Avoid cloud jump when switching between mainmenu and loading screen (#15163)

... by using the same Clouds object for both.
The mainmenu clouds already used shaders before. I had to choose between
both or neither, so now both the mainmenu clouds and the loading screen
clouds use shaders if available.

src/client/clientlauncher.cpp

@@ -140,8 +140,10 @@ bool ClientLauncher::run(GameStartData &start_data, const Settings &cmd_args)
 	// Create the menu clouds
 	// This is only global so it can be used by RenderingEngine::draw_load_screen().
 	assert(!g_menucloudsmgr && !g_menuclouds);
+	std::unique_ptr<IWritableShaderSource> ssrc(createShaderSource());
+	ssrc->addShaderConstantSetterFactory(new FogShaderConstantSetterFactory());
 	g_menucloudsmgr = m_rendering_engine->get_scene_manager()->createNewSceneManager();
-	g_menuclouds = new Clouds(g_menucloudsmgr, nullptr, -1, rand());
+	g_menuclouds = new Clouds(g_menucloudsmgr, ssrc.get(), -1, rand());
 	g_menuclouds->setHeight(100.0f);
 	g_menuclouds->update(v3f(0, 0, 0), video::SColor(255, 240, 240, 255));
 	scene::ICameraSceneNode* camera;

src/client/clouds.cpp

@@ -28,11 +28,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "settings.h"
 #include <cmath>
 
-
-// Menu clouds are created later
 class Clouds;
-Clouds *g_menuclouds = NULL;
-scene::ISceneManager *g_menucloudsmgr = NULL;
+scene::ISceneManager *g_menucloudsmgr = nullptr;
+Clouds *g_menuclouds = nullptr;
 
 // Constant for now
 static constexpr const float cloud_size = BS * 64.0f;
@@ -49,9 +47,8 @@ Clouds::Clouds(scene::ISceneManager* mgr, IShaderSource *ssrc,
 	scene::ISceneNode(mgr->getRootSceneNode(), mgr, id),
 	m_seed(seed)
 {
+	assert(ssrc);
 	m_enable_shaders = g_settings->getBool("enable_shaders");
-	// menu clouds use shader-less clouds for simplicity (ssrc == NULL)
-	m_enable_shaders = m_enable_shaders && ssrc;
 
 	m_material.Lighting = false;
 	m_material.BackfaceCulling = true;

src/client/clouds.h

@@ -36,11 +36,11 @@ namespace irr::scene
 }
 
 // Menu clouds
+// The mainmenu and the loading screen use the same Clouds object so that the
+// clouds don't jump when switching between the two.
 class Clouds;
-extern Clouds *g_menuclouds;
-
-// Scene manager used for menu clouds
 extern scene::ISceneManager *g_menucloudsmgr;
+extern Clouds *g_menuclouds;
 
 class Clouds : public scene::ISceneNode
 {

src/gui/guiEngine.cpp

@@ -142,10 +142,6 @@ GUIEngine::GUIEngine(JoystickController *joystick,
 	// create texture source
 	m_texture_source = std::make_unique<MenuTextureSource>(rendering_engine->get_video_driver());
 
-	// create shader source
-	// (currently only used by clouds)
-	m_shader_source.reset(createShaderSource());
-
 	// create soundmanager
 #if USE_SOUND
 	if (g_settings->getBool("enable_sound") && g_sound_manager_singleton.get()) {
@@ -296,10 +292,6 @@ void GUIEngine::run()
 	IrrlichtDevice *device = m_rendering_engine->get_raw_device();
 	video::IVideoDriver *driver = device->getVideoDriver();
 
-	// Always create clouds because they may or may not be
-	// needed based on the game selected
-	cloudInit();
-
 	unsigned int text_height = g_fontengine->getTextHeight();
 
 	// Reset fog color
@@ -395,8 +387,6 @@ GUIEngine::~GUIEngine()
 
 	m_irr_toplefttext->remove();
 
-	m_cloud.clouds.reset();
-
 	// delete textures
 	for (image_definition &texture : m_textures) {
 		if (texture.texture)
@@ -404,26 +394,11 @@ GUIEngine::~GUIEngine()
 	}
 }
 
-/******************************************************************************/
-void GUIEngine::cloudInit()
-{
-	m_shader_source->addShaderConstantSetterFactory(
-		new FogShaderConstantSetterFactory());
-
-	m_cloud.clouds = make_irr<Clouds>(m_smgr, m_shader_source.get(), -1, rand());
-	m_cloud.clouds->setHeight(100.0f);
-	m_cloud.clouds->update(v3f(0, 0, 0), video::SColor(255,240,240,255));
-
-	m_cloud.camera = m_smgr->addCameraSceneNode(0,
-				v3f(0,0,0), v3f(0, 60, 100));
-	m_cloud.camera->setFarValue(10000);
-}
-
 /******************************************************************************/
 void GUIEngine::drawClouds(float dtime)
 {
-	m_cloud.clouds->step(dtime*3);
-	m_smgr->drawAll();
+	g_menuclouds->step(dtime * 3);
+	g_menucloudsmgr->drawAll();
 }
 
 /******************************************************************************/

src/gui/guiEngine.h

@@ -203,8 +203,6 @@ private:
 	MainMenuData                         *m_data = nullptr;
 	/** texture source */
 	std::unique_ptr<ISimpleTextureSource> m_texture_source;
-	/** shader source */
-	std::unique_ptr<IWritableShaderSource> m_shader_source;
 	/** sound manager */
 	std::unique_ptr<ISoundManager>        m_sound_manager;
 
@@ -279,23 +277,11 @@ private:
 	/** and text that is in it */
 	EnrichedString m_toplefttext;
 
-	/** initialize cloud subsystem */
-	void cloudInit();
 	/** do preprocessing for cloud subsystem */
 	void drawClouds(float dtime);
 
-	/** internam data required for drawing clouds */
-	struct clouddata {
-		/** pointer to cloud class */
-		irr_ptr<Clouds> clouds;
-		/** camera required for drawing clouds */
-		scene::ICameraSceneNode *camera = nullptr;
-	};
-
 	/** is drawing of clouds enabled atm */
-	bool        m_clouds_enabled = true;
-	/** data used to draw clouds */
-	clouddata   m_cloud;
+	bool m_clouds_enabled = true;
 
 	static void fullscreenChangedCallback(const std::string &name, void *data);
 };