unit uLandOutline;

interface

uses uConsts, SDLh, uFloat;

type TPixAr = record

              Count: Longword;

              ar: array[0..Pred(cMaxEdgePoints)] of TPoint;

              end;

procedure DrawEdge(var pa: TPixAr; Color: Longword);

procedure FillLand(x, y: LongInt);

procedure BezierizeEdge(var pa: TPixAr; Delta: hwFloat);

procedure RandomizePoints(var pa: TPixAr);

implementation

var Stack: record

           Count: Longword;

           points: array[0..8192] of record

                                     xl, xr, y, dir: LongInt;

                                     end

           end;

procedure Push(_xl, _xr, _y, _dir: LongInt);

begin

    TryDo(Stack.Count <= 8192, 'FillLand: stack overflow', true);

    _y:= _y + _dir;

    if (_y < 0) or (_y >= LAND_HEIGHT) then exit;

    with Stack.points[Stack.Count] do

            begin

            xl:= _xl;

            xr:= _xr;

            y:= _y;

            dir:= _dir

            end;

    inc(Stack.Count)

end;

procedure Pop(var _xl, _xr, _y, _dir: LongInt);

begin

    dec(Stack.Count);

    with Stack.points[Stack.Count] do

        begin

        _xl:= xl;

        _xr:= xr;

        _y:= y;

        _dir:= dir

        end

end;

procedure FillLand(x, y: LongInt);

var xl, xr, dir: LongInt;

begin

    Stack.Count:= 0;

    xl:= x - 1;

    xr:= x;

    Push(xl, xr, y, -1);

    Push(xl, xr, y,  1);

    dir:= 0;

    while Stack.Count > 0 do

        begin

        Pop(xl, xr, y, dir);

        while (xl > 0) and (Land[y, xl] <> 0) do dec(xl);

        while (xr < LAND_WIDTH - 1) and (Land[y, xr] <> 0) do inc(xr);

        while (xl < xr) do

            begin

            while (xl <= xr) and (Land[y, xl] = 0) do inc(xl);

            x:= xl;

            while (xl <= xr) and (Land[y, xl] <> 0) do

                begin

                Land[y, xl]:= 0;

                inc(xl)

                end;

            if x < xl then

                begin

                Push(x, Pred(xl), y, dir);

                Push(x, Pred(xl), y,-dir);

                end;

            end;

        end;

end;

procedure DrawEdge(var pa: TPixAr; Color: Longword);

var i: LongInt;

begin

    i:= 0;

    with pa do

        while i < LongInt(Count) - 1 do

            if (ar[i + 1].X = NTPX) then 

                inc(i, 2)

            else 

                begin

                DrawLine(ar[i].x, ar[i].y, ar[i + 1].x, ar[i + 1].y, Color);

                inc(i)

                end

end;

procedure Vector(p1, p2, p3: TPoint; var Vx, Vy: hwFloat);

var d1, d2, d: hwFloat;

begin

    Vx:= int2hwFloat(p1.X - p3.X);

    Vy:= int2hwFloat(p1.Y - p3.Y);

    d:= DistanceI(p2.X - p1.X, p2.Y - p1.Y);

    d1:= DistanceI(p2.X - p3.X, p2.Y - p3.Y);

    d2:= Distance(Vx, Vy);

    if d1 < d then d:= d1;

    if d2 < d then d:= d2;

    d:= d * _1div3;

    if d2.QWordValue = 0 then

        begin

        Vx:= _0;

        Vy:= _0

        end 

    else

        begin

        d2:= _1 / d2;

        Vx:= Vx * d2;

        Vy:= Vy * d2;

        Vx:= Vx * d;

        Vy:= Vy * d

        end

end;

procedure AddLoopPoints(var pa, opa: TPixAr; StartI, EndI: LongInt; Delta: hwFloat);

var i, pi, ni: LongInt;

    NVx, NVy, PVx, PVy: hwFloat;

    x1, x2, y1, y2: LongInt;

    tsq, tcb, t, r1, r2, r3, cx1, cx2, cy1, cy2: hwFloat;

    X, Y: LongInt;

begin

pi:= EndI;

i:= StartI;

ni:= Succ(StartI);

{$HINTS OFF}

Vector(opa.ar[pi], opa.ar[i], opa.ar[ni], NVx, NVy);

{$HINTS ON}

repeat

    inc(pi);

    if pi > EndI then pi:= StartI;

    inc(i);

    if i > EndI then i:= StartI;

    inc(ni);

    if ni > EndI then ni:= StartI;

    PVx:= NVx;

    PVy:= NVy;

    Vector(opa.ar[pi], opa.ar[i], opa.ar[ni], NVx, NVy);

    x1:= opa.ar[pi].x;

    y1:= opa.ar[pi].y;

    x2:= opa.ar[i].x;

    y2:= opa.ar[i].y;

    cx1:= int2hwFloat(x1) - PVx;

    cy1:= int2hwFloat(y1) - PVy;

    cx2:= int2hwFloat(x2) + NVx;

    cy2:= int2hwFloat(y2) + NVy;

    t:= _0;

    while t.Round = 0 do

          begin

          tsq:= t * t;

          tcb:= tsq * t;

          r1:= (_1 - t*3 + tsq*3 - tcb);

          r2:= (     t*3 - tsq*6 + tcb*3);

          r3:= (           tsq*3 - tcb*3);

          X:= hwRound(r1 * x1 + r2 * cx1 + r3 * cx2 + tcb * x2);

          Y:= hwRound(r1 * y1 + r2 * cy1 + r3 * cy2 + tcb * y2);

          t:= t + Delta;

          pa.ar[pa.Count].x:= X;

          pa.ar[pa.Count].y:= Y;

          inc(pa.Count);

          TryDo(pa.Count <= cMaxEdgePoints, 'Edge points overflow', true)

          end;

until i = StartI;

pa.ar[pa.Count].x:= opa.ar[StartI].X;

pa.ar[pa.Count].y:= opa.ar[StartI].Y;

inc(pa.Count)

end;

procedure BezierizeEdge(var pa: TPixAr; Delta: hwFloat);

var i, StartLoop: LongInt;

    opa: TPixAr;

begin

opa:= pa;

pa.Count:= 0;

i:= 0;

StartLoop:= 0;

while i < LongInt(opa.Count) do

    if (opa.ar[i + 1].X = NTPX) then

       begin

       AddLoopPoints(pa, opa, StartLoop, i, Delta);

       inc(i, 2);

       StartLoop:= i;

       pa.ar[pa.Count].X:= NTPX;

       pa.ar[pa.Count].Y:= 0;

       inc(pa.Count);

       end else inc(i)

end;

function CheckIntersect(V1, V2, V3, V4: TPoint): boolean;

var c1, c2, dm: LongInt;

begin

    dm:= (V4.y - V3.y) * (V2.x - V1.x) - (V4.x - V3.x) * (V2.y - V1.y);

    c1:= (V4.x - V3.x) * (V1.y - V3.y) - (V4.y - V3.y) * (V1.x - V3.x);

    if dm = 0 then exit(false);

    c2:= (V2.x - V3.x) * (V1.y - V3.y) - (V2.y - V3.y) * (V1.x - V3.x);

    if dm > 0 then

        begin

        if (c1 < 0) or (c1 > dm) then exit(false);

        if (c2 < 0) or (c2 > dm) then exit(false)

        end 

    else

        begin

        if (c1 > 0) or (c1 < dm) then exit(false);

        if (c2 > 0) or (c2 < dm) then exit(false)

        end;

    //AddFileLog('1  (' + inttostr(V1.x) + ',' + inttostr(V1.y) + ')x(' + inttostr(V2.x) + ',' + inttostr(V2.y) + ')');

    //AddFileLog('2  (' + inttostr(V3.x) + ',' + inttostr(V3.y) + ')x(' + inttostr(V4.x) + ',' + inttostr(V4.y) + ')');

    CheckIntersect:= true

end;

function CheckSelfIntersect(var pa: TPixAr; ind: Longword): boolean;

var i: Longword;

begin

    if (ind <= 0) or (ind >= Pred(pa.Count)) then exit(false);

    for i:= 1 to pa.Count - 3 do

        if (i <= ind - 1) or (i >= ind + 2) then

        begin

        if (i <> ind - 1) and

            CheckIntersect(pa.ar[ind], pa.ar[ind - 1], pa.ar[i], pa.ar[i - 1]) then exit(true);

        if (i <> ind + 2) and

            CheckIntersect(pa.ar[ind], pa.ar[ind + 1], pa.ar[i], pa.ar[i - 1]) then exit(true);

        end;

    CheckSelfIntersect:= false

end;

procedure RandomizePoints(var pa: TPixAr);

const cEdge = 55;

      cMinDist = 8;

var radz: array[0..Pred(cMaxEdgePoints)] of LongInt;

    i, k, dist, px, py: LongInt;

begin

    for i:= 0 to Pred(pa.Count) do

    begin

    radz[i]:= 0;

        with pa.ar[i] do

            if x <> NTPX then

            begin

            radz[i]:= Min(Max(x - cEdge, 0), Max(LAND_WIDTH - cEdge - x, 0));

            radz[i]:= Min(radz[i], Min(Max(y - cEdge, 0), Max(LAND_HEIGHT - cEdge - y, 0)));

            if radz[i] > 0 then

                for k:= 0 to Pred(i) do

                begin

                dist:= Max(abs(x - pa.ar[k].x), abs(y - pa.ar[k].y));

                radz[k]:= Max(0, Min((dist - cMinDist) div 2, radz[k]));

                radz[i]:= Max(0, Min(dist - radz[k] - cMinDist, radz[i]))

                end

            end;

    end;

    for i:= 0 to Pred(pa.Count) do

        with pa.ar[i] do

            if ((x and LAND_WIDTH_MASK) = 0) and ((y and LAND_HEIGHT_MASK) = 0) then

            begin

            px:= x;

            py:= y;

            x:= x + LongInt(GetRandom(7) - 3) * (radz[i] * 5 div 7) div 3;

            y:= y + LongInt(GetRandom(7) - 3) * (radz[i] * 5 div 7) div 3;

            if CheckSelfIntersect(pa, i) then

                begin

                x:= px;

                y:= py

                end;

            end

end;

end.