play: add play_pointer_{own,disown}() api

Abstract the sdl relative mouse things behind an ownership
concept.

In the future libplay will probably get more involved in
projection transformation and pointer event coordinates mapping
to the projection when owned.  Though for now libplay doesn't get
involved in such things.

1 files changed, 36 insertions, 1 deletions

diff --git a/src/play.c b/src/play.c
index c15a26f..5c51cbf 100644
--- a/src/play.c
+++ b/src/play.c
@@ -39,6 +39,7 @@ typedef struct play_t {
 	unsigned		ticks_paused:1;
 	unsigned		update_needed:1;
 	unsigned		has_audio:1;
+	unsigned		pointer_owned:1;
 	const play_ops_t	**ops;
 	int			n_ops;
 	int			context;
@@ -196,7 +197,7 @@ void play_context_enter(play_t *play, int context)
 /* return context pointer of specified context,
  * a negative context requests the current context.
  */
-void * play_context(play_t *play, int context)
+void * play_context(const play_t *play, int context)
 {
 	assert(play);
 
@@ -285,6 +286,40 @@ int play_ticks_elapsed(play_t *play, play_ticks_t timer, unsigned duration)
 }
 
 
+void play_pointer_own(play_t *play)
+{
+	assert(play);
+
+	if (play->pointer_owned)
+		return;
+
+	SDL_SetRelativeMouseMode(SDL_TRUE);
+
+	play->pointer_owned = 1;
+}
+
+
+void play_pointer_disown(play_t *play)
+{
+	assert(play);
+
+	if (!play->pointer_owned)
+		return;
+
+	SDL_SetRelativeMouseMode(SDL_FALSE);
+
+	play->pointer_owned = 0;
+}
+
+
+int play_pointer_owned(const play_t *play)
+{
+	assert(play);
+
+	return !!play->pointer_owned;
+}
+
+
 void play_quit(play_t *play)
 {
 	SDL_Event	ev = { .type = SDL_QUIT };