(*

 * Hedgewars, a worms-like game

 * Copyright (c) 2005-2007 Andrey Korotaev <unC0Rr@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 of the License

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

 *)

unit uCollisions;

interface

uses uGears, uFloat;

{$INCLUDE options.inc}

const cMaxGearArrayInd = 255;

type PGearArray = ^TGearArray;

     TGearArray = record

                  ar: array[0..cMaxGearArrayInd] of PGear;

                  Count: Longword

                  end;

procedure AddGearCI(Gear: PGear);

procedure DeleteCI(Gear: PGear);

function CheckGearsCollision(Gear: PGear): PGearArray;

function TestCollisionXwithGear(Gear: PGear; Dir: LongInt): boolean;

function TestCollisionYwithGear(Gear: PGear; Dir: LongInt): boolean;

function TestCollisionY(Gear: PGear; Dir: LongInt): boolean;

function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): boolean;

implementation

uses uMisc, uConsts, uLand, uLandGraphics;

type TCollisionEntry = record

                       X, Y, Radius: LongInt;

                       cGear: PGear;

                       end;

const MAXRECTSINDEX = 255;

var Count: Longword = 0;

    cinfos: array[0..MAXRECTSINDEX] of TCollisionEntry;

    ga: TGearArray;

procedure AddGearCI(Gear: PGear);

begin

if Gear^.CollIndex < High(Longword) then exit;

TryDo(Count <= MAXRECTSINDEX, 'Collision rects array overflow', true);

with cinfos[Count] do

     begin

     X:= hwRound(Gear^.X);

     Y:= hwRound(Gear^.Y);

     Radius:= Gear^.Radius;

     FillRoundInLand(X, Y, Radius-1, $FF);

     cGear:= Gear

     end;

Gear^.CollIndex:= Count;

inc(Count)

end;

procedure DeleteCI(Gear: PGear);

begin

if Gear^.CollIndex < Count then

   begin

   with cinfos[Gear^.CollIndex] do FillRoundInLand(X, Y, Radius-1, 0);

   cinfos[Gear^.CollIndex]:= cinfos[Pred(Count)];

   cinfos[Gear^.CollIndex].cGear^.CollIndex:= Gear^.CollIndex;

   Gear^.CollIndex:= High(Longword);

   dec(Count)

   end;

end;

function CheckGearsCollision(Gear: PGear): PGearArray;

var mx, my: LongInt;

    i: Longword;

    Result: PGearArray;

begin

Result:= @ga;

ga.Count:= 0;

if Count = 0 then exit;

mx:= hwRound(Gear^.X);

my:= hwRound(Gear^.Y);

for i:= 0 to Pred(Count) do

   with cinfos[i] do

      if (Gear <> cGear) and

         (sqrt(sqr(mx - x) + sqr(my - y)) <= Radius + Gear^.Radius) then

             begin

             ga.ar[ga.Count]:= cinfos[i].cGear;

             inc(ga.Count)

             end;

CheckGearsCollision:= Result

end;

function TestCollisionXwithGear(Gear: PGear; Dir: LongInt): boolean;

var x, y, i: LongInt;

begin

x:= hwRound(Gear^.X);

if Dir < 0 then x:= x - Gear^.Radius

           else x:= x + Gear^.Radius;

if (x and $FFFFF800) = 0 then

   begin

   y:= hwRound(Gear^.Y) - Gear^.Radius + 1;

   i:= y + Gear^.Radius * 2 - 2;

   repeat

     if (y and $FFFFFC00) = 0 then

        if Land[y, x] <> 0 then exit(true);

     inc(y)

   until (y > i);

   end;

TestCollisionXwithGear:= false

end;

begin

Gear^.X:= Gear^.X + ShiftX;

TestCollisionXwithXYShift:= TestCollisionXwithGear(Gear, Dir);

Gear^.X:= Gear^.X - ShiftX;

end;

function TestCollisionYwithGear(Gear: PGear; Dir: LongInt): boolean;

var x, y, i: LongInt;

begin

y:= hwRound(Gear^.Y);

if Dir < 0 then y:= y - Gear^.Radius

           else y:= y + Gear^.Radius;

if (y and $FFFFFC00) = 0 then

   begin

   x:= hwRound(Gear^.X) - Gear^.Radius + 1;

   i:= x + Gear^.Radius * 2 - 2;

   repeat

     if (x and $FFFFF800) = 0 then

        if Land[y, x] <> 0 then exit(true);

     inc(x)

   until (x > i);

   end;

TestCollisionYwithGear:= false

end;

function TestCollisionY(Gear: PGear; Dir: LongInt): boolean;

var x, y, i: LongInt;

begin

y:= hwRound(Gear^.Y);

if Dir < 0 then y:= y - Gear^.Radius

           else y:= y + Gear^.Radius;

if (y and $FFFFFC00) = 0 then

   begin

   x:= hwRound(Gear^.X) - Gear^.Radius + 1;

   i:= x + Gear^.Radius * 2 - 2;

   repeat

     if (x and $FFFFF800) = 0 then

        if Land[y, x] = COLOR_LAND then exit(true);

     inc(x)

   until (x > i);

   end;

TestCollisionY:= false

end;

function TestCollisionYwithXYShift(Gear: PGear; ShiftX, ShiftY: LongInt; Dir: LongInt): boolean;

begin

TestCollisionYwithXYShift:= TestCollisionYwithGear(Gear, Dir);

end;

end.