feat: add experimental game engine & demo game, fix ACPI events

GNUmakefile

@@ -6,7 +6,7 @@ MAKEFLAGS += -rR
 ARCH := x86_64
 
 # Default user QEMU flags. These are appended to the QEMU command calls.
-QEMUFLAGS := -m 2G -d int -D qemu.log
+QEMUFLAGS := -smp 4 -m 2G -d int -D qemu.log
 
 override IMAGE_NAME := montauk-$(ARCH)
 

kernel/src/ACPI/AcpiEvents.cpp

@@ -79,8 +79,7 @@ namespace Hal {
                 KernelLogStream(INFO, "ACPI") << "Sleep button pressed";
             }
 
-            // Send EOI
+            // Note: EOI is sent by HalIrqDispatch after this handler returns.
-            LocalApic::SendEOI();
         }
 
         // ============================================================================
@@ -88,7 +87,13 @@ namespace Hal {
         // Initialize
 
         // ============================================================================
-        void Initialize(const FADT::ParsedFADT& fadt) {
+        void Initialize(ACPI::CommonSDTHeader* xsdt) {
+            FADT::ParsedFADT fadt{};
+            if (!FADT::Parse(xsdt, fadt) || !fadt.Valid) {
+                KernelLogStream(ERROR, "ACPI") << "Failed to parse FADT - ACPI events unavailable";
+                return;
+            }
+
             g_pm1aEventBlock = fadt.PM1aEventBlock;
             g_pm1bEventBlock = fadt.PM1bEventBlock;
             g_pm1EventLength = fadt.PM1EventLength;

kernel/src/ACPI/AcpiEvents.hpp

@@ -13,8 +13,8 @@ namespace Hal {
 
         // Initialize ACPI event handling: route the SCI interrupt,
         // register the handler, and enable fixed events (power button).
-        // Must be called after APIC and FADT initialization.
+        // Must be called after APIC initialization.
-        void Initialize(const FADT::ParsedFADT& fadt);
+        void Initialize(ACPI::CommonSDTHeader* xsdt);
 
         // Re-enable ACPI events after S3 resume.
         void Reinitialize();

kernel/src/ACPI/AcpiShutdown.cpp

@@ -69,8 +69,8 @@ namespace Hal {
             // Initialize S3 suspend support (reads FACS and \_S3_ from namespace)
             AcpiSleep::Initialize(xsdt);
 
-            // Initialize ACPI event handling (SCI interrupt, power button)
+            // Note: ACPI event handling (SCI, power button) is initialized
-            AcpiEvents::Initialize(fadt);
+            // from Main.cpp after the APIC subsystem is ready.
         }
 
         bool IsAvailable() {

kernel/src/Main.cpp

@@ -21,6 +21,7 @@
 #include <Memory/Paging.hpp>
 #include <ACPI/ACPI.hpp>
 #include <ACPI/AcpiShutdown.hpp>
+#include <ACPI/AcpiEvents.hpp>
 #include <Hal/Apic/ApicInit.hpp>
 #include <Pci/Pci.hpp>
 #include <Timekeeping/ApicTimer.hpp>
@@ -144,6 +145,9 @@ extern "C" void kmain() {
 
         Hal::ApicInitialize(g_acpi.GetXSDT());
 
+        // Initialize ACPI events (SCI, power button) after APIC is ready
+        Hal::AcpiEvents::Initialize(g_acpi.GetXSDT());
+
         Pci::Initialize(g_acpi.GetXSDT());
 
         Drivers::ProbeEarly();

programs/GNUmakefile

@@ -59,7 +59,7 @@ BINDIR := bin
 PROGRAMS := $(notdir $(wildcard src/*))
 
 # Programs with custom Makefiles (built separately).
-CUSTOM_BUILDS := doom fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth desktop login shell
+CUSTOM_BUILDS := doom fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth desktop login shell rpgdemo
 SYSTEM_PROGRAMS := $(filter-out $(CUSTOM_BUILDS),$(PROGRAMS))
 
 # Build targets: system programs go to bin/os/, apps go to bin/apps/<name>/.
@@ -81,9 +81,9 @@ CA_CERTS := $(BINDIR)/etc/ca-certificates.crt
 # Common shared assets (wallpapers, etc.)
 COMMONKEEP := $(BINDIR)/common/.keep
 
-.PHONY: all clean doom fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth login desktop shell icons fonts bearssl libc tls libjpeg install-apps
+.PHONY: all clean doom fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth login desktop shell rpgdemo icons fonts bearssl libc tls libjpeg install-apps
 
-all: bearssl libc libjpeg tls $(TARGETS) fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth doom login desktop shell icons fonts install-apps $(MANDST) $(WWWDST) $(CA_CERTS) $(COMMONKEEP)
+all: bearssl libc libjpeg tls $(TARGETS) fetch wiki wikipedia weather imageviewer fontpreview spreadsheet pdfviewer disks devexplorer installer volume music bluetooth doom rpgdemo login desktop shell icons fonts install-apps $(MANDST) $(WWWDST) $(CA_CERTS) $(COMMONKEEP)
 
 # Build BearSSL static library (cross-compiled for freestanding x86_64).
 BEARSSL_INCLUDES := -isystem $(shell cd .. && pwd)/kernel/freestnd-c-hdrs/x86_64/include -isystem $(abspath include/libc)
@@ -184,12 +184,16 @@ icons:
 fonts:
 	../scripts/copy_fonts.sh
 
+# Build RPG demo game via its own Makefile (depends on libc).
+rpgdemo: libc
+	$(MAKE) -C src/rpgdemo
+
 # Build doom via its own Makefile.
 doom:
 	$(MAKE) -C src/doom
 
 # Install app bundles (manifests, icons, data files) into bin/apps/<name>/.
-install-apps: doom spreadsheet weather wikipedia imageviewer fontpreview pdfviewer disks devexplorer installer volume music bluetooth
+install-apps: doom rpgdemo spreadsheet weather wikipedia imageviewer fontpreview pdfviewer disks devexplorer installer volume music bluetooth
 	../scripts/install_apps.sh
 
 # Copy man pages into bin/man/ so mkramdisk.sh picks them up.
@@ -241,3 +245,4 @@ clean:
 	$(MAKE) -C src/volume clean
 	$(MAKE) -C src/music clean
 	$(MAKE) -C src/bluetooth clean
+	$(MAKE) -C src/rpgdemo clean

programs/gameengine/Cute_Fantasy_Free/read_me.txt

@@ -0,0 +1,10 @@
+Hello! Thank you for downloading the Cute Fantasy asset pack.
+
+This project will be getting updates over time. This version of the asset pack is not final and there will be few more additional sprites.
+	
+License - Free Version
+   - You can use these assets in non-commercial projects.
+   - You can modify the assets.
+   - You can not redistribute or resale, even if modified
+
+If you like the asset pack leave a comment. It helps to support the asset pack and get more people to see it. Thanks!

programs/include/engine/audio.h

@@ -0,0 +1,81 @@
+/*
+ * audio.h
+ * MontaukOS 2D Game Engine - Audio System
+ * Wraps MontaukOS audio syscalls for game sound playback
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include <montauk/syscall.h>
+
+namespace engine {
+
+static constexpr int AUDIO_SAMPLE_RATE = 44100;
+static constexpr int AUDIO_CHANNELS = 2;
+static constexpr int AUDIO_BITS = 16;
+
+struct AudioEngine {
+    int handle = -1;
+    int volume = 80;
+
+    bool init() {
+        handle = montauk::audio_open(AUDIO_SAMPLE_RATE, AUDIO_CHANNELS, AUDIO_BITS);
+        if (handle < 0) return false;
+        montauk::audio_set_volume(handle, volume);
+        return true;
+    }
+
+    void shutdown() {
+        if (handle >= 0) {
+            montauk::audio_close(handle);
+            handle = -1;
+        }
+    }
+
+    void set_volume(int percent) {
+        volume = percent;
+        if (handle >= 0)
+            montauk::audio_set_volume(handle, volume);
+    }
+
+    // Write raw PCM samples to the audio device.
+    // data: signed 16-bit stereo PCM samples
+    // size: number of bytes
+    bool write_pcm(const void* data, uint32_t size) {
+        if (handle < 0) return false;
+        return montauk::audio_write(handle, data, size) >= 0;
+    }
+
+    // Generate and play a simple tone (square wave) for duration_ms.
+    // Useful for basic sound effects. Non-blocking (writes samples to buffer).
+    void play_tone(int freq_hz, int duration_ms, int tone_volume = 50) {
+        if (handle < 0 || freq_hz <= 0) return;
+
+        int total_samples = (AUDIO_SAMPLE_RATE * duration_ms) / 1000;
+        int half_period = AUDIO_SAMPLE_RATE / (2 * freq_hz);
+        if (half_period <= 0) half_period = 1;
+
+        int16_t amp = (int16_t)(327 * tone_volume / 100); // ~1% of max
+        static constexpr int CHUNK = 512;
+        int16_t buf[CHUNK * 2]; // stereo
+
+        int written = 0;
+        while (written < total_samples) {
+            int n = total_samples - written;
+            if (n > CHUNK) n = CHUNK;
+
+            for (int i = 0; i < n; i++) {
+                int sample_pos = written + i;
+                int16_t val = ((sample_pos / half_period) % 2 == 0) ? amp : -amp;
+                buf[i * 2] = val;
+                buf[i * 2 + 1] = val;
+            }
+
+            montauk::audio_write(handle, buf, n * 4);
+            written += n;
+        }
+    }
+};
+
+} // namespace engine

programs/include/engine/collision.h

@@ -0,0 +1,48 @@
+/*
+ * collision.h
+ * MontaukOS 2D Game Engine - Collision Detection
+ * AABB overlap testing and tile-based collision response
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include "engine/tilemap.h"
+
+namespace engine {
+
+struct AABB {
+    float x, y, w, h;
+
+    bool overlaps(const AABB& other) const {
+        return x < other.x + other.w && x + w > other.x &&
+               y < other.y + other.h && y + h > other.y;
+    }
+
+    bool contains_point(float px, float py) const {
+        return px >= x && px < x + w && py >= y && py < y + h;
+    }
+};
+
+// Try to move an entity by (dx, dy) on the tilemap.
+// Uses separate X/Y axis resolution so the entity slides along walls.
+// box: the entity's collision box in world pixel coordinates.
+// Returns adjusted dx, dy after collision.
+inline void resolve_tilemap_collision(const Tilemap& map,
+                                      float bx, float by, float bw, float bh,
+                                      float& dx, float& dy) {
+    // Try X movement
+    float new_x = bx + dx;
+    if (map.collides((int)new_x, (int)by, (int)bw, (int)bh)) {
+        dx = 0.0f;
+        new_x = bx;
+    }
+
+    // Try Y movement
+    float new_y = by + dy;
+    if (map.collides((int)new_x, (int)new_y, (int)bw, (int)bh)) {
+        dy = 0.0f;
+    }
+}
+
+} // namespace engine

programs/include/engine/engine.h

@@ -0,0 +1,200 @@
+/*
+ * engine.h
+ * MontaukOS 2D Game Engine - Core
+ * Window management, timing, pixel buffer helpers
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include <montauk/syscall.h>
+#include <montauk/heap.h>
+#include <montauk/string.h>
+#include <gui/gui.hpp>
+#include <gui/truetype.hpp>
+
+extern "C" {
+#include <stdio.h>
+}
+
+namespace engine {
+
+// ============================================================================
+// Core engine
+// ============================================================================
+
+struct Engine {
+    int win_id = -1;
+    uint32_t* pixels = nullptr;
+    int screen_w = 0;
+    int screen_h = 0;
+
+    // Timing
+    uint64_t last_time_ms = 0;
+    float dt = 0.016f;       // delta time in seconds
+    uint64_t frame_count = 0;
+
+    // Font
+    gui::TrueTypeFont* font = nullptr;
+
+    bool running = true;
+
+    // ---- Lifecycle ----
+
+    bool init(const char* title, int w, int h) {
+        screen_w = w;
+        screen_h = h;
+
+        // Load font
+        font = (gui::TrueTypeFont*)montauk::malloc(sizeof(gui::TrueTypeFont));
+        if (font) {
+            montauk::memset(font, 0, sizeof(gui::TrueTypeFont));
+            if (!font->init("0:/fonts/Roboto-Medium.ttf")) {
+                montauk::mfree(font);
+                font = nullptr;
+            }
+        }
+
+        // Create window
+        Montauk::WinCreateResult wres;
+        if (montauk::win_create(title, w, h, &wres) < 0 || wres.id < 0)
+            return false;
+
+        win_id = wres.id;
+        pixels = (uint32_t*)(uintptr_t)wres.pixelVa;
+        last_time_ms = montauk::get_milliseconds();
+        return true;
+    }
+
+    void update_timing() {
+        uint64_t now = montauk::get_milliseconds();
+        uint64_t elapsed = now - last_time_ms;
+        if (elapsed == 0) elapsed = 1;
+        if (elapsed > 100) elapsed = 100; // cap to avoid spiral
+        dt = (float)elapsed / 1000.0f;
+        last_time_ms = now;
+        frame_count++;
+    }
+
+    // Poll one window event. Returns true if an event was received.
+    bool poll(Montauk::WinEvent* ev) {
+        int r = montauk::win_poll(win_id, ev);
+        if (r < 0) { running = false; return false; }
+        if (r == 0) return false;
+        if (ev->type == 3) { running = false; return false; } // close
+        if (ev->type == 2) { // resize
+            screen_w = ev->resize.w;
+            screen_h = ev->resize.h;
+            pixels = (uint32_t*)(uintptr_t)montauk::win_resize(
+                win_id, screen_w, screen_h);
+        }
+        return true;
+    }
+
+    void present() {
+        montauk::win_present(win_id);
+    }
+
+    void shutdown() {
+        if (win_id >= 0) montauk::win_destroy(win_id);
+        win_id = -1;
+    }
+
+    // ---- Drawing helpers ----
+
+    void clear(uint32_t color) {
+        int count = screen_w * screen_h;
+        for (int i = 0; i < count; i++)
+            pixels[i] = color;
+    }
+
+    void fill_rect(int x, int y, int w, int h, uint32_t color) {
+        int x0 = x < 0 ? 0 : x;
+        int y0 = y < 0 ? 0 : y;
+        int x1 = x + w > screen_w ? screen_w : x + w;
+        int y1 = y + h > screen_h ? screen_h : y + h;
+        for (int row = y0; row < y1; row++)
+            for (int col = x0; col < x1; col++)
+                pixels[row * screen_w + col] = color;
+    }
+
+    void fill_rect_alpha(int x, int y, int w, int h, uint32_t color) {
+        uint8_t sa = (color >> 24) & 0xFF;
+        uint8_t sr = (color >> 16) & 0xFF;
+        uint8_t sg = (color >> 8) & 0xFF;
+        uint8_t sb = color & 0xFF;
+        if (sa == 0) return;
+        int x0 = x < 0 ? 0 : x;
+        int y0 = y < 0 ? 0 : y;
+        int x1 = x + w > screen_w ? screen_w : x + w;
+        int y1 = y + h > screen_h ? screen_h : y + h;
+        for (int row = y0; row < y1; row++) {
+            for (int col = x0; col < x1; col++) {
+                uint32_t dst = pixels[row * screen_w + col];
+                uint8_t dr = (dst >> 16) & 0xFF;
+                uint8_t dg = (dst >> 8) & 0xFF;
+                uint8_t db = dst & 0xFF;
+                uint32_t inv = 255 - sa;
+                uint32_t rr = (sa * sr + inv * dr + 128) / 255;
+                uint32_t gg = (sa * sg + inv * dg + 128) / 255;
+                uint32_t bb = (sa * sb + inv * db + 128) / 255;
+                pixels[row * screen_w + col] =
+                    0xFF000000 | (rr << 16) | (gg << 8) | bb;
+            }
+        }
+    }
+
+    void draw_rect_outline(int x, int y, int w, int h, uint32_t color) {
+        fill_rect(x, y, w, 1, color);
+        fill_rect(x, y + h - 1, w, 1, color);
+        fill_rect(x, y, 1, h, color);
+        fill_rect(x + w - 1, y, 1, h, color);
+    }
+
+    void draw_text(int x, int y, const char* text, gui::Color c, int size = 16) {
+        if (font)
+            font->draw_to_buffer(pixels, screen_w, screen_h, x, y, text, c, size);
+    }
+
+    int text_width(const char* text, int size = 16) {
+        return font ? font->measure_text(text, size) : 0;
+    }
+
+    int text_height(int size = 16) {
+        if (!font) return size;
+        auto* gc = font->get_cache(size);
+        if (!gc) return size;
+        return gc->ascent - gc->descent;
+    }
+};
+
+// ============================================================================
+// File loading helper
+// ============================================================================
+
+struct FileData {
+    uint8_t* data = nullptr;
+    uint64_t size = 0;
+
+    bool load(const char* vfs_path) {
+        int fd = montauk::open(vfs_path);
+        if (fd < 0) return false;
+        size = montauk::getsize(fd);
+        if (size == 0 || size > 16 * 1024 * 1024) {
+            montauk::close(fd);
+            return false;
+        }
+        data = (uint8_t*)montauk::malloc(size);
+        if (!data) { montauk::close(fd); return false; }
+        montauk::read(fd, data, 0, size);
+        montauk::close(fd);
+        return true;
+    }
+
+    void free() {
+        if (data) { montauk::mfree(data); data = nullptr; }
+        size = 0;
+    }
+};
+
+} // namespace engine

programs/include/engine/input.h

@@ -0,0 +1,87 @@
+/*
+ * input.h
+ * MontaukOS 2D Game Engine - Input State
+ * Keyboard and mouse state tracking across frames
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include <montauk/string.h>
+#include <Api/Syscall.hpp>
+
+namespace engine {
+
+// Scancode constants for common keys
+namespace key {
+    static constexpr uint8_t ESC      = 0x01;
+    static constexpr uint8_t W        = 0x11;
+    static constexpr uint8_t A        = 0x1E;
+    static constexpr uint8_t S        = 0x1F;
+    static constexpr uint8_t D        = 0x20;
+    static constexpr uint8_t E        = 0x12;
+    static constexpr uint8_t SPACE    = 0x39;
+    static constexpr uint8_t UP       = 0x48;
+    static constexpr uint8_t DOWN     = 0x50;
+    static constexpr uint8_t LEFT     = 0x4B;
+    static constexpr uint8_t RIGHT    = 0x4D;
+    static constexpr uint8_t ENTER    = 0x1C;
+    static constexpr uint8_t TAB      = 0x0F;
+}
+
+struct InputState {
+    // Key states: true = currently held
+    bool keys[256];
+    // Keys pressed this frame (edge-triggered)
+    bool keys_pressed[256];
+
+    // Mouse
+    int mouse_x = 0;
+    int mouse_y = 0;
+    int mouse_scroll = 0;
+    uint8_t mouse_buttons = 0;
+    uint8_t prev_mouse_buttons = 0;
+
+    void init() {
+        montauk::memset(keys, 0, sizeof(keys));
+        montauk::memset(keys_pressed, 0, sizeof(keys_pressed));
+    }
+
+    // Call at the start of each frame to clear per-frame state
+    void begin_frame() {
+        montauk::memset(keys_pressed, 0, sizeof(keys_pressed));
+        mouse_scroll = 0;
+        prev_mouse_buttons = mouse_buttons;
+    }
+
+    // Process a window event
+    void handle_event(const Montauk::WinEvent& ev) {
+        if (ev.type == 0) { // keyboard
+            // PS/2 scan code set 1: release codes have bit 7 set.
+            // Mask to base scancode so press and release map to the same index.
+            uint8_t sc = ev.key.scancode & 0x7F;
+            if (ev.key.pressed) {
+                if (!keys[sc])
+                    keys_pressed[sc] = true;
+                keys[sc] = true;
+            } else {
+                keys[sc] = false;
+            }
+        } else if (ev.type == 1) { // mouse
+            mouse_x = ev.mouse.x;
+            mouse_y = ev.mouse.y;
+            mouse_scroll = ev.mouse.scroll;
+            mouse_buttons = ev.mouse.buttons;
+        }
+    }
+
+    bool key_held(uint8_t scancode) const { return keys[scancode]; }
+    bool key_just_pressed(uint8_t scancode) const { return keys_pressed[scancode]; }
+
+    bool mouse_clicked() const {
+        return (mouse_buttons & 1) && !(prev_mouse_buttons & 1);
+    }
+    bool mouse_held() const { return mouse_buttons & 1; }
+};
+
+} // namespace engine

programs/include/engine/sprite.h

@@ -0,0 +1,264 @@
+/*
+ * sprite.h
+ * MontaukOS 2D Game Engine - Sprite and Animation System
+ * PNG spritesheet loading, frame extraction, alpha-blended rendering
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include <montauk/heap.h>
+#include <montauk/string.h>
+#include "engine/engine.h"
+
+extern "C" {
+#include <gui/stb_image.h>
+}
+
+namespace engine {
+
+// ============================================================================
+// Convert stb_image RGBA output to MontaukOS ARGB pixel format
+// stb on little-endian x86: pixel bytes in memory are R,G,B,A
+// When read as uint32_t: 0xAABBGGRR
+// MontaukOS format: 0xAARRGGBB
+// ============================================================================
+
+inline void rgba_to_argb(uint32_t* data, int count) {
+    for (int i = 0; i < count; i++) {
+        uint32_t px = data[i];
+        uint8_t r = px & 0xFF;
+        uint8_t g = (px >> 8) & 0xFF;
+        uint8_t b = (px >> 16) & 0xFF;
+        uint8_t a = (px >> 24) & 0xFF;
+        data[i] = ((uint32_t)a << 24) | ((uint32_t)r << 16) |
+                  ((uint32_t)g << 8) | b;
+    }
+}
+
+// ============================================================================
+// Spritesheet
+// ============================================================================
+
+struct Spritesheet {
+    uint32_t* pixels = nullptr;
+    int width = 0;
+    int height = 0;
+    int frame_w = 0;
+    int frame_h = 0;
+    int cols = 0;
+    int rows = 0;
+
+    // Load a PNG spritesheet from VFS and split into frames of given size.
+    // If frame_w/frame_h are 0, treat the entire image as a single frame.
+    bool load(const char* vfs_path, int fw = 0, int fh = 0) {
+        FileData file;
+        if (!file.load(vfs_path)) return false;
+
+        int w, h, channels;
+        uint32_t* img = (uint32_t*)stbi_load_from_memory(
+            file.data, (int)file.size, &w, &h, &channels, 4);
+        file.free();
+
+        if (!img) return false;
+
+        // Convert RGBA to ARGB
+        rgba_to_argb(img, w * h);
+
+        pixels = img;
+        width = w;
+        height = h;
+        frame_w = fw > 0 ? fw : w;
+        frame_h = fh > 0 ? fh : h;
+        cols = w / frame_w;
+        rows = h / frame_h;
+        return true;
+    }
+
+    void unload() {
+        if (pixels) {
+            stbi_image_free(pixels);
+            pixels = nullptr;
+        }
+    }
+
+    // Blit a single frame to the destination buffer with scaling and alpha.
+    // frame_col/frame_row select which frame from the spritesheet.
+    // dst_x/dst_y is the screen position. scale is the integer scale factor.
+    // flip_h mirrors the sprite horizontally.
+    void draw_frame(uint32_t* dst, int dst_w, int dst_h,
+                    int frame_col, int frame_row,
+                    int dst_x, int dst_y, int scale = 1,
+                    bool flip_h = false) const {
+        if (!pixels) return;
+        if (frame_col < 0 || frame_col >= cols) return;
+        if (frame_row < 0 || frame_row >= rows) return;
+
+        int src_ox = frame_col * frame_w;
+        int src_oy = frame_row * frame_h;
+        int out_w = frame_w * scale;
+        int out_h = frame_h * scale;
+
+        for (int py = 0; py < out_h; py++) {
+            int dy = dst_y + py;
+            if (dy < 0 || dy >= dst_h) continue;
+            int sy = src_oy + py / scale;
+
+            for (int px = 0; px < out_w; px++) {
+                int dx = dst_x + px;
+                if (dx < 0 || dx >= dst_w) continue;
+
+                int sx_local = px / scale;
+                if (flip_h) sx_local = frame_w - 1 - sx_local;
+                int sx = src_ox + sx_local;
+
+                uint32_t src_px = pixels[sy * width + sx];
+                uint8_t sa = (src_px >> 24) & 0xFF;
+                if (sa == 0) continue;
+
+                if (sa == 255) {
+                    dst[dy * dst_w + dx] = src_px;
+                } else {
+                    uint32_t d = dst[dy * dst_w + dx];
+                    uint8_t sr = (src_px >> 16) & 0xFF;
+                    uint8_t sg = (src_px >> 8) & 0xFF;
+                    uint8_t sb = src_px & 0xFF;
+                    uint8_t dr = (d >> 16) & 0xFF;
+                    uint8_t dg = (d >> 8) & 0xFF;
+                    uint8_t db = d & 0xFF;
+                    uint32_t inv = 255 - sa;
+                    uint32_t rr = (sa * sr + inv * dr + 128) / 255;
+                    uint32_t gg = (sa * sg + inv * dg + 128) / 255;
+                    uint32_t bb = (sa * sb + inv * db + 128) / 255;
+                    dst[dy * dst_w + dx] =
+                        0xFF000000 | (rr << 16) | (gg << 8) | bb;
+                }
+            }
+        }
+    }
+
+    // Draw an arbitrary sub-rectangle of the spritesheet (not frame-aligned)
+    void draw_region(uint32_t* dst, int dst_w, int dst_h,
+                     int src_x, int src_y, int src_w, int src_h,
+                     int dst_x, int dst_y, int scale = 1) const {
+        if (!pixels) return;
+
+        int out_w = src_w * scale;
+        int out_h = src_h * scale;
+
+        for (int py = 0; py < out_h; py++) {
+            int dy = dst_y + py;
+            if (dy < 0 || dy >= dst_h) continue;
+            int sy = src_y + py / scale;
+            if (sy < 0 || sy >= height) continue;
+
+            for (int px = 0; px < out_w; px++) {
+                int dx = dst_x + px;
+                if (dx < 0 || dx >= dst_w) continue;
+                int sx = src_x + px / scale;
+                if (sx < 0 || sx >= width) continue;
+
+                uint32_t src_px = pixels[sy * width + sx];
+                uint8_t sa = (src_px >> 24) & 0xFF;
+                if (sa == 0) continue;
+
+                if (sa == 255) {
+                    dst[dy * dst_w + dx] = src_px;
+                } else {
+                    uint32_t d = dst[dy * dst_w + dx];
+                    uint8_t sr = (src_px >> 16) & 0xFF;
+                    uint8_t sg = (src_px >> 8) & 0xFF;
+                    uint8_t sb = src_px & 0xFF;
+                    uint8_t dr = (d >> 16) & 0xFF;
+                    uint8_t dg = (d >> 8) & 0xFF;
+                    uint8_t db = d & 0xFF;
+                    uint32_t inv = 255 - sa;
+                    uint32_t rr = (sa * sr + inv * dr + 128) / 255;
+                    uint32_t gg = (sa * sg + inv * dg + 128) / 255;
+                    uint32_t bb = (sa * sb + inv * db + 128) / 255;
+                    dst[dy * dst_w + dx] =
+                        0xFF000000 | (rr << 16) | (gg << 8) | bb;
+                }
+            }
+        }
+    }
+};
+
+// ============================================================================
+// Animation
+// ============================================================================
+
+struct Animation {
+    int row = 0;         // spritesheet row for this animation
+    int start_col = 0;   // first frame column
+    int num_frames = 1;  // number of frames
+    float speed = 8.0f;  // frames per second
+
+    float timer = 0.0f;
+    int current = 0;
+
+    void update(float dt) {
+        timer += dt * speed;
+        while (timer >= 1.0f) {
+            timer -= 1.0f;
+            current++;
+            if (current >= num_frames) current = 0;
+        }
+    }
+
+    void reset() {
+        timer = 0.0f;
+        current = 0;
+    }
+
+    int frame_col() const { return start_col + current; }
+    int frame_row() const { return row; }
+};
+
+// ============================================================================
+// Animated Sprite - combines a spritesheet with named animations
+// ============================================================================
+
+static constexpr int MAX_ANIMS = 16;
+
+struct AnimatedSprite {
+    Spritesheet* sheet = nullptr;
+    Animation anims[MAX_ANIMS];
+    int anim_count = 0;
+    int current_anim = 0;
+    bool flip_h = false;
+
+    int add_anim(int row, int start_col, int num_frames, float speed = 8.0f) {
+        if (anim_count >= MAX_ANIMS) return -1;
+        int idx = anim_count++;
+        anims[idx].row = row;
+        anims[idx].start_col = start_col;
+        anims[idx].num_frames = num_frames;
+        anims[idx].speed = speed;
+        return idx;
+    }
+
+    void play(int anim_idx) {
+        if (anim_idx < 0 || anim_idx >= anim_count) return;
+        if (current_anim != anim_idx) {
+            current_anim = anim_idx;
+            anims[current_anim].reset();
+        }
+    }
+
+    void update(float dt) {
+        if (current_anim >= 0 && current_anim < anim_count)
+            anims[current_anim].update(dt);
+    }
+
+    void draw(uint32_t* dst, int dst_w, int dst_h,
+              int x, int y, int scale = 1) const {
+        if (!sheet || current_anim < 0 || current_anim >= anim_count) return;
+        const Animation& a = anims[current_anim];
+        sheet->draw_frame(dst, dst_w, dst_h,
+                          a.frame_col(), a.frame_row(),
+                          x, y, scale, flip_h);
+    }
+};
+
+} // namespace engine

programs/include/engine/tilemap.h

@@ -0,0 +1,134 @@
+/*
+ * tilemap.h
+ * MontaukOS 2D Game Engine - Tile Map
+ * Grid-based terrain with per-tile rendering and collision
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include <montauk/heap.h>
+#include <montauk/string.h>
+#include "engine/sprite.h"
+
+namespace engine {
+
+static constexpr int MAX_TILE_TYPES = 16;
+
+struct TileType {
+    Spritesheet* sheet;   // tile image (may be a single-tile spritesheet)
+    int src_x, src_y;     // source position within the sheet
+    int src_w, src_h;     // source size (typically tile_size x tile_size)
+    bool solid;           // blocks movement
+};
+
+struct Tilemap {
+    int* data = nullptr;
+    int map_w = 0;
+    int map_h = 0;
+    int tile_size = 16;   // native tile size in pixels
+
+    TileType types[MAX_TILE_TYPES];
+    int type_count = 0;
+
+    bool alloc(int w, int h, int ts = 16) {
+        map_w = w;
+        map_h = h;
+        tile_size = ts;
+        data = (int*)montauk::malloc(w * h * sizeof(int));
+        if (!data) return false;
+        montauk::memset(data, 0, w * h * sizeof(int));
+        return true;
+    }
+
+    void free_map() {
+        if (data) { montauk::mfree(data); data = nullptr; }
+    }
+
+    // Register a tile type. Returns the tile ID.
+    int add_type(Spritesheet* sheet, int sx, int sy, int sw, int sh, bool solid) {
+        if (type_count >= MAX_TILE_TYPES) return -1;
+        int id = type_count++;
+        types[id].sheet = sheet;
+        types[id].src_x = sx;
+        types[id].src_y = sy;
+        types[id].src_w = sw;
+        types[id].src_h = sh;
+        types[id].solid = solid;
+        return id;
+    }
+
+    void set(int x, int y, int tile_id) {
+        if (x >= 0 && x < map_w && y >= 0 && y < map_h)
+            data[y * map_w + x] = tile_id;
+    }
+
+    int get(int x, int y) const {
+        if (x < 0 || x >= map_w || y < 0 || y >= map_h) return -1;
+        return data[y * map_w + x];
+    }
+
+    bool is_solid(int x, int y) const {
+        int id = get(x, y);
+        if (id < 0 || id >= type_count) return true; // out of bounds = solid
+        return types[id].solid;
+    }
+
+    // Check if a world-pixel rectangle collides with any solid tile.
+    // World coordinates are in native (unscaled) pixels.
+    bool collides(int wx, int wy, int ww, int wh) const {
+        // Negative coordinates are always solid (out of bounds)
+        if (wx < 0 || wy < 0) return true;
+        int tx0 = wx / tile_size;
+        int ty0 = wy / tile_size;
+        int tx1 = (wx + ww - 1) / tile_size;
+        int ty1 = (wy + wh - 1) / tile_size;
+
+        for (int ty = ty0; ty <= ty1; ty++)
+            for (int tx = tx0; tx <= tx1; tx++)
+                if (is_solid(tx, ty))
+                    return true;
+        return false;
+    }
+
+    // Draw visible tiles to the pixel buffer.
+    // cam_x/cam_y: camera position in world pixels (native scale).
+    // scale: rendering scale factor.
+    void draw(uint32_t* dst, int dst_w, int dst_h,
+              int cam_x, int cam_y, int scale) const {
+        if (!data) return;
+
+        int ts = tile_size * scale;
+
+        // Determine visible tile range
+        int tx0 = cam_x / tile_size;
+        int ty0 = cam_y / tile_size;
+        int tx1 = tx0 + dst_w / ts + 2;
+        int ty1 = ty0 + dst_h / ts + 2;
+
+        if (tx0 < 0) tx0 = 0;
+        if (ty0 < 0) ty0 = 0;
+        if (tx1 > map_w) tx1 = map_w;
+        if (ty1 > map_h) ty1 = map_h;
+
+        for (int ty = ty0; ty < ty1; ty++) {
+            for (int tx = tx0; tx < tx1; tx++) {
+                int id = data[ty * map_w + tx];
+                if (id < 0 || id >= type_count) continue;
+
+                const TileType& tt = types[id];
+                if (!tt.sheet) continue;
+
+                int sx = tx * ts - cam_x * scale;
+                int sy = ty * ts - cam_y * scale;
+
+                tt.sheet->draw_region(dst, dst_w, dst_h,
+                                      tt.src_x, tt.src_y,
+                                      tt.src_w, tt.src_h,
+                                      sx, sy, scale);
+            }
+        }
+    }
+};
+
+} // namespace engine

programs/include/engine/ui.h

@@ -0,0 +1,114 @@
+/*
+ * ui.h
+ * MontaukOS 2D Game Engine - UI Rendering
+ * Health bars, text overlays, dialog boxes, menus
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#pragma once
+#include <cstdint>
+#include "engine/engine.h"
+
+extern "C" {
+#include <stdio.h>
+}
+
+namespace engine {
+
+// ============================================================================
+// Health / stat bar
+// ============================================================================
+
+inline void draw_bar(Engine& eng, int x, int y, int w, int h,
+                     int value, int max_value,
+                     uint32_t fill_color, uint32_t bg_color,
+                     uint32_t border_color) {
+    eng.fill_rect(x, y, w, h, bg_color);
+    if (max_value > 0 && value > 0) {
+        int fw = (value * (w - 2)) / max_value;
+        if (fw < 1) fw = 1;
+        eng.fill_rect(x + 1, y + 1, fw, h - 2, fill_color);
+    }
+    eng.draw_rect_outline(x, y, w, h, border_color);
+}
+
+// ============================================================================
+// Text box / dialog
+// ============================================================================
+
+inline void draw_dialog(Engine& eng, int x, int y, int w, int h,
+                        const char* text, gui::Color text_color,
+                        int font_size = 16) {
+    // Background with border
+    eng.fill_rect(x, y, w, h, 0xF0FFFFFF);
+    eng.draw_rect_outline(x, y, w, h, 0xFF333333);
+    eng.draw_rect_outline(x + 1, y + 1, w - 2, h - 2, 0xFFCCCCCC);
+
+    // Text (with word wrapping)
+    int tx = x + 8;
+    int ty = y + 6;
+    int max_w = w - 16;
+    int line_h = eng.text_height(font_size) + 2;
+
+    // Simple word wrap
+    char line_buf[128];
+    int li = 0;
+    const char* p = text;
+    while (*p) {
+        li = 0;
+        while (*p && *p != '\n') {
+            // Save state before adding next word
+            int word_start = li;
+            const char* word_p = p;
+
+            while (*p && *p != ' ' && *p != '\n' && li < 126) {
+                line_buf[li++] = *p++;
+            }
+            line_buf[li] = '\0';
+
+            // Check width
+            if (eng.text_width(line_buf, font_size) > max_w && word_start > 0) {
+                // Line too long - rewind to before this word
+                li = word_start;
+                if (li > 0 && line_buf[li - 1] == ' ') li--;
+                line_buf[li] = '\0';
+                p = word_p; // rewind pointer to retry this word on next line
+                break;
+            }
+
+            if (*p == ' ') { line_buf[li++] = ' '; p++; }
+        }
+        line_buf[li] = '\0';
+        if (*p == '\n') p++;
+
+        if (ty + line_h > y + h - 4) break;
+        eng.draw_text(tx, ty, line_buf, text_color, font_size);
+        ty += line_h;
+    }
+}
+
+// ============================================================================
+// Prompt bar (bottom of screen)
+// ============================================================================
+
+inline void draw_prompt(Engine& eng, const char* text, int font_size = 14) {
+    int bar_h = eng.text_height(font_size) + 8;
+    int y = eng.screen_h - bar_h;
+    eng.fill_rect_alpha(0, y, eng.screen_w, bar_h, 0xCC000000);
+    int tw = eng.text_width(text, font_size);
+    eng.draw_text((eng.screen_w - tw) / 2, y + 4, text,
+                  gui::Color::from_rgb(0xFF, 0xFF, 0xFF), font_size);
+}
+
+// ============================================================================
+// Simple HUD text
+// ============================================================================
+
+inline void draw_hud_text(Engine& eng, int x, int y,
+                          const char* text, gui::Color c, int size = 14) {
+    // Draw shadow first for readability
+    eng.draw_text(x + 1, y + 1, text, gui::Color::from_rgba(0, 0, 0, 180), size);
+    eng.draw_text(x, y, text, c, size);
+}
+
+} // namespace engine

programs/src/rpgdemo/Makefile

@@ -0,0 +1,116 @@
+# Makefile for rpgdemo (Montauk Quest - 2D RPG demo) on MontaukOS
+# Copyright (c) 2026 Daniel Hammer
+
+MAKEFLAGS += -rR
+.SUFFIXES:
+
+# ---- Toolchain ----
+
+TOOLCHAIN_PREFIX := $(shell cd ../../.. && pwd)/toolchain/local/bin/x86_64-elf-
+ifneq ($(wildcard $(TOOLCHAIN_PREFIX)gcc),)
+    CXX := $(TOOLCHAIN_PREFIX)g++
+else
+    CXX := g++
+endif
+
+# ---- Paths ----
+
+PROG_INC := ../../include
+LINK_LD  := ../../link.ld
+BINDIR   := ../../bin
+OBJDIR   := obj
+LIBDIR   := ../../lib
+
+# Game asset source directory
+ASSET_SRC := ../../gameengine/Cute_Fantasy_Free
+
+# ---- Compiler flags ----
+
+CXXFLAGS := \
+    -std=gnu++20 \
+    -g -O2 -pipe \
+    -Wall \
+    -Wextra \
+    -Wno-unused-parameter \
+    -Wno-unused-function \
+    -Wno-missing-field-initializers \
+    -nostdinc \
+    -ffreestanding \
+    -fno-stack-protector \
+    -fno-stack-check \
+    -fno-PIC \
+    -fno-rtti \
+    -fno-exceptions \
+    -ffunction-sections \
+    -fdata-sections \
+    -fno-tree-loop-distribute-patterns \
+    -m64 \
+    -march=x86-64 \
+    -msse \
+    -msse2 \
+    -mno-red-zone \
+    -mcmodel=small \
+    -I $(PROG_INC) \
+    -I . \
+    -isystem $(PROG_INC)/libc \
+    -isystem ../../../kernel/freestnd-c-hdrs/x86_64/include \
+    -isystem ../../../kernel/freestnd-cxx-hdrs/x86_64/include
+
+# ---- Linker flags ----
+
+LDFLAGS := \
+    -nostdlib \
+    -static \
+    -Wl,--build-id=none \
+    -Wl,--gc-sections \
+    -Wl,-m,elf_x86_64 \
+    -z max-page-size=0x1000 \
+    -T $(LINK_LD)
+
+# ---- Source files ----
+
+SRCS := main.cpp stb_impl.cpp
+OBJS := $(addprefix $(OBJDIR)/,$(SRCS:.cpp=.o))
+
+# ---- Target ----
+
+TARGET := $(BINDIR)/apps/rpgdemo/rpgdemo.elf
+APP_DIR := $(BINDIR)/apps/rpgdemo
+
+.PHONY: all clean assets
+
+all: $(TARGET) assets
+
+$(TARGET): $(OBJS) $(LINK_LD) Makefile
+	mkdir -p $(APP_DIR)
+	$(CXX) $(CXXFLAGS) $(LDFLAGS) $(OBJS) $(LIBDIR)/libc/liblibc.a -o $@
+
+$(OBJDIR)/%.o: %.cpp Makefile
+	mkdir -p $(OBJDIR)
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+# Copy game assets into the app bundle
+assets:
+	mkdir -p $(APP_DIR)
+	cp $(ASSET_SRC)/Player/Player.png $(APP_DIR)/Player.png
+	cp $(ASSET_SRC)/Player/Player_Actions.png $(APP_DIR)/Player_Actions.png
+	cp $(ASSET_SRC)/Enemies/Skeleton.png $(APP_DIR)/Skeleton.png
+	cp $(ASSET_SRC)/Enemies/Slime_Green.png $(APP_DIR)/Slime_Green.png
+	cp $(ASSET_SRC)/Tiles/Grass_Middle.png $(APP_DIR)/Grass_Middle.png
+	cp $(ASSET_SRC)/Tiles/Path_Middle.png $(APP_DIR)/Path_Middle.png
+	cp $(ASSET_SRC)/Tiles/Water_Middle.png $(APP_DIR)/Water_Middle.png
+	cp $(ASSET_SRC)/Tiles/Cliff_Tile.png $(APP_DIR)/Cliff_Tile.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Oak_Tree.png" $(APP_DIR)/Oak_Tree.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Oak_Tree_Small.png" $(APP_DIR)/Oak_Tree_Small.png
+	cp "$(ASSET_SRC)/Outdoor decoration/House_1_Wood_Base_Blue.png" $(APP_DIR)/House.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Chest.png" $(APP_DIR)/Chest.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Fences.png" $(APP_DIR)/Fences.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Bridge_Wood.png" $(APP_DIR)/Bridge_Wood.png
+	cp "$(ASSET_SRC)/Outdoor decoration/Outdoor_Decor_Free.png" $(APP_DIR)/Outdoor_Decor.png
+	cp $(ASSET_SRC)/Animals/Chicken/Chicken.png $(APP_DIR)/Chicken.png
+	cp $(ASSET_SRC)/Animals/Cow/Cow.png $(APP_DIR)/Cow.png
+	cp $(ASSET_SRC)/Animals/Pig/Pig.png $(APP_DIR)/Pig.png
+	cp $(ASSET_SRC)/Animals/Sheep/Sheep.png $(APP_DIR)/Sheep.png
+
+clean:
+	rm -rf $(OBJDIR) $(TARGET)

programs/src/rpgdemo/manifest.toml

@@ -0,0 +1,8 @@
+[app]
+name = "Montauk Quest"
+binary = "rpgdemo.elf"
+icon = "icon.svg"
+
+[menu]
+category = "Games"
+visible = true

programs/src/rpgdemo/stb_impl.cpp

@@ -0,0 +1,69 @@
+/*
+ * stb_impl.cpp
+ * Single compilation unit for stb_image (PNG) and stb_truetype
+ * for MontaukOS freestanding environment
+ * Copyright (c) 2026 Daniel Hammer
+ */
+
+#include <cstdint>
+#include <cstddef>
+#include <montauk/heap.h>
+#include <montauk/string.h>
+#include <gui/stb_math.h>
+
+extern "C" {
+#include <stdlib.h>
+#include <string.h>
+}
+
+// ============================================================================
+// stb_image - PNG decoder
+// ============================================================================
+
+#define STBI_ONLY_PNG
+#define STBI_NO_JPEG
+#define STBI_NO_BMP
+#define STBI_NO_PSD
+#define STBI_NO_TGA
+#define STBI_NO_GIF
+#define STBI_NO_HDR
+#define STBI_NO_PIC
+#define STBI_NO_PNM
+#define STBI_NO_LINEAR
+#define STBI_NO_STDIO
+#define STBI_NO_THREAD_LOCALS
+
+#define STBI_MALLOC(sz)         malloc(sz)
+#define STBI_FREE(p)            free(p)
+#define STBI_REALLOC(p, newsz)  realloc(p, newsz)
+
+#define STBI_ASSERT(x)          ((void)(x))
+
+#define STB_IMAGE_IMPLEMENTATION
+#include <gui/stb_image.h>
+
+// ============================================================================
+// stb_truetype - TrueType font renderer
+// ============================================================================
+
+#define STBTT_ifloor(x)   ((int) stb_floor(x))
+#define STBTT_iceil(x)    ((int) stb_ceil(x))
+#define STBTT_sqrt(x)     stb_sqrt(x)
+#define STBTT_pow(x,y)    stb_pow(x,y)
+#define STBTT_fmod(x,y)   stb_fmod(x,y)
+#define STBTT_cos(x)      stb_cos(x)
+#define STBTT_acos(x)     stb_acos(x)
+#define STBTT_fabs(x)     stb_fabs(x)
+
+#define STBTT_malloc(x,u)  ((void)(u), montauk::malloc(x))
+#define STBTT_free(x,u)    ((void)(u), montauk::mfree(x))
+
+#define STBTT_memcpy(d,s,n) montauk::memcpy(d,s,n)
+#define STBTT_memset(d,v,n) montauk::memset(d,v,n)
+
+#define STBTT_strlen(x)    montauk::slen(x)
+
+#define STBTT_assert(x)    ((void)(x))
+
+#define STB_TRUETYPE_IMPLEMENTATION
+#include <gui/stb_truetype.h>

scripts/install_apps.sh

@@ -29,6 +29,7 @@ APPS=(
     "music|apps/scalable/audio-player.svg"
     "video|apps/scalable/multimedia-video-player.svg"
     "bluetooth|apps/scalable/bluetooth.svg"
+    "rpgdemo|apps/scalable/utilities-terminal.svg"
 )
 
 installed=0