From 796496013368d216b404e390f965381a7cffc0d1 Mon Sep 17 00:00:00 2001
From: Vladimir Sumarov <summeroff@gmail.com>
Date: Thu, 26 May 2022 15:56:58 -0700
Subject: [PATCH] add a function to put filter into a exact position

---
 libobs/obs-source.c | 50 +++++++++++++++++++++++++++++++++++++--------
 libobs/obs.h        |  9 ++++++++
 2 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/libobs/obs-source.c b/libobs/obs-source.c
index 571c7e8629f13b..090225994ef152 100644
--- a/libobs/obs-source.c
+++ b/libobs/obs-source.c
@@ -2705,6 +2705,19 @@ static size_t find_prev_filter(obs_source_t *source, obs_source_t *filter,
 		return find_prev_filter(source, filter, cur_idx - 1);
 }
 
+/* reorder filter targets, not the nicest way of dealing with things */
+static void reorder_filters(obs_source_t *source)
+{
+	for (size_t i = 0; i < source->filters.num; i++) {
+		obs_source_t *next_filter =
+			(i == source->filters.num - 1)
+				? source
+				: source->filters.array[i + 1];
+
+		source->filters.array[i]->filter_target = next_filter;
+	}
+}
+
 /* moves filters above/below matching filter types */
 static bool move_filter_dir(obs_source_t *source, obs_source_t *filter,
 			    enum obs_order_movement movement)
@@ -2738,15 +2751,7 @@ static bool move_filter_dir(obs_source_t *source, obs_source_t *filter,
 		da_move_item(source->filters, idx, 0);
 	}
 
-	/* reorder filter targets, not the nicest way of dealing with things */
-	for (size_t i = 0; i < source->filters.num; i++) {
-		obs_source_t *next_filter =
-			(i == source->filters.num - 1)
-				? source
-				: source->filters.array[i + 1];
-
-		source->filters.array[i]->filter_target = next_filter;
-	}
+	reorder_filters(source);
 
 	return true;
 }
@@ -2769,6 +2774,33 @@ void obs_source_filter_set_order(obs_source_t *source, obs_source_t *filter,
 		obs_source_dosignal(source, NULL, "reorder_filters");
 }
 
+void obs_source_filter_set_position(obs_source_t *source, obs_source_t *filter,
+				 size_t position)
+{
+	bool success = false;
+
+	if (!obs_source_valid(source, "obs_source_filter_set_position"))
+		return;
+	if (!obs_ptr_valid(filter, "obs_source_filter_set_position"))
+		return;
+
+	pthread_mutex_lock(&source->filter_mutex);
+	if (position < source->filters.num) {
+		size_t new_idx = source->filters.num - 1 - position;
+		size_t idx = da_find(source->filters, &filter, 0);
+		if (idx != DARRAY_INVALID && idx != new_idx) {
+			da_move_item(source->filters, idx, new_idx);
+			success = true;
+
+			reorder_filters(source);
+		}
+	}
+	pthread_mutex_unlock(&source->filter_mutex);
+
+	if (success)
+		obs_source_dosignal(source, NULL, "reorder_filters");
+}
+
 obs_data_t *obs_source_get_settings(const obs_source_t *source)
 {
 	if (!obs_source_valid(source, "obs_source_get_settings"))
diff --git a/libobs/obs.h b/libobs/obs.h
index 4defdc280774d4..3c26fbd12e273f 100644
--- a/libobs/obs.h
+++ b/libobs/obs.h
@@ -1104,6 +1104,15 @@ EXPORT void obs_source_filter_set_order(obs_source_t *source,
 					obs_source_t *filter,
 					enum obs_order_movement movement);
 
+/**
+ * Set the position of a specific filter,
+ * positions refered to obs_source_enum_filters
+ * so it goes backward to filters array indexes
+ */
+EXPORT void obs_source_filter_set_position(obs_source_t *source,
+					obs_source_t *filter,
+					size_t position);
+
 /** Gets the settings string for a source */
 EXPORT obs_data_t *obs_source_get_settings(const obs_source_t *source);