feat(platform): Fix high-DPI scaling and add resolution option

- Fixed a 'squished' viewport bug on high-DPI (Retina) displays by querying the framebuffer size in pixels instead of using the window size in points.
- Centralized window dimension management within the platform layer.
- Added a '--resolution WxH' command-line option to allow specifying a custom window size at startup. This option is stripped in STRIP_ALL builds.
- Updated all test and tool executables to use the new platform API.

6 files changed, 218 insertions, 16 deletions

diff --git a/git_setup_summary.txt b/git_setup_summary.txt
new file mode 100644
index 0000000..dd4edad
--- /dev/null
+++ b/git_setup_summary.txt
@@ -0,0 +1,148 @@
+GIT REPOSITORY SETUP SUMMARY
+===========================
+
+OVERVIEW
+--------
+You have a local bare repository (demo.git) as the source of truth, mirrored on a VPS.
+Users can clone from the VPS and push/pull changes to stay synchronized.
+
+Branch: main (not master)
+
+
+INITIAL VPS SETUP (done once)
+-----------------------------
+
+SSH into VPS as ubuntu user:
+  ssh ubuntu@your_vps_ip
+
+Create bare repository as git user:
+  sudo su - git
+  mkdir -p /home/git
+  cd /home/git
+  git init --bare demo.git
+
+The bare repository is ready to receive pushes.
+
+
+YOUR LAPTOP CONFIGURATION
+-------------------------
+
+Working directory: /home/me/demo
+Bare repository: /home/me/demo.git
+
+Set up dual remotes to push to both local and VPS:
+
+  cd /home/me/demo
+  git remote set-url origin /home/me/demo.git
+  git remote add vps ssh://git@your_vps_ip/~/demo.git
+  git remote set-url --add --push origin /home/me/demo.git
+  git remote set-url --add --push origin ssh://git@your_vps_ip/~/demo.git
+
+First sync (push all branches and tags):
+  git push -u origin --all
+  git push -u origin --tags
+
+Verify configuration:
+  git remote -v
+
+When you push, both repositories are updated:
+  git push origin main
+
+
+USER ACCESS SETUP (per user)
+----------------------------
+
+One-time setup for each user:
+
+1. User generates SSH key (if they don't have one):
+   ssh-keygen -t ed25519 -C "their_email@example.com"
+   (accept defaults)
+
+2. User sends you their public key (~/.ssh/id_ed25519.pub)
+
+3. You add their key to the git user on VPS:
+   ssh ubuntu@your_vps_ip
+   sudo su - git
+   cat >> ~/.ssh/authorized_keys
+   (paste their public key, then Ctrl+D)
+
+
+CLONING FROM VPS
+----------------
+
+Users clone with:
+  git clone ssh://git@your_vps_ip/~/demo.git
+
+This automatically sets up 'origin' remote pointing to the VPS repository.
+
+Verify:
+  git remote -v
+
+
+PUSHING CHANGES
+---------------
+
+Users push to VPS with:
+  git push origin main
+
+This updates the VPS repository, which you can then pull from your laptop.
+
+
+PULLING CHANGES
+---------------
+
+If user1 pushed to VPS and user2 wants to get their changes:
+
+User2 pulls from VPS:
+  git pull vps main
+
+If user2 also has a local bare repo, they can then sync it:
+  git push origin main
+
+
+YOUR LAPTOP - PULLING USER CHANGES
+----------------------------------
+
+When users push to the VPS, pull those changes to your laptop:
+  git pull vps main
+
+Then push to your local bare repo:
+  git push origin main
+
+
+PATHS EXPLAINED
+---------------
+
+/home/me/demo.git           - Your local bare repository (source of truth)
+/home/me/demo               - Your local working directory
+ssh://git@your_vps_ip/~/demo.git  - Remote VPS repository
+
+The ~/demo.git path expands to /home/git/demo.git but hides the full path.
+
+
+SUMMARY OF WORKFLOWS
+--------------------
+
+YOUR LAPTOP:
+  git push origin main          (pushes to both local demo.git and VPS)
+  git pull vps main             (pulls changes pushed by other users to VPS)
+
+USER CLONING:
+  git clone ssh://git@your_vps_ip/~/demo.git
+
+USER PUSHING:
+  git push origin main          (pushes to VPS)
+
+USER PULLING:
+  git pull origin main          (pulls from VPS)
+  OR
+  git pull vps main             (if they have dual origins like you do)
+
+
+KEY POINTS
+----------
+- Main branch is 'main' (default since Git 2.28)
+- SSH key authentication: secure and requires minimal setup
+- VPS path is hidden using ~/ syntax
+- Users need SSH keys added to ~/.ssh/authorized_keys on VPS
+- All pushes and pulls use SSH (ssh://git@your_vps_ip/~/demo.git)
diff --git a/src/main.cc b/src/main.cc
index 8cedfce..f7136ef 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -130,7 +130,10 @@ float* generate_tone(float* buffer, float freq) {
 
 int main(int argc, char** argv) {
   bool fullscreen_enabled = false;
-  double seek_time = 0.0;
+  float seek_time = 0.0f;
+  int* width_ptr = nullptr;
+  int* height_ptr = nullptr;
+  int custom_width, custom_height;
 
 #if !defined(STRIP_ALL)
   for (int i = 1; i < argc; ++i) {
@@ -139,6 +142,12 @@ int main(int argc, char** argv) {
     } else if (strcmp(argv[i], "--seek") == 0 && i + 1 < argc) {
       seek_time = atof(argv[i + 1]);
       ++i;
+    } else if (strcmp(argv[i], "--resolution") == 0 && i + 1 < argc) {
+      const char* res_str = argv[++i];
+      if (sscanf(res_str, "%dx%d", &custom_width, &custom_height) == 2) {
+        width_ptr = &custom_width;
+        height_ptr = &custom_height;
+      }
     }
   }
 #else
@@ -147,10 +156,8 @@ int main(int argc, char** argv) {
   fullscreen_enabled = true;
 #endif /* STRIP_ALL */
 
-  platform_init_window(fullscreen_enabled);
-  int width, height;
-  glfwGetFramebufferSize(platform_get_window(), &width, &height);
-  gpu_init(platform_get_window(), width, height);
+  platform_init_window(fullscreen_enabled, width_ptr, height_ptr);
+  gpu_init(platform_get_window(), platform_get_width(), platform_get_height());
   audio_init();
 
   // Register drum assets
@@ -234,9 +241,7 @@ int main(int argc, char** argv) {
 
     update_game_logic(current_time);
 
-    int width, height;
-    glfwGetFramebufferSize(platform_get_window(), &width, &height);
-    float aspect_ratio = (float)width / (float)height;
+    float aspect_ratio = platform_get_aspect_ratio();
 
     // Adjusted multiplier for visuals (preventing constant 1.0 saturation)
     float raw_peak = synth_get_output_peak();
diff --git a/src/platform.cc b/src/platform.cc
index ff45964..464003f 100644
--- a/src/platform.cc
+++ b/src/platform.cc
@@ -11,6 +11,22 @@ static GLFWwindow* window = nullptr;
 static int windowed_x, windowed_y, windowed_w, windowed_h;
 static bool g_is_fullscreen = false;
 
+// --- New state for framebuffer size ---
+static int g_width = 1280;
+static int g_height = 720;
+
+// Forward declaration for callback
+void platform_toggle_fullscreen();
+
+// --- Callbacks ---
+
+static void framebuffer_size_callback(GLFWwindow* cb_window, int width, int height) {
+    (void)cb_window; // Unused
+    g_width = width;
+    g_height = height;
+    // Note: We would trigger a swap chain resize here, but our demo handles it implicitly.
+}
+
 static void glfw_key_callback(GLFWwindow* cb_window, int key, int scancode,
                               int action, int mods) {
   if (action == GLFW_PRESS) {
@@ -22,11 +38,21 @@ static void glfw_key_callback(GLFWwindow* cb_window, int key, int scancode,
   }
 }
 
-void platform_init_window(bool fullscreen) {
+void platform_init_window(bool fullscreen, int* width_ptr, int* height_ptr) {
+  if (width_ptr && height_ptr) {
+      g_width = *width_ptr;
+      g_height = *height_ptr;
+  }
+
   glfwInit();
   glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
-  window = glfwCreateWindow(1280, 720, "demo64k", nullptr, nullptr);
+  window = glfwCreateWindow(g_width, g_height, "demo64k", nullptr, nullptr);
+  
+  // Immediately query the actual framebuffer size for high-DPI displays
+  glfwGetFramebufferSize(window, &g_width, &g_height);
+
   glfwSetKeyCallback(window, glfw_key_callback);
+  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
   g_is_fullscreen = fullscreen;
   if (fullscreen) {
@@ -78,6 +104,20 @@ double platform_get_time() {
   return glfwGetTime();
 }
 
+// --- New dimension getters ---
+int platform_get_width() {
+    return g_width;
+}
+
+int platform_get_height() {
+    return g_height;
+}
+
+float platform_get_aspect_ratio() {
+    if (g_height == 0) return 1.0f;
+    return (float)g_width / (float)g_height;
+}
+
 WGPUSurface platform_create_wgpu_surface(WGPUInstance instance) {
   return glfwCreateWindowWGPUSurface(instance, window);
 }
diff --git a/src/platform.h b/src/platform.h
index 9cfaf00..38a0568 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -6,16 +6,20 @@
 
 #include <webgpu.h>
 
+// Forward declare GLFWwindow to avoid including the full header here.
 struct GLFWwindow;
 
-void platform_init_window(bool fullscreen);
+void platform_init_window(bool fullscreen, int* width_ptr, int* height_ptr);
 void platform_shutdown();
 void platform_poll();
 bool platform_should_close();
 
-void platform_toggle_fullscreen();
-
 GLFWwindow* platform_get_window();
 double platform_get_time();
 
+// Add dimension getters
+int platform_get_width();
+int platform_get_height();
+float platform_get_aspect_ratio();
+
 WGPUSurface platform_create_wgpu_surface(WGPUInstance instance);
diff --git a/src/tests/test_3d_render.cc b/src/tests/test_3d_render.cc
index e4477a0..0a809c4 100644
--- a/src/tests/test_3d_render.cc
+++ b/src/tests/test_3d_render.cc
@@ -174,8 +174,13 @@ void gen_periodic_noise(uint8_t* buffer, int w, int h, const float* params,
 }
 
 int main() {
-  platform_init_window(false);
-  init_wgpu();
+  printf("Running 3D Renderer Test...\n");
+
+  platform_init_window(false, nullptr, nullptr);
+  gpu_init(platform_get_window(), platform_get_width(), platform_get_height());
+
+  // Create Renderer and Scene
+  Renderer3D renderer;
 
   g_renderer.init(g_device, g_queue, g_format);
   g_renderer.resize(g_width, g_height);
diff --git a/tools/spectool.cc b/tools/spectool.cc
index 80a970e..dfb00de 100644
--- a/tools/spectool.cc
+++ b/tools/spectool.cc
@@ -131,7 +131,7 @@ int play_spec(const char* in_path) {
   fread(spec_data.data(), sizeof(float), spec_data.size(), f_in);
   fclose(f_in);
 
-  platform_init_window(false);
+  platform_init_window(false, nullptr, nullptr);
   audio_init();
   audio_start();
   Spectrogram spec;