diff --git a/README.md b/README.md
index dfbf107..72c5ceb 100644
--- a/README.md
+++ b/README.md
@@ -129,15 +129,23 @@ A list of layers in the codebase and their associated namespaces are below:
 - `base` (no namespace): Universal, codebase-wide constructs. It contains
   strings, math, memory allocators, threading, and logging.
   It depends on no other codebase layers.
-- `es/core` (`ES_`): Short for Engine Subsystem. Implements the 
-- `es/gfx` (`ES_`): Engine Subsystem graphical frontend. Builds on top of
-   `es/core` to provide graphical features such as windows, panels, and all
-   interfaces needed for using the scanner. It is the main user of `os/gfx`.
-- `os/core` (`OS_`): An abstraction layer that provides core, non-graphical
-  functionality from the operating sytem under a general use abstraction API.
-  This is implemented per supported operating system.
-- `os/gfx` (`OS_`): This layer builds on top of `os/core`, it provides
-   graphical operating functionalities under a general use abstraction API.
+
+- `ef/core` (`EF_`): The scanner engine's non-graphical frontend. It implements
+   interfacing with the scanner over usb, colour space settings, and all intricate
+   details that have to do with the software working with the scanner.
+- `ef/gfx` (`EF_`): The scanner engine`s graphical frontend. It provides all
+   graphical features, including windows, panels, and all other various interfaces
+   needed by the engine to function.
+
+- `render` (`R_`): An abstraction layer providing an abstract API for rendering using
+   various GPU APIs under a common interface. This layer does not implement a high level
+   API for drawing, it is strictly for minimal abstractions on a needed basis. Higher
+   level drawing features are implemented in the `draw` layer
+
+- `draw` (`D_`): Implements a high level graphics drawing API for the scanning engine.
+   It uses the underlying `render` abstraction API. It provides a high-level API for various
+   draw commands, but takes care to bath them together.
+
 - `ui` (`UI_`): For building graphical user interfaces. Provides a core
   immediate mode hierarchical user interface data structure building API, and
   has helper layers for building higher level widgets.
\ No newline at end of file
diff --git a/src/base/base_context_switching.h b/src/base/base_context_switching.h
index 92c998e..ca9f147 100644
--- a/src/base/base_context_switching.h
+++ b/src/base/base_context_switching.h
@@ -44,6 +44,10 @@
  #define BUILD_DEBUG 1
 #endif
 
+#if !defined(BUILD_ENTRY_DEFINING_UNIT)
+ #define BUILD_ENTRY_DEFINING_UNIT 1
+#endif
+
 #if !defined(BUILD_VERSION_MAJOR)
  #define BUILD_VERSION_MAJOR 0
 #endif
diff --git a/src/base/base_core.c b/src/base/base_core.c
new file mode 100644
index 0000000..7e657c1
--- /dev/null
+++ b/src/base/base_core.c
@@ -0,0 +1,6 @@
+// Safe Casts
+internal u16 safe_cast_u16(u32 x) {
+  // Assert
+  u16 result = (u16)x;
+  return result;
+}
diff --git a/src/base/base_core.h b/src/base/base_core.h
index 411ff6f..719e8dc 100644
--- a/src/base/base_core.h
+++ b/src/base/base_core.h
@@ -134,6 +134,9 @@ global const u32 bit30     = (1 << 29);
 global const u32 bit31     = (1 << 30);
 global const u32 bit32     = (1 << 31);
 
+// Safe Casts
+internal u16 safe_cast_u16(u32 x);
+
 // Misc helpers
 // NOTE(tijani): Divides total size of array by size of one element in the array gives
 // the number of elements in the array.
@@ -168,7 +171,7 @@ global const u32 bit32     = (1 << 31);
 
 // Helpers
 // ??(tijani): the calculation of how this works breaks my brain, need to bust out the pen and  paper to figure it out.
-#define AlignPow2(x, b) (((x) + (b)-1) & (~((b)-1)))
+#define AlignPow2(x, b) (((x) + (b) - 1) & (~((b) - 1)))
 
 // Linkedlist building macros
 
diff --git a/src/base/base_entry_point.c b/src/base/base_entry_point.c
index 84bb0a7..b6006a4 100644
--- a/src/base/base_entry_point.c
+++ b/src/base/base_entry_point.c
@@ -1,7 +1,12 @@
-internal void main_thread_entry_point(void) {
+internal void main_thread_base_entry_point(void) {
   ThreadNameF("[main thread]");
 
 #if defined(OS_GFX_H)
   os_gfx_init();
 #endif
+
+#if defined(GFX_H)
+  gfx_init(update_and_render);
+#endif
+  entry_point();
 }
diff --git a/src/base/base_entry_point.h b/src/base/base_entry_point.h
index 2324531..bed74cb 100644
--- a/src/base/base_entry_point.h
+++ b/src/base/base_entry_point.h
@@ -1,6 +1,6 @@
 #ifndef BASE_ENTRY_POINT_H
 #define BASE_ENTRY_POINT_H
 
-internal void main_thread_entry_point(void);
+internal void main_thread_base_entry_point(void);
 
 #endif // BASE_ENTRY_POINT_H
diff --git a/src/base/base_inc.c b/src/base/base_inc.c
index baebe29..18afaaf 100644
--- a/src/base/base_inc.c
+++ b/src/base/base_inc.c
@@ -1,7 +1,10 @@
 // clang-format off
 
+#include "base_core.c"
 #include "base_arena.c"
 #include "base_strings.c"
 #include "base_markup.c"
 #include "base_threading_context.c"
+#include "base_entry_point.c"
+
 // clang-format on
diff --git a/src/base/base_inc.h b/src/base/base_inc.h
index 9e776a0..8ca0ad0 100644
--- a/src/base/base_inc.h
+++ b/src/base/base_inc.h
@@ -10,6 +10,8 @@
 #include "base_strings.h"
 #include "base_markup.h"
 #include "base_threading_context.h"
+#include "base_entry_point.h"
+
 // clang-format on
 
 #endif // BASE_INC_H
diff --git a/src/ef/gfx/ef_gfx.c b/src/ef/gfx/ef_gfx.c
new file mode 100644
index 0000000..0069ce8
--- /dev/null
+++ b/src/ef/gfx/ef_gfx.c
@@ -0,0 +1,46 @@
+
+// Window State functions
+internal EF_Window *ef_window_open(Vec2F32 size, OS_Handle preferred_monitor) {
+  EF_Window *window = ef_gfx_state->free_window;
+  if (window != 0) {
+    SLLStackPop(ef_gfx_state->free_window);
+    u64 gen = window->gen;
+    MemoryZeroStruct(window);
+    window->gen = gen;
+  } else {
+    window = push_array(ef_gfx_state->arena, EF_Window, 1);
+  }
+  window->gen   += 1;
+  window->arena  = arena_alloc();
+
+  {
+    String8 title = str8_lit_comp(BUILD_TITLE_STRING_LITERAL);
+    window->os    = os_window_open(size, OS_WindowFlag_CustomBorder, title);
+  }
+  window->last_dpi = os_dpi_fram_window(window->os);
+
+  // NOTE(tijani): Setting preferred monitor, not important
+  // OS_Handle zero_monitor = {0};
+  // if(!os_handle_match(zero_monitor, preferred_window)){
+  //   os_set_window
+  // }
+
+  os_window_equip_repaint(window->os, ef_gfx_state->repaint_hook, window);
+  DLLPushBack(ef_gfx_state->first_winow, ef_gfx_state->last_window, window);
+  return window;
+}
+internal EF_Window *ef_window_from_os_handle(OS_Handle os) {}
+internal void       df_window_update_and_render(Arena *arena, EF_Window *window_state) {}
+
+// Main layer top level calls
+internal void ef_gfx_init(OS_WindowRepaintFunctionType *window_repaint_entry_point) {
+  // Begin profiling
+  Arena *arena                      = arena_alloc();
+  ef_gfx_state                      = push_array(arena, EF_GfxState, 1);
+  ef_gfx_state->arena               = arena;
+  ef_gfx_state->num_frame_requested = 2;
+  ef_gfx_state->repaint_hook        = window_repaint_entry_point;
+}
+
+internal void ef_gfx_begin_frame(Arena *arena) {}
+internal void ef_gfx_end_frame(void) {}
diff --git a/src/ef/gfx/ef_gfx.h b/src/ef/gfx/ef_gfx.h
new file mode 100644
index 0000000..b7b0901
--- /dev/null
+++ b/src/ef/gfx/ef_gfx.h
@@ -0,0 +1,84 @@
+#ifndef EF_GFX_H
+#define EF_GFX_H
+
+// Per-Window State
+typedef struct EF_Window EF_Window;
+struct EF_Window {
+  // Links and metadata
+  EF_Window *next;
+  EF_Window *previous;
+  u64        gen;
+  u64        frames_alive;
+  // EF_ConfigSource config_source;
+
+  // Top level info & handles
+  Arena    *arena;
+  OS_Handle os;
+  // R_handle render; // not needed for now, will revisit
+  // UI_State *ui_state; // not needed for now, will revisit
+  f32 last_dpi;
+
+  // config / settings
+
+  // view state delta histor
+
+  // menu bar state
+
+  // tab context menu state
+
+  // error state
+
+  // panel state
+
+  // per-frame drawing state
+};
+
+// Graphical state
+typedef struct EF_GfxState EF_GfxState;
+struct EF_GfxState {
+  Arena *arena;
+
+  // frame request state
+  u64 num_frames_requested;
+
+  // history cache
+
+  // key map table  NOTE(tijani): ??
+
+  // confirmation popup state
+
+  // windows
+  OS_WindowRepaintFunctionType *repaint_hook;
+  EF_Window                    *first_window;
+  EF_Window                    *last_window;
+  EF_Window                    *free_window;
+  u64                           window_count;
+  b32                           last_window_queued_save;
+
+  // view state
+
+  // drag/drop satte machine
+
+  // rich hove info
+
+  // running theme state
+
+  // global setting
+
+  // icon texture
+};
+
+// Globals
+global EF_GfxState *ef_gfx_satet = 0;
+
+// Window State functions
+internal EF_Window *ef_window_open(Vec2F32 size, OS_Handle preferred_monitor);
+internal EF_Window *ef_window_from_os_handle(OS_Handle os);
+internal void       df_window_update_and_render(Arena *arena, EF_Window *window_state);
+
+// Main layer top level calls
+internal void ef_gfx_init(OS_WindowRepaintFunctionType *window_repaint_entry_point);
+internal void ef_gfx_begin_frame(Arena *arena);
+internal void ef_gfx_end_frame(void);
+
+#endif // EF_GFX_H
diff --git a/src/goff/goff.c b/src/goff/goff.c
index f0c5e37..e2fea26 100644
--- a/src/goff/goff.c
+++ b/src/goff/goff.c
@@ -1,20 +1,28 @@
 internal void update_and_render(OS_Handle repaint_window_handle) {
+  // Profiling start
   Temp scratch = scratch_begin(0, 0);
 
-  // pick target hz
-  f32 target_hz = os_get_gfx_info()->default_referesh_rate;
-
-  // Target HZ -> delta time
-  f32 dt = 1.f / target_hz;
-
   // Get events from OS
   OS_EventList events = {0};
   if (os_handle_match(repaint_window_handle, os_handle_zero())) {
-    events = os_get_events(scratch.arena, df_gfx_state->num_frames_requested == 0);
+    events = os_get_events(scratch.arena, gfx_state->num_frames_requested == 0);
   }
 
   // begin frames
-  {
-    df_core_begin(scratch.arena,
-  }
+  { gfx_begin_frame(scratch.arena); }
+
+  // Update and render
+  {}
+
+  // End frondend frame
+  { gfx_end_frame(); }
+
+  // Submit rendering to all windows
+  {}
+
+  // Show windows after first frame
+  {}
+
+  scratch_end(scratch);
+  // Profiling end
 }
diff --git a/src/goff/goff.h b/src/goff/goff.h
index a905b21..f97581e 100644
--- a/src/goff/goff.h
+++ b/src/goff/goff.h
@@ -1,6 +1,8 @@
 #ifndef GOFF_H
 #define GOFF_H
 
+// Frontend entry point
+
 internal void update_and_render(OS_HANDLE repaint_window);
 
 #endif // GOFF_H
diff --git a/src/goff/goff_main.c b/src/goff/goff_main.c
index b29decf..fcfedf1 100644
--- a/src/goff/goff_main.c
+++ b/src/goff/goff_main.c
@@ -10,28 +10,36 @@
 
 // clang-format on
 
+// Build Options
+// #define BUILD_VERSION_MAJOR                0
+// #define BUILD_VERSION_MINOR                1
+// #define BUILD_VERSION_PATCH                0
+// #define BUILD_RELEASE_PHASE_STRING_LITERAL "ALPHA"
+// #define BUILD_TITLE                        "Goff Film Scanner"
+// #define OS_GRAPHICAL                       1
+
 // Entry Point
 
 internal void entry_point() {
   Temp scratch = scratch_begin(0, 0);
 
   // Setup layers
-  // {
-  //   df_core_init();
-  //   df_gfx_init();
-  // }
+  { gfx_init(); }
 
-// Main application loop
-{
-  for (;;) {
+  // Main application loop
+  {
+    for (;;) {
 
-    // Update and render frame here
-    OS_Handle repaint_window = {0};
-    update_and_render(repaint_window);
+      // Update and render frame here
+      OS_Handle repaint_window = {0};
+      update_and_render(repaint_window);
 
-    // Quit
+      // Quit
+      // if (gfx_state->first_window == 0) {
+      //   break;
+      // }
+    }
   }
-}
 
-scratch_end(scratch);
+  scratch_end(scratch);
 }
diff --git a/src/os/core/os_core.c b/src/os/core/os_core.c
new file mode 100644
index 0000000..e69de29
diff --git a/src/os/core/os_core.h b/src/os/core/os_core.h
index dbc22b6..3569a91 100644
--- a/src/os/core/os_core.h
+++ b/src/os/core/os_core.h
@@ -51,4 +51,14 @@ internal void os_set_thread_name(String8 name);
 
 // %os_hooks(implemented per-os) Aborting
 internal void os_abort(s32 exit_code);
+
+// %os_hooks(implemented per-os) Entry Points
+// os_core defines a low level entry point if BUILD_ENTRY_DEFINING_UNIT is
+// defined to 1. This will call into the standard cocdebase program entry point
+// called "entry_point"
+
+#if BUILD_ENTRY_DEFINING_UNIT
+internal void entry_point(void);
+#endif
+
 #endif // OS_CORE_H
diff --git a/src/os/core/win32/os_core_win32.c b/src/os/core/win32/os_core_win32.c
index 40a49e5..86a23ac 100644
--- a/src/os/core/win32/os_core_win32.c
+++ b/src/os/core/win32/os_core_win32.c
@@ -2,8 +2,8 @@
 // compatibility with older versions of windows where the modern WIN32
 // SetThreadDescription function is not available and use old ways.
 // This way it can be done dynamically at runtime without any hiccups.
-typedef HRESULT                  W32_SetThreadDescription(HANDLE hThread, PCWSTR lpThreadDescription);
-global W32_SetThreadDescription *w32_SetThreadDescription_func = 0;
+typedef HRESULT                       W32_SetThreadDescription_Type(HANDLE hThread, PCWSTR lpThreadDescription);
+global W32_SetThreadDescription_Type *w32_SetThreadDescription_func = 0;
 
 // %os_hooks(implemented per-os) System and process info
 internal OS_SystemInfo *os_get_system_info(void) { return &os_w32_state.system_info; }
@@ -46,7 +46,7 @@ internal b32 os_commit_large(void *ptr, u64 size) { return -1; }
 
 // %os_hooks(implemented per-os)  Threads
 internal u32 os_thread_id(void) {
-  u32 id = GetCurrentThreadID();
+  u32 id = GetCurrentThreadId();
   return (id);
 }
 
@@ -90,3 +90,41 @@ internal void os_set_thread_name(String8 name) {
 
 // %os_hooks(implemented per-os) Aborting
 internal void os_abort(s32 exit_code) { ExitProcess(exit_code); }
+
+internal void w32_entry_point_caller() {
+  // OS layer initialization
+  {
+    // dynamically load windows functions, not guaranteed on all SDKs
+    {
+      HMODULE module                = LoadLibraryA("kernel32.dll");
+      w32_SetThreadDescription_func = (W32_SetThreadDescription_Type *)GetProcAddress(module, "SetThreadDescription");
+      FreeLibrary(module);
+    }
+
+    // enable large pages if possible
+    {
+      HANDLE token;
+      if (OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &token)) {
+        LUID luid;
+        if (LookupPrivilegeValue(0, SE_LOCK_MEMORY_NAME, &luid)) {
+          TOKEN_PRIVILEGES priv;
+          priv.PrivilegeCount           = 1;
+          priv.Privileges[0].Luid       = luid;
+          priv.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+          AdjustTokenPrivileges(token, 0, &priv, sizeof(priv), 0, 0);
+        }
+        CloseHandle(token);
+      }
+    }
+
+    // Get system info
+  }
+
+  // call into the actual entry point
+  main_thread_base_entry_point();
+}
+
+int wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nShowCmd) {
+  w32_entry_point_caller();
+  return 0;
+}
diff --git a/src/os/core/win32/os_core_win32.h b/src/os/core/win32/os_core_win32.h
index 76de155..b5846e4 100644
--- a/src/os/core/win32/os_core_win32.h
+++ b/src/os/core/win32/os_core_win32.h
@@ -4,8 +4,12 @@
 // clang-format off
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
+#include <windowsx.h>
 #include <processthreadsapi.h>
 
+#pragma comment(lib, "user32")
+#pragma comment(lib, "advapi32")
+
 // clang-format on
 
 // Application State
diff --git a/src/os/os_inc.c b/src/os/os_inc.c
index 7f33e0d..048ec39 100644
--- a/src/os/os_inc.c
+++ b/src/os/os_inc.c
@@ -1,5 +1,18 @@
-// clang-format off
+#include "os/core/os_core.c"
+#if OS_GRAPHICAL
+ #include "os/gfx/os_gfx.c"
+#endif
 
-#include "core/win32/os_core_win32.c"
+#if OS_WINDOWS
+ #include "os/core/win32/os_core_win32.c"
+#else
+ #error OS core layer not implemented for this operating system.
+#endif
 
-// clang-format on
+#if OS_GRAPHICAL
+ #if OS_WINDOWS
+  #include "os/gfx/win32/os_gfx_win32.c"
+ #else
+  #error OS graphical layer not implemented for this operating system.
+ #endif
+#endif
diff --git a/src/os/os_inc.h b/src/os/os_inc.h
index 48469cd..437c2ef 100644
--- a/src/os/os_inc.h
+++ b/src/os/os_inc.h
@@ -1,11 +1,27 @@
 #ifndef OS_INC_H
 #define OS_INC_H
 
-// clang-format off
+#if !defined(OS_GRAPHICAL)
+ #define OS_GRAPHICAL 0
+#endif
 
-#include "core/os_core.h"
-#include "core/win32/os_core_win32.h"
+#include "os/core/os_core.h"
+#if OS_GRAHICAL
+ #include "os/gfx/os_gfx.h"
+#endif
 
-// clang-format on
+#if OS_WINDOWS
+ #include "os/core/win32/os_core_win32.h"
+#else
+ #error OS core layer not implemented for this operating system.
+#endif
+
+#if OS_GRAPHICAL
+ #if OS_WINDOWS
+  #include "os/gfx/win32/os_gfx_win32.h"
+ #else
+  #error OS graphical layer not implemented for this operating system.
+ #endif
+#endif
 
 #endif // OS_INC_H