unit uLandGenTemplateBased;
interface

uses uLandTemplates;

procedure GenTemplated(var Template: TEdgeTemplate);

implementation
uses uVariables, uConsts, uFloat, uLandOutline, uLandUtils, uRandom, SDLh, math;


procedure SetPoints(var Template: TEdgeTemplate; var pa: TPixAr; fps: PPointArray);
var i: LongInt;
begin
    with Template do
        begin
        pa.Count:= BasePointsCount;
        for i:= 0 to pred(pa.Count) do
            begin
            pa.ar[i].x:= BasePoints^[i].x + LongInt(GetRandom(BasePoints^[i].w));
            if pa.ar[i].x <> NTPX then
                pa.ar[i].x:= pa.ar[i].x + ((LAND_WIDTH - Template.TemplateWidth) div 2);
            pa.ar[i].y:= BasePoints^[i].y + LongInt(GetRandom(BasePoints^[i].h)) + LAND_HEIGHT - LongInt(Template.TemplateHeight)
            end;

        if canMirror then
            if getrandom(2) = 0 then
                begin
                for i:= 0 to pred(BasePointsCount) do
                if pa.ar[i].x <> NTPX then
                    pa.ar[i].x:= LAND_WIDTH - 1 - pa.ar[i].x;
                for i:= 0 to pred(FillPointsCount) do
                    fps^[i].x:= LAND_WIDTH - 1 - fps^[i].x;
                end;

(*  Experiment in making this option more useful
     if ((not isNegative) and (cTemplateFilter = 4)) or
        (canFlip and (getrandom(2) = 0)) then
           begin
           for i:= 0 to pred(BasePointsCount) do
               begin
               pa.ar[i].y:= LAND_HEIGHT - 1 - pa.ar[i].y + (LAND_HEIGHT - TemplateHeight) * 2;
               if pa.ar[i].y > LAND_HEIGHT - 1 then
                   pa.ar[i].y:= LAND_HEIGHT - 1;
               end;
           for i:= 0 to pred(FillPointsCount) do
               begin
               FillPoints^[i].y:= LAND_HEIGHT - 1 - FillPoints^[i].y + (LAND_HEIGHT - TemplateHeight) * 2;
               if FillPoints^[i].y > LAND_HEIGHT - 1 then
                   FillPoints^[i].y:= LAND_HEIGHT - 1;
               end;
           end;
     end
*)
// template recycling.  Pull these off the floor a bit
    if (not isNegative) and (cTemplateFilter = 4) then
        begin
        for i:= 0 to pred(BasePointsCount) do
            begin
            dec(pa.ar[i].y, 100);
            if pa.ar[i].y < 0 then
                pa.ar[i].y:= 0;
            end;
        for i:= 0 to pred(FillPointsCount) do
            begin
            dec(fps^[i].y, 100);
            if fps^[i].y < 0 then
                fps^[i].y:= 0;
            end;
        end;

    if (canFlip and (getrandom(2) = 0)) then
        begin
        for i:= 0 to pred(BasePointsCount) do
            pa.ar[i].y:= LAND_HEIGHT - 1 - pa.ar[i].y;
        for i:= 0 to pred(FillPointsCount) do
            fps^[i].y:= LAND_HEIGHT - 1 - fps^[i].y;
        end;
    end
end;


procedure Distort1(var Template: TEdgeTemplate; var pa: TPixAr);
var i: Longword;
begin
    for i:= 1 to Template.BezierizeCount do
        begin
        BezierizeEdge(pa, _0_5);
        RandomizePoints(pa);
        RandomizePoints(pa)
        end;
    for i:= 1 to Template.RandPassesCount do
        RandomizePoints(pa);
    BezierizeEdge(pa, _0_1);
end;

procedure FindPoint(si: LongInt; fillPointsCount: LongWord; var newPoint: TPoint; var pa: TPixAr);
const mapBorderMargin = 40;
    minDistance = 32; // adjust/parametrize this for different details size
var p1, p2, p4, fp, mp: TPoint;
    i, t1, t2, iy, ix, aqpb: LongInt;
    a, b, p, q: LongInt;
    dab, d, distL, distR: LongInt;
begin
    // [p1, p2] is the segment we're trying to divide
    p1:= pa.ar[si];
    p2:= pa.ar[si + 1];

    if p2.x = NTPX then
    // it is segment from last to first point, so need to find first point
    begin
        i:= si - 2;
        while (i >= 0) and (pa.ar[i].x <> NTPX) do
            dec(i);
        p2:= pa.ar[i + 1]
    end;

    // perpendicular vector
    a:= p2.y - p1.y;
    b:= p1.x - p2.x;
    dab:= DistanceI(a, b).Round;

    // its middle point
    mp.x:= (p1.x + p2.x) div 2;
    mp.y:= (p1.y + p2.y) div 2;

    // don't process too short segments or those which are too close to map borders
    if (p1.x = NTPX)
            or (dab < minDistance * 3) 
            or (mp.x < LongInt(leftX) + mapBorderMargin)
            or (mp.x > LongInt(rightX) - mapBorderMargin)
            or (mp.y < LongInt(topY) + mapBorderMargin)
            or (mp.y > LongInt(LAND_HEIGHT) - mapBorderMargin)
    then
    begin
        newPoint:= p1;
        exit;
    end;

    // find distances to map borders
    if a <> 0 then
    begin
        // left border
        iy:= (LongInt(leftX) + mapBorderMargin - mp.x) * b div a + mp.y;
        d:= DistanceI(mp.x - leftX - mapBorderMargin, mp.y - iy).Round;
        t1:= a * (mp.x - mapBorderMargin) + b * (mp.y - iy);
        if t1 > 0 then distL:= d else distR:= d;

        // right border
        iy:= (rightX - mapBorderMargin - mp.x) * b div a + mp.y;
        d:= DistanceI(mp.x - rightX + mapBorderMargin, mp.y - iy).Round;
        if t1 > 0 then distR:= d else distL:= d;
    end;

    if b <> 0 then
    begin
        // top border
        ix:= (LongInt(topY) + mapBorderMargin - mp.y) * a div b + mp.x;
        d:= DistanceI(mp.y - topY - mapBorderMargin, mp.x - ix).Round;
        t2:= b * (mp.y - mapBorderMargin) + a * (mp.x - ix);
        if t2 > 0 then distL:= min(d, distL) else distR:= min(d, distR);

        // bottom border
        ix:= (LAND_HEIGHT - mapBorderMargin - mp.y) * a div b + mp.x;
        d:= DistanceI(mp.y - LAND_HEIGHT + mapBorderMargin, mp.x - ix).Round;
        if t2 > 0 then distR:= min(d, distR) else distL:= min(d, distL);
    end;

    // now go through all other segments
    fp:= pa.ar[0];
    for i:= 0 to pa.Count - 2 do
        if pa.ar[i].x = NTPX then
            fp:= pa.ar[i + 1]
        else if (i <> si) then
        begin
        p4:= pa.ar[i + 1];
        if p4.x = NTPX then
            p4:= fp;

            // check if it intersects
            t1:= (mp.x - pa.ar[i].x) * b - a * (mp.y - pa.ar[i].y);
            t2:= (mp.x - p4.x) * b - a * (mp.y - p4.y);

            if (t1 > 0) <> (t2 > 0) then // yes it does, hard arith follows
            begin
                p:= p4.x - pa.ar[i].x;
                q:= p4.y - pa.ar[i].y;
                aqpb:= a * q - p * b;

                if (aqpb <> 0) then
                begin
                    // (ix; iy) is intersection point
                    iy:= ((Int64(pa.ar[i].x - mp.x) * b + Int64(mp.y) * a) * q - Int64(pa.ar[i].y) * p * b) div aqpb;
                    if abs(b) > abs(q) then
                        ix:= (iy - mp.y) * a div b + mp.x
                    else
                        ix:= (iy - pa.ar[i].y) * p div q + pa.ar[i].x;

                    d:= DistanceI(mp.y - iy, mp.x - ix).Round;
                    t1:= b * (mp.y - iy) + a * (mp.x - ix);
                    if t1 > 0 then distL:= min(d, distL) else distR:= min(d, distR);
                end;
            end;
        end;

    // go through all points, including fill points
    for i:= 0 to Pred(pa.Count + fillPointsCount) do
        // if this point isn't on current segment
        if (si <> i) and (i <> si + 1) and (pa.ar[i].x <> NTPX) then
        begin
            // also check intersection with rays through pa.ar[i] if this point is good
            t1:= (p1.x - pa.ar[i].x) * b - a * (p1.y - pa.ar[i].y);
            t2:= (p2.x - pa.ar[i].x) * b - a * (p2.y - pa.ar[i].y);
            if (t1 > 0) <> (t2 > 0) then
            begin
                // ray from p1
                p:= pa.ar[i].x - p1.x;
                q:= pa.ar[i].y - p1.y;
                aqpb:= a * q - p * b;

                if (aqpb <> 0) then
                begin
                    // (ix; iy) is intersection point
                    iy:= ((Int64(p1.x - mp.x) * b + Int64(mp.y) * a) * q - Int64(p1.y) * p * b) div aqpb;
                    if abs(b) > abs(q) then
                        ix:= (iy - mp.y) * a div b + mp.x
                    else
                        ix:= (iy - p1.y) * p div q + p1.x;

                    d:= DistanceI(mp.y - iy, mp.x - ix).Round;
                    t1:= b * (mp.y - iy) + a * (mp.x - ix);
                    if t1 > 0 then distL:= min(d, distL) else distR:= min(d, distR);
                end;

                // and ray from p2
                p:= pa.ar[i].x - p2.x;
                q:= pa.ar[i].y - p2.y;
                aqpb:= a * q - p * b;

                if (aqpb <> 0) then
                begin
                    // (ix; iy) is intersection point
                    iy:= ((Int64(p2.x - mp.x) * b + Int64(mp.y) * a) * q - Int64(p2.y) * p * b) div aqpb;
                    if abs(b) > abs(q) then
                        ix:= (iy - mp.y) * a div b + mp.x
                    else
                        ix:= (iy - p2.y) * p div q + p2.x;

                    d:= DistanceI(mp.y - iy, mp.x - ix).Round;
                    t2:= b * (mp.y - iy) + a * (mp.x - ix);
                    if t2 > 0 then distL:= min(d, distL) else distR:= min(d, distR);
                end;
            end;
        end;

    // don't move new point for more than length of initial segment
    // adjust/parametrize for more flat surfaces (try values 3/4, 1/2 of dab, or even 1/4)
    d:= dab;
    if distL > d then distL:= d;
    if distR > d then distR:= d;

    if distR + distL < minDistance * 2 + 10 then
    begin
        // limits are too narrow, just divide
        newPoint.x:= mp.x;
        newPoint.y:= mp.y;
    end
    else
    begin
        // select distance within [-distL; distR]
        d:= -distL + minDistance + LongInt(GetRandom(distR + distL - minDistance * 2));
        //d:= distR - minDistance;
        //d:= - distL + minDistance;

        // calculate new point
        newPoint.x:= mp.x + a * d div dab;
        newPoint.y:= mp.y + b * d div dab;
    end;
end;

procedure DivideEdges(fillPointsCount: LongWord; var pa: TPixAr);
var i, t: LongInt;
    newPoint: TPoint;
begin
    newPoint.x:= 0;
    newPoint.y:= 0;
    i:= 0;

    while i < pa.Count - 1 do
    begin
        FindPoint(i, fillPointsCount, newPoint, pa);

        if (newPoint.x <> pa.ar[i].x) or (newPoint.y <> pa.ar[i].y) then
        begin
            // point found, free a slot for it in array, don't forget to move appended fill points
            for t:= pa.Count + fillPointsCount downto i + 2 do
                pa.ar[t]:= pa.ar[t - 1];
            inc(pa.Count);
            pa.ar[i + 1]:= newPoint;
            inc(i)
        end;
        inc(i)
    end;
end;

procedure Distort2(var Template: TEdgeTemplate; fps: PPointArray; var pa: TPixAr);
var i: Longword;
begin
    // append fill points to ensure distortion won't move them to other side of segment
    for i:= 0 to pred(Template.FillPointsCount) do
        begin
            pa.ar[pa.Count + i].x:= fps^[i].x;
            pa.ar[pa.Count + i].y:= fps^[i].y;
        end;

    // divide while it divides
    repeat
        i:= pa.Count;
        DivideEdges(Template.FillPointsCount, pa)
    until i = pa.Count;

    // make it smooth
    BezierizeEdge(pa, _0_2);
end;


procedure GenTemplated(var Template: TEdgeTemplate);
var pa: TPixAr;
    i: Longword;
    y, x: Longword;
    fps: TPointArray;
begin
    fps:=Template.FillPoints^;
    ResizeLand(Template.TemplateWidth, Template.TemplateHeight);
    for y:= 0 to LAND_HEIGHT - 1 do
        for x:= 0 to LAND_WIDTH - 1 do
            Land[y, x]:= lfBasic;
            
    MaxHedgehogs:= Template.MaxHedgehogs;
    hasGirders:= Template.hasGirders;
    playHeight:= Template.TemplateHeight;
    playWidth:= Template.TemplateWidth;
    leftX:= (LAND_WIDTH - playWidth) div 2;
    rightX:= Pred(leftX + playWidth);
    topY:= LAND_HEIGHT - playHeight;
    
    {$HINTS OFF}
    SetPoints(Template, pa, @fps);
    {$HINTS ON}

    Distort2(Template, @fps, pa);

    DrawEdge(pa, 0);

    with Template do
        for i:= 0 to pred(FillPointsCount) do
            with fps[i] do
                FillLand(x, y, 0, 0);

    DrawEdge(pa, lfBasic);

    // HACK: force to only cavern even if a cavern map is invertable if cTemplateFilter = 4 ?
    if (cTemplateFilter = 4)
    or (Template.canInvert and (getrandom(2) = 0))
    or (not Template.canInvert and Template.isNegative) then
        begin
        hasBorder:= true;
        for y:= 0 to LAND_HEIGHT - 1 do
            for x:= 0 to LAND_WIDTH - 1 do
                if (y < topY) or (x < leftX) or (x > rightX) then
                    Land[y, x]:= 0
                else
                    begin
                    if Land[y, x] = 0 then
                        Land[y, x]:= lfBasic
                    else if Land[y, x] = lfBasic then
                        Land[y, x]:= 0;
                    end;
        end;
end;


end.