src/game/g_phys.pas

   1 (* Copyright (C)  DooM 2D:Forever Developers
   2  *
   3  * This program is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  *)
  16 {$INCLUDE g_amodes.inc}
  17 unit g_phys;
  18
  19 interface
  20
  21 uses
  22   e_graphics;
  23
  24 type
  25   PObj = ^TObj;
  26   TObj = record
  27     X, Y:    Integer;
  28     Rect:    TRectWH;
  29     Vel:     TPoint2i;
  30     Accel:   TPoint2i;
  31   end;
  32
  33 const
  34   MAX_YV = 30;
  35   LIMIT_VEL   = 16384;
  36   LIMIT_ACCEL = 1024;
  37
  38   MOVE_NONE       = 0;
  39   MOVE_HITWALL    = 1;
  40   MOVE_HITCEIL    = 2;
  41   MOVE_HITLAND    = 4;
  42   MOVE_FALLOUT    = 8;
  43   MOVE_INWATER    = 16;
  44   MOVE_HITWATER   = 32;
  45   MOVE_HITAIR     = 64;
  46   MOVE_BLOCK      = 128;
  47
  48 procedure g_Obj_Init(Obj: PObj);
  49 function  g_Obj_Move(Obj: PObj; Fallable: Boolean; Splash: Boolean; ClimbSlopes: Boolean = False): Word;
  50 function  g_Obj_Collide(Obj1, Obj2: PObj): Boolean; overload;
  51 function  g_Obj_Collide(X, Y: Integer; Width, Height: Word; Obj: PObj): Boolean; overload;
  52 function  g_Obj_CollidePoint(X, Y: Integer; Obj: PObj): Boolean;
  53 function  g_Obj_CollideLevel(Obj: PObj; XInc, YInc: Integer): Boolean;
  54 function  g_Obj_CollideStep(Obj: PObj; XInc, YInc: Integer): Boolean;
  55 function  g_Obj_CollideWater(Obj: PObj; XInc, YInc: Integer): Boolean;
  56 function  g_Obj_CollideLiquid(Obj: PObj; XInc, YInc: Integer): Boolean;
  57 function  g_Obj_CollidePanel(Obj: PObj; XInc, YInc: Integer; PanelType: Word): Boolean;
  58 function  g_Obj_StayOnStep(Obj: PObj): Boolean;
  59 procedure g_Obj_Push(Obj: PObj; VelX, VelY: Integer);
  60 procedure g_Obj_PushA(Obj: PObj; Vel: Integer; Angle: SmallInt);
  61 procedure g_Obj_SetSpeed(Obj: PObj; s: Integer);
  62 function  z_dec(a, b: Integer): Integer;
  63 function  z_fdec(a, b: Double): Double;
  64
  65 var
  66   gMon: Boolean = False;
  67
  68 implementation
  69
  70 uses
  71   g_map, g_basic, Math, g_player, g_console, SysUtils,
  72   g_sound, g_gfx, MAPDEF, g_monsters, g_game, BinEditor;
  73
  74 function g_Obj_StayOnStep(Obj: PObj): Boolean;
  75 begin
  76   Result := not g_Map_CollidePanel(Obj^.X+Obj^.Rect.X, Obj^.Y+Obj^.Rect.Y+Obj^.Rect.Height-1,
  77                                    Obj^.Rect.Width, 1,
  78                                    PANEL_STEP, False)
  79             and g_Map_CollidePanel(Obj^.X+Obj^.Rect.X, Obj^.Y+Obj^.Rect.Y+Obj^.Rect.Height,
  80                                    Obj^.Rect.Width, 1,
  81                                    PANEL_STEP, False);
  82 end;
  83
  84 function CollideLiquid(Obj: PObj; XInc, YInc: Integer): Boolean;
  85 begin
  86   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
  87                                Obj^.Rect.Width, Obj^.Rect.Height*2 div 3,
  88                                PANEL_WATER or PANEL_ACID1 or PANEL_ACID2, False);
  89 end;
  90
  91 function CollideLift(Obj: PObj; XInc, YInc: Integer): Integer;
  92 begin
  93   if g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
  94                         Obj^.Rect.Width, Obj^.Rect.Height,
  95                         PANEL_LIFTUP, False) then
  96     Result := -1
  97   else if g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
  98                           Obj^.Rect.Width, Obj^.Rect.Height,
  99                           PANEL_LIFTDOWN, False) then
 100     Result := 1
 101   else
 102     Result := 0;
 103 end;
 104
 105 function CollideHorLift(Obj: PObj; XInc, YInc: Integer): Integer;
 106 var
 107   left, right: Boolean;
 108 begin
 109   left := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
 110                              Obj^.Rect.Width, Obj^.Rect.Height,
 111                              PANEL_LIFTLEFT, False);
 112   right := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
 113                              Obj^.Rect.Width, Obj^.Rect.Height,
 114                              PANEL_LIFTRIGHT, False);
 115   if left and not right then
 116     Result := -1
 117   else if right and not left then
 118     Result := 1
 119   else
 120     Result := 0;
 121 end;
 122
 123 function CollidePlayers(_Obj: PObj; XInc, YInc: Integer): Boolean;
 124 var
 125   a: Integer;
 126 begin
 127   Result := False;
 128
 129   if gPlayers = nil then
 130     Exit;
 131
 132   for a := 0 to High(gPlayers) do
 133     if gPlayers[a] <> nil then
 134       with gPlayers[a] do
 135         if Live and
 136            g_Collide(GameX+PLAYER_RECT.X, GameY+PLAYER_RECT.Y,
 137                      PLAYER_RECT.Width, PLAYER_RECT.Height,
 138                      _Obj^.X+_Obj^.Rect.X+XInc, _Obj^.Y+_Obj^.Rect.Y+YInc,
 139                      _Obj^.Rect.Width, _Obj^.Rect.Height) then
 140         begin
 141           Result := True;
 142           Exit;
 143         end;
 144 end;
 145
 146 function CollideMonsters(Obj: PObj; XInc, YInc: Integer): Boolean;
 147 var
 148   a: Integer;
 149 begin
 150   Result := False;
 151
 152   if gMonsters = nil then
 153     Exit;
 154
 155   for a := 0 to High(gMonsters) do
 156     if gMonsters[a] <> nil then
 157       if gMonsters[a].Live and
 158          gMonsters[a].Collide(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj^.Rect.Y+YInc,
 159                               Obj^.Rect.Width, Obj^.Rect.Height) then
 160       begin
 161         Result := True;
 162         Exit;
 163       end;
 164 end;
 165
 166 function Blocked(Obj: PObj; XInc, YInc: Integer): Boolean;
 167 begin
 168   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 169                                Obj^.Rect.Width, Obj^.Rect.Height,
 170                                PANEL_BLOCKMON, False);
 171 end;
 172
 173 function g_Obj_CollideLevel(Obj: PObj; XInc, YInc: Integer): Boolean;
 174 begin
 175   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 176                                Obj^.Rect.Width, Obj^.Rect.Height,
 177                                PANEL_WALL, False);
 178 end;
 179
 180 function g_Obj_CollideStep(Obj: PObj; XInc, YInc: Integer): Boolean;
 181 begin
 182   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 183                                Obj^.Rect.Width, Obj^.Rect.Height,
 184                                PANEL_STEP, False);
 185 end;
 186
 187 function g_Obj_CollideWater(Obj: PObj; XInc, YInc: Integer): Boolean;
 188 begin
 189   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 190                                Obj^.Rect.Width, Obj^.Rect.Height,
 191                                PANEL_WATER, False);
 192 end;
 193
 194 function g_Obj_CollideLiquid(Obj: PObj; XInc, YInc: Integer): Boolean;
 195 begin
 196   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 197                                Obj^.Rect.Width, Obj^.Rect.Height,
 198                                PANEL_WATER or PANEL_ACID1 or PANEL_ACID2, False);
 199 end;
 200
 201 function g_Obj_CollidePanel(Obj: PObj; XInc, YInc: Integer; PanelType: Word): Boolean;
 202 begin
 203   Result := g_Map_CollidePanel(Obj^.X+Obj^.Rect.X+XInc, Obj^.Y+Obj.Rect.Y+YInc,
 204                                Obj^.Rect.Width, Obj^.Rect.Height,
 205                                PanelType, False);
 206 end;
 207
 208 procedure g_Obj_Splash(Obj: PObj; Color: Byte);
 209 var
 210   MaxVel: Integer;
 211 begin
 212   MaxVel := Max(Abs(Obj^.Vel.X), Abs(Obj^.Vel.Y));
 213   if MaxVel > 4 then begin
 214     if MaxVel < 10 then
 215       g_Sound_PlayExAt('SOUND_GAME_BULK1', Obj^.X, Obj^.Y)
 216     else
 217       g_Sound_PlayExAt('SOUND_GAME_BULK2', Obj^.X, Obj^.Y);
 218   end;
 219
 220   g_GFX_Water(Obj^.X+Obj^.Rect.X+(Obj^.Rect.Width div 2),
 221               Obj^.Y+Obj^.Rect.Y+(Obj^.Rect.Height div 2),
 222               Min(5*(Abs(Obj^.Vel.X)+Abs(Obj^.Vel.Y)), 50),
 223               -Obj^.Vel.X, -Obj^.Vel.Y,
 224               Obj^.Rect.Width, 16, Color);
 225 end;
 226
 227 function move(Obj: PObj; dx, dy: Integer; ClimbSlopes: Boolean): Word;
 228 var
 229   i: Integer;
 230   sx, sy: ShortInt;
 231   st: Word;
 232
 233   procedure slope(s: Integer);
 234   var
 235     i: Integer;
 236   begin
 237     i := 0;
 238     while g_Obj_CollideLevel(Obj, sx, 0) and (i < 4) do
 239     begin
 240       Obj^.Y := Obj^.Y + s;
 241       Inc(i);
 242     end;
 243     Obj^.X := Obj^.X + sx;
 244   end;
 245
 246   function movex(): Boolean;
 247   begin
 248     Result := False;
 249
 250   // Åñëè ìîíñòðó øàãíóòü â ñòîðîíó, à òàì áëîêìîí:
 251     if gMon and not WordBool(st and MOVE_BLOCK) then
 252       if Blocked(Obj, sx, 0) then
 253         st := st or MOVE_BLOCK;
 254
 255   // Åñëè øàãíóòü â ñòîðîíó, à òàì ñòåíà => øàãàòü íåëüçÿ:
 256     if g_Obj_CollideLevel(Obj, sx, 0) then
 257       begin
 258         if ClimbSlopes and (Abs(dy) < 2) then
 259           begin
 260             Result := True;
 261             if (not g_Obj_CollideLevel(Obj, sx, -12)) // çàáèðàåìñÿ íà 12 ïèêñåëåé âëåâî/âïðàâî
 262             and g_Obj_CollidePanel(Obj, 0, 1, PANEL_WALL or PANEL_STEP) // òîëüêî åñëè åñòü çåìëÿ ïîä íîãàìè
 263             then
 264               slope(-1)
 265             else
 266               begin
 267                 Result := False;
 268                 st := st or MOVE_HITWALL;
 269               end;
 270           end
 271           else
 272             st := st or MOVE_HITWALL;
 273       end
 274     else // Òàì ñòåíû íåò
 275       begin
 276         if CollideLiquid(Obj, sx, 0) then
 277           begin // Åñëè øàãíóòü â ñòîðîíó, à òàì òåïåðü æèäêîñòü
 278             if not WordBool(st and MOVE_INWATER) then
 279               st := st or MOVE_HITWATER;
 280           end
 281         else // Åñëè øàãíóòü â ñòîðîíó, à òàì óæå íåò æèäêîñòè
 282           if WordBool(st and MOVE_INWATER) then
 283             st := st or MOVE_HITAIR;
 284
 285       // Øàã:
 286         Obj^.X := Obj^.X + sx;
 287         Result := True;
 288       end;
 289   end;
 290
 291   function movey(): Boolean;
 292   begin
 293     Result := False;
 294
 295   // Åñëè ìîíñòðó øàãíóòü ïî âåðòèêàëè, à òàì áëîêìîí:
 296     if gMon and not WordBool(st and MOVE_BLOCK) then
 297       if Blocked(Obj, 0, sy) then
 298         st := st or MOVE_BLOCK;
 299
 300   // Åñëè øàãíóòü â ïî âåðòèêàëè, à òàì ñòåíà => øàãàòü íåëüçÿ:
 301   // Èëè åñëè øàãíóòü âíèç, à òàì ñòóïåíü => øàãàòü íåëüçÿ:
 302     if g_Obj_CollideLevel(Obj, 0, sy) or
 303        ((sy > 0) and g_Obj_StayOnStep(Obj)) then
 304       begin
 305         if sy > 0 then
 306           st := st or MOVE_HITLAND
 307         else
 308           st := st or MOVE_HITCEIL;
 309       end
 310     else // Òàì ñòåíû íåò. È ñòóïåíè ñíèçó òîæå íåò
 311       begin
 312         if CollideLiquid(Obj, 0, sy) then
 313           begin // Åñëè øàãíóòü â ïî âåðòèêàëè, à òàì òåïåðü æèäêîñòü
 314             if not WordBool(st and MOVE_INWATER) then
 315               st := st or MOVE_HITWATER;
 316           end
 317         else // Åñëè øàãíóòü â ïî âåðòèêàëè, à òàì óæå íåò æèäêîñòè
 318           if WordBool(st and MOVE_INWATER) then
 319             st := st or MOVE_HITAIR;
 320
 321       // Øàã:
 322         Obj^.Y := Obj^.Y + sy;
 323
 324         Result := True;
 325       end;
 326   end;
 327
 328 begin
 329   st := MOVE_NONE;
 330
 331 // Îáúåêò â æèäêîñòè:
 332   if CollideLiquid(Obj, 0, 0) then
 333     st := st or MOVE_INWATER;
 334
 335 // Ìîíñòð â áëîêìîíå:
 336   if gMon then
 337     if Blocked(Obj, 0, 0) then
 338       st := st or MOVE_BLOCK;
 339
 340 // Äâèãàòüñÿ íå íàäî:
 341   if (dx = 0) and (dy = 0) then
 342   begin
 343     Result := st;
 344     Exit;
 345   end;
 346
 347   sx := g_basic.Sign(dx);
 348   sy := g_basic.Sign(dy);
 349   dx := Abs(dx);
 350   dy := Abs(dy);
 351
 352   for i := 1 to dx do
 353     if not movex() then
 354       Break;
 355
 356   for i := 1 to dy do
 357     if not movey() then
 358       Break;
 359
 360   Result := st;
 361 end;
 362
 363 procedure g_Obj_Init(Obj: PObj);
 364 begin
 365   ZeroMemory(Obj, SizeOf(TObj));
 366 end;
 367
 368 function g_Obj_Move(Obj: PObj; Fallable: Boolean; Splash: Boolean; ClimbSlopes: Boolean = False): Word;
 369 var
 370   xv, yv, dx, dy: Integer;
 371   inwater: Boolean;
 372   c: Boolean;
 373   wtx: DWORD;
 374 label
 375   _move;
 376 begin
 377 // Ëèìèòû íà ñêîðîñòü è óñêîðåíèå
 378   if      Obj^.Vel.X < -LIMIT_VEL then Obj^.Vel.X := -LIMIT_VEL
 379   else if Obj^.Vel.X >  LIMIT_VEL then Obj^.Vel.X :=  LIMIT_VEL;
 380   if      Obj^.Vel.Y < -LIMIT_VEL then Obj^.Vel.Y := -LIMIT_VEL
 381   else if Obj^.Vel.Y >  LIMIT_VEL then Obj^.Vel.Y :=  LIMIT_VEL;
 382   if      Obj^.Accel.X < -LIMIT_ACCEL then Obj^.Accel.X := -LIMIT_ACCEL
 383   else if Obj^.Accel.X >  LIMIT_ACCEL then Obj^.Accel.X :=  LIMIT_ACCEL;
 384   if      Obj^.Accel.Y < -LIMIT_ACCEL then Obj^.Accel.Y := -LIMIT_ACCEL
 385   else if Obj^.Accel.Y >  LIMIT_ACCEL then Obj^.Accel.Y :=  LIMIT_ACCEL;
 386
 387 // Âûëåòåë çà íèæíþþ ãðàíèöó êàðòû:
 388   if Obj^.Y > gMapInfo.Height+128 then
 389   begin
 390     Result := MOVE_FALLOUT;
 391     Exit;
 392   end;
 393
 394 // Ìåíÿåì ñêîðîñòü è óñêîðåíèå òîëüêî ïî ÷åòíûì êàäðàì:
 395   c := gTime mod (GAME_TICK*2) <> 0;
 396
 397   if c then
 398     goto _move;
 399
 400   case CollideLift(Obj, 0, 0) of
 401     -1: //up
 402       begin
 403         Obj^.Vel.Y := Obj^.Vel.Y - 1; // Ëèôò ââåðõ
 404         if Obj^.Vel.Y < -5 then
 405           Obj^.Vel.Y := Obj^.Vel.Y + 1;
 406       end;
 407
 408     1: //down
 409       begin
 410         if Obj^.Vel.Y > 5 then
 411           Obj^.Vel.Y := Obj^.Vel.Y - 1;
 412         Obj^.Vel.Y := Obj^.Vel.Y + 1; // Ãðàâèòàöèÿ èëè ëèôò âíèç
 413       end;
 414
 415     0:
 416       begin
 417         if Fallable then
 418           Obj^.Vel.Y := Obj^.Vel.Y + 1; // Ãðàâèòàöèÿ
 419         if Obj^.Vel.Y > MAX_YV then
 420           Obj^.Vel.Y := Obj^.Vel.Y - 1;
 421       end;
 422   end;
 423
 424   case CollideHorLift(Obj, 0, 0) of
 425     -1: //left
 426       begin
 427         Obj^.Vel.X := Obj^.Vel.X - 3; // Ëèôò ââåðõ
 428         if Obj^.Vel.X < -9 then
 429           Obj^.Vel.X := Obj^.Vel.X + 3;
 430       end;
 431
 432     1: //right
 433       begin
 434         Obj^.Vel.X := Obj^.Vel.X + 3;
 435         if Obj^.Vel.X > 9 then
 436           Obj^.Vel.X := Obj^.Vel.X - 3;
 437       end;
 438     // 0 is not needed here
 439   end;
 440
 441   inwater := CollideLiquid(Obj, 0, 0);
 442   if inwater then
 443   begin
 444     xv := Abs(Obj^.Vel.X)+1;
 445     if xv > 5 then
 446       Obj^.Vel.X := z_dec(Obj^.Vel.X, (xv div 2)-2);
 447
 448     yv := Abs(Obj^.Vel.Y)+1;
 449     if yv > 5 then
 450       Obj^.Vel.Y := z_dec(Obj^.Vel.Y, (yv div 2)-2);
 451
 452     xv := Abs(Obj^.Accel.X)+1;
 453     if xv > 5 then
 454       Obj^.Accel.X := z_dec(Obj^.Accel.X, (xv div 2)-2);
 455
 456     yv := Abs(Obj^.Accel.Y)+1;
 457     if yv > 5 then
 458       Obj^.Accel.Y := z_dec(Obj^.Accel.Y, (yv div 2)-2);
 459   end;
 460
 461 // Óìåíüøàåì ïðèáàâêó ê ñêîðîñòè:
 462   Obj^.Accel.X := z_dec(Obj^.Accel.X, 1);
 463   Obj^.Accel.Y := z_dec(Obj^.Accel.Y, 1);
 464
 465 _move:
 466
 467   xv := Obj^.Vel.X + Obj^.Accel.X;
 468   yv := Obj^.Vel.Y + Obj^.Accel.Y;
 469
 470   dx := xv;
 471   dy := yv;
 472
 473   Result := move(Obj, dx, dy, ClimbSlopes);
 474
 475 // Áðûçãè (åñëè íóæíû):
 476   if Splash then
 477     if WordBool(Result and MOVE_HITWATER) then
 478     begin
 479       wtx := g_Map_CollideLiquid_Texture(Obj^.X+Obj^.Rect.X,
 480                                          Obj^.Y+Obj^.Rect.Y,
 481                                          Obj^.Rect.Width,
 482                                          Obj^.Rect.Height*2 div 3);
 483       case wtx of
 484         TEXTURE_SPECIAL_WATER:
 485           g_Obj_Splash(Obj, 3);
 486         TEXTURE_SPECIAL_ACID1:
 487           g_Obj_Splash(Obj, 2);
 488         TEXTURE_SPECIAL_ACID2:
 489           g_Obj_Splash(Obj, 1);
 490         TEXTURE_NONE:
 491           ;
 492         else
 493           g_Obj_Splash(Obj, 0);
 494       end;
 495     end;
 496
 497 // Ìåíÿåì ñêîðîñòü è óñêîðåíèå òîëüêî ïî ÷åòíûì êàäðàì:
 498   if c then
 499     Exit;
 500
 501 // Âðåçàëèñü â ñòåíó - ñòîï:
 502   if WordBool(Result and MOVE_HITWALL) then
 503   begin
 504     Obj^.Vel.X := 0;
 505     Obj^.Accel.X := 0;
 506   end;
 507
 508 // Âðåçàëèñü â ïîë èëè ïîòîëîê - ñòîï:
 509   if WordBool(Result and (MOVE_HITCEIL or MOVE_HITLAND)) then
 510   begin
 511     Obj^.Vel.Y := 0;
 512     Obj^.Accel.Y := 0;
 513   end;
 514 end;
 515
 516 function g_Obj_Collide(Obj1, Obj2: PObj): Boolean;
 517 begin
 518   Result := g_Collide(Obj1^.X+Obj1^.Rect.X, Obj1^.Y+Obj1^.Rect.Y,
 519                       Obj1^.Rect.Width, Obj1^.Rect.Height,
 520                       Obj2^.X+Obj2^.Rect.X, Obj2^.Y+Obj2^.Rect.Y,
 521                       Obj2^.Rect.Width, Obj2^.Rect.Height);
 522 end;
 523
 524 function g_Obj_Collide(X, Y: Integer; Width, Height: Word; Obj: PObj): Boolean;
 525 begin
 526   Result := g_Collide(X, Y,
 527                       Width, Height,
 528                       Obj^.X+Obj^.Rect.X, Obj^.Y+Obj^.Rect.Y,
 529                       Obj^.Rect.Width, Obj^.Rect.Height);
 530 end;
 531
 532 function g_Obj_CollidePoint(X, Y: Integer; Obj: PObj): Boolean;
 533 begin
 534   Result := g_CollidePoint(X, Y, Obj^.X+Obj^.Rect.X, Obj^.Y+Obj^.Rect.Y,
 535                            Obj^.Rect.Width, Obj^.Rect.Height);
 536 end;
 537
 538 procedure g_Obj_Push(Obj: PObj; VelX, VelY: Integer);
 539 begin
 540   Obj^.Vel.X := Obj^.Vel.X + VelX;
 541   Obj^.Vel.Y := Obj^.Vel.Y + VelY;
 542 end;
 543
 544 procedure g_Obj_PushA(Obj: PObj; Vel: Integer; Angle: SmallInt);
 545 var
 546   s, c: Extended;
 547
 548 begin
 549   SinCos(DegToRad(-Angle), s, c);
 550
 551   Obj^.Vel.X := Obj^.Vel.X + Round(Vel*c);
 552   Obj^.Vel.Y := Obj^.Vel.Y + Round(Vel*s);
 553 end;
 554
 555 procedure g_Obj_SetSpeed(Obj: PObj; s: Integer);
 556 var
 557   m, vx, vy: Integer;
 558 begin
 559   vx := Obj^.Vel.X;
 560   vy := Obj^.Vel.Y;
 561
 562   m := Max(Abs(vx), Abs(vy));
 563   if m = 0 then
 564     m := 1;
 565
 566   Obj^.Vel.X := (vx*s) div m;
 567   Obj^.Vel.Y := (vy*s) div m;
 568 end;
 569
 570 function z_dec(a, b: Integer): Integer;
 571 begin
 572 // Ïðèáëèæàåì a ê 0 íà b åäèíèö:
 573   if Abs(a) < b then
 574     Result := 0
 575   else
 576     if a > 0 then
 577       Result := a - b
 578     else
 579       if a < 0 then
 580         Result := a + b
 581       else // a = 0
 582         Result := 0;
 583 end;
 584
 585 function z_fdec(a, b: Double): Double;
 586 begin
 587 // Ïðèáëèæàåì a ê 0.0 íà b åäèíèö:
 588   if Abs(a) < b then
 589     Result := 0.0
 590   else
 591     if a > 0.0 then
 592       Result := a - b
 593     else
 594       if a < 0.0 then
 595         Result := a + b
 596       else // a = 0.0
 597         Result := 0.0;
 598 end;
 599
 600 end.