hedgewars/uLandGenPerlin.pas
author Simon McVittie <smcv@debian.org>
Mon, 12 Sep 2022 10:40:53 -0400
branch1.0.0
changeset 15881 7b1d6dfa3173
parent 15176 c0ae9f4f9589
child 15929 128ace913837
permissions -rw-r--r--
Remove FindSDL2 find-module, use sdl2-config.cmake instead This requires SDL >= 2.0.4. Since <https://bugzilla.libsdl.org/show_bug.cgi?id=2464> was fixed in SDL 2.0.4, SDL behaves as a CMake "config-file package", even if it was not itself built using CMake: it installs a sdl2-config.cmake file to ${libdir}/cmake/SDL2, which tells CMake where to find SDL's headers and library, analogous to a pkg-config .pc file. As a result, we no longer need to copy/paste a "find-module package" to be able to find a system copy of SDL >= 2.0.4 with find_package(SDL2). Find-module packages are now discouraged by the CMake developers, in favour of having upstream projects behave as config-file packages. This results in a small API change: FindSDL2 used to set SDL2_INCLUDE_DIR and SDL2_LIBRARY, but the standard behaviour for config-file packages is to set <name>_INCLUDE_DIRS and <name>_LIBRARIES. Use the CONFIG keyword to make sure we search in config-file package mode, and will not find a FindSDL2.cmake in some other directory that implements the old interface. In addition to deleting redundant code, this avoids some assumptions in FindSDL2 about the layout of a SDL installation. The current libsdl2-dev package in Debian breaks those assumptions; this is considered a bug and will hopefully be fixed soon, but it illustrates how fragile these assumptions can be. We can be more robust against different installation layouts by relying on SDL's own CMake integration. When linking to a copy of CMake in a non-standard location, users can now set the SDL2_DIR or CMAKE_PREFIX_PATH environment variable to point to it; previously, these users would have used the SDL2DIR environment variable. This continues to be unnecessary if using matching system-wide installations of CMake and SDL2, for example both from Debian.

{$INCLUDE "options.inc"}

unit uLandGenPerlin;
interface

procedure GenPerlin;

implementation
uses uVariables
    , uConsts
    , uRandom
    , uLandOutline // FillLand
    , uUtils
    ;

var p: array[0..511] of LongInt;

const fadear: array[byte] of LongInt =
(0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 3, 4, 6, 7, 9, 10, 12,
14, 17, 19, 22, 25, 29, 32, 36, 40, 45, 49, 54, 60, 65, 71,
77, 84, 91, 98, 105, 113, 121, 130, 139, 148, 158, 167, 178,
188, 199, 211, 222, 234, 247, 259, 273, 286, 300, 314, 329, 344,
359, 374, 390, 407, 424, 441, 458, 476, 494, 512, 531, 550,
570, 589, 609, 630, 651, 672, 693, 715, 737, 759, 782, 805, 828,
851, 875, 899, 923, 948, 973, 998, 1023, 1049, 1074, 1100, 1127,
1153, 1180, 1207, 1234, 1261, 1289, 1316, 1344, 1372, 1400, 1429,
1457, 1486, 1515, 1543, 1572, 1602, 1631, 1660, 1690, 1719, 1749,
1778, 1808, 1838, 1868, 1898, 1928, 1958, 1988, 2018, 2048, 2077,
2107, 2137, 2167, 2197, 2227, 2257, 2287, 2317, 2346, 2376, 2405,
2435, 2464, 2493, 2523, 2552, 2580, 2609, 2638, 2666, 2695, 2723,
2751, 2779, 2806, 2834, 2861, 2888, 2915, 2942, 2968, 2995, 3021,
3046, 3072, 3097, 3122, 3147, 3172, 3196, 3220, 3244, 3267, 3290,
3313, 3336, 3358, 3380, 3402, 3423, 3444, 3465, 3486, 3506, 3525,
3545, 3564, 3583, 3601, 3619, 3637, 3654, 3672, 3688, 3705, 3721,
3736, 3751, 3766, 3781, 3795, 3809, 3822, 3836, 3848, 3861, 3873,
3884, 3896, 3907, 3917, 3928, 3937, 3947, 3956, 3965, 3974, 3982,
3990, 3997, 4004, 4011, 4018, 4024, 4030, 4035, 4041, 4046, 4050,
4055, 4059, 4063, 4066, 4070, 4073, 4076, 4078, 4081, 4083, 4085,
4086, 4088, 4089, 4091, 4092, 4092, 4093, 4094, 4094, 4095, 4095,
4095, 4095, 4095, 4095, 4095);

function fade(t: LongInt) : LongInt; inline;
var t0, t1: LongInt;
begin
    t0:= fadear[t shr 8];

    if t0 = fadear[255] then
        t1:= t0
    else
        t1:= fadear[t shr 8 + 1];

    fade:= t0 + ((t and 255) * (t1 - t0) shr 8)
end;


function lerp(t, a, b: LongInt) : LongInt; inline;
begin
    lerp:= a + ((Int64(b) - a) * t shr 12)
end;


function grad(hash, x, y: LongInt) : LongInt; inline;
var h, v, u: LongInt;
begin
    h:= hash and 15;
    if h < 8 then u:= x else u:= y;
    if h < 4 then v:= y else
        if (h = 12) or (h = 14) then v:= x else v:= 0;

    if (h and 1) <> 0 then u:= -u;
    if (h and 2) <> 0 then v:= -v;

    grad:= u + v
end;


function inoise(x, y: LongInt) : LongInt; inline;
const N = $10000;
var xx, yy, u, v, A, AA, AB, B, BA, BB: LongInt;
begin
    xx:= (x shr 16) and 255;
    yy:= (y shr 16) and 255;

    x:= x and $FFFF;
    y:= y and $FFFF;

    u:= fade(x);
    v:= fade(y);

    A:= p[xx    ] + yy; AA:= p[A]; AB:= p[A + 1];
    B:= p[xx + 1] + yy; BA:= p[B]; BB:= p[B + 1];

    inoise:=
            lerp(v, lerp(u, grad(p[AA  ], x   , y  ),
                            grad(p[BA  ], x-N , y  )),
                    lerp(u, grad(p[AB  ], x   , y-N),
                            grad(p[BB  ], x-N , y-N)));
end;

procedure inoise_setup();
var i, ii, t: Longword;
begin
    for i:= 0 to 254 do
        p[i]:= i + 1;
    p[255]:= 0;

    for i:= 0 to 254 do
    begin
        ii:= GetRandom(256 - i) + i;
        t:= p[i];
        p[i]:= p[ii];
        p[ii]:= t
    end;

    for i:= 0 to 255 do
        p[256 + i]:= p[i];
end;

const width = 4096;
      height = 2048;
      minY = 500;

    //bottomPlateHeight = 90;
    //bottomPlateMargin = 1200;
    margin = 200;

procedure GenPerlin;
var y, x, di, dj, r, param1, param2, rCutoff, detail: LongInt;
var df: Int64;
begin
    param1:= cTemplateFilter div 3;
    param2:= cTemplateFilter mod 3;
    rCutoff:= min(max((26-cFeatureSize)*4,15),85);
    detail:= (26-cFeatureSize)*16000+50000; // feature size is a slider from 1-25 at present. flip it for perlin

    df:= detail * (6 - param2 * 2);

    // Calculate estimate for max. hedgehog count
    // Tunnels
    if param1 = 0 then
        begin
        // Small tunnels
        if param2 = 0 then
            // 12..24
            MaxHedgehogs:= 12 + 1 * (cFeatureSize - 1)
        // Medium tunnels
        else if param2 = 1 then
            // 14..24
            MaxHedgehogs:= 14 + max(0, 1 * (cFeatureSize - 3))
        // Large tunnels
        else if param2 = 2 then
            // 16..24
            MaxHedgehogs:= 16 + max(0, 1 * (cFeatureSize - 5));
        if MaxHedgehogs > 24 then
            MaxHedgehogs:= 24;
        end
    // Islands
    else if (param1 = 1) and (cFeatureSize <= 25) then
        // Small islands
        if param2 = 0 then
            // 64..32
            MaxHedgehogs:= 32 + ((((25 - (cFeatureSize-1))*1000000) div 24) * 32) div 1000000
        // Medium islands
        else if param2 = 1 then
            // 56..28
            MaxHedgehogs:= 28 + ((((25 - (cFeatureSize-1))*1000000) div 24) * 28) div 1000000
        // Large islands
        else if param2 = 2 then
            // 48..24
            MaxHedgehogs:= 24 + ((((25 - (cFeatureSize-1))*1000000) div 24) * 24) div 1000000;
    // We only want even numbers
    if (MaxHedgehogs > 0) and ((MaxHedgehogs mod 2) = 1) then
        MaxHedgehogs:= MaxHedgehogs - 1;

    inoise_setup();

    for y:= minY to pred(height) do
    begin
        di:= df * y div height;
        for x:= 0 to pred(width) do
        begin
            dj:= df * x div width;

            r:= ((abs(inoise(di, dj)) + y*4) mod 65536 - (height - y) * 8) div 256;

            //r:= (abs(inoise(di, dj))) shr 8 and $ff;
            if (x < margin) or (x > width - margin) then r:= r - abs(x - width div 2) + width div 2 - margin; // fade on edges

            //r:= r - max(0, - abs(x - width div 2) + width * 2 div 100); // split vertically in the middle
            //r:= r + (trunc(1000 - sqrt(sqr(x - (width div 2)) * 4 + sqr(y - height * 5 div 4) * 22))) div 600 * 20; // ellipse
            //r:= r + 1 - ((abs(x - (width div 2)) + abs(y - height) * 2)) div 32; // manhattan length ellipse

            {
            if (y > height - bottomPlateHeight) and (x > bottomPlateMargin) and (x + bottomPlateMargin < width) then
            begin
                dy:= (y - height + bottomPlateHeight);
                r:= r + dy;

                if x < bottomPlateMargin + bottomPlateHeight then
                    r:= r + (x - bottomPlateMargin - bottomPlateHeight)
                else
                if x + bottomPlateMargin + bottomPlateHeight > width then
                    r:= r - (x - width + bottomPlateMargin + bottomPlateHeight);
            end;
            }

            if r < rCutoff then
                Land[y, x]:= 0
            else if param1 = 0 then
                Land[y, x]:= lfObjMask
            else
                Land[y, x]:= lfBasic
        end;
    end;

    if param1 = 0 then
        begin
        for x:= 0 to width do
            if Land[height - 1, x] = lfObjMask then FillLand(x, height - 1, 0, lfBasic);

        // strip all lfObjMask pixels
        for y:= minY to LAND_HEIGHT - 1 do
            for x:= 0 to LAND_WIDTH - 1 do
                if Land[y, x] = lfObjMask then
                    Land[y, x]:= 0;
        end;

    playWidth:= width;
    playHeight:= height;
    leftX:= 0;
    rightX:= playWidth - 1;
    topY:= 0;
    hasBorder:= false;
end;

end.