Reduce duration of delays when the game is running slowly (#560)

changes/autoexplore-delay.md

@@ -0,0 +1 @@
+Animations such as autoexplore and using a staff now run at the same speed regardless of game performance (up to a limit).

src/platform/curses-platform.c

@@ -113,9 +113,24 @@ static uint64_t getTime() {
     return (uint64_t)tv.tv_sec * 1000 + tv.tv_usec / 1000;
 }
 
+static long lastDelayTime = 0;
+
+// Like SDL_Delay, but reduces the delay if time has passed since the last delay
+static void _delayUpTo(short ms) {
+    long curTime = getTime();
+    long timeDiff = curTime - lastDelayTime;
+    ms -= timeDiff;
+
+    if (ms > 0) {
+        Term.wait(ms);
+    } // else delaying further would go past the time we want to delay until
+
+    lastDelayTime = getTime();
+}
+
 static boolean curses_pauseForMilliseconds(short milliseconds) {
     Term.refresh();
-    Term.wait(milliseconds);
+    _delayUpTo(milliseconds);
 
     // hasKey returns true if we have a mouse event, too.
     return Term.hasKey();
@@ -124,14 +139,11 @@ static boolean curses_pauseForMilliseconds(short milliseconds) {
 static void curses_nextKeyOrMouseEvent(rogueEvent *returnEvent, boolean textInput, boolean colorsDance) {
     int key;
     // TCOD_mouse_t mouse;
-    uint64_t theTime, waitTime;
     // short x, y;
 
     Term.refresh();
 
     for (;;) {
-        theTime = getTime(); //TCOD_sys_elapsed_milli();
-
         /*if (TCOD_console_is_window_closed()) {
             rogue.gameHasEnded = true; // causes the game loop to terminate quickly
             returnEvent->eventType = KEYSTROKE;
@@ -189,11 +201,7 @@ static void curses_nextKeyOrMouseEvent(rogueEvent *returnEvent, boolean textInpu
             return;
         }
 
-        waitTime = PAUSE_BETWEEN_EVENT_POLLING + theTime - getTime();
-
-        if (waitTime > 0 && waitTime <= PAUSE_BETWEEN_EVENT_POLLING) {
-            curses_pauseForMilliseconds(waitTime);
-        }
+        _delayUpTo(PAUSE_BETWEEN_EVENT_POLLING);
     }
 }
 

src/platform/sdl2-platform.c

@@ -282,10 +282,24 @@ static void _gameLoop() {
     exit(statusCode);
 }
 
+static long lastDelayTime = 0;
+
+// Like SDL_Delay, but reduces the delay if time has passed since the last delay
+static void _delayUpTo(short ms) {
+    long curTime = SDL_GetTicks();
+    long timeDiff = curTime - lastDelayTime;
+    ms -= timeDiff;
+
+    if (ms > 0) {
+        SDL_Delay(ms);
+    } // else delaying further would go past the time we want to delay until
+
+    lastDelayTime = SDL_GetTicks();
+}
 
 static boolean _pauseForMilliseconds(short ms) {
     updateScreen();
-    SDL_Delay(ms);
+    _delayUpTo(ms);
 
     if (lastEvent.eventType != EVENT_ERROR
         && lastEvent.eventType != MOUSE_ENTERED_CELL) {
@@ -299,8 +313,6 @@ static boolean _pauseForMilliseconds(short ms) {
 
 
 static void _nextKeyOrMouseEvent(rogueEvent *returnEvent, boolean textInput, boolean colorsDance) {
-    long tstart, dt;
-
     updateScreen();
 
     if (lastEvent.eventType != EVENT_ERROR) {
@@ -310,8 +322,6 @@ static void _nextKeyOrMouseEvent(rogueEvent *returnEvent, boolean textInput, boo
     }
 
     while (true) {
-        tstart = SDL_GetTicks();
-
         if (colorsDance) {
             shuffleTerrainColors(3, true);
             commitDraws();
@@ -321,10 +331,7 @@ static void _nextKeyOrMouseEvent(rogueEvent *returnEvent, boolean textInput, boo
 
         if (pollBrogueEvent(returnEvent, textInput)) break;
 
-        dt = PAUSE_BETWEEN_EVENT_POLLING - (SDL_GetTicks() - tstart);
-        if (dt > 0) {
-            SDL_Delay(dt);
-        }
+        _delayUpTo(PAUSE_BETWEEN_EVENT_POLLING);
     }
 }