Revamp rendering system to allow custom rendering

Originally, the rendering system was designed to only display sources
and such, but I realized there would be a flaw; if you wanted to render
the main viewport in a custom way, or maybe even the entire application
as a graphics-based front end, you wouldn't have been able to do that.

Displays have now been separated in to viewports and displays.  A
viewport is used to store and draw sources, a display is used to handle
draw callbacks.  You can even use displays without using viewports to
draw custom render displays containing graphics calls if you wish, but
usually they would be used in combination with source viewports at
least.

This requires a tiny bit more work to create simple source displays, but
in the end its worth it for the added flexibility and options it brings.

libobs/obs.c

@@ -1,5 +1,5 @@
 /******************************************************************************
-    Copyright (C) 2013 by Hugh Bailey <obs.jim@gmail.com>
+    Copyright (C) 2013-2014 by Hugh Bailey <obs.jim@gmail.com>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -140,6 +140,12 @@ static bool obs_init_video(struct obs_video_info *ovi)
 		return false;
 	}
 
+	if (!obs_display_init(&video->main_display, NULL))
+		return false;
+
+	video->main_display.cx = ovi->window_width;
+	video->main_display.cy = ovi->window_height;
+
 	errorcode = pthread_create(&video->video_thread, NULL,
 			obs_video_thread, obs);
 	if (errorcode != 0)
@@ -149,25 +155,33 @@ static bool obs_init_video(struct obs_video_info *ovi)
 	return true;
 }
 
-static void obs_free_video()
+static void stop_video(void)
 {
 	struct obs_core_video *video = &obs->video;
+	void *thread_retval;
 
 	if (video->video) {
-		void *thread_retval;
-
 		video_output_stop(video->video);
 		if (video->thread_initialized) {
 			pthread_join(video->video_thread, &thread_retval);
 			video->thread_initialized = false;
 		}
+	}
 
+}
+
+static void obs_free_video(void)
+{
+	struct obs_core_video *video = &obs->video;
+
+	if (video->video) {
+		obs_display_free(&video->main_display);
 		video_output_close(video->video);
 		video->video = NULL;
 	}
 }
 
-static void obs_free_graphics()
+static void obs_free_graphics(void)
 {
 	struct obs_core_video *video = &obs->video;
 	size_t i;
@@ -248,6 +262,8 @@ static bool obs_init_data(void)
 		goto fail;
 	if (pthread_mutex_init(&data->encoders_mutex, &attr) != 0)
 		goto fail;
+	if (!obs_viewport_init(&data->main_viewport))
+		goto fail;
 
 	data->valid = true;
 
@@ -263,8 +279,7 @@ static void obs_free_data(void)
 
 	data->valid = false;
 
-	for (i = 0; i < MAX_CHANNELS; i++)
-		obs_set_output_source(i, NULL);
+	obs_viewport_free(&data->main_viewport);
 
 	while (data->outputs.num)
 		obs_output_destroy(data->outputs.array[0]);
@@ -303,7 +318,7 @@ static bool obs_init(void)
 	return obs_init_handlers();
 }
 
-bool obs_startup()
+bool obs_startup(void)
 {
 	bool success;
 
@@ -334,6 +349,8 @@ void obs_shutdown(void)
 	da_free(obs->modal_ui_callbacks);
 	da_free(obs->modeless_ui_callbacks);
 
+	stop_video();
+
 	obs_free_data();
 	obs_free_video();
 	obs_free_graphics();
@@ -349,6 +366,11 @@ void obs_shutdown(void)
 	obs = NULL;
 }
 
+bool obs_initialized(void)
+{
+	return obs != NULL;
+}
+
 bool obs_reset_video(struct obs_video_info *ovi)
 {
 	struct obs_core_video *video = &obs->video;
@@ -535,21 +557,23 @@ bool obs_add_source(obs_source_t source)
 
 obs_source_t obs_get_output_source(uint32_t channel)
 {
-	struct obs_source *source;
-	assert(channel < MAX_CHANNELS);
-	source = obs->data.channels[channel];
-
-	obs_source_addref(source);
-	return source;
+	return obs_viewport_getsource(&obs->data.main_viewport, channel);
 }
 
 void obs_set_output_source(uint32_t channel, obs_source_t source)
 {
-	struct obs_source *prev_source;
-	struct calldata params = {0};
 	assert(channel < MAX_CHANNELS);
 
-	prev_source = obs->data.channels[channel];
+	if (!obs) return;
+	if (channel >= MAX_CHANNELS) return;
+
+	struct obs_source *prev_source;
+	struct obs_viewport *viewport = &obs->data.main_viewport;
+	struct calldata params = {0};
+
+	pthread_mutex_lock(&viewport->channels_mutex);
+
+	prev_source = viewport->channels[channel];
 
 	calldata_setuint32(&params, "channel", channel);
 	calldata_setptr(&params, "prev_source", prev_source);
@@ -558,14 +582,14 @@ void obs_set_output_source(uint32_t channel, obs_source_t source)
 	calldata_getptr(&params, "source", &source);
 	calldata_free(&params);
 
-	obs->data.channels[channel] = source;
+	viewport->channels[channel] = source;
 
-	if (source != prev_source) {
-		if (source)
-			obs_source_addref(source);
-		if (prev_source)
-			obs_source_release(prev_source);
-	}
+	if (source)
+		obs_source_addref(source);
+	if (prev_source)
+		obs_source_release(prev_source);
+
+	pthread_mutex_unlock(&viewport->channels_mutex);
 }
 
 void obs_enum_outputs(bool (*enum_proc)(void*, obs_output_t), void *param)
@@ -630,15 +654,48 @@ obs_source_t obs_get_source_by_name(const char *name)
 
 effect_t obs_get_default_effect(void)
 {
+	if (!obs) return NULL;
 	return obs->video.default_effect;
 }
 
 signal_handler_t obs_signalhandler(void)
 {
+	if (!obs) return NULL;
 	return obs->signals;
 }
 
 proc_handler_t obs_prochandler(void)
 {
+	if (!obs) return NULL;
 	return obs->procs;
 }
+
+void obs_add_draw_callback(
+		void (*draw)(void *param, uint32_t cx, uint32_t cy),
+		void *param)
+{
+	if (!obs) return;
+
+	obs_display_add_draw_callback(&obs->video.main_display, draw, param);
+}
+
+void obs_remove_draw_callback(
+		void (*draw)(void *param, uint32_t cx, uint32_t cy),
+		void *param)
+{
+	if (!obs) return;
+
+	obs_display_remove_draw_callback(&obs->video.main_display, draw, param);
+}
+
+void obs_resize(uint32_t cx, uint32_t cy)
+{
+	if (!obs || !obs->video.video || !obs->video.graphics) return;
+	obs_display_resize(&obs->video.main_display, cx, cy);
+}
+
+void obs_render_main_viewport(void)
+{
+	if (!obs) return;
+	obs_viewport_render(&obs->data.main_viewport);
+}