src/mesa/drivers/d3d/D3DUTILS.CPP

   1 /*===========================================================================*/
   2 /*                                                                           */
   3 /* Mesa-3.0 DirectX 6 Driver                                                 */
   4 /*                                                                           */
   5 /* By Leigh McRae                                                            */
   6 /*                                                                           */
   7 /* http://www.altsoftware.com/                                               */
   8 /*                                                                           */
   9 /* Copyright (c) 1999-1998  alt.software inc.  All Rights Reserved           */
  10 /*===========================================================================*/
  11 #include "D3DHAL.h"
  12 /*===========================================================================*/
  13 /* Local only functions.                                                     */
  14 /*===========================================================================*/
  15 static int  CountTrailingZeros( DWORD dwMask );
  16 /*===========================================================================*/
  17 /*  This function is used to get the pointer to the surface and the pitch for*/
  18 /* the scanline rendering functions.                                         */
  19 /*===========================================================================*/
  20 /* RETURN:                                                                   */
  21 /*===========================================================================*/
  22 extern "C" DDSURFACEDESC2 *LockHAL( PMESAD3DSHARED pShared, BOOL bBack )
  23 {
  24   PMESAD3DHAL                   pHAL = (PMESAD3DHAL)pShared;
  25   static DDSURFACEDESC2 ddsd2;
  26   HRESULT                       rc;
  27
  28   DPF(( DBG_FUNC, "LockHAL();" ));
  29
  30   /* Set the request structure up first. */
  31   memset( &ddsd2, 0, sizeof(DDSURFACEDESC2) );
  32   ddsd2.dwSize = sizeof(DDSURFACEDESC2);
  33
  34   /* Make sure we have enough info. */
  35   if ( pHAL )
  36   {
  37     rc = pHAL->lpDDSRender->Lock( NULL, &ddsd2, DDLOCK_WAIT, NULL );
  38     if ( FAILED(rc) )
  39     {
  40          RIP( pHAL, "Lock (RENDER) ->", ErrorStringD3D(rc) );
  41     }
  42   }
  43
  44   return &ddsd2;
  45 }
  46 /*===========================================================================*/
  47 /*  This is just a simple wrapper.  I probably don't need to do any error    */
  48 /* checking as the Lock must have worked inorder to get here...              */
  49 /*===========================================================================*/
  50 /* RETURN:                                                                   */
  51 /*===========================================================================*/
  52 extern "C" void UnlockHAL( PMESAD3DSHARED pShared, BOOL bBack )
  53 {
  54   PMESAD3DHAL   pHAL = (PMESAD3DHAL)pShared;
  55   HRESULT               rc;
  56
  57   DPF(( DBG_FUNC, "UnlockHAL();" ));
  58
  59   /* Make sure we have enough info. */
  60   if ( pHAL )
  61   {
  62     rc = pHAL->lpDDSRender->Unlock( NULL );
  63     if ( FAILED(rc) )
  64     {
  65          RIP( pHAL, "Unlock (RENDER) ->", ErrorStringD3D(rc) );
  66     }
  67   }
  68 }
  69 /*===========================================================================*/
  70 /*  This function will track the main/Primary window that will be used as the*/
  71 /* target for the Blt in SwapBuffers.  As a side effect the call will check  */
  72 /* to see if the primary surface is the same size and position as the screen.*/
  73 /* If they are the same size we will call it fullscreen...                   */
  74 /*===========================================================================*/
  75 /* RETURN:                                                                   */
  76 /*===========================================================================*/
  77 extern "C" void UpdateScreenPosHAL( PMESAD3DSHARED pShared )
  78 {
  79   PMESAD3DHAL   pHAL = (PMESAD3DHAL)pShared;
  80   POINT         pt;
  81   DWORD         dwWidth, dwHeight;
  82
  83   DPF(( DBG_FUNC, "UpdateScreenPosHAL();" ));
  84
  85   /* Make sure we have enough info. */
  86   if ( pHAL != NULL )
  87   {
  88     /* Update the windows screen position. */
  89     GetClientRect( pShared->hwnd, &pShared->rectW );
  90     pt.x = pt.y = 0;
  91     ClientToScreen( pShared->hwnd, &pt );
  92     OffsetRect( &pShared->rectW, pt.x, pt.y);
  93
  94     /* Compare the primary to the screen. */
  95     dwWidth = GetSystemMetrics( SM_CXSCREEN );
  96     dwHeight =  GetSystemMetrics( SM_CYSCREEN );
  97     if ( (pShared->rectW.left > 0) ||  (pShared->rectW.top > 0)  ||
  98             (pShared->rectW.right > dwWidth) || (pShared->rectW.bottom > dwHeight) )
  99          pShared->bWindow = TRUE;
 100     else
 101          pShared->bWindow = FALSE;
 102   }
 103 }
 104 /*===========================================================================*/
 105 /*  This function will fill in the pixel info structure defined in D3Dshared.*/
 106 /* Basicly it will take a DirectDraw pixelformat structure and make scaling  */
 107 /* values that will convert from 8bit channels to whatever the supplied ddpf */
 108 /* uses.  Also we will generate shift values that will be used to get move   */
 109 /* each component of the pixel into place.                                   */
 110 /*  I have now added a special case for a 1bit alpha channel.  If I find a 1b*/
 111 /* alpha then I will set the scale to -1.0 which should be unique.  Later I  */
 112 /* can check the alpha scale value too see if its -1.0 and thus handle it.  I*/
 113 /* was finding that the case was not working tom my advantage so this is my  */
 114 /* HACK for the day.  As a TODO I should work on this...                     */
 115 /*===========================================================================*/
 116 /* RETURN:                                                                   */
 117 /*===========================================================================*/
 118 void    Solve8BitChannelPixelFormat( DDPIXELFORMAT *pddpf, PPIXELINFO pPixel )
 119 {
 120   DPF(( DBG_FUNC, "Solve8BitChannelPixelFromat();" ));
 121
 122   memset( pPixel, 0, sizeof(PPIXELINFO) );
 123
 124   /* Check too see if the color space is valid in the PF. */
 125   if ( pddpf->dwFlags & DDPF_RGB )
 126   {
 127     /* Solve the red stuff. */
 128     pPixel->dwRMask = pddpf->dwRBitMask;
 129     pPixel->rShift = CountTrailingZeros( pPixel->dwRMask );
 130     pPixel->rScale = (float)0.00392156 * (float)(pPixel->dwRMask >> pPixel->rShift);
 131
 132     /* Solve the green thingy's. */
 133     pPixel->dwGMask = pddpf->dwGBitMask;
 134     pPixel->gShift = CountTrailingZeros( pPixel->dwGMask );
 135     pPixel->gScale = (float)0.00392156 * (float)(pPixel->dwGMask >> pPixel->gShift);
 136
 137     /* Solve the blues. */
 138     pPixel->dwBMask = pddpf->dwBBitMask;
 139     pPixel->bShift = CountTrailingZeros( pddpf->dwBBitMask );
 140     pPixel->bScale = (float)0.00392156 * (float)(pddpf->dwBBitMask >> pPixel->bShift);
 141   }
 142
 143   /* Do the alpha channel if there is one. */
 144   if ( pddpf->dwFlags & DDPF_ALPHAPIXELS )
 145   {
 146     pPixel->dwAMask = pddpf->dwRGBAlphaBitMask;
 147     pPixel->aShift = CountTrailingZeros( pPixel->dwAMask );
 148
 149     /* Special case a 1bit alpha. */
 150     if ( (pPixel->dwAMask >> pPixel->aShift) == 1 )
 151          pPixel->aScale = -1.0;
 152     else
 153          pPixel->aScale = (float)0.00392156 * (float)(pPixel->dwAMask >> pPixel->aShift);
 154   }
 155
 156   /* Get the size of the pixel in bytes. Should work as dwRGBBitCount is in a union. */
 157   pPixel->cb = pddpf->dwRGBBitCount / 8;
 158 }
 159 /*===========================================================================*/
 160 /*  See RETURN :)                                                            */
 161 /*===========================================================================*/
 162 /* RETURN: number of contiguous zeros starting from the right.               */
 163 /*===========================================================================*/
 164 static int  CountTrailingZeros( DWORD dwMask )
 165 {
 166   DWORD Mask;
 167
 168   if ( dwMask == 0 )
 169     return 32;
 170
 171   /* Can't take credit for this one! */
 172   Mask = dwMask & -(int)dwMask;
 173   return ((Mask & 0xFFFF0000)!=0) << 4
 174          | ((Mask & 0xFF00FF00)!=0) << 3
 175          | ((Mask & 0xF0F0F0F0)!=0) << 2
 176          | ((Mask & 0xCCCCCCCC)!=0) << 1
 177          | ((Mask & 0xAAAAAAAA)!=0);
 178 }
 179 /*===========================================================================*/
 180 /*  This function will convert the DDraw error code to its macro string.  The*/
 181 /* returned pointer is static so you need not worry about memory managemnet  */
 182 /* but the error message gets written over from call to call...              */
 183 /*===========================================================================*/
 184 /* RETURN: pointer to the single static buffer that hold the error message.  */
 185 /*===========================================================================*/
 186 char *ErrorStringD3D( HRESULT hr )
 187 {
 188   static   char  errorString[128];
 189
 190   switch( hr )
 191     {
 192     case DDERR_ALREADYINITIALIZED:
 193          strcpy( errorString, "DDERR_ALREADYINITIALIZED" );
 194          break;
 195
 196     case DDERR_CANNOTATTACHSURFACE:
 197          strcpy( errorString, "DDERR_CANNOTATTACHSURFACE" );
 198          break;
 199
 200     case DDERR_CANNOTDETACHSURFACE:
 201          strcpy( errorString, "DDERR_CANNOTDETACHSURFACE" );
 202          break;
 203
 204     case DDERR_CURRENTLYNOTAVAIL:
 205          strcpy( errorString, "DDERR_CURRENTLYNOTAVAIL" );
 206          break;
 207
 208     case DDERR_EXCEPTION:
 209          strcpy( errorString, "DDERR_EXCEPTION" );
 210          break;
 211
 212     case DDERR_GENERIC:
 213          strcpy( errorString, "DDERR_GENERIC" );
 214          break;
 215
 216     case DDERR_HEIGHTALIGN:
 217          strcpy( errorString, "DDERR_HEIGHTALIGN" );
 218          break;
 219
 220     case DDERR_INCOMPATIBLEPRIMARY:
 221          strcpy( errorString, "DDERR_INCOMPATIBLEPRIMARY" );
 222          break;
 223
 224     case DDERR_INVALIDCAPS:
 225          strcpy( errorString, "DDERR_INVALIDCAPS" );
 226          break;
 227
 228     case DDERR_INVALIDCLIPLIST:
 229          strcpy( errorString, "DDERR_INVALIDCLIPLIST" );
 230          break;
 231
 232     case DDERR_INVALIDMODE:
 233          strcpy( errorString, "DDERR_INVALIDMODE" );
 234          break;
 235
 236     case DDERR_INVALIDOBJECT:
 237          strcpy( errorString, "DDERR_INVALIDOBJECT" );
 238          break;
 239
 240     case DDERR_INVALIDPARAMS:
 241          strcpy( errorString, "DDERR_INVALIDPARAMS" );
 242          break;
 243
 244     case DDERR_INVALIDPIXELFORMAT:
 245          strcpy( errorString, "DDERR_INVALIDPIXELFORMAT" );
 246          break;
 247
 248     case DDERR_INVALIDRECT:
 249          strcpy( errorString, "DDERR_INVALIDRECT" );
 250          break;
 251
 252     case DDERR_LOCKEDSURFACES:
 253          strcpy( errorString, "DDERR_LOCKEDSURFACES" );
 254          break;
 255
 256     case DDERR_NO3D:
 257          strcpy( errorString, "DDERR_NO3D" );
 258          break;
 259
 260     case DDERR_NOALPHAHW:
 261          strcpy( errorString, "DDERR_NOALPHAHW" );
 262          break;
 263
 264     case DDERR_NOCLIPLIST:
 265          strcpy( errorString, "DDERR_NOCLIPLIST" );
 266          break;
 267
 268     case DDERR_NOCOLORCONVHW:
 269          strcpy( errorString, "DDERR_NOCOLORCONVHW" );
 270          break;
 271
 272     case DDERR_NOCOOPERATIVELEVELSET:
 273          strcpy( errorString, "DDERR_NOCOOPERATIVELEVELSET" );
 274          break;
 275
 276     case DDERR_NOCOLORKEY:
 277          strcpy( errorString, "DDERR_NOCOLORKEY" );
 278          break;
 279
 280     case DDERR_NOCOLORKEYHW:
 281          strcpy( errorString, "DDERR_NOCOLORKEYHW" );
 282          break;
 283
 284     case DDERR_NODIRECTDRAWSUPPORT:
 285          strcpy( errorString, "DDERR_NODIRECTDRAWSUPPORT" );
 286          break;
 287
 288     case DDERR_NOEXCLUSIVEMODE:
 289          strcpy( errorString, "DDERR_NOEXCLUSIVEMODE" );
 290          break;
 291
 292     case DDERR_NOFLIPHW:
 293          strcpy( errorString, "DDERR_NOFLIPHW" );
 294          break;
 295
 296     case DDERR_NOGDI:
 297          strcpy( errorString, "DDERR_NOGDI" );
 298          break;
 299
 300     case DDERR_NOMIRRORHW:
 301          strcpy( errorString, "DDERR_NOMIRRORHW" );
 302          break;
 303
 304     case DDERR_NOTFOUND:
 305          strcpy( errorString, "DDERR_NOTFOUND" );
 306          break;
 307
 308     case DDERR_NOOVERLAYHW:
 309          strcpy( errorString, "DDERR_NOOVERLAYHW" );
 310          break;
 311
 312     case DDERR_OVERLAPPINGRECTS:
 313          strcpy( errorString, "DDERR_OVERLAPPINGRECTS" );
 314          break;
 315
 316     case DDERR_NORASTEROPHW:
 317          strcpy( errorString, "DDERR_NORASTEROPHW" );
 318          break;
 319
 320     case DDERR_NOROTATIONHW:
 321          strcpy( errorString, "DDERR_NOROTATIONHW" );
 322          break;
 323
 324     case DDERR_NOSTRETCHHW:
 325          strcpy( errorString, "DDERR_NOSTRETCHHW" );
 326          break;
 327
 328     case DDERR_NOT4BITCOLOR:
 329          strcpy( errorString, "DDERR_NOT4BITCOLOR" );
 330          break;
 331
 332     case DDERR_NOT4BITCOLORINDEX:
 333          strcpy( errorString, "DDERR_NOT4BITCOLORINDEX" );
 334          break;
 335
 336     case DDERR_NOT8BITCOLOR:
 337          strcpy( errorString, "DDERR_NOT8BITCOLOR" );
 338          break;
 339
 340     case DDERR_NOTEXTUREHW:
 341          strcpy( errorString, "DDERR_NOTEXTUREHW" );
 342          break;
 343
 344     case DDERR_NOVSYNCHW:
 345          strcpy( errorString, "DDERR_NOVSYNCHW" );
 346          break;
 347
 348     case DDERR_NOZBUFFERHW:
 349          strcpy( errorString, "DDERR_NOZBUFFERHW" );
 350          break;
 351
 352     case DDERR_NOZOVERLAYHW:
 353          strcpy( errorString, "DDERR_NOZOVERLAYHW" );
 354          break;
 355
 356     case DDERR_OUTOFCAPS:
 357          strcpy( errorString, "DDERR_OUTOFCAPS" );
 358          break;
 359
 360     case DDERR_OUTOFMEMORY:
 361          strcpy( errorString, "DDERR_OUTOFMEMORY" );
 362          break;
 363
 364     case DDERR_OUTOFVIDEOMEMORY:
 365          strcpy( errorString, "DDERR_OUTOFVIDEOMEMORY" );
 366          break;
 367
 368     case DDERR_OVERLAYCANTCLIP:
 369          strcpy( errorString, "DDERR_OVERLAYCANTCLIP" );
 370          break;
 371
 372     case DDERR_OVERLAYCOLORKEYONLYONEACTIVE:
 373          strcpy( errorString, "DDERR_OVERLAYCOLORKEYONLYONEACTIVE" );
 374          break;
 375
 376     case DDERR_PALETTEBUSY:
 377          strcpy( errorString, "DDERR_PALETTEBUSY" );
 378          break;
 379
 380     case DDERR_COLORKEYNOTSET:
 381          strcpy( errorString, "DDERR_COLORKEYNOTSET" );
 382          break;
 383
 384     case DDERR_SURFACEALREADYATTACHED:
 385          strcpy( errorString, "DDERR_SURFACEALREADYATTACHED" );
 386          break;
 387
 388     case DDERR_SURFACEALREADYDEPENDENT:
 389          strcpy( errorString, "DDERR_SURFACEALREADYDEPENDENT" );
 390          break;
 391
 392     case DDERR_SURFACEBUSY:
 393          strcpy( errorString, "DDERR_SURFACEBUSY" );
 394          break;
 395
 396     case DDERR_CANTLOCKSURFACE:
 397          strcpy( errorString, "DDERR_CANTLOCKSURFACE" );
 398          break;
 399
 400     case DDERR_SURFACEISOBSCURED:
 401          strcpy( errorString, "DDERR_SURFACEISOBSCURED" );
 402          break;
 403
 404     case DDERR_SURFACELOST:
 405          strcpy( errorString, "DDERR_SURFACELOST" );
 406          break;
 407
 408     case DDERR_SURFACENOTATTACHED:
 409          strcpy( errorString, "DDERR_SURFACENOTATTACHED" );
 410          break;
 411
 412     case DDERR_TOOBIGHEIGHT:
 413          strcpy( errorString, "DDERR_TOOBIGHEIGHT" );
 414          break;
 415
 416     case DDERR_TOOBIGSIZE:
 417          strcpy( errorString, "DDERR_TOOBIGSIZE" );
 418          break;
 419
 420     case DDERR_TOOBIGWIDTH:
 421          strcpy( errorString, "DDERR_TOOBIGWIDTH" );
 422          break;
 423
 424     case DDERR_UNSUPPORTED:
 425          strcpy( errorString, "DDERR_UNSUPPORTED" );
 426          break;
 427
 428     case DDERR_UNSUPPORTEDFORMAT:
 429          strcpy( errorString, "DDERR_UNSUPPORTEDFORMAT" );
 430          break;
 431
 432     case DDERR_UNSUPPORTEDMASK:
 433          strcpy( errorString, "DDERR_UNSUPPORTEDMASK" );
 434          break;
 435
 436     case DDERR_INVALIDSTREAM:
 437          strcpy( errorString, "DDERR_INVALIDSTREAM" );
 438          break;
 439
 440     case DDERR_VERTICALBLANKINPROGRESS:
 441          strcpy( errorString, "DDERR_VERTICALBLANKINPROGRESS" );
 442          break;
 443
 444     case DDERR_WASSTILLDRAWING:
 445          strcpy( errorString, "DDERR_WASSTILLDRAWING" );
 446          break;
 447
 448     case DDERR_XALIGN:
 449          strcpy( errorString, "DDERR_XALIGN" );
 450          break;
 451
 452     case DDERR_INVALIDDIRECTDRAWGUID:
 453          strcpy( errorString, "DDERR_INVALIDDIRECTDRAWGUID" );
 454          break;
 455
 456     case DDERR_DIRECTDRAWALREADYCREATED:
 457          strcpy( errorString, "DDERR_DIRECTDRAWALREADYCREATED" );
 458          break;
 459
 460     case DDERR_NODIRECTDRAWHW:
 461          strcpy( errorString, "DDERR_NODIRECTDRAWHW" );
 462          break;
 463
 464     case DDERR_PRIMARYSURFACEALREADYEXISTS:
 465          strcpy( errorString, "DDERR_PRIMARYSURFACEALREADYEXISTS" );
 466          break;
 467
 468     case DDERR_NOEMULATION:
 469          strcpy( errorString, "DDERR_NOEMULATION" );
 470          break;
 471
 472     case DDERR_REGIONTOOSMALL:
 473          strcpy( errorString, "DDERR_REGIONTOOSMALL" );
 474          break;
 475
 476     case DDERR_CLIPPERISUSINGHWND:
 477          strcpy( errorString, "DDERR_CLIPPERISUSINGHWND" );
 478          break;
 479
 480     case DDERR_NOCLIPPERATTACHED:
 481          strcpy( errorString, "DDERR_NOCLIPPERATTACHED" );
 482          break;
 483
 484     case DDERR_NOHWND:
 485          strcpy( errorString, "DDERR_NOHWND" );
 486          break;
 487
 488     case DDERR_HWNDSUBCLASSED:
 489          strcpy( errorString, "DDERR_HWNDSUBCLASSED" );
 490          break;
 491
 492     case DDERR_HWNDALREADYSET:
 493          strcpy( errorString, "DDERR_HWNDALREADYSET" );
 494          break;
 495
 496     case DDERR_NOPALETTEATTACHED:
 497          strcpy( errorString, "DDERR_NOPALETTEATTACHED" );
 498          break;
 499
 500     case DDERR_NOPALETTEHW:
 501          strcpy( errorString, "DDERR_NOPALETTEHW" );
 502          break;
 503
 504     case DDERR_BLTFASTCANTCLIP:
 505          strcpy( errorString, "DDERR_BLTFASTCANTCLIP" );
 506          break;
 507
 508       case DDERR_NOBLTHW:
 509          strcpy( errorString, "DDERR_NOBLTHW" );
 510          break;
 511
 512       case DDERR_NODDROPSHW:
 513          strcpy( errorString, "DDERR_NODDROPSHW" );
 514          break;
 515
 516       case DDERR_OVERLAYNOTVISIBLE:
 517          strcpy( errorString, "DDERR_OVERLAYNOTVISIBLE" );
 518          break;
 519
 520       case DDERR_NOOVERLAYDEST:
 521          strcpy( errorString, "DDERR_NOOVERLAYDEST" );
 522          break;
 523
 524       case DDERR_INVALIDPOSITION:
 525          strcpy( errorString, "DDERR_INVALIDPOSITION" );
 526          break;
 527
 528       case DDERR_NOTAOVERLAYSURFACE:
 529          strcpy( errorString, "DDERR_NOTAOVERLAYSURFACE" );
 530          break;
 531
 532       case DDERR_EXCLUSIVEMODEALREADYSET:
 533          strcpy( errorString, "DDERR_EXCLUSIVEMODEALREADYSET" );
 534          break;
 535
 536       case DDERR_NOTFLIPPABLE:
 537          strcpy( errorString, "DDERR_NOTFLIPPABLE" );
 538          break;
 539
 540       case DDERR_CANTDUPLICATE:
 541          strcpy( errorString, "DDERR_CANTDUPLICATE" );
 542          break;
 543
 544       case DDERR_NOTLOCKED:
 545          strcpy( errorString, "DDERR_NOTLOCKED" );
 546          break;
 547
 548       case DDERR_CANTCREATEDC:
 549          strcpy( errorString, "DDERR_CANTCREATEDC" );
 550          break;
 551
 552       case DDERR_NODC:
 553          strcpy( errorString, "DDERR_NODC" );
 554          break;
 555
 556       case DDERR_WRONGMODE:
 557          strcpy( errorString, "DDERR_WRONGMODE" );
 558          break;
 559
 560       case DDERR_IMPLICITLYCREATED:
 561          strcpy( errorString, "DDERR_IMPLICITLYCREATED" );
 562          break;
 563
 564       case DDERR_NOTPALETTIZED:
 565          strcpy( errorString, "DDERR_NOTPALETTIZED" );
 566          break;
 567
 568       case DDERR_UNSUPPORTEDMODE:
 569          strcpy( errorString, "DDERR_UNSUPPORTEDMODE" );
 570          break;
 571
 572       case DDERR_NOMIPMAPHW:
 573          strcpy( errorString, "DDERR_NOMIPMAPHW" );
 574          break;
 575
 576       case DDERR_INVALIDSURFACETYPE:
 577          strcpy( errorString, "DDERR_INVALIDSURFACETYPE" );
 578          break;
 579
 580       case DDERR_NOOPTIMIZEHW:
 581          strcpy( errorString, "DDERR_NOOPTIMIZEHW" );
 582          break;
 583
 584       case DDERR_NOTLOADED:
 585          strcpy( errorString, "DDERR_NOTLOADED" );
 586          break;
 587
 588       case DDERR_NOFOCUSWINDOW:
 589          strcpy( errorString, "DDERR_NOFOCUSWINDOW" );
 590          break;
 591
 592       case DDERR_DCALREADYCREATED:
 593          strcpy( errorString, "DDERR_DCALREADYCREATED" );
 594          break;
 595
 596       case DDERR_NONONLOCALVIDMEM:
 597          strcpy( errorString, "DDERR_NONONLOCALVIDMEM" );
 598          break;
 599
 600       case DDERR_CANTPAGELOCK:
 601          strcpy( errorString, "DDERR_CANTPAGELOCK" );
 602          break;
 603
 604       case DDERR_CANTPAGEUNLOCK:
 605          strcpy( errorString, "DDERR_CANTPAGEUNLOCK" );
 606          break;
 607
 608       case DDERR_NOTPAGELOCKED:
 609          strcpy( errorString, "DDERR_NOTPAGELOCKED" );
 610          break;
 611
 612       case DDERR_MOREDATA:
 613          strcpy( errorString, "DDERR_MOREDATA" );
 614          break;
 615
 616       case DDERR_EXPIRED:
 617          strcpy( errorString, "DDERR_EXPIRED" );
 618          break;
 619
 620       case DDERR_VIDEONOTACTIVE:
 621          strcpy( errorString, "DDERR_VIDEONOTACTIVE" );
 622          break;
 623
 624       case DDERR_DEVICEDOESNTOWNSURFACE:
 625          strcpy( errorString, "DDERR_DEVICEDOESNTOWNSURFACE" );
 626          break;
 627
 628       case DDERR_NOTINITIALIZED:
 629          strcpy( errorString, "DDERR_NOTINITIALIZED" );
 630          break;
 631
 632       default:
 633          strcpy( errorString, "<unknown error code>" );
 634          break;
 635    }
 636
 637    return &errorString[0];
 638 }