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

#define RELEASE(x) if(x){x->Release();x=NULL;}

#define SCREEN_FPS 60
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480

HINSTANCE g_Inst;
HWND g_hWnd;
LPCSTR szAppName = "Direct3D";

LRESULT CALLBACK WndProc(HWND hWnd,UINT msg,UINT wParam,LONG lParam);

int bActive = 0;
int bFullScreen = 0;

D3DPRESENT_PARAMETERS d3dpp;
D3DFORMAT dspfmt;
LPDIRECT3D9 pD3D = NULL;
LPDIRECT3DDEVICE9 pDevice = NULL;
LPDIRECT3DTEXTURE9 pTexture = NULL;
LPDIRECT3DPIXELSHADER9 pPS = NULL;

typedef struct _D3DLVERTEX_{
  float x, y, z;
  float tu0, tv0;
}LVERTEX;

LVERTEX ver1[4] ={
  {-2,  2, 0, 0.0f, 0.0f},
  {-2, -2, 0, 0.0f, 1.0f},
  { 2, -2, 0, 1.0f, 1.0f},
  { 2,  2, 0, 1.0f, 0.0f}
};

// ピクセル・シェーダ
const char szPS[] =
  "ps.1.1 \n"\
  "tex t0 \n"\
  "mul r0, t0, c0 \n";

void drawPoint(int x, int y, int r, int g, int b, int a){
  D3DLOCKED_RECT pLockedRect;

  pTexture->LockRect(0, &pLockedRect, NULL, 0);

  unsigned char *p = (unsigned char *)pLockedRect.pBits + pLockedRect.Pitch * y + x * 4;

  p[0] = (unsigned char)b;
  p[1] = (unsigned char)g;
  p[2] = (unsigned char)r;
  p[3] = (unsigned char)a;

  pTexture->UnlockRect(0);
}

int initD3D(void){
  int i, t;
  DWORD vprocessing = D3DCREATE_HARDWARE_VERTEXPROCESSING;
  D3DCAPS9 caps;
  D3DDISPLAYMODE dsp;

  pD3D = Direct3DCreate9(D3D_SDK_VERSION);

  if(pD3D == NULL){
    return false;
  }

  // 画面のチェック
  if(FAILED(pD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &dsp))){
    return false;
  }

  // シェーダのチェック
  pD3D->GetDeviceCaps(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, &caps);

  if(caps.MaxVertexShaderConst < 4){
    vprocessing = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
  }
  else if(caps.VertexShaderVersion < D3DVS_VERSION(1, 1)){
    vprocessing = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
  }
  else if(caps.PixelShaderVersion < D3DVS_VERSION(1, 1)){
    vprocessing = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
  }

  dspfmt = dsp.Format;

  ZeroMemory(&d3dpp, sizeof(d3dpp));

  d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;

  // 全画面 or ウィンドウ
  if(bFullScreen == 1){
    d3dpp.BackBufferFormat = D3DFMT_R5G6B5;
    d3dpp.Windowed = 0;
  }
  else{
    d3dpp.BackBufferFormat = dsp.Format;
    d3dpp.Windowed = 1;
  }

  d3dpp.BackBufferWidth = SCREEN_WIDTH;
  d3dpp.BackBufferHeight = SCREEN_HEIGHT;
  d3dpp.BackBufferCount = 1;
  d3dpp.EnableAutoDepthStencil = FALSE;

  // T&L HAL or HAL
  if(FAILED(pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, g_hWnd, vprocessing, &d3dpp, &pDevice))){
  // HEL
    if(FAILED(pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_REF, g_hWnd,D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &pDevice))){
      return false;
    }
  }

  D3DXCreateTexture(pDevice, 4, 4, 1, 0, D3DFMT_A8R8G8B8, D3DPOOL_MANAGED, &pTexture);

  for(t = 0; t < 4; t++){
    for(i = 0; i < 4; i++){
      if(t == 0 || t == 3 || i == 0 || i == 3){
        drawPoint(i, t, 255, 255, 255, 255);
      }
      else{
        drawPoint(i, t, 0, 0, 0, 0);
      }
    }
  }

  return 1;
}

int initRender(void){
  float fAspect;
  D3DVIEWPORT9 vp;
  D3DXMATRIX mat;
  LPD3DXBUFFER pCode;

  pDevice->GetViewport(&vp);
  fAspect = (float)vp.Width / (float)vp.Height;

  // 可視台の設定
  D3DXMatrixPerspectiveFovLH(&mat, D3DXToRadian(90.0f), fAspect, 230.0f, 250.0f);
  pDevice->SetTransform(D3DTS_PROJECTION, &mat);
  // z方向の -240 の位置から原点から 
  D3DXMatrixLookAtLH(&mat, &D3DXVECTOR3(0.0f, 0.0f, -240.0f), &D3DXVECTOR3(0, 0, 0), &D3DXVECTOR3(0, 1, 0));
  pDevice->SetTransform(D3DTS_VIEW, &mat);

  // カリングを時計周りで
  pDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_CW);  // NONE or CW or CCW
  // ライティングをオフ
  pDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
  // Ｚバッファをオフ
  pDevice->SetRenderState(D3DRS_ZENABLE, FALSE);
  // ミップマップをオフ
  pDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_NONE);
  pDevice->SetSamplerState(0, D3DSAMP_MIPFILTER, D3DTEXF_NONE);

  // アルファブレンドを有効に
  pDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
  pDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
  pDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);

  // 加算ブレンドを有効に
  //pDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, TRUE);
  //pDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ONE);
  //pDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_ONE);

  // アセンブルシェーダを有効に
  D3DXAssembleShader(szPS, sizeof(szPS) - 1, NULL, NULL, 0, &pCode, NULL);
  pDevice->CreatePixelShader((DWORD *)pCode->GetBufferPointer(), &pPS);
  RELEASE(pCode);

  return 1;
}

void deinitD3d(void){
  RELEASE(pPS);
  RELEASE(pTexture);
  RELEASE(pDevice);
  RELEASE(pD3D);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, UINT wParam, LONG lParam){
  switch(msg){
  case WM_ACTIVATE:
    bActive = HIWORD(wParam)?0:1;
    break;
  case WM_KEYDOWN:
    switch(wParam){
    case VK_F3:
      bFullScreen = !bFullScreen;
      if(bFullScreen == 1){
        d3dpp.BackBufferFormat = D3DFMT_R5G6B5;
        d3dpp.Windowed = 0;
      }else{
        d3dpp.BackBufferFormat = dspfmt;
        d3dpp.Windowed = 1;
      }
      if(FAILED(pDevice->Reset(&d3dpp))){
        PostMessage(hWnd, WM_CLOSE, 0, 0);
        return 0L;
      }
      if(bFullScreen != 1)DrawMenuBar(g_hWnd);
      initRender();
      break;
    case VK_ESCAPE:
      PostMessage(hWnd, WM_CLOSE, 0, 0);
      break;
    default:
      break;
    }
    break;
  case WM_DESTROY:
    PostQuitMessage(0);
    break;
    case WM_IME_NOTIFY:
    //
    break;
  default:
    return DefWindowProc(hWnd, msg, wParam, lParam);
  }
  return 0L;
}

int drawIdle(void){
  static int r = 0;
  D3DXMATRIX mat, mat2;

  r += 1;

  // 画面のクリア
  pDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0, 0);

  pDevice->SetFVF(D3DFVF_XYZ | D3DFVF_TEX1);  

  pDevice->SetTexture(0, pTexture);

  if(SUCCEEDED(pDevice->BeginScene())){
    D3DXMatrixIdentity(&mat);
    // 拡大
    D3DXMatrixScaling(&mat2, 10.0f, 10.0f, 10.0f);
    mat *= mat2;
    // 回転
    D3DXMatrixRotationZ(&mat2, D3DXToRadian((float)r + 20.0f));
    mat *= mat2;
    // 移動
    D3DXMatrixTranslation(&mat2, 0.0f - 2.0f, 0.0f + 2.0f, 0.0f);
    mat *= mat2;
    pDevice->SetTransform(D3DTS_WORLD, &mat);

    // シェーダ処理
    D3DXVECTOR4 c0(1.0f, 0.0f, 0.0f, 0.1f * (r % 10));
    pDevice->SetPixelShaderConstantF(0, (float *)&c0, 1);
    pDevice->SetPixelShader(pPS);
    pDevice->DrawPrimitiveUP(D3DPT_TRIANGLEFAN, 2, ver1, sizeof(LVERTEX));
    pDevice->SetPixelShader(NULL);

    pDevice->EndScene();

    if(FAILED(pDevice->Present(NULL, NULL, NULL, NULL))){
      if(FAILED(pDevice->Reset(&d3dpp))){
        return 0;
      }
    }
  }

  return 1;
}

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow){
  int result;
  int cx, cy;
  WNDCLASS wc;
  MSG msg;
  DWORD waittime;

  // 256色モードでは起動できません
  HDC dc = GetDC(0);
  int iBit = GetDeviceCaps(dc, BITSPIXEL);
  ReleaseDC(0, dc);
  if(iBit < 15){
    MessageBox(0, "256色モードでは起動できません", szAppName, MB_ICONSTOP|MB_OK);
    return 0;
  }

  g_Inst=hInst;

  if(!hPrevInst){
    wc.lpszClassName = "Direct3D";
    wc.lpfnWndProc = WndProc;
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.hInstance = hInst;
    wc.hIcon = NULL;
    wc.hCursor = LoadCursor(NULL,IDC_ARROW);
    wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
    wc.lpszMenuName = NULL;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    if(!RegisterClass(&wc)){
      return 0;
    }
  }

  cx = SCREEN_WIDTH + GetSystemMetrics(SM_CXDLGFRAME) * 2;
  cy = SCREEN_HEIGHT + GetSystemMetrics(SM_CYDLGFRAME) * 2 + GetSystemMetrics(SM_CYCAPTION);

  g_hWnd = CreateWindowEx(0, szAppName, szAppName,
             WS_OVERLAPPED | WS_SYSMENU | WS_MINIMIZEBOX,
             CW_USEDEFAULT, CW_USEDEFAULT, cx, cy,
             (HWND)NULL, (HMENU)NULL,
             hInst, (LPSTR)NULL);

  ShowWindow(g_hWnd, nCmdShow);
  UpdateWindow(g_hWnd);

  result = initD3D();

  if(result == 0){
    goto fin;
  }

  result = initRender();

  if(result == 0){
    goto fin;
  }

  msg.wParam = 0;

  while(1){
    waittime = GetTickCount();
    if(bActive){
      if(!drawIdle()){
        goto fin;
      }
    }
    else{
      WaitMessage();
    }
    do{
      while(PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)){
        if(!GetMessage(&msg, NULL, 0, 0)){
          goto fin;
        }
        TranslateMessage(&msg);
        DispatchMessage(&msg);
      }
    }while(GetTickCount() < waittime + SCREEN_FPS);
  }

fin:

  deinitD3d();

  return msg.wParam;
}