libobs: Add obs_render_main_texture

(Note: This commit also modifies UI and test)

This makes it so that main preview panes are rendered with the main
output texture rather than re-rendering the main view.  The view will
render all objects again, whereas the output texture will be a single
texture render of the same exact thing.

Also fixes some abnormal artifacting when scaling the main preview pane.

UI/window-basic-main-transitions.cpp

@@ -1222,7 +1222,7 @@ void OBSBasic::RenderProgram(void *data, uint32_t cx, uint32_t cy)
 
 	window->DrawBackdrop(float(ovi.base_width), float(ovi.base_height));
 
-	obs_render_main_view();
+	obs_render_main_texture();
 	gs_load_vertexbuffer(nullptr);
 
 	/* --------------------------------------- */

UI/window-basic-main.cpp

@@ -2968,7 +2968,7 @@ void OBSBasic::RenderMain(void *data, uint32_t cx, uint32_t cy)
 		if (source)
 			obs_source_video_render(source);
 	} else {
-		obs_render_main_view();
+		obs_render_main_texture();
 	}
 	gs_load_vertexbuffer(nullptr);
 

UI/window-projector.cpp

@@ -408,7 +408,7 @@ void OBSProjector::OBSRenderMultiview(void *data, uint32_t cx, uint32_t cy)
 	if (studioMode) {
 		obs_source_video_render(previewSrc);
 	} else {
-		obs_render_main_view();
+		obs_render_main_texture();
 	}
 
 	resetRegion();
@@ -453,7 +453,7 @@ void OBSProjector::OBSRenderMultiview(void *data, uint32_t cx, uint32_t cy)
 	gs_matrix_scale3f(hiScaleX, hiScaleY, 1.0f);
 
 	setRegion(halfCX + 2.0f, 2.0f, hiCX, hiCY);
-	obs_render_main_view();
+	obs_render_main_texture();
 	resetRegion();
 
 	gs_matrix_pop();
@@ -540,7 +540,7 @@ void OBSProjector::OBSRender(void *data, uint32_t cx, uint32_t cy)
 	if (source) {
 		obs_source_video_render(source);
 	} else {
-		obs_render_main_view();
+		obs_render_main_texture();
 	}
 
 	gs_projection_pop();

docs/sphinx/frontends.rst

@@ -57,7 +57,7 @@ display, then you must assign a draw callback with
 callback, call :c:func:`obs_display_remove_draw_callback()` similarly.
 
 When drawing, to draw the main preview window (if any), call
-:c:func:`obs_render_main_view()`.  If you need to render a specific
+:c:func:`obs_render_main_texture()`.  If you need to render a specific
 source on a secondary display, you can increment its "showing" state
 with :c:func:`obs_source_inc_showing()` while it's showing in the
 secondary display, draw it with :c:func:`obs_source_video_render()` in

docs/sphinx/reference-core.rst

@@ -380,6 +380,15 @@ Video, Audio, and Graphics
 
    Renders the main view.
 
+   Note: This function is deprecated.
+
+---------------------
+
+.. function:: void obs_render_main_texture(void)
+
+   Renders the main output texture.  Useful for rendering a preview pane
+   of the main output.
+
 ---------------------
 
 .. function:: void obs_set_master_volume(float volume)

libobs/obs-video.c

@@ -614,14 +614,14 @@ void *obs_graphics_thread(void *param)
 		last_time = tick_sources(obs->video.video_time, last_time);
 		profile_end(tick_sources_name);
 
-		profile_start(render_displays_name);
-		render_displays();
-		profile_end(render_displays_name);
-
 		profile_start(output_frame_name);
 		output_frame();
 		profile_end(output_frame_name);
 
+		profile_start(render_displays_name);
+		render_displays();
+		profile_end(render_displays_name);
+
 		frame_time_ns = os_gettime_ns() - frame_start;
 
 		profile_end(video_thread_name);

libobs/obs.c

@@ -1430,6 +1430,32 @@ void obs_render_main_view(void)
 	obs_view_render(&obs->data.main_view);
 }
 
+void obs_render_main_texture(void)
+{
+	struct obs_core_video *video = &obs->video;
+	gs_texture_t *tex;
+	gs_effect_t *effect;
+	gs_eparam_t *param;
+	int last_tex;
+
+	if (!obs) return;
+
+	last_tex = video->cur_texture == 0
+		? NUM_TEXTURES - 1
+		: video->cur_texture - 1;
+
+	if (!video->textures_rendered[last_tex])
+		return;
+
+	tex = video->render_textures[last_tex];
+	effect = obs_get_base_effect(OBS_EFFECT_DEFAULT);
+	param = gs_effect_get_param_by_name(effect, "image");
+	gs_effect_set_texture(param, tex);
+
+	while (gs_effect_loop(effect, "Draw"))
+		gs_draw_sprite(tex, 0, 0, 0);
+}
+
 void obs_set_master_volume(float volume)
 {
 	struct calldata data = {0};

libobs/obs.h

@@ -550,8 +550,12 @@ EXPORT signal_handler_t *obs_get_signal_handler(void);
 EXPORT proc_handler_t *obs_get_proc_handler(void);
 
 /** Renders the main view */
+DEPRECATED
 EXPORT void obs_render_main_view(void);
 
+/** Renders the last main output texture */
+EXPORT void obs_render_main_texture(void);
+
 /** Sets the master user volume */
 EXPORT void obs_set_master_volume(float volume);
 

test/osx/test.mm

@@ -146,7 +146,7 @@ static SceneContext SetupScene()
 
 		obs_display_add_draw_callback(display.get(),
 				[](void *, uint32_t, uint32_t) {
-					obs_render_main_view();
+					obs_render_main_texture();
 				}, nullptr);
 
 	} catch (char const *error) {

test/win/test.cpp

@@ -150,7 +150,7 @@ static HWND CreateTestWindow(HINSTANCE instance)
 
 static void RenderWindow(void *data, uint32_t cx, uint32_t cy)
 {
-	obs_render_main_view();
+	obs_render_main_texture();
 
 	UNUSED_PARAMETER(data);
 	UNUSED_PARAMETER(cx);