nost: touch piano mode (#830)

## Link to GitHub Issue or related Pull Request, if one exists
n/a

## Description of change
Touch piano mode. Allows piano keys to be played with the touch screen.
Since the touch screen is still needed for menu navigation (including
during songs) a toggle switch is added so that the user can flip between
navigation mode and piano mode.

The touch targets are pixel-perfect. Don't let the game's piano
animations fool you.

## Testing

src/spice2x/launcher/launcher.cpp

@@ -1786,7 +1786,16 @@ int main_implementation(int argc, char *argv[]) {
             games::iidx::poke::enable();
         }
         if (options[launcher::Options::NostalgiaPoke].is_active()) {
-            games::nost::ENABLE_POKE = TRUE;
+            games::nost::ENABLE_POKE = true;
+        }
+        if (options[launcher::Options::NostalgiaTouchMode].is_active()) {
+            if (overlay::ENABLED) {
+                games::nost::ENABLE_TOUCH_MODE = true;
+            } else {
+                log_warning(
+                    "launcher",
+                    "Nostalgia Touch Mode requires the global overlay; ignoring -nosttouch");
+            }
         }
     }
 

src/spice2x/launcher/options.cpp

@@ -3149,6 +3149,21 @@ static const std::vector<OptionDefinition> OPTION_DEFINITIONS = {
         .type = OptionType::Bool,
         .game_name = "Nostalgia",
         .category = "Game Options",
+        .quick_setting_category = "Game",
+    },
+    {
+        // NostalgiaTouchMode
+        .title = "Nostalgia Touch Piano",
+        .name = "nosttouch",
+        .desc =
+            "Allows you to play the piano by touching the screen instead of a controller. "
+            "Use the mode switch button to toggle between interacting with the menu and playing the piano.\n\n"
+            "Velocity sensitivity is not supported. Touch targets will be pixel-perfect aligned with the "
+            "judgement line, key beams, and notes.",
+        .type = OptionType::Bool,
+        .game_name = "Nostalgia",
+        .category = "Game Options",
+        .quick_setting_category = "Game",
     },
     {
         // ForceBackBufferCount

src/spice2x/launcher/options.h

@@ -297,6 +297,7 @@ namespace launcher {
             DDRP4IOBufferMode,
             InputRequiresFocus,
             NostalgiaPoke,
+            NostalgiaTouchMode,
             ForceBackBufferCount,
             SDVXWindowedSubscreenSize,
             SDVXWindowedSubscreenPosition,