// include the basic windows header files and the Direct3D header file
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
#include <d3dx9.h>

// define the screen resolution and keyboard macros
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
#define KEY_DOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)
#define KEY_UP(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)

// include the Direct3D Library files
#pragma comment (lib, "d3d9.lib")
#pragma comment (lib, "d3dx9.lib")

// global declarations
LPDIRECT3D9 d3d;    // the pointer to our Direct3D interface
LPDIRECT3DDEVICE9 d3ddev;    // the pointer to the device class
LPDIRECT3DVERTEXBUFFER9 t_buffer = NULL;    // the pointer to the vertex buffer

// texture declarations
LPDIRECT3DTEXTURE9 texture_1;    // our first texture

// function prototypes
void initD3D(HWND hWnd);    // sets up and initializes Direct3D
void render_frame(void);    // renders a single frame
void cleanD3D(void);    // closes Direct3D and releases memory
void init_graphics(void);    // 3D declarations
void init_light(void);

struct CUSTOMVERTEX {FLOAT X, Y, Z; D3DVECTOR NORMAL; FLOAT U, V;};
#define CUSTOMFVF (D3DFVF_XYZ | D3DFVF_NORMAL | D3DFVF_TEX1)

// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);


// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    HWND hWnd;
    WNDCLASSEX wc;

    ZeroMemory(&wc, sizeof(WNDCLASSEX));

    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = (WNDPROC)WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.lpszClassName = L"WindowClass";

    RegisterClassEx(&wc);

    hWnd = CreateWindowEx(NULL, L"WindowClass", L"Our Direct3D Program",
                          WS_EX_TOPMOST | WS_POPUP, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,
                          NULL, NULL, hInstance, NULL);

    ShowWindow(hWnd, nCmdShow);

    // set up and initialize Direct3D
    initD3D(hWnd);

    // enter the main loop:

    MSG msg;

    while(TRUE)
    {
        DWORD starting_point = GetTickCount();

        if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            if (msg.message == WM_QUIT)
                break;

            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }

        render_frame();

        // check the 'escape' key
        if(KEY_DOWN(VK_ESCAPE))
            PostMessage(hWnd, WM_DESTROY, 0, 0);

        while ((GetTickCount() - starting_point) < 25);
    }

    // clean up DirectX and COM
    cleanD3D();

    return static_cast<int>(msg.wParam);
}


// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
        case WM_DESTROY:
            {
                PostQuitMessage(0);
                return 0;
            } break;
    }

    return DefWindowProc (hWnd, message, wParam, lParam);
}


// this function initializes and prepares Direct3D for use
void initD3D(HWND hWnd)
{
    d3d = Direct3DCreate9(D3D_SDK_VERSION);

    D3DPRESENT_PARAMETERS d3dpp;

    ZeroMemory(&d3dpp, sizeof(d3dpp));
    d3dpp.Windowed = FALSE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.hDeviceWindow = hWnd;
    d3dpp.BackBufferFormat = D3DFMT_X8R8G8B8;
    d3dpp.BackBufferWidth = SCREEN_WIDTH;
    d3dpp.BackBufferHeight = SCREEN_HEIGHT;
    d3dpp.EnableAutoDepthStencil = TRUE;
    d3dpp.AutoDepthStencilFormat = D3DFMT_D16;

    // create a device class using this information and the info from the d3dpp stuct
    d3d->CreateDevice(D3DADAPTER_DEFAULT,
                      D3DDEVTYPE_HAL,
                      hWnd,
                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                      &d3dpp,
                      &d3ddev);

    init_graphics();    // call the function to initialize the square
	init_light(); // call the function to initialize the light and material

    d3ddev->SetRenderState(D3DRS_LIGHTING, TRUE);    // turn off the 3D lighting
    d3ddev->SetRenderState(D3DRS_ZENABLE, TRUE);    // turn on the z-buffer
	d3ddev->SetRenderState(D3DRS_AMBIENT, D3DCOLOR_XRGB(0, 0, 70)); // ambient light

    return;
}


// this is the function used to render a single frame
void render_frame(void)
{
    d3ddev->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
    d3ddev->Clear(0, NULL, D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);

    d3ddev->BeginScene();

    // select which vertex format we are using
    d3ddev->SetFVF(CUSTOMFVF);

    // set the view transform
    D3DXMATRIX matView;    // the view transform matrix
    D3DXMatrixLookAtLH(&matView,
    &D3DXVECTOR3 (0.0f, 8.0f, 25.0f),    // the camera position
    &D3DXVECTOR3 (0.0f, 0.0f, 0.0f),      // the look-at position
    &D3DXVECTOR3 (0.0f, 1.0f, 0.0f));    // the up direction
    d3ddev->SetTransform(D3DTS_VIEW, &matView);    // set the view transform to matView 

    // set the projection transform
    D3DXMATRIX matProjection;    // the projection transform matrix
    D3DXMatrixPerspectiveFovLH(&matProjection,
                               D3DXToRadian(45),    // the horizontal field of view
                               (FLOAT)SCREEN_WIDTH / (FLOAT)SCREEN_HEIGHT, // aspect ratio
                               1.0f,   // the near view-plane
                               100.0f);    // the far view-plane
    d3ddev->SetTransform(D3DTS_PROJECTION, &matProjection); // set the projection

    // set the world transform
    static float index = 0.0f; index+=0.03f; // an ever-increasing float value
    D3DXMATRIX matRotateY;    // a matrix to store the rotation for each triangle
    D3DXMatrixRotationY(&matRotateY, index);    // the rotation matrix
    d3ddev->SetTransform(D3DTS_WORLD, &(matRotateY));    // set the world transform

    // select the vertex buffer to display
    d3ddev->SetStreamSource(0, t_buffer, 0, sizeof(CUSTOMVERTEX));

    // set the texture
    d3ddev->SetTexture(0, texture_1);

    // draw the textured square
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 4, 2);
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 8, 2);
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 12, 2);
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 16, 2);
    d3ddev->DrawPrimitive(D3DPT_TRIANGLESTRIP, 20, 2);

    d3ddev->EndScene(); 

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

    return;
}


// this is the function that cleans up Direct3D and COM
void cleanD3D(void)
{
    t_buffer->Release();    // close and release the vertex buffer
    texture_1->Release();    // close and release the texture
    d3ddev->Release();    // close and release the 3D device
    d3d->Release();    // close and release Direct3D

    return;
}


// this is the function that puts the 3D models into video RAM
void init_graphics(void)
{
    // load the texture we will use
    D3DXCreateTextureFromFile(d3ddev,
                              L"Wood1.png",
                              &texture_1);

    // create the vertices using the CUSTOMVERTEX
    struct CUSTOMVERTEX t_vert[] =
    {
		{ -3.0f, 3.0f, -3.0f, 0, 0, -1, 0, 1, },
		{ 3.0f, 3.0f, -3.0f, 0, 0, -1, 1, 1, },
		{ -3.0f, -3.0f, -3.0f, 0, 0, -1, 0, 0, },
		{ 3.0f, -3.0f, -3.0f, 0, 0, -1, 1, 0, },

		// side 2
        { -3.0f, 3.0f, 3.0f, 0, 0, 1, 0, 1, },
        { -3.0f, -3.0f, 3.0f, 0, 0, 1, 0, 0, },
        { 3.0f, 3.0f, 3.0f, 0, 0, 1, 1, 1, },
        { 3.0f, -3.0f, 3.0f, 0, 0, 1, 1, 0, },

		// side 3
        { -3.0f, 3.0f, 3.0f, 0, 1, 0, 0, 1, },
        { 3.0f, 3.0f, 3.0f, 0, 1, 0, 1, 1, },
        { -3.0f, 3.0f, -3.0f, 0, 1, 0, 0, 0, },
        { 3.0f, 3.0f, -3.0f, 0, 1, 0, 1, 0, },

		// side 4
        { -3.0f, -3.0f, 3.0f, 0, -1, 0, 0, 1, },
        { -3.0f, -3.0f, -3.0f, 0, -1, 0, 0, 0, },
        { 3.0f, -3.0f, 3.0f, 0, -1, 0, 1, 1, },
        { 3.0f, -3.0f, -3.0f, 0, -1, 0, 1, 0, },

		// side 5
        { 3.0f, 3.0f, -3.0f, 1, 0, 0, 1, 0, },
        { 3.0f, 3.0f, 3.0f, 1, 0, 0, 1, 1, },
        { 3.0f, -3.0f, -3.0f, 1, 0, 0, 0, 0, },
        { 3.0f, -3.0f, 3.0f, 1, 0, 0, 0, 1, },

		// side 6
        { -3.0f, 3.0f, -3.0f, -1, 0, 0, 1, 0, },
        { -3.0f, -3.0f, -3.0f, -1, 0, 0, 0, 0, },
        { -3.0f, 3.0f, 3.0f, -1, 0, 0, 1, 1, },
        { -3.0f, -3.0f, 3.0f, -1, 0, 0, 0, 1, },
    };

    // create a vertex buffer interface called t_buffer
    d3ddev->CreateVertexBuffer(24*sizeof(CUSTOMVERTEX),
                               0,
                               CUSTOMFVF,
                               D3DPOOL_MANAGED,
                               &t_buffer,
                               NULL);

    VOID* pVoid;    // a void pointer

    // lock t_buffer and load the vertices into it
    t_buffer->Lock(0, 0, (void**)&pVoid, 0);
    memcpy(pVoid, t_vert, sizeof(t_vert));
    t_buffer->Unlock();

    return;
}

// this is the function that sets up the lights and meterials
void init_light(void)
{
	D3DLIGHT9 light; // create the light struct
	D3DMATERIAL9 material; // create the material struct

	ZeroMemory(&light, sizeof(light)); // clear out the light struct for use
	light.Type = D3DLIGHT_DIRECTIONAL; // make the light type 'directional light'
	light.Diffuse.r = 0.5f; // .5 red
	light.Diffuse.g = 0.5f; // .5 green
	light.Diffuse.b = 0.5f; // the .5 blue
	light.Diffuse.a = 1.0f; // full alpha (we'll get to that soon)

	D3DVECTOR vecDirection = {-1.0f, -0.3f, -1.0f}; // the direction of the light
	light.Direction = vecDirection; // set the direction

	d3ddev->SetLight(0, &light); // send the light struct properties to light 
	d3ddev->LightEnable(0, TRUE); // turn on the light

	ZeroMemory(&material, sizeof(D3DMATERIAL9)); // clear out the struct for use
	material.Diffuse.r = material.Ambient.r = 1.0f; // set the material to full red
	material.Diffuse.g = material.Ambient.g = 1.0f; // set the material to full green
	material.Diffuse.b = material.Ambient.b = 1.0f; // set the material to full blue
	material.Diffuse.a = material.Ambient.a = 1.0f; // set the material to full alpha

	d3ddev->SetMaterial(&material); // set the globaly-used material to &material
	
	return;
}