Fix menus wrapping in the up direction

SourceX/DiabloUI/diabloui.cpp

@@ -24,9 +24,7 @@
 
 namespace dvl {
 
-std::size_t SelectedItemMin = 1;
-std::size_t SelectedItemMax = 1;
-
+std::size_t SelectedItemMax;
 std::size_t ListViewportSize = 1;
 const std::size_t *ListOffset = NULL;
 
@@ -78,9 +76,8 @@ void UiDestroy()
 void UiInitList(int count, void (*fnFocus)(int value), void (*fnSelect)(int value), void (*fnEsc)(), std::vector<UiItemBase *> items, bool itemsWraps, bool (*fnYesNo)())
 {
 	SelectedItem = 0;
-	SelectedItemMin = 0;
 	SelectedItemMax = std::max(count - 1, 0);
-	ListViewportSize = SelectedItemMax - SelectedItemMin + 1;
+	ListViewportSize = count;
 	gfnListFocus = fnFocus;
 	gfnListSelect = fnSelect;
 	gfnListEsc = fnEsc;
@@ -114,7 +111,7 @@ void UiInitScrollBar(UiScrollBar *ui_sb, std::size_t viewport_size, const std::s
 {
 	ListViewportSize = viewport_size;
 	ListOffset = current_offset;
-	if (ListViewportSize >= static_cast<std::size_t>(SelectedItemMax - SelectedItemMin + 1)) {
+	if (ListViewportSize >= static_cast<std::size_t>(SelectedItemMax + 1)) {
 		ui_sb->add_flag(UIS_HIDDEN);
 	} else {
 		ui_sb->remove_flag(UIS_HIDDEN);
@@ -124,8 +121,7 @@ void UiInitScrollBar(UiScrollBar *ui_sb, std::size_t viewport_size, const std::s
 void UiInitList_clear()
 {
 	SelectedItem = 0;
-	SelectedItemMin = 1;
-	SelectedItemMax = 1;
+	SelectedItemMax = 0;
 	ListViewportSize = 1;
 	gfnListFocus = NULL;
 	gfnListSelect = NULL;
@@ -147,22 +143,8 @@ void UiPlaySelectSound()
 		gfnSoundFunction("sfx\\items\\titlslct.wav");
 }
 
-void UiFocus(std::size_t itemIndex, bool wrap = false)
+void UiFocus(std::size_t itemIndex)
 {
-	if (!wrap) {
-		if (itemIndex < SelectedItemMin) {
-			itemIndex = SelectedItemMin;
-			return;
-		} else if (itemIndex > SelectedItemMax) {
-			itemIndex = SelectedItemMax ? SelectedItemMax : SelectedItemMin;
-			return;
-		}
-	} else if (itemIndex < SelectedItemMin) {
-		itemIndex = SelectedItemMax ? SelectedItemMax : SelectedItemMin;
-	} else if (itemIndex > SelectedItemMax) {
-		itemIndex = SelectedItemMin;
-	}
-
 	if (SelectedItem == itemIndex)
 		return;
 
@@ -174,14 +156,30 @@ void UiFocus(std::size_t itemIndex, bool wrap = false)
 		gfnListFocus(itemIndex);
 }
 
+void UiFocusUp()
+{
+	if (SelectedItem > 0)
+		UiFocus(SelectedItem - 1);
+	else if (UiItemsWraps)
+		UiFocus(SelectedItemMax);
+}
+
+void UiFocusDown()
+{
+	if (SelectedItem < SelectedItemMax)
+		UiFocus(SelectedItem + 1);
+	else if (UiItemsWraps)
+		UiFocus(0);
+}
+
 // UiFocusPageUp/Down mimics the slightly weird behaviour of actual Diablo.
 
 void UiFocusPageUp()
 {
 	if (ListOffset == NULL || *ListOffset == 0) {
-		UiFocus(SelectedItemMin);
+		UiFocus(0);
 	} else {
-		const std::size_t relpos = (SelectedItem - SelectedItemMin) - *ListOffset;
+		const std::size_t relpos = SelectedItem - *ListOffset;
 		std::size_t prev_page_start = SelectedItem - relpos;
 		if (prev_page_start >= ListViewportSize)
 			prev_page_start -= ListViewportSize;
@@ -197,7 +195,7 @@ void UiFocusPageDown()
 	if (ListOffset == NULL || *ListOffset + ListViewportSize > static_cast<std::size_t>(SelectedItemMax)) {
 		UiFocus(SelectedItemMax);
 	} else {
-		const std::size_t relpos = (SelectedItem - SelectedItemMin) - *ListOffset;
+		const std::size_t relpos = SelectedItem - *ListOffset;
 		std::size_t next_page_end = SelectedItem + (ListViewportSize - relpos - 1);
 		if (next_page_end + ListViewportSize <= static_cast<std::size_t>(SelectedItemMax))
 			next_page_end += ListViewportSize;
@@ -244,10 +242,10 @@ void UiFocusNavigation(SDL_Event *event)
 		UiFocusNavigationSelect();
 		return;
 	case MenuAction_UP:
-		UiFocus(SelectedItem - 1, UiItemsWraps);
+		UiFocusUp();
 		return;
 	case MenuAction_DOWN:
-		UiFocus(SelectedItem + 1, UiItemsWraps);
+		UiFocusDown();
 		return;
 	case MenuAction_PAGE_UP:
 		UiFocusPageUp();
@@ -270,9 +268,9 @@ void UiFocusNavigation(SDL_Event *event)
 #ifndef USE_SDL1
 	if (event->type == SDL_MOUSEWHEEL) {
 		if (event->wheel.y > 0) {
-			UiFocus(SelectedItem - 1, UiItemsWraps);
+			UiFocusUp();
 		} else if (event->wheel.y < 0) {
-			UiFocus(SelectedItem + 1, UiItemsWraps);
+			UiFocusDown();
 		}
 		return;
 	}
@@ -749,9 +747,8 @@ void Render(const UiScrollBar *ui_sb)
 	}
 
 	// Thumb:
-	if (SelectedItemMax - SelectedItemMin > 0) {
-		const SDL_Rect rect = ThumbRect(
-		    ui_sb, SelectedItem - SelectedItemMin, SelectedItemMax - SelectedItemMin + 1);
+	if (SelectedItemMax > 0) {
+		const SDL_Rect rect = ThumbRect(ui_sb, SelectedItem, SelectedItemMax + 1);
 		DrawArt(rect.x, rect.y, ui_sb->m_thumb);
 	}
 }
@@ -842,17 +839,16 @@ bool HandleMouseEventScrollBar(const SDL_Event &event, const UiScrollBar *ui_sb)
 		return false;
 	if (event.type == SDL_MOUSEBUTTONUP) {
 		if (scrollBarState.upArrowPressed && IsInsideRect(event, UpArrowRect(ui_sb))) {
-			UiFocus(SelectedItem - 1);
+			UiFocusUp();
 			return true;
 		} else if (scrollBarState.downArrowPressed && IsInsideRect(event, DownArrowRect(ui_sb))) {
-			UiFocus(SelectedItem + 1);
+			UiFocusDown();
 			return true;
 		}
 	} else if (event.type == SDL_MOUSEBUTTONDOWN) {
 		if (IsInsideRect(event, BarRect(ui_sb))) {
 			// Scroll up or down based on thumb position.
-			const SDL_Rect thumb_rect = ThumbRect(
-			    ui_sb, SelectedItem - SelectedItemMin, SelectedItemMax - SelectedItemMin + 1);
+			const SDL_Rect thumb_rect = ThumbRect(ui_sb, SelectedItem, SelectedItemMax + 1);
 			if (event.button.y < thumb_rect.y) {
 				UiFocusPageUp();
 			} else if (event.button.y > thumb_rect.y + thumb_rect.h) {