Hide the cursor during gameplay (#4861)

* Hide the cursor during gameplay

The cursor will show back up whenever:
- The mouse is moved
- The game is paused
- The race finished

This is probably not the best implementation, but it's a start.

* Wrap mouse display code in PT_MAIN checker

* Moved mouse display code to updateGraphics

* Protect SDL calls with #ifndef SERVER_ONLY

---------

Co-authored-by: Semphris <semphris@protonmail.com>

src/modes/world.cpp

@@ -91,6 +91,9 @@
 #include <IrrlichtDevice.h>
 #include <ISceneManager.h>
 
+/** Hide the cursor after this many seconds without movement */
+#define HIDE_CURSOR_STARTINGAT 1.0f
+
 World* World::m_world[PT_COUNT];
 
 /** The main world class is used to handle the track and the karts.
@@ -161,6 +164,8 @@ void World::init()
 {
     m_ended_early         = false;
     m_faster_music_active = false;
+    m_time_since_last_mouse_mvmt = HIDE_CURSOR_STARTINGAT;
+    m_force_show_cursor   = false;
     m_fastest_kart        = 0;
     m_eliminated_karts    = 0;
     m_eliminated_players  = 0;
@@ -419,6 +424,16 @@ void World::reset(bool restart)
     // Start music from beginning
     music_manager->stopMusic();
 
+#ifndef SERVER_ONLY
+    if (m_process_type == PT_MAIN)
+    {
+        m_force_show_cursor = false;
+        m_time_since_last_mouse_mvmt = HIDE_CURSOR_STARTINGAT;
+        SDL_GetMouseState(&m_last_mouse_pos_x, &m_last_mouse_pos_y);
+        SDL_ShowCursor(SDL_DISABLE);
+    }
+#endif
+
     // Enable SFX again
     SFXManager::get()->resumeAll();
 
@@ -609,6 +624,11 @@ World::~World()
 {
     if (m_process_type == PT_MAIN)
     {
+#ifndef SERVER_ONLY
+        // This shouldn't be necessary, but just to be sure
+        SDL_ShowCursor(SDL_ENABLE);
+#endif
+
         GUIEngine::getDevice()->setResizable(false);
         material_manager->unloadAllTextures();
     }
@@ -727,6 +747,8 @@ void World::onGo()
  */
 void World::terminateRace()
 {
+    m_force_show_cursor = true;
+
     // In case the user opened paused dialog in network
     if (!GUIEngine::isNoGraphics())
     {
@@ -1006,7 +1028,6 @@ void World::updateWorld(int ticks)
     assert(m_magic_number == 0xB01D6543);
 #endif
 
-
     if (m_schedule_pause)
     {
         pause(m_scheduled_pause_phase);
@@ -1122,6 +1143,27 @@ void World::scheduleTutorial()
  */
 void World::updateGraphics(float dt)
 {
+#ifndef SERVER_ONLY
+    if (m_process_type == PT_MAIN)
+    {
+        int x, y;
+        SDL_GetMouseState(&x, &y);
+        if (m_last_mouse_pos_x != x || m_last_mouse_pos_y != y)
+        {
+            m_time_since_last_mouse_mvmt = 0;
+            m_last_mouse_pos_x = x;
+            m_last_mouse_pos_y = y;
+        }
+        else
+        {
+            m_time_since_last_mouse_mvmt += dt;
+        }
+
+        SDL_ShowCursor((m_time_since_last_mouse_mvmt < HIDE_CURSOR_STARTINGAT
+                        || m_force_show_cursor) ? SDL_ENABLE : SDL_DISABLE);
+    }
+#endif
+
     if (auto cl = LobbyProtocol::get<ClientLobby>())
     {
         // Reset all smooth network body of rewinders so the rubber band effect
@@ -1479,6 +1521,8 @@ void World::getDefaultCollectibles(int *collectible_type, int *amount )
  */
 void World::pause(Phase phase)
 {
+    m_force_show_cursor = true;
+
     if (m_stop_music_when_dialog_open)
         music_manager->pauseMusic();
     SFXManager::get()->pauseAll();
@@ -1489,6 +1533,9 @@ void World::pause(Phase phase)
 //-----------------------------------------------------------------------------
 void World::unpause()
 {
+    m_force_show_cursor = false;
+    m_time_since_last_mouse_mvmt = HIDE_CURSOR_STARTINGAT;
+
     if (m_stop_music_when_dialog_open)
         music_manager->resumeMusic();
     SFXManager::get()->resumeAll();

src/modes/world.hpp

@@ -184,6 +184,11 @@ protected:
 
     bool m_ended_early;
 
+    int m_last_mouse_pos_x;
+    int m_last_mouse_pos_y;
+    float m_time_since_last_mouse_mvmt;
+    bool m_force_show_cursor;
+
     virtual void  onGo() OVERRIDE;
     /** Returns true if the race is over. Must be defined by all modes. */
     virtual bool  isRaceOver() = 0;