diff --git a/CMakeLists.txt b/CMakeLists.txt
index ec0f042..72b10d4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,6 +31,8 @@ add_library(${PROJECT_NAME} STATIC
 	"src/resource_manager.cpp"
 
 	"src/gfx_device_vulkan.cpp"
+	"src/gfx_device_null.cpp"
+	"src/gfx_device_opengl45.cpp"
 
 	# PUBLIC API
 
diff --git a/src/gfx_device_null.cpp b/src/gfx_device_null.cpp
new file mode 100644
index 0000000..61110a3
--- /dev/null
+++ b/src/gfx_device_null.cpp
@@ -0,0 +1,48 @@
+// The implementation of the graphics layer using Vulkan 1.3.
+// This uses SDL specific code
+
+#ifdef ENGINE_BUILD_NULLGFX
+
+#include "gfx_device.hpp"
+#include "util.hpp"
+#include "config.h"
+#include "log.hpp"
+
+namespace engine {
+
+	// class definitions
+
+	struct GFXDevice::Impl {
+		
+	};
+
+	GFXDevice::GFXDevice(const char* appName, const char* appVersion, SDL_Window* window)
+	{
+		pimpl = std::make_unique<Impl>();
+	}
+
+	GFXDevice::~GFXDevice()
+	{
+		TRACE("Destroying GFXDevice...");
+	}
+
+	void GFXDevice::draw()
+	{
+	}
+	
+	void GFXDevice::createPipeline(const char* vertShaderPath, const char* fragShaderPath)
+	{
+	}
+
+	bool GFXDevice::createBuffer(const gfx::BufferDesc& desc, const void* data, gfx::BufferHandle* out)
+	{
+		return true;
+	}
+
+	void GFXDevice::waitIdle()
+	{
+	}
+
+}
+
+#endif
diff --git a/src/gfx_device_opengl45.cpp b/src/gfx_device_opengl45.cpp
new file mode 100644
index 0000000..9b42ec9
--- /dev/null
+++ b/src/gfx_device_opengl45.cpp
@@ -0,0 +1,82 @@
+// The implementation of the graphics layer using Vulkan 1.3.
+// This uses SDL specific code
+
+#ifdef ENGINE_BUILD_OPENGL
+
+#include "gfx_device.hpp"
+#include "util.hpp"
+#include "config.h"
+#include "log.hpp"
+
+#include <glad/glad.h>
+
+#include <SDL2/SDL.h>
+
+#include <assert.h>
+#include <unordered_set>
+#include <array>
+#include <fstream>
+#include <filesystem>
+#include <optional>
+
+namespace engine {
+
+	// structures and enums
+
+	static std::vector<char> readFile(const std::string& filename)
+	{
+		std::ifstream file(filename, std::ios::ate | std::ios::binary);
+		if (file.is_open() == false) {
+			throw std::runtime_error("Unable to open file " + filename);
+		}
+		std::vector<char> buffer(file.tellg());
+		file.seekg(0);
+		file.read(buffer.data(), buffer.size());
+		file.close();
+		return buffer;
+	}
+
+
+
+	// class definitions
+
+	struct GFXDevice::Impl {
+
+		SDL_GLContext context = nullptr;
+		
+	};
+
+	GFXDevice::GFXDevice(const char* appName, const char* appVersion, SDL_Window* window)
+	{
+		pimpl = std::make_unique<Impl>();
+
+		pimpl->context = SDL_GL_CreateContext(window);
+
+	}
+
+	GFXDevice::~GFXDevice()
+	{
+		TRACE("Destroying GFXDevice...");
+	}
+
+	void GFXDevice::draw()
+	{
+	}
+	
+	void GFXDevice::createPipeline(const char* vertShaderPath, const char* fragShaderPath)
+	{
+	}
+
+	bool GFXDevice::createBuffer(const gfx::BufferDesc& desc, const void* data, gfx::BufferHandle* out)
+	{
+		return false;
+	}
+
+	void GFXDevice::waitIdle()
+	{
+		glFinish();
+	}
+
+}
+
+#endif
diff --git a/src/gfx_device_vulkan.cpp b/src/gfx_device_vulkan.cpp
index 0e6338b..7571d1d 100644
--- a/src/gfx_device_vulkan.cpp
+++ b/src/gfx_device_vulkan.cpp
@@ -24,6 +24,7 @@
 #include <array>
 #include <fstream>
 #include <filesystem>
+#include <optional>
 
 namespace engine {