* midend.c: general middle fragment sitting between the
* platform-specific front end and game-specific back end.
* Maintains a move list, takes care of Undo and Redo commands, and
- * processes standard keystrokes for undo/redo/new/restart/quit.
+ * processes standard keystrokes for undo/redo/new/quit.
*/
#include <stdio.h>
+#include <string.h>
#include <assert.h>
#include "puzzles.h"
+enum { DEF_PARAMS, DEF_SEED, DEF_DESC }; /* for midend_game_id_int */
+
+struct midend_state_entry {
+ game_state *state;
+ int special; /* created by solve or restart */
+};
+
struct midend_data {
- char *seed;
+ frontend *frontend;
+ random_state *random;
+ const game *ourgame;
+
+ char *desc, *seedstr;
+ game_aux_info *aux_info;
+ enum { GOT_SEED, GOT_DESC, GOT_NOTHING } genmode;
int nstates, statesize, statepos;
- game_params *params;
- game_state **states;
+
+ game_params **presets;
+ char **preset_names;
+ int npresets, presetsize;
+
+ game_params *params, *tmpparams;
+ struct midend_state_entry *states;
+ game_drawstate *drawstate;
+ game_state *oldstate;
+ game_ui *ui;
+ float anim_time, anim_pos;
+ float flash_time, flash_pos;
+ int dir;
+
+ int pressed_mouse_button;
};
#define ensure(me) do { \
if ((me)->nstates >= (me)->statesize) { \
(me)->statesize = (me)->nstates + 128; \
- (me)->states = sresize((me)->states, (me)->statesize, game_state *); \
+ (me)->states = sresize((me)->states, (me)->statesize, \
+ struct midend_state_entry); \
} \
} while (0)
-midend_data *midend_new(void)
+midend_data *midend_new(frontend *fe, const game *ourgame)
{
midend_data *me = snew(midend_data);
+ void *randseed;
+ int randseedsize;
+
+ get_random_seed(&randseed, &randseedsize);
+ me->frontend = fe;
+ me->ourgame = ourgame;
+ me->random = random_init(randseed, randseedsize);
me->nstates = me->statesize = me->statepos = 0;
me->states = NULL;
- me->params = default_params();
- me->seed = NULL;
+ me->params = ourgame->default_params();
+ me->tmpparams = NULL;
+ me->desc = NULL;
+ me->seedstr = NULL;
+ me->aux_info = NULL;
+ me->genmode = GOT_NOTHING;
+ me->drawstate = NULL;
+ me->oldstate = NULL;
+ me->presets = NULL;
+ me->preset_names = NULL;
+ me->npresets = me->presetsize = 0;
+ me->anim_time = me->anim_pos = 0.0F;
+ me->flash_time = me->flash_pos = 0.0F;
+ me->dir = 0;
+ me->ui = NULL;
+ me->pressed_mouse_button = 0;
+
+ sfree(randseed);
return me;
}
void midend_free(midend_data *me)
{
sfree(me->states);
- sfree(me->seed);
- free_params(me->params);
+ sfree(me->desc);
+ sfree(me->seedstr);
+ random_free(me->random);
+ if (me->aux_info)
+ me->ourgame->free_aux_info(me->aux_info);
+ me->ourgame->free_params(me->params);
+ if (me->tmpparams)
+ me->ourgame->free_params(me->tmpparams);
sfree(me);
}
void midend_size(midend_data *me, int *x, int *y)
{
- game_size(me->params, x, y);
+ me->ourgame->size(me->params, x, y);
}
void midend_set_params(midend_data *me, game_params *params)
{
- free_params(me->params);
- me->params = params;
+ me->ourgame->free_params(me->params);
+ me->params = me->ourgame->dup_params(params);
}
-void midend_new_game(midend_data *me, char *seed)
+void midend_new_game(midend_data *me)
{
while (me->nstates > 0)
- free_game(me->states[--me->nstates]);
+ me->ourgame->free_game(me->states[--me->nstates].state);
+
+ if (me->drawstate)
+ me->ourgame->free_drawstate(me->drawstate);
assert(me->nstates == 0);
- sfree(me->seed);
- if (seed)
- me->seed = dupstr(seed);
- else
- me->seed = new_game_seed(me->params);
+ if (me->genmode == GOT_DESC) {
+ me->genmode = GOT_NOTHING;
+ } else {
+ random_state *rs;
+
+ if (me->genmode == GOT_SEED) {
+ me->genmode = GOT_NOTHING;
+ } else {
+ /*
+ * Generate a new random seed. 15 digits comes to about
+ * 48 bits, which should be more than enough.
+ */
+ char newseed[16];
+ int i;
+ newseed[15] = '\0';
+ for (i = 0; i < 15; i++)
+ newseed[i] = '0' + random_upto(me->random, 10);
+ sfree(me->seedstr);
+ me->seedstr = dupstr(newseed);
+ }
+
+ sfree(me->desc);
+ if (me->aux_info)
+ me->ourgame->free_aux_info(me->aux_info);
+ me->aux_info = NULL;
+
+ rs = random_init(me->seedstr, strlen(me->seedstr));
+ me->desc = me->ourgame->new_desc
+ (me->tmpparams ? me->tmpparams : me->params, rs, &me->aux_info);
+ random_free(rs);
+
+ if (me->tmpparams) {
+ me->ourgame->free_params(me->tmpparams);
+ me->tmpparams = NULL;
+ }
+ }
ensure(me);
- me->states[me->nstates++] = new_game(me->params, me->seed);
+ me->states[me->nstates].state = me->ourgame->new_game(me->params, me->desc);
+ me->states[me->nstates].special = TRUE;
+ me->nstates++;
me->statepos = 1;
+ me->drawstate = me->ourgame->new_drawstate(me->states[0].state);
+ if (me->ui)
+ me->ourgame->free_ui(me->ui);
+ me->ui = me->ourgame->new_ui(me->states[0].state);
+ me->pressed_mouse_button = 0;
}
-void midend_restart_game(midend_data *me)
+static int midend_undo(midend_data *me)
{
- while (me->nstates > 1)
- free_game(me->states[--me->nstates]);
- me->statepos = me->nstates;
+ if (me->statepos > 1) {
+ me->statepos--;
+ me->dir = -1;
+ return 1;
+ } else
+ return 0;
}
-void midend_undo(midend_data *me)
+static int midend_redo(midend_data *me)
{
- if (me->statepos > 1)
- me->statepos--;
+ if (me->statepos < me->nstates) {
+ me->statepos++;
+ me->dir = +1;
+ return 1;
+ } else
+ return 0;
}
-void midend_redo(midend_data *me)
+static void midend_finish_move(midend_data *me)
{
- if (me->statepos < me->nstates)
- me->statepos++;
+ float flashtime;
+
+ /*
+ * We do not flash if the later of the two states is special.
+ * This covers both forward Solve moves and backward (undone)
+ * Restart moves.
+ */
+ if ((me->oldstate || me->statepos > 1) &&
+ ((me->dir > 0 && !me->states[me->statepos-1].special) ||
+ (me->dir < 0 && me->statepos < me->nstates &&
+ !me->states[me->statepos].special))) {
+ flashtime = me->ourgame->flash_length(me->oldstate ? me->oldstate :
+ me->states[me->statepos-2].state,
+ me->states[me->statepos-1].state,
+ me->oldstate ? me->dir : +1);
+ if (flashtime > 0) {
+ me->flash_pos = 0.0F;
+ me->flash_time = flashtime;
+ }
+ }
+
+ if (me->oldstate)
+ me->ourgame->free_game(me->oldstate);
+ me->oldstate = NULL;
+ me->anim_pos = me->anim_time = 0;
+ me->dir = 0;
+
+ if (me->flash_time == 0 && me->anim_time == 0)
+ deactivate_timer(me->frontend);
+ else
+ activate_timer(me->frontend);
}
-int midend_process_key(midend_data *me, int x, int y, int button)
+static void midend_stop_anim(midend_data *me)
+{
+ if (me->oldstate || me->anim_time) {
+ midend_finish_move(me);
+ midend_redraw(me);
+ }
+}
+
+void midend_restart_game(midend_data *me)
{
game_state *s;
+ midend_stop_anim(me);
+
+ assert(me->statepos >= 1);
+ if (me->statepos == 1)
+ return; /* no point doing anything at all! */
+
+ s = me->ourgame->dup_game(me->states[0].state);
+
+ /*
+ * Now enter the restarted state as the next move.
+ */
+ midend_stop_anim(me);
+ while (me->nstates > me->statepos)
+ me->ourgame->free_game(me->states[--me->nstates].state);
+ ensure(me);
+ me->states[me->nstates].state = s;
+ me->states[me->nstates].special = TRUE; /* we just restarted */
+ me->statepos = ++me->nstates;
+ me->anim_time = 0.0;
+ midend_finish_move(me);
+ midend_redraw(me);
+ activate_timer(me->frontend);
+}
+
+static int midend_really_process_key(midend_data *me, int x, int y, int button)
+{
+ game_state *oldstate =
+ me->ourgame->dup_game(me->states[me->statepos - 1].state);
+ int special = FALSE, gotspecial = FALSE;
+ float anim_time;
+
if (button == 'n' || button == 'N' || button == '\x0E') {
- midend_new_game(me, NULL);
- return 1;
- } else if (button == 'r' || button == 'R') {
- midend_restart_game(me);
- return 1;
+ midend_stop_anim(me);
+ midend_new_game(me);
+ midend_redraw(me);
+ return 1; /* never animate */
} else if (button == 'u' || button == 'u' ||
- button == '\x1A' || button == '\x1F') {
- midend_undo(me);
- return 1;
- } else if (button == '\x12') {
- midend_redo(me);
- return 1;
+ button == '\x1A' || button == '\x1F') {
+ midend_stop_anim(me);
+ special = me->states[me->statepos-1].special;
+ gotspecial = TRUE;
+ if (!midend_undo(me))
+ return 1;
+ } else if (button == 'r' || button == 'R' ||
+ button == '\x12') {
+ midend_stop_anim(me);
+ if (!midend_redo(me))
+ return 1;
} else if (button == 'q' || button == 'Q' || button == '\x11') {
- return 0;
+ me->ourgame->free_game(oldstate);
+ return 0;
+ } else {
+ game_state *s =
+ me->ourgame->make_move(me->states[me->statepos-1].state,
+ me->ui, x, y, button);
+
+ if (s == me->states[me->statepos-1].state) {
+ /*
+ * make_move() is allowed to return its input state to
+ * indicate that although no move has been made, the UI
+ * state has been updated and a redraw is called for.
+ */
+ midend_redraw(me);
+ return 1;
+ } else if (s) {
+ midend_stop_anim(me);
+ while (me->nstates > me->statepos)
+ me->ourgame->free_game(me->states[--me->nstates].state);
+ ensure(me);
+ me->states[me->nstates].state = s;
+ me->states[me->nstates].special = FALSE; /* normal move */
+ me->statepos = ++me->nstates;
+ me->dir = +1;
+ } else {
+ me->ourgame->free_game(oldstate);
+ return 1;
+ }
}
- s = make_move(me->states[me->statepos-1], x, y, button);
+ if (!gotspecial)
+ special = me->states[me->statepos-1].special;
- if (s) {
- while (me->nstates > me->statepos)
- free_game(me->states[--me->nstates]);
- ensure(me);
- me->states[me->nstates] = s;
- me->statepos = ++me->nstates;
+ /*
+ * See if this move requires an animation.
+ */
+ if (special) {
+ anim_time = 0;
+ } else {
+ anim_time = me->ourgame->anim_length(oldstate,
+ me->states[me->statepos-1].state,
+ me->dir);
}
+ me->oldstate = oldstate;
+ if (anim_time > 0) {
+ me->anim_time = anim_time;
+ } else {
+ me->anim_time = 0.0;
+ midend_finish_move(me);
+ }
+ me->anim_pos = 0.0;
+
+ midend_redraw(me);
+
+ activate_timer(me->frontend);
+
return 1;
}
+
+int midend_process_key(midend_data *me, int x, int y, int button)
+{
+ int ret = 1;
+
+ /*
+ * Harmonise mouse drag and release messages.
+ *
+ * Some front ends might accidentally switch from sending, say,
+ * RIGHT_DRAG messages to sending LEFT_DRAG, half way through a
+ * drag. (This can happen on the Mac, for example, since
+ * RIGHT_DRAG is usually done using Command+drag, and if the
+ * user accidentally releases Command half way through the drag
+ * then there will be trouble.)
+ *
+ * It would be an O(number of front ends) annoyance to fix this
+ * in the front ends, but an O(number of back ends) annoyance
+ * to have each game capable of dealing with it. Therefore, we
+ * fix it _here_ in the common midend code so that it only has
+ * to be done once.
+ *
+ * The possible ways in which things can go screwy in the front
+ * end are:
+ *
+ * - in a system containing multiple physical buttons button
+ * presses can inadvertently overlap. We can see ABab (caps
+ * meaning button-down and lowercase meaning button-up) when
+ * the user had semantically intended AaBb.
+ *
+ * - in a system where one button is simulated by means of a
+ * modifier key and another button, buttons can mutate
+ * between press and release (possibly during drag). So we
+ * can see Ab instead of Aa.
+ *
+ * Definite requirements are:
+ *
+ * - button _presses_ must never be invented or destroyed. If
+ * the user presses two buttons in succession, the button
+ * presses must be transferred to the backend unchanged. So
+ * if we see AaBb , that's fine; if we see ABab (the button
+ * presses inadvertently overlapped) we must somehow
+ * `correct' it to AaBb.
+ *
+ * - every mouse action must end up looking like a press, zero
+ * or more drags, then a release. This allows back ends to
+ * make the _assumption_ that incoming mouse data will be
+ * sane in this regard, and not worry about the details.
+ *
+ * So my policy will be:
+ *
+ * - treat any button-up as a button-up for the currently
+ * pressed button, or ignore it if there is no currently
+ * pressed button.
+ *
+ * - treat any drag as a drag for the currently pressed
+ * button, or ignore it if there is no currently pressed
+ * button.
+ *
+ * - if we see a button-down while another button is currently
+ * pressed, invent a button-up for the first one and then
+ * pass the button-down through as before.
+ *
+ */
+ if (IS_MOUSE_DRAG(button) || IS_MOUSE_RELEASE(button)) {
+ if (me->pressed_mouse_button) {
+ if (IS_MOUSE_DRAG(button)) {
+ button = me->pressed_mouse_button +
+ (LEFT_DRAG - LEFT_BUTTON);
+ } else {
+ button = me->pressed_mouse_button +
+ (LEFT_RELEASE - LEFT_BUTTON);
+ }
+ } else
+ return ret; /* ignore it */
+ } else if (IS_MOUSE_DOWN(button) && me->pressed_mouse_button) {
+ /*
+ * Fabricate a button-up for the previously pressed button.
+ */
+ ret = ret && midend_really_process_key
+ (me, x, y, (me->pressed_mouse_button +
+ (LEFT_RELEASE - LEFT_BUTTON)));
+ }
+
+ /*
+ * Now send on the event we originally received.
+ */
+ ret = ret && midend_really_process_key(me, x, y, button);
+
+ /*
+ * And update the currently pressed button.
+ */
+ if (IS_MOUSE_RELEASE(button))
+ me->pressed_mouse_button = 0;
+ else if (IS_MOUSE_DOWN(button))
+ me->pressed_mouse_button = button;
+
+ return ret;
+}
+
+void midend_redraw(midend_data *me)
+{
+ if (me->statepos > 0 && me->drawstate) {
+ start_draw(me->frontend);
+ if (me->oldstate && me->anim_time > 0 &&
+ me->anim_pos < me->anim_time) {
+ assert(me->dir != 0);
+ me->ourgame->redraw(me->frontend, me->drawstate, me->oldstate,
+ me->states[me->statepos-1].state, me->dir,
+ me->ui, me->anim_pos, me->flash_pos);
+ } else {
+ me->ourgame->redraw(me->frontend, me->drawstate, NULL,
+ me->states[me->statepos-1].state, +1 /*shrug*/,
+ me->ui, 0.0, me->flash_pos);
+ }
+ end_draw(me->frontend);
+ }
+}
+
+void midend_timer(midend_data *me, float tplus)
+{
+ me->anim_pos += tplus;
+ if (me->anim_pos >= me->anim_time ||
+ me->anim_time == 0 || !me->oldstate) {
+ if (me->anim_time > 0)
+ midend_finish_move(me);
+ }
+ me->flash_pos += tplus;
+ if (me->flash_pos >= me->flash_time || me->flash_time == 0) {
+ me->flash_pos = me->flash_time = 0;
+ }
+ if (me->flash_time == 0 && me->anim_time == 0)
+ deactivate_timer(me->frontend);
+ midend_redraw(me);
+}
+
+float *midend_colours(midend_data *me, int *ncolours)
+{
+ game_state *state = NULL;
+ float *ret;
+
+ if (me->nstates == 0) {
+ game_aux_info *aux = NULL;
+ char *desc = me->ourgame->new_desc(me->params, me->random, &aux);
+ state = me->ourgame->new_game(me->params, desc);
+ sfree(desc);
+ if (aux)
+ me->ourgame->free_aux_info(aux);
+ } else
+ state = me->states[0].state;
+
+ ret = me->ourgame->colours(me->frontend, state, ncolours);
+
+ if (me->nstates == 0)
+ me->ourgame->free_game(state);
+
+ return ret;
+}
+
+int midend_num_presets(midend_data *me)
+{
+ if (!me->npresets) {
+ char *name;
+ game_params *preset;
+
+ while (me->ourgame->fetch_preset(me->npresets, &name, &preset)) {
+ if (me->presetsize <= me->npresets) {
+ me->presetsize = me->npresets + 10;
+ me->presets = sresize(me->presets, me->presetsize,
+ game_params *);
+ me->preset_names = sresize(me->preset_names, me->presetsize,
+ char *);
+ }
+
+ me->presets[me->npresets] = preset;
+ me->preset_names[me->npresets] = name;
+ me->npresets++;
+ }
+ }
+
+ return me->npresets;
+}
+
+void midend_fetch_preset(midend_data *me, int n,
+ char **name, game_params **params)
+{
+ assert(n >= 0 && n < me->npresets);
+ *name = me->preset_names[n];
+ *params = me->presets[n];
+}
+
+int midend_wants_statusbar(midend_data *me)
+{
+ return me->ourgame->wants_statusbar();
+}
+
+config_item *midend_get_config(midend_data *me, int which, char **wintitle)
+{
+ char *titlebuf, *parstr;
+ config_item *ret;
+
+ titlebuf = snewn(40 + strlen(me->ourgame->name), char);
+
+ switch (which) {
+ case CFG_SETTINGS:
+ sprintf(titlebuf, "%s configuration", me->ourgame->name);
+ *wintitle = dupstr(titlebuf);
+ return me->ourgame->configure(me->params);
+ case CFG_SEED:
+ case CFG_DESC:
+ sprintf(titlebuf, "%s %s selection", me->ourgame->name,
+ which == CFG_SEED ? "random" : "game");
+ *wintitle = dupstr(titlebuf);
+
+ ret = snewn(2, config_item);
+
+ ret[0].type = C_STRING;
+ if (which == CFG_SEED)
+ ret[0].name = "Game random seed";
+ else
+ ret[0].name = "Game ID";
+ ret[0].ival = 0;
+ /*
+ * For CFG_DESC the text going in here will be a string
+ * encoding of the restricted parameters, plus a colon,
+ * plus the game description. For CFG_SEED it will be the
+ * full parameters, plus a hash, plus the random seed data.
+ * Either of these is a valid full game ID (although only
+ * the former is likely to persist across many code
+ * changes).
+ */
+ parstr = me->ourgame->encode_params(me->params, which == CFG_SEED);
+ if (which == CFG_DESC) {
+ ret[0].sval = snewn(strlen(parstr) + strlen(me->desc) + 2, char);
+ sprintf(ret[0].sval, "%s:%s", parstr, me->desc);
+ } else if (me->seedstr) {
+ ret[0].sval = snewn(strlen(parstr) + strlen(me->seedstr) + 2, char);
+ sprintf(ret[0].sval, "%s#%s", parstr, me->seedstr);
+ } else {
+ /*
+ * If the current game was not randomly generated, the
+ * best we can do is to give a template for typing a
+ * new seed in.
+ */
+ ret[0].sval = snewn(strlen(parstr) + 2, char);
+ sprintf(ret[0].sval, "%s#", parstr);
+ }
+ sfree(parstr);
+
+ ret[1].type = C_END;
+ ret[1].name = ret[1].sval = NULL;
+ ret[1].ival = 0;
+
+ return ret;
+ }
+
+ assert(!"We shouldn't be here");
+ return NULL;
+}
+
+static char *midend_game_id_int(midend_data *me, char *id, int defmode)
+{
+ char *error, *par, *desc, *seed;
+
+ seed = strchr(id, '#');
+ desc = strchr(id, ':');
+
+ if (desc && (!seed || desc < seed)) {
+ /*
+ * We have a colon separating parameters from game
+ * description. So `par' now points to the parameters
+ * string, and `desc' to the description string.
+ */
+ *desc++ = '\0';
+ par = id;
+ seed = NULL;
+ } else if (seed && (!desc || seed < desc)) {
+ /*
+ * We have a hash separating parameters from random seed.
+ * So `par' now points to the parameters string, and `seed'
+ * to the seed string.
+ */
+ *seed++ = '\0';
+ par = id;
+ desc = NULL;
+ } else {
+ /*
+ * We only have one string. Depending on `defmode', we take
+ * it to be either parameters, seed or description.
+ */
+ if (defmode == DEF_SEED) {
+ seed = id;
+ par = desc = NULL;
+ } else if (defmode == DEF_DESC) {
+ desc = id;
+ par = seed = NULL;
+ } else {
+ par = id;
+ seed = desc = NULL;
+ }
+ }
+
+ if (par) {
+ game_params *tmpparams;
+ tmpparams = me->ourgame->dup_params(me->params);
+ me->ourgame->decode_params(tmpparams, par);
+ error = me->ourgame->validate_params(tmpparams);
+ if (error) {
+ me->ourgame->free_params(tmpparams);
+ return error;
+ }
+ if (me->tmpparams)
+ me->ourgame->free_params(me->tmpparams);
+ me->tmpparams = tmpparams;
+
+ /*
+ * Now filter only the persistent parts of this state into
+ * the long-term params structure, unless we've _only_
+ * received a params string in which case the whole lot is
+ * persistent.
+ */
+ if (seed || desc) {
+ char *tmpstr = me->ourgame->encode_params(tmpparams, FALSE);
+ me->ourgame->decode_params(me->params, tmpstr);
+ } else {
+ me->ourgame->free_params(me->params);
+ me->params = me->ourgame->dup_params(tmpparams);
+ }
+ }
+
+ if (desc) {
+ error = me->ourgame->validate_desc(me->params, desc);
+ if (error)
+ return error;
+
+ sfree(me->desc);
+ me->desc = dupstr(desc);
+ me->genmode = GOT_DESC;
+ if (me->aux_info)
+ me->ourgame->free_aux_info(me->aux_info);
+ me->aux_info = NULL;
+ }
+
+ if (seed) {
+ sfree(me->seedstr);
+ me->seedstr = dupstr(seed);
+ me->genmode = GOT_SEED;
+ }
+
+ return NULL;
+}
+
+char *midend_game_id(midend_data *me, char *id)
+{
+ return midend_game_id_int(me, id, DEF_PARAMS);
+}
+
+char *midend_set_config(midend_data *me, int which, config_item *cfg)
+{
+ char *error;
+ game_params *params;
+
+ switch (which) {
+ case CFG_SETTINGS:
+ params = me->ourgame->custom_params(cfg);
+ error = me->ourgame->validate_params(params);
+
+ if (error) {
+ me->ourgame->free_params(params);
+ return error;
+ }
+
+ me->ourgame->free_params(me->params);
+ me->params = params;
+ break;
+
+ case CFG_SEED:
+ case CFG_DESC:
+ error = midend_game_id_int(me, cfg[0].sval,
+ (which == CFG_SEED ? DEF_SEED : DEF_DESC));
+ if (error)
+ return error;
+ break;
+ }
+
+ return NULL;
+}
+
+char *midend_text_format(midend_data *me)
+{
+ if (me->ourgame->can_format_as_text && me->statepos > 0)
+ return me->ourgame->text_format(me->states[me->statepos-1].state);
+ else
+ return NULL;
+}
+
+char *midend_solve(midend_data *me)
+{
+ game_state *s;
+ char *msg;
+
+ if (!me->ourgame->can_solve)
+ return "This game does not support the Solve operation";
+
+ if (me->statepos < 1)
+ return "No game set up to solve"; /* _shouldn't_ happen! */
+
+ msg = "Solve operation failed"; /* game _should_ overwrite on error */
+ s = me->ourgame->solve(me->states[0].state, me->aux_info, &msg);
+ if (!s)
+ return msg;
+
+ /*
+ * Now enter the solved state as the next move.
+ */
+ midend_stop_anim(me);
+ while (me->nstates > me->statepos)
+ me->ourgame->free_game(me->states[--me->nstates].state);
+ ensure(me);
+ me->states[me->nstates].state = s;
+ me->states[me->nstates].special = TRUE; /* created using solve */
+ me->statepos = ++me->nstates;
+ me->anim_time = 0.0;
+ midend_finish_move(me);
+ midend_redraw(me);
+ activate_timer(me->frontend);
+ return NULL;
+}