--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/battle/spell-fire.c	Sat Nov 07 16:00:39 2020 +0100
@@ -0,0 +1,116 @@
+/*
+ * spell-fire.c -- example of spell: fire
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+
+#include <core/action.h>
+#include <core/animation.h>
+#include <core/alloc.h>
+
+#include <ui/align.h>
+
+#include <rpg/battle.h>
+#include <rpg/character.h>
+#include <rpg/spell.h>
+
+#include "registry.h"
+#include "spell-fire.h"
+
+struct data {
+	struct battle *battle;
+	struct animation animation;
+	struct action action;
+	unsigned int selection;
+};
+
+static bool
+update(struct action *act, unsigned int ticks)
+{
+	struct data *data = act->data;
+
+	return animation_update(&data->animation, ticks);
+}
+
+static void
+draw(struct action *act)
+{
+	const struct data *data = act->data;
+	const struct battle_entity *et = &data->battle->enemies[data->selection];
+	int x, y;
+
+	align(ALIGN_CENTER,
+	    &x, &y, data->animation.sprite->cellw, data->animation.sprite->cellh,
+	    et->x, et->y, et->ch->sprite->cellw, et->ch->sprite->cellh);
+
+	animation_draw(&data->animation, x, y);
+}
+
+static void
+end(struct action *act)
+{
+	struct data *data = act->data;
+	struct character *ch = data->battle->enemies[data->selection].ch;
+
+	/* TODO: compute damage. */
+	const unsigned int damage = 100;
+	if ((unsigned int)ch->hp < damage)
+		ch->hp = 0;
+	else
+		ch->hp -= damage;
+
+	battle_indicator_hp(data->battle, data->battle->enemies[data->selection].ch, 100);
+}
+
+static void
+finish(struct action *act)
+{
+	free(act->data);
+}
+
+static void
+fire_action(struct battle *bt, struct character *owner, unsigned int selection)
+{
+	struct data *data;
+
+	(void)owner;
+
+	data = alloc_zero(1, sizeof (*data));
+	data->battle = bt;
+	data->selection = selection;
+	data->action.data = data;
+	data->action.update = update;
+	data->action.draw = draw;
+	data->action.finish = finish;
+	data->action.end = end;
+
+	animation_init(&data->animation, &registry_sprites[REGISTRY_TEXTURE_EXPLOSION], 12);
+	animation_start(&data->animation);
+
+	sound_play(&registry_sounds[REGISTRY_SOUND_FIRE]);
+
+	action_stack_add(&bt->actions[0], &data->action);
+}
+
+const struct spell spell_fire = {
+	.name = "Fire",
+	.description = "A delicate fire.",
+	.mp = 5,
+	.type = SPELL_TYPE_FIRE,
+	.selection = SELECTION_ENEMY_ONE,
+	.action = fire_action
+};