#ifdef TSP_DIAGNOSTICS
printf("after reduction, moves are ");
x = nodes[circuit[0]] / DP1 % w;
y = nodes[circuit[0]] / DP1 / w;
for (i = 1; i < circuitlen; i++) {
int x2, y2, dx, dy;
if (nodes[circuit[i]] % DP1 != DIRECTIONS)
continue;
x2 = nodes[circuit[i]] / DP1 % w;
y2 = nodes[circuit[i]] / DP1 / w;
dx = (x2 > x ? +1 : x2 < x ? -1 : 0);
dy = (y2 > y ? +1 : y2 < y ? -1 : 0);
for (d = 0; d < DIRECTIONS; d++)
if (DX(d) == dx && DY(d) == dy)
printf("%c", "89632147"[d]);
x = x2;
y = y2;
}
printf("\n");
#endif
/*
* If we've managed an entire reduction pass and not made
* the solution any shorter, we're _really_ done.
*/
if (circuitlen == oldlen)
break;
}
/*
* Encode the solution as a move string.
*/
if (!err) {
soln = snewn(circuitlen+2, char);
p = soln;
*p++ = 'S';
x = nodes[circuit[0]] / DP1 % w;
y = nodes[circuit[0]] / DP1 / w;
for (i = 1; i < circuitlen; i++) {
int x2, y2, dx, dy;
if (nodes[circuit[i]] % DP1 != DIRECTIONS)
continue;
x2 = nodes[circuit[i]] / DP1 % w;
y2 = nodes[circuit[i]] / DP1 / w;
dx = (x2 > x ? +1 : x2 < x ? -1 : 0);
dy = (y2 > y ? +1 : y2 < y ? -1 : 0);
for (d = 0; d < DIRECTIONS; d++)
if (DX(d) == dx && DY(d) == dy) {
*p++ = '0' + d;
break;
}
assert(d < DIRECTIONS);
x = x2;
y = y2;
}
*p++ = '\0';
assert(p - soln < circuitlen+2);
}
sfree(list);
sfree(dist);
sfree(dist2);
sfree(unvisited);
sfree(circuit);
sfree(backedgei);
sfree(backedges);
sfree(edgei);
sfree(edges);
sfree(nodeindex);
sfree(nodes);
if (err)
*error = err;
return soln;
}
static char *game_text_format(game_state *state)
@ -785,6 +1530,8 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
dir = 1;
else if (button == (MOD_NUM_KEYPAD | '3'))
dir = 3;
else if (button == ' ' && state->soln && state->solnpos < state->soln->len)
dir = state->soln->list[state->solnpos];
if (dir < 0)
return NULL;
@ -814,9 +1561,33 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
static game_state *execute_move(game_state *state, char *move)
{
int w = state->p.w, h = state->p.h /*, wh = w*h */;
int dir = atoi(move);
int dir;
game_state *ret;
if (*move == 'S') {
int len, i;
soln *sol;
/*
* This is a solve move, so we don't actually _change_ the
* grid but merely set up a stored solution path.
*/
move++;
len = strlen(move);
sol = snew(soln);
sol->len = len;
sol->list = snewn(len, unsigned char);
for (i = 0; i < len; i++)
sol->list[i] = move[i] - '0';
ret = dup_game(state);
ret->cheated = TRUE;
ret->soln = sol;
ret->solnpos = 0;
sol->refcount = 1;
return ret;
}
dir = atoi(move);
if (dir < 0 || dir >= DIRECTIONS)
return NULL; /* huh? */
@ -852,6 +1623,26 @@ static game_state *execute_move(game_state *state, char *move)
break;
}
if (ret->soln) {
/*
* If this move is the correct next one in the stored
* solution path, advance solnpos.
*/
if (ret->soln->list[ret->solnpos] == dir &&
ret->solnpos+1 < ret->soln->len) {
ret->solnpos++;
} else {
/*
* Otherwise, the user has strayed from the path, so
* the path is no longer valid.
*/
ret->soln->refcount--;
assert(ret->soln->refcount > 0);/* `state' at least still exists */
ret->soln = NULL;
ret->solnpos = 0;
}
}
return ret;
}
@ -913,6 +1704,10 @@ static float *game_colours(frontend *fe, game_state *state, int *ncolours)
1 * ret[COL_HIGHLIGHT * 3 + i]) / 4;
}
ret[COL_HINT * 3 + 0] = 1.0F;
ret[COL_HINT * 3 + 1] = 1.0F;
ret[COL_HINT * 3 + 2] = 0.0F;
*ncolours = NCOLOURS;
return ret;
}
@ -949,7 +1744,7 @@ static void game_free_drawstate(drawing *dr, game_drawstate *ds)
}
static void draw_player(drawing *dr, game_drawstate *ds, int x, int y,
int dead)
int dead, int hintdir)
{
if (dead) {
int coords[DIRECTIONS*4];
@ -979,6 +1774,33 @@ static void draw_player(drawing *dr, game_drawstate *ds, int x, int y,
draw_circle(dr, x + TILESIZE/2, y + TILESIZE/2,
TILESIZE/3, COL_PLAYER, COL_OUTLINE);
}
if (!dead && hintdir >= 0) {
float scale = (DX(hintdir) && DY(hintdir) ? 0.8F : 1.0F);
int ax = (TILESIZE*2/5) * scale * DX(hintdir);
int ay = (TILESIZE*2/5) * scale * DY(hintdir);
int px = -ay, py = ax;
int ox = x + TILESIZE/2, oy = y + TILESIZE/2;
int coords[14], *c;
c = coords;
*c++ = ox + px/9;
*c++ = oy + py/9;
*c++ = ox + px/9 + ax*2/3;
*c++ = oy + py/9 + ay*2/3;
*c++ = ox + px/3 + ax*2/3;
*c++ = oy + py/3 + ay*2/3;
*c++ = ox + ax;
*c++ = oy + ay;
*c++ = ox - px/3 + ax*2/3;
*c++ = oy - py/3 + ay*2/3;
*c++ = ox - px/9 + ax*2/3;
*c++ = oy - py/9 + ay*2/3;
*c++ = ox - px/9;
*c++ = oy - py/9;
draw_polygon(dr, coords, 7, COL_HINT, COL_OUTLINE);
}
draw_update(dr, x, y, TILESIZE, TILESIZE);
}
@ -1204,12 +2026,19 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
* shown between the collection of the last gem and the
* completion of the move animation that did it.)
*/
if (state->dead && (!oldstate || oldstate->dead))
if (state->dead && (!oldstate || oldstate->dead)) {
sprintf(status, "DEAD!");
else if (state->gems || (oldstate && oldstate->gems))
sprintf(status, "Gems: %d", gems);
} else if (state->gems || (oldstate && oldstate->gems)) {
if (state->cheated)
sprintf(status, "Auto-solver used. ");
else
*status = '\0';
sprintf(status + strlen(status), "Gems: %d", gems);
} else if (state->cheated) {
sprintf(status, "Auto-solved.");
} else {
sprintf(status, "COMPLETED!");
}
/* We subtract one from the visible death counter if we're still
* animating the move at the end of which the death took place. */
deaths = ui->deaths;
@ -1241,7 +2070,10 @@ static void game_redraw(drawing *dr, game_drawstate *ds, game_state *oldstate,
ds->pbgy = oy + ap * (ny - oy);
}
blitter_save(dr, ds->player_background, ds->pbgx, ds->pbgy);
draw_player(dr, ds, ds->pbgx, ds->pbgy, (state->dead && !oldstate));
draw_player(dr, ds, ds->pbgx, ds->pbgy,
(state->dead && !oldstate),
(!oldstate && state->soln ?
state->soln->list[state->solnpos] : -1));
ds->player_bg_saved = TRUE;
}
@ -1307,7 +2139,7 @@ const struct game thegame = {
new_game,
dup_game,
free_game,
FALSE, solve_game,
TRUE, solve_game,
FALSE, game_text_format,
new_ui,
free_ui,

12
puzzles.but
View File

@ -1775,6 +1775,18 @@ numeric keypad. Alternatively, if you click the left mouse button on
the grid, the ball will begin a move in the general direction of
where you clicked.
If you use the \q{Solve} function on this game, the program will
compute a path through the grid which collects all the remaining
gems and returns to the current position. A hint arrow will appear
on the ball indicating the direction in which you should move to
begin on this path. If you then move in that direction, the arrow
will update to indicate the next direction on the path. You can also
press Space to automatically move in the direction of the hint
arrow. If you move in a different direction from the one shown by
the arrow, the hint arrows will stop appearing because you have
strayed from the provided path; you can then use \q{Solve} again to
generate a new path if you want to.
All the actions described in \k{common-actions} are also available.
In particular, if you do run into a mine and die, you can use the
Undo function and resume playing from before the fatal move. The