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/overlay/overlay.cpp

@@ -5,6 +5,7 @@
 #include "games/io.h"
 #include "games/gitadora/gitadora.h"
 #include "games/iidx/iidx.h"
+#include "games/nost/nost.h"
 #include "games/popn/popn.h"
 #include "games/rb/touch_debug.h"
 #include "hooks/graphics/graphics.h"
@@ -51,6 +52,7 @@
 #include "windows/sdvx_sub.h"
 #include "windows/keypad.h"
 #include "windows/log.h"
+#include "windows/nostalgia_touch_piano.h"
 #include "windows/obs.h"
 #include "windows/patch_manager.h"
 #include "windows/exitprompt.cpp"
@@ -404,6 +406,12 @@ void overlay::SpiceOverlay::init() {
         window_fps->set_active(true);
     }
 
+    if (!cfg::CONFIGURATOR_STANDALONE &&
+        avs::game::is_model("PAN") && games::nost::ENABLE_TOUCH_MODE) {
+        window_nostalgia_touch_piano =
+            std::make_unique<overlay::windows::NostalgiaTouchPiano>(this);
+    }
+
     // owned separately from `windows` so it is not part of the overlay window layer
     window_main_menu = std::make_unique<overlay::windows::ExitPrompt>(this);
 
@@ -556,13 +564,18 @@ void overlay::SpiceOverlay::new_frame() {
     const bool draw_fps_persistent = this->renderer != OverlayRenderer::SOFTWARE
         && this->window_fps->get_active();
 
+    const bool draw_nostalgia_touch_piano = this->renderer != OverlayRenderer::SOFTWARE
+        && this->window_nostalgia_touch_piano
+        && this->window_nostalgia_touch_piano->get_active();
+
     // draw RB touch diagnostics
     const bool draw_rb_touch_debug = this->renderer != OverlayRenderer::SOFTWARE
         && games::rb::touch_debug_overlay_enabled();
 
     // check if there is nothing to draw
     this->has_pending_frame = false;
-    if (!this->active && !draw_notifications && !draw_fps_persistent && !draw_rb_touch_debug) {
+    if (!this->active && !draw_notifications && !draw_fps_persistent &&
+        !draw_nostalgia_touch_piano && !draw_rb_touch_debug) {
         return;
     }
 
@@ -596,7 +609,13 @@ void overlay::SpiceOverlay::new_frame() {
         for (auto &window : this->windows) {
             window->build();
         }
+    }
 
+    if (draw_nostalgia_touch_piano) {
+        this->window_nostalgia_touch_piano->build();
+    }
+
+    if (this->active) {
         // draw the main menu on top of the overlay windows
         this->window_main_menu->build();
 
@@ -819,6 +838,10 @@ void overlay::SpiceOverlay::update() {
     // FPS window
     this->window_fps->update();
 
+    if (this->window_nostalgia_touch_piano) {
+        this->window_nostalgia_touch_piano->update();
+    }
+
     // main menu (owned separately from the overlay window layer)
     this->window_main_menu->update();
 

src/spice2x/overlay/overlay.h

@@ -83,6 +83,7 @@ namespace overlay {
         // not part of `windows`: drawn/updated on the persistent layer (like
         // notifications), independent of the overlay's active state and input gates.
         std::unique_ptr<Window> window_fps;
+        std::unique_ptr<Window> window_nostalgia_touch_piano;
 
         // not part of `windows`: the main menu / launcher. owned and drawn
         // separately from the overlay window layer; it drives the overlay's
@@ -138,6 +139,9 @@ namespace overlay {
         inline IDirect3DDevice9 *get_device() {
             return this->device;
         }
+        inline HWND get_window() {
+            return this->hWnd;
+        }
 
         bool can_transform_touch_input() {
             return (this->subscreen_mouse_handler != nullptr);

src/spice2x/overlay/windows/nostalgia_touch_piano.cpp

@@ -0,0 +1,149 @@
+#include "nostalgia_touch_piano.h"
+
+#include <cmath>
+
+#include "external/imgui/imgui_internal.h"
+#include "games/nost/touch_mode.h"
+
+namespace overlay::windows {
+
+    static constexpr float BUTTON_WIDTH = 144.f;
+    static constexpr float BUTTON_HEIGHT = 40.f;
+    static constexpr float WINDOW_PADDING = 4.f;
+    static constexpr float EDGE_MARGIN = 4.f;
+    static constexpr float PIANO_HEIGHT_RATIO = 0.08f;
+    static constexpr float PIANO_LEFT_GAP = 11.f;
+    static constexpr float PIANO_RIGHT_GAP = 10.f;
+    static constexpr uint32_t PIANO_KEY_COUNT = 28;
+
+    static constexpr ImU32 PIANO_KEY_COLOR = IM_COL32(255, 255, 255, 50);
+    static constexpr ImU32 PIANO_KEY_ACTIVE_COLOR = IM_COL32(255, 48, 48, 160);
+    static constexpr ImU32 PIANO_KEY_BORDER_COLOR = IM_COL32(0, 0, 0, 100);
+
+    struct ButtonPalette {
+        ImVec4 normal;
+        ImVec4 hovered;
+        ImVec4 active;
+    };
+
+    static const ButtonPalette NAV_MODE_PALETTE {
+        ImVec4(0.10f, 0.45f, 0.28f, 0.72f),
+        ImVec4(0.14f, 0.58f, 0.36f, 0.82f),
+        ImVec4(0.08f, 0.34f, 0.21f, 0.90f),
+    };
+    static const ButtonPalette PIANO_MODE_PALETTE {
+        ImVec4(0.15f, 0.32f, 0.62f, 0.72f),
+        ImVec4(0.20f, 0.42f, 0.78f, 0.82f),
+        ImVec4(0.10f, 0.24f, 0.50f, 0.90f),
+    };
+
+    static void draw_piano_keys(
+        const ImVec2 &display_size,
+        LONG client_width,
+        uint32_t key_state) {
+
+        if (display_size.x <= 0.f || display_size.y <= 0.f || client_width <= 0) {
+            return;
+        }
+
+        // this is only a visual guide; native touch routing owns the actual input
+        const float left_gap = PIANO_LEFT_GAP * display_size.x / client_width;
+        const float right_gap = PIANO_RIGHT_GAP * display_size.x / client_width;
+        const float piano_width = display_size.x - left_gap - right_gap;
+        if (piano_width <= 0.f) {
+            return;
+        }
+
+        const float key_width = piano_width / PIANO_KEY_COUNT;
+        const float key_top = display_size.y * (1.f - PIANO_HEIGHT_RATIO);
+        auto *draw_list = ImGui::GetBackgroundDrawList();
+
+        for (uint32_t key = 0; key < PIANO_KEY_COUNT; key++) {
+            const ImVec2 key_min(left_gap + key * key_width, key_top);
+            const ImVec2 key_max(left_gap + (key + 1) * key_width, display_size.y);
+            const bool active = (key_state & (UINT32_C(1) << key)) != 0;
+            draw_list->AddRectFilled(
+                key_min,
+                key_max,
+                active ? PIANO_KEY_ACTIVE_COLOR : PIANO_KEY_COLOR);
+            draw_list->AddRect(key_min, key_max, PIANO_KEY_BORDER_COLOR);
+        }
+    }
+
+    NostalgiaTouchPiano::NostalgiaTouchPiano(SpiceOverlay *overlay) : Window(overlay) {
+        this->title = "Nostalgia Touch Piano";
+        this->flags = ImGuiWindowFlags_NoTitleBar
+            | ImGuiWindowFlags_NoResize
+            | ImGuiWindowFlags_NoCollapse
+            | ImGuiWindowFlags_NoMove
+            | ImGuiWindowFlags_NoDocking
+            | ImGuiWindowFlags_NoBackground
+            | ImGuiWindowFlags_NoSavedSettings
+            | ImGuiWindowFlags_NoNav
+            | ImGuiWindowFlags_NoBringToFrontOnFocus;
+        this->window_padding = overlay::apply_scaling_to_vector(WINDOW_PADDING, WINDOW_PADDING);
+        this->set_active(true);
+    }
+
+    void NostalgiaTouchPiano::calculate_initial_window() {
+        this->init_size = overlay::apply_scaling_to_vector(
+            BUTTON_WIDTH + WINDOW_PADDING * 2,
+            BUTTON_HEIGHT + WINDOW_PADDING * 2);
+        this->init_pos = overlay::apply_scaling_to_vector(EDGE_MARGIN, EDGE_MARGIN);
+    }
+
+    void NostalgiaTouchPiano::build_content() {
+        // keep the control anchored while the game window changes size or mode
+        ImGui::SetWindowPos(
+            overlay::apply_scaling_to_vector(EDGE_MARGIN, EDGE_MARGIN),
+            ImGuiCond_Always);
+
+        // stay above regular overlay windows, but never cover a blocking modal
+        ImGuiWindow *mode_window = ImGui::GetCurrentWindow();
+        if (ImGuiWindow *modal = ImGui::GetTopMostPopupModal()) {
+            ImGui::BringWindowToDisplayBehind(mode_window, modal);
+        } else {
+            ImGui::BringWindowToDisplayFront(mode_window);
+        }
+
+        const bool nav_mode =
+            games::nost::touch_mode::current_mode() == games::nost::touch_mode::Mode::Nav;
+        const char *label = nav_mode ? "Nav Mode" : "Piano Mode";
+
+        // make the active routing mode recognizable without reading the label
+        const auto &palette = nav_mode ? NAV_MODE_PALETTE : PIANO_MODE_PALETTE;
+        ImGui::PushStyleColor(ImGuiCol_Button, palette.normal);
+        ImGui::PushStyleColor(ImGuiCol_ButtonHovered, palette.hovered);
+        ImGui::PushStyleColor(ImGuiCol_ButtonActive, palette.active);
+        ImGui::Button(label, overlay::apply_scaling_to_vector(BUTTON_WIDTH, BUTTON_HEIGHT));
+        ImGui::PopStyleColor(3);
+
+        const auto &io = ImGui::GetIO();
+        RECT client_rect {};
+        if (io.DisplaySize.x > 0.f && io.DisplaySize.y > 0.f &&
+            GetClientRect(this->overlay->get_window(), &client_rect)) {
+
+            // convert the rendered imgui rectangle into the client coordinates
+            // used by hardware touch publication and piano-key mapping
+            const auto item_min = ImGui::GetItemRectMin();
+            const auto item_max = ImGui::GetItemRectMax();
+            const auto client_width = client_rect.right - client_rect.left;
+            const auto client_height = client_rect.bottom - client_rect.top;
+            if (!nav_mode) {
+                draw_piano_keys(
+                    io.DisplaySize,
+                    client_width,
+                    games::nost::touch_mode::piano_key_state());
+            }
+
+            RECT button_bounds {
+                static_cast<LONG>(std::lround(item_min.x * client_width / io.DisplaySize.x)),
+                static_cast<LONG>(std::lround(item_min.y * client_height / io.DisplaySize.y)),
+                static_cast<LONG>(std::lround(item_max.x * client_width / io.DisplaySize.x)),
+                static_cast<LONG>(std::lround(item_max.y * client_height / io.DisplaySize.y)),
+            };
+            games::nost::touch_mode::publish_button_bounds(
+                this->overlay->get_window(), button_bounds);
+        }
+    }
+}

src/spice2x/overlay/windows/nostalgia_touch_piano.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include "overlay/window.h"
+
+namespace overlay::windows {
+
+    // persistent mode control rendered independently of the main overlay visibility
+    class NostalgiaTouchPiano : public Window {
+    public:
+        explicit NostalgiaTouchPiano(SpiceOverlay *overlay);
+
+        void calculate_initial_window() override;
+        void build_content() override;
+    };
+}