#include <windows.h>
#include <stdio.h>
#include "d3d9.h"
#include "d3dx9.h"

#pragma comment(lib, "d3d9.lib")
#pragma comment(lib, "d3dx9.lib")

#define WINDOW_WIDTH    400
#define WINDOW_HEIGHT   400

#define Safe_Release(p) if((p)) (p)->Release();

// window handles, class and caption text.
HWND g_hwnd;
HINSTANCE g_inst;
static char g_class_name[] = "Draw2DClass";
static char g_caption[]    = "Draw2D Demo";

// the Direct3D and device object
IDirect3D9* g_d3d = NULL;
IDirect3DDevice9* g_d3d_device = NULL;

// The 2D vertex format and descriptor
typedef struct
{
    float x, y, z;  // 2D coordinates
    float rhw;      // rhw
    float u, v;     // texture coordinates
} VERTEX;

#define VERTEX_FVF   (D3DFVF_XYZRHW | D3DFVF_TEX1)

IDirect3DVertexBuffer9* g_vertex_buffer = NULL;
IDirect3DTexture9*      g_texture = NULL;

//--------------------------------------------------------------------------------
// Window procedure.
//--------------------------------------------------------------------------------
long WINAPI Window_Proc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }

return (long) DefWindowProc(hwnd, msg, wParam, lParam);
}

//--------------------------------------------------------------------------------
// Initialize d3d, d3d device, vertex buffer, texutre. 
//--------------------------------------------------------------------------------
BOOL Do_Init()
{
    D3DPRESENT_PARAMETERS present_param;
    D3DDISPLAYMODE  display_mode;
    BYTE* vertex_ptr;

// initialize vertex data
    VERTEX verts[] = {
      {  50.0f,  50.0f, 1.0f, 1.0f, 0.0f, 0.0f },
      { 350.0f,  50.0f, 1.0f, 1.0f, 1.0f, 0.0f },
      {  50.0f, 350.0f, 1.0f, 1.0f, 0.0f, 1.0f },
      { 350.0f, 350.0f, 1.0f, 1.0f, 1.0f, 1.0f }
    };

// do a windowed mode initialization of Direct3D
    if((g_d3d = Direct3DCreate9(D3D_SDK_VERSION)) == NULL)
        return FALSE;

// retrieves the current display mode of the adapter
    if(FAILED(g_d3d->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &display_mode)))
        return FALSE;

ZeroMemory(&present_param, sizeof(present_param));

// initialize d3d presentation parameter
    present_param.Windowed          = TRUE;
    present_param.SwapEffect        = D3DSWAPEFFECT_DISCARD;
    present_param.BackBufferFormat  = display_mode.Format;

// creates a device to represent the display adapter
    if(FAILED(g_d3d->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, g_hwnd,
                                  D3DCREATE_SOFTWARE_VERTEXPROCESSING, &present_param, &g_d3d_device)))
        return FALSE;

// create the vertex buffer and set data
    g_d3d_device->CreateVertexBuffer(sizeof(VERTEX) * 4, 0, VERTEX_FVF, D3DPOOL_DEFAULT, &g_vertex_buffer, NULL);

// locks a range of vertex data and obtains a pointer to the vertex buffer memory
    g_vertex_buffer->Lock(0, 0, (void**)&vertex_ptr, 0);

memcpy(vertex_ptr, verts, sizeof(verts));

// unlocks vertex data
    g_vertex_buffer->Unlock();

// load the texture map
    D3DXCreateTextureFromFile(g_d3d_device, "Texture.bmp", &g_texture);

return TRUE;
}

//--------------------------------------------------------------------------------
// Release all d3d resource.
//--------------------------------------------------------------------------------
BOOL Do_Shutdown()
{
    Safe_Release(g_vertex_buffer);
    Safe_Release(g_texture);
    Safe_Release(g_d3d_device);
    Safe_Release(g_d3d);

return TRUE;
}

//--------------------------------------------------------------------------------
// Render a frame.
//--------------------------------------------------------------------------------
BOOL Do_Frame()
{
    // clear device back buffer
    g_d3d_device->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_RGBA(0, 64, 128, 255), 1.0f, 0);

// Begin scene
    if(SUCCEEDED(g_d3d_device->BeginScene()))
    {
        // set the vertex stream, shader, and texture.

// binds a vertex buffer to a device data stream
        g_d3d_device->SetStreamSource(0, g_vertex_buffer, 0, sizeof(VERTEX));

// set the current vertex stream declation
        g_d3d_device->SetFVF(VERTEX_FVF);

// assigns a texture to a stage for a device
        g_d3d_device->SetTexture(0, g_texture);

// renders a sequence of noindexed, geometric primitives of the specified type from the current set
        // of data input stream.
        g_d3d_device->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);

// release texture
        g_d3d_device->SetTexture(0, NULL);

// end the scene
        g_d3d_device->EndScene();
    }

// present the contents of the next buffer in the sequence of back buffers owned by the device
    g_d3d_device->Present(NULL, NULL, NULL, NULL);

return TRUE;
}

//--------------------------------------------------------------------------------
// Main function, routine entry.
//--------------------------------------------------------------------------------
int WINAPI WinMain(HINSTANCE inst, HINSTANCE, LPSTR cmd_line, int cmd_show)
{
    WNDCLASSEX  win_class;
    MSG         msg;

g_inst = inst;

// create window class and register it
    win_class.cbSize        = sizeof(win_class);
    win_class.style         = CS_CLASSDC;
    win_class.lpfnWndProc   = Window_Proc;
    win_class.cbClsExtra    = 0;
    win_class.cbWndExtra    = 0;
    win_class.hInstance     = inst;
    win_class.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
    win_class.hCursor       = LoadCursor(NULL, IDC_ARROW);
    win_class.hbrBackground = NULL;
    win_class.lpszMenuName  = NULL;
    win_class.lpszClassName = g_class_name;
    win_class.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);

if(! RegisterClassEx(&win_class))
        return FALSE;

// create the main window
    g_hwnd = CreateWindow(g_class_name, g_caption, WS_CAPTION | WS_SYSMENU, 0, 0,
                          WINDOW_WIDTH, WINDOW_HEIGHT, NULL, NULL, inst, NULL);

if(g_hwnd == NULL)
        return FALSE;

ShowWindow(g_hwnd, SW_NORMAL);
    UpdateWindow(g_hwnd);

// initialize game
    if(Do_Init() == FALSE)
        return FALSE;

// start message pump, waiting for signal to quit.
    ZeroMemory(&msg, sizeof(MSG));

while(msg.message != WM_QUIT)
    {
        if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        
        // draw a frame
        if(Do_Frame() == FALSE)
            break;
    }

// run shutdown function
    Do_Shutdown();

UnregisterClass(g_class_name, inst);
    
    return (int) msg.wParam;
}