--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libmlk-example/mlk/example/spell-fire.c	Sun Feb 26 19:44:47 2023 +0100
@@ -0,0 +1,132 @@
+/*
+ * spell-fire.c -- example of spell: fire
+ *
+ * Copyright (c) 2020-2023 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 <mlk/core/action.h>
+#include <mlk/core/animation.h>
+#include <mlk/core/drawable.h>
+#include <mlk/core/alloc.h>
+
+#include <mlk/ui/align.h>
+
+#include <mlk/rpg/battle-state-check.h>
+#include <mlk/rpg/battle-state-rendering.h>
+#include <mlk/rpg/battle.h>
+#include <mlk/rpg/character.h>
+#include <mlk/rpg/spell.h>
+
+#include "registry.h"
+#include "spell-fire.h"
+
+struct self {
+	struct battle *battle;
+	struct character *target;
+	struct mlk_animation animation;
+	struct mlk_drawable drawable;
+	unsigned int selection;
+};
+
+static int
+update(struct mlk_drawable *dw, unsigned int ticks)
+{
+	struct self *self = dw->data;
+
+	return mlk_animation_update(&self->animation, ticks);
+}
+
+static void
+draw(struct mlk_drawable *dw)
+{
+	const struct self *self = dw->data;
+	const struct battle_entity *et = self->battle->enemies[self->selection];
+	const struct sprite *sprite = et->ch->sprites[CHARACTER_SPRITE_NORMAL];
+	int x, y;
+
+	align(ALIGN_CENTER,
+	    &x, &y, self->animation.sprite->cellw, self->animation.sprite->cellh,
+	    et->x, et->y, sprite->cellw, sprite->cellh);
+
+	mlk_animation_draw(&self->animation, x, y);
+}
+
+static void
+end(struct mlk_drawable *dw)
+{
+	struct self *self = dw->data;
+	struct character *ch = self->battle->enemies[self->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(self->battle, self->battle->enemies[self->selection]->ch, 100);
+	battle_state_check(self->battle);
+}
+
+static void
+finish(struct mlk_drawable *dw)
+{
+	free(dw->data);
+}
+
+static void
+fire_select(const struct battle *bt, struct selection *slt)
+{
+	slt->index_side = 0;
+
+	selection_first(slt, bt);
+}
+
+static void
+fire_action(struct battle *bt, struct character *owner, const struct selection *slt)
+{
+	struct self *self;
+
+	(void)owner;
+
+	self = mlk_alloc_new0(1, sizeof (*self));
+	self->selection = slt->index_character;
+	self->battle = bt;
+	self->drawable.data = self;
+	self->drawable.update = update;
+	self->drawable.draw = draw;
+	self->drawable.finish = finish;
+	self->drawable.end = end;
+
+	mlk_animation_init(&self->animation, &registry_sprites[REGISTRY_TEXTURE_EXPLOSION], 12);
+	mlk_animation_start(&self->animation);
+
+	sound_play(&registry_sounds[REGISTRY_SOUND_FIRE]);
+	battle_state_rendering(bt, &self->drawable);
+}
+
+const struct spell spell_fire = {
+	.name = "Fire",
+	.description = "A delicate fire.",
+	.mp = 5,
+	.type = SPELL_TYPE_FIRE,
+	.select = fire_select,
+	.select_kind = SELECTION_KIND_ONE,
+	.select_side = SELECTION_SIDE_ENEMY,
+	.action = fire_action
+};