(*

 * Hedgewars, a worms-like game

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

 *

 * Distributed under the terms of the BSD-modified licence:

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * with the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote products

 *    derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO

 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *)

unit uCollisions;

interface

uses uGears;

{$INCLUDE options.inc}

type TCollisionEntry = record

                       X, Y, HWidth, HHeight: integer;

                       cGear: PGear;

                       end;

procedure AddGearCR(Gear: PGear);

procedure UpdateCR(NewX, NewY: integer; Index: Longword);

procedure DeleteCR(Gear: PGear);

function  CheckGearsCollision(Gear: PGear; Dir: integer; forX: boolean): PGear;

function  HHTestCollisionYwithGear(Gear: PGear; Dir: integer): boolean;

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

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

function TestCollisionXwithXYShift(Gear: PGear; ShiftX, ShiftY: integer; Dir: integer): boolean;

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

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

implementation

uses uMisc, uConsts, uLand;

const MAXRECTSINDEX = 255;

var Count: Longword = 0;

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

procedure AddGearCR(Gear: PGear);

begin

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

with crects[Count] do

     begin

     X:= round(Gear.X);

     Y:= round(Gear.Y);

     HWidth:= Gear.HalfWidth;

     HHeight:= Gear.HalfHeight;

     cGear:= Gear

     end;

Gear.CollIndex:= Count;

inc(Count)

end;

procedure UpdateCR(NewX, NewY: integer; Index: Longword);

begin

with crects[Index] do

     begin

     X:= NewX;

     Y:= NewY

     end

end;

procedure DeleteCR(Gear: PGear);

begin

if Gear.CollIndex < Pred(Count) then

   begin

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

   crects[Gear.CollIndex].cGear.CollIndex:= Gear.CollIndex

   end;

Gear.CollIndex:= High(Longword);

dec(Count)

end;

function CheckGearsCollision(Gear: PGear; Dir: integer; forX: boolean): PGear;

var x1, x2, y1, y2: integer;

    i: Longword;

begin

Result:= nil;

if Count = 0 then exit;

x1:= round(Gear.X);

y1:= round(Gear.Y);

if forX then

   begin

   x1:= x1 + Dir*Gear.HalfWidth;

   x2:= x1;

   y2:= y1 + Gear.HalfHeight - 1;

   y1:= y1 - Gear.HalfHeight + 1

   end else

   begin

   y1:= y1 + Dir*Gear.HalfHeight;

   y2:= y1;

   x2:= x1 + Gear.HalfWidth - 1;

   x1:= x1 - Gear.HalfWidth + 1

   end;

for i:= 0 to Pred(Count) do

   with crects[i] do

      if  (Gear.CollIndex <> i)

         and (x1 <= X + HWidth)

         and (x2 >= X - HWidth)

         and (y1 <= Y + HHeight)

         and (y2 >= Y - HHeight) then

             begin

             Result:= crects[i].cGear;

             exit

             end;

end;

function HHTestCollisionYwithGear(Gear: PGear; Dir: integer): boolean;

var x, y, i: integer;

begin

Result:= false;

y:= round(Gear.Y);

if Dir < 0 then y:= y - Gear.HalfHeight

           else y:= y + Gear.HalfHeight;

if ((y - Dir) and $FFFFFC00) = 0 then

   begin

   x:= round(Gear.X);

   if (((x - Gear.HalfWidth) and $FFFFF800) = 0)and(Land[y - Dir, x - Gear.HalfWidth] <> 0)

    or(((x + Gear.HalfWidth) and $FFFFF800) = 0)and(Land[y - Dir, x + Gear.HalfWidth] <> 0) then

      begin

      Result:= true;

      exit

      end

    end;

if (y and $FFFFFC00) = 0 then

   begin

   x:= round(Gear.X) - Gear.HalfWidth + 1;

   i:= x + Gear.HalfWidth * 2 - 2;

   repeat

     if (x and $FFFFF800) = 0 then Result:= Land[y, x]<>0;

     inc(x)

   until (x > i) or Result;

   if Result then exit;

   Result:= CheckGearsCollision(Gear, Dir, false) <> nil

   end

end;

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

var x, y, i: integer;

begin

Result:= false;

x:= round(Gear.X);

if Dir < 0 then x:= x - Gear.HalfWidth

           else x:= x + Gear.HalfWidth;

if (x and $FFFFF800) = 0 then

   begin

   y:= round(Gear.Y) - Gear.HalfHeight + 1; {*}

   i:= y + Gear.HalfHeight * 2 - 2;         {*}

   repeat

     if (y and $FFFFFC00) = 0 then Result:= Land[y, x]<>0;

     inc(y)

   until (y > i) or Result;

   if Result then exit;

   Result:= CheckGearsCollision(Gear, Dir, true) <> nil

   end

end;

function TestCollisionXwithXYShift(Gear: PGear; ShiftX, ShiftY: integer; Dir: integer): boolean;

begin

Gear.X:= Gear.X + ShiftX;

Gear.Y:= Gear.Y + ShiftY;

Result:= TestCollisionXwithGear(Gear, Dir);

Gear.X:= Gear.X - ShiftX;

Gear.Y:= Gear.Y - ShiftY

end;

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

var x, y, i: integer;

begin

Result:= false;

y:= round(Gear.Y);

if Dir < 0 then y:= y - Gear.HalfHeight

           else y:= y + Gear.HalfHeight;

if (y and $FFFFFC00) = 0 then

   begin

   x:= round(Gear.X) - Gear.HalfWidth + 1;    {*}

   i:= x + Gear.HalfWidth * 2 - 2;            {*}

   repeat

     if (x and $FFFFF800) = 0 then Result:= Land[y, x]<>0;

     inc(x)

   until (x > i) or Result;

   if Result then exit;

   Result:= CheckGearsCollision(Gear, Dir, false) <> nil;

   end

end;

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

var x, y, i: integer;

begin

Result:= false;

y:= round(Gear.Y);

if Dir < 0 then y:= y - Gear.HalfHeight

           else y:= y + Gear.HalfHeight;

if (y and $FFFFFC00) = 0 then

   begin

   x:= round(Gear.X) - Gear.HalfWidth + 1;    {*}

   i:= x + Gear.HalfWidth * 2 - 2;            {*}

   repeat

     if (x and $FFFFF800) = 0 then Result:= Land[y, x]<>0;

     inc(x)

   until (x > i) or Result;

   end

end;

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

begin

Gear.X:= Gear.X + ShiftX;

Gear.Y:= Gear.Y + ShiftY;

Result:= TestCollisionYwithGear(Gear, Dir);

Gear.X:= Gear.X - ShiftX;

Gear.Y:= Gear.Y - ShiftY

end;

end.