--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/libmlk-core/core/drawable.c	Fri Oct 01 20:30:00 2021 +0200
@@ -0,0 +1,153 @@
+/*
+ * drawable.c -- automatic drawable objects
+ *
+ * Copyright (c) 2020-2021 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 <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "animation.h"
+#include "drawable.h"
+#include "util.h"
+#include "sprite.h"
+
+#define DRAWABLE_FOREACH(st, iter) \
+	for (size_t i = 0; i < DRAWABLE_STACK_MAX && ((iter) = (st)->objects[i], 1); ++i)
+
+int
+drawable_update(struct drawable *dw, unsigned int ticks)
+{
+	assert(dw);
+
+	return dw->update(dw, ticks);
+}
+
+void
+drawable_draw(struct drawable *dw)
+{
+	assert(dw);
+
+	dw->draw(dw);
+}
+
+void
+drawable_end(struct drawable *dw)
+{
+	assert(dw);
+
+	if (dw->end)
+		dw->end(dw);
+}
+
+void
+drawable_finish(struct drawable *dw)
+{
+	assert(dw);
+
+	if (dw->finish)
+		dw->finish(dw);
+}
+
+void
+drawable_stack_init(struct drawable_stack *st)
+{
+	assert(st);
+
+	memset(st, 0, sizeof (*st));
+}
+
+int
+drawable_stack_add(struct drawable_stack *st, struct drawable *dw)
+{
+	assert(st);
+	assert(dw);
+
+	for (size_t i = 0; i < DRAWABLE_STACK_MAX; ++i) {
+		if (!st->objects[i]) {
+			st->objects[i] = dw;
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+int
+drawable_stack_update(struct drawable_stack *st, unsigned int ticks)
+{
+	assert(st);
+
+	for (size_t i = 0; i < DRAWABLE_STACK_MAX; ++i) {
+		struct drawable *dw = st->objects[i];
+
+		if (dw && drawable_update(dw, ticks)) {
+			drawable_end(dw);
+			drawable_finish(dw);
+			st->objects[i] = NULL;
+		}
+	}
+
+	/*
+	 * We process the array again in case a drawable added a new drawable
+	 * within the update function.
+	 */
+	return drawable_stack_completed(st);
+}
+
+void
+drawable_stack_draw(struct drawable_stack *st)
+{
+	assert(st);
+
+	struct drawable *dw;
+
+	DRAWABLE_FOREACH(st, dw)
+		if (dw)
+			drawable_draw(dw);
+}
+
+int
+drawable_stack_completed(const struct drawable_stack *st)
+{
+	assert(st);
+
+	struct drawable *dw;
+
+	DRAWABLE_FOREACH(st, dw)
+		if (dw)
+			return 0;
+
+	return 1;
+}
+
+void
+drawable_stack_finish(struct drawable_stack *st)
+{
+	assert(st);
+
+	struct drawable *dw;
+
+	DRAWABLE_FOREACH(st, dw) {
+		if (dw) {
+			drawable_end(dw);
+			drawable_finish(dw);
+		}
+	}
+
+	memset(st, 0, sizeof (*st));
+}