#include <windows.h>
#include <d3d9.h>

#pragma comment(lib, "d3d9.lib")

// Definitions
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
#define FULLSCREEN false
#define CUSTOMFVF (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)

LONG APIENTRY WindowProc(HWND hWnd, UINT message, WPARAM
							wParam, LPARAM lParam);

//Function Prototypes
void initWindow(HINSTANCE hInstance);
HWND createWindow(HINSTANCE hInstance);
void initD3D(HWND hWnd);
void cleanD3D();
void render_frame();
void initGraphics();

//Global Variables
LPDIRECT3D9 d3d;
LPDIRECT3DDEVICE9 d3ddev;
LPDIRECT3DVERTEXBUFFER9 v_buffer = NULL;

// Structures
struct CUSTOMVERTEX {
	float x, y, z, RHW;
	DWORD color;
};

int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
					LPSTR lpCmdLine, int nCmdShow)
{
	HWND hWnd;
	
	initWindow(hInstance);
	hWnd = createWindow(hInstance);
	ShowWindow(hWnd, nCmdShow);

	initD3D(hWnd);	

	MSG msg;

	while (true)
	{

		while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}

		if (msg.message == WM_QUIT)
			break;

		render_frame();
	}

	return msg.wParam;
}

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message,
							WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
		case WM_KEYDOWN:
				if (wParam == VK_ESCAPE)
					PostQuitMessage(0);
				break; 

		case WM_DESTROY:
				PostQuitMessage(0);
				break;

		default:
				return DefWindowProc(hWnd, message, wParam, lParam);
				break;
	}

	return 0;
}

void initD3D(HWND hWnd)
{
	d3d = Direct3DCreate9(D3D_SDK_VERSION);
	D3DPRESENT_PARAMETERS d3dpp;

	ZeroMemory(&d3dpp, sizeof(D3DPRESENT_PARAMETERS));

	if (FULLSCREEN)
		d3dpp.Windowed = false;
	else
		d3dpp.Windowed = true;
	d3dpp.SwapEffect = D3DSWAPEFFECT_COPY;
	d3dpp.hDeviceWindow = hWnd;
	d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
	d3dpp.BackBufferWidth = SCREEN_WIDTH;
	d3dpp.BackBufferHeight = SCREEN_HEIGHT;

	d3d->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
				D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &d3ddev);

	initGraphics();
}

void cleanD3D()
{
	v_buffer->Release();
	d3ddev->Release();
	d3d->Release();
}

void render_frame()
{
	d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f,  0);

	d3ddev->BeginScene();

	d3ddev->SetFVF(CUSTOMFVF);
	d3ddev->SetStreamSource(0, v_buffer, 0, sizeof(CUSTOMVERTEX));
	d3ddev->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

	d3ddev->EndScene();

	d3ddev->Present(NULL, NULL, NULL, NULL);
}

void initWindow(HINSTANCE hInstance)
{
	WNDCLASSEX wc;

	ZeroMemory(&wc, sizeof(WNDCLASSEX));

	wc.cbSize = sizeof(WNDCLASSEX);
	wc.style = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc = WindowProc;
	wc.hInstance = hInstance;
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	// wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
	wc.lpszClassName = L"WindowClass";

	RegisterClassEx(&wc);
}

HWND createWindow(HINSTANCE hInstance)
{
	HWND hWnd;
	DWORD style;
	int x, y;

	if (FULLSCREEN)
	{
		style = WS_EX_TOPMOST | WS_POPUP;
		x = 0, y = 0;
	}
	else
	{
		style = WS_OVERLAPPEDWINDOW;
		x = 50, y = 50;
	}

	hWnd = CreateWindowEx(NULL, L"WindowClass", L"Murray", style,
						x, y, SCREEN_WIDTH, SCREEN_HEIGHT, NULL, 
						NULL, hInstance, NULL);

	return hWnd;
}
void initGraphics()
{
	CUSTOMVERTEX vertices[] = 
	{
		{400.0f, 50.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)},
		{100.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)},
		{700.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)}
	};

	d3ddev->CreateVertexBuffer(3*sizeof(CUSTOMVERTEX), 0, CUSTOMFVF, D3DPOOL_MANAGED,
							&v_buffer, NULL);

	VOID* pVoid;

	v_buffer->Lock(0, 0, &pVoid, 0);
	memcpy(pVoid, vertices, sizeof(vertices));
	v_buffer->Unlock();
}

CUSTOMVERTEX vertices[] = {	{700.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0)},	{100.0f, 500.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0)},	{400.0f, 50.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255)}};