Delay reinitializing hwcursor until fade 1

With fade 0 the cursor is never visible because everything is black.

While this is a very minor optimization, it works around
one of the instances of a bug in certain drivers as seen in #5618.

Source/DiabloUI/diabloui.cpp

@@ -331,12 +331,12 @@ void UiOnBackgroundChange()
 	fadeTc = 0;
 	fadeValue = 0;
 
+	BlackPalette();
+
 	if (IsHardwareCursorEnabled() && ArtCursor && ControlDevice == ControlTypes::KeyboardAndMouse && GetCurrentCursorInfo().type() != CursorType::UserInterface) {
 		SetHardwareCursor(CursorInfo::UserInterfaceCursor());
 	}
 
-	BlackPalette();
-
 	SDL_FillRect(DiabloUiSurface(), nullptr, 0x000000);
 	if (DiabloUiSurface() == PalSurface)
 		BltFast(nullptr, nullptr);
@@ -749,8 +749,10 @@ void UiFadeIn()
 			fadeValue = 256;
 			fadeTc = 0;
 		}
-		if (fadeValue != prevFadeValue)
-			SetFadeLevel(fadeValue);
+		if (fadeValue != prevFadeValue) {
+			// We can skip hardware cursor update for fade level 0 (everything is black).
+			SetFadeLevel(fadeValue, /*updateHardwareCursor=*/fadeValue != 0);
+		}
 	}
 
 	if (DiabloUiSurface() == PalSurface)
@@ -796,8 +798,9 @@ void UiPollAndRender(std::optional<tl::function_ref<bool(SDL_Event &)>> eventHan
 	DrawMouse();
 	UiFadeIn();
 
-	// Must happen after the very first UiFadeIn, which sets the cursor.
-	if (IsHardwareCursor())
+	// Must happen after at least one call to `UiFadeIn` with non-zero fadeValue.
+	// `UiFadeIn` calls `SetFadeLevel` which reinitializes the hardware cursor.
+	if (IsHardwareCursor() && fadeValue != 0)
 		SetHardwareCursorVisible(ControlDevice == ControlTypes::KeyboardAndMouse);
 
 #ifdef __3DS__

Source/engine/palette.cpp

@@ -274,7 +274,7 @@ int UpdateGamma(int gamma)
 	return 130 - *sgOptions.Graphics.gammaCorrection;
 }
 
-void SetFadeLevel(int fadeval)
+void SetFadeLevel(int fadeval, bool updateHardwareCursor)
 {
 	if (HeadlessMode)
 		return;
@@ -285,14 +285,17 @@ void SetFadeLevel(int fadeval)
 		system_palette[i].b = (fadeval * logical_palette[i].b) / 256;
 	}
 	palette_update();
-	if (IsHardwareCursor()) {
+	if (updateHardwareCursor && IsHardwareCursor()) {
 		ReinitializeHardwareCursor();
 	}
 }
 
 void BlackPalette()
 {
-	SetFadeLevel(0);
+	// With fade level 0 updating the hardware cursor may be redundant
+	// since everything is black. The caller should update the cursor
+	// when needed instead.
+	SetFadeLevel(0, /*updateHardwareCursor=*/false);
 }
 
 void PaletteFadeIn(int fr)
@@ -310,7 +313,8 @@ void PaletteFadeIn(int fr)
 		uint32_t prevFadeValue = 255;
 		for (uint32_t i = 0; i < 256; i = fr * (SDL_GetTicks() - tc) / 50) {
 			if (i != prevFadeValue) {
-				SetFadeLevel(i);
+				// We can skip hardware cursor update for fade level 0 (everything is black).
+				SetFadeLevel(i, /*updateHardwareCursor=*/i != 0u);
 				prevFadeValue = i;
 			}
 			BltFast(nullptr, nullptr);

Source/engine/palette.h

@@ -60,7 +60,7 @@ void ApplyGamma(std::array<SDL_Color, 256> &dst, const std::array<SDL_Color, 256
 void DecreaseGamma();
 int UpdateGamma(int gamma);
 void BlackPalette();
-void SetFadeLevel(int fadeval);
+void SetFadeLevel(int fadeval, bool updateHardwareCursor = true);
 /**
  * @brief Fade screen from black
  * @param fr Steps per 50ms

Source/interfac.cpp

@@ -295,6 +295,10 @@ void ShowProgress(interface_mode uMsg)
 		interface_msg_pump();
 		ClearScreenBuffer();
 		scrollrt_draw_game_screen();
+
+		if (IsHardwareCursor())
+			SetHardwareCursorVisible(false);
+
 		BlackPalette();
 
 		// Blit the background once and then free it.
@@ -315,9 +319,6 @@ void ShowProgress(interface_mode uMsg)
 		}
 		FreeCutsceneBackground();
 
-		if (IsHardwareCursor())
-			SetHardwareCursorVisible(false);
-
 		PaletteFadeIn(8);
 		IncProgress();
 		sound_init();