unit WorldGen;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, allegro, PerlinNoiseUnit, Tilesets, Sprites,boolUtils;

type
TChunk = array of array of byte;

{ TWorldGenerator }

TWorldGenerator = class
  public
    constructor Create(seed: Integer);
    destructor Destroy();
    function GenerateChunk(ChunkX,ChunkY, chunksize:Integer):TChunk;
    function Draw(bitmap:AL_BITMAPptr; x,y:Integer; Tileset:TTileset; Chunk:TChunk):TSprite;
    function GetChunkWithBlocks(Chunk: TChunk):TChunk; //blocks are destroyable by the player, so we need a way to get them
                                                       //so we can destroy them in world (by displaying as TSprite).

  private
    PerlinGenerator: TPerlinNoise;
    cx,cy:Integer;
    function _genStepTerrain(Chunk:TChunk):TChunk;
    function _genStepGround(Chunk:TChunk):TChunk;
    function _genStepCarve(Chunk:TChunk):TChunk;
    function _genStepTraps(Chunk:TChunk):TChunk;
    function _genStepBlocks(Chunk:TChunk):TChunk;
    function GetTrapSprite(Chunk:TChunk; Tileset:TTileset):TSprite;  //util functions so we can get collidable terrain
    function GetChunkSprite(Chunk:TChunk; Tileset:TTileset):TSprite; //and spikes as sprites for easy collision checking.

end;


implementation
uses ChunkUtils;
const
  Octaves=4;
  Persistance=6.5;
  Frequency=2;
  TrapChance=14; //there is 14 percent of chance that spike will spawn on ground or block.
{ TWorldGenerator }

constructor TWorldGenerator.Create(seed: Integer);
begin
  inherited Create;
  PerlinGenerator:= TPerlinNoise.Create(seed);

end;

destructor TWorldGenerator.Destroy;
begin
  inherited;
  PerlinGenerator.Destroy;
end;

function TWorldGenerator.GenerateChunk(ChunkX, ChunkY, chunksize: Integer
  ): TChunk;
var x:Integer;

  Chunk:TChunk;
begin
    cx:=Chunkx;
    cy:=Chunky;
    //setting dimensions of chunk
    SetLength(Chunk,chunksize);
    for x:=0 to chunksize-1 do SetLength(Chunk[x],chunksize);
    Chunk:=_genStepTerrain(Chunk);
    Chunk:=_genStepCarve(Chunk);
    Chunk:=_genStepGround(Chunk);
    Chunk:=_genStepBlocks(Chunk);
    Chunk:=_genStepTraps(Chunk);
    result:=Chunk;
end;


function TWorldGenerator.Draw(bitmap: AL_BITMAPptr; x, y: Integer;
  Tileset: TTileset; Chunk:TChunk):TSprite;
begin

end;

function TWorldGenerator._genStepTerrain(Chunk: TChunk): TChunk;
var  i,perlinresult:Byte;
     x,y,temp,chunksize:Integer;
     neighbors:array[0..7]of byte;
begin
  //getting length of chunk
  chunksize:=Length(Chunk);
  //generation
    for x:=0 to chunksize-1 do
    begin
      for y:=0 to chunksize-1 do
      begin
        //getting perlin for specified point
        perlinresult:=Trunc(PerlinGenerator.PerlinNoise2d((cx*chunksize)+x,(cy*chunksize)+y,Persistance,Frequency,Octaves)*255);
        //smoothing it so it won't look awful
        neighbors[0]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)-1,(cy*chunksize)+y,Persistance,Frequency,Octaves)*255);
        neighbors[1]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)+1,(cy*chunksize)+y,Persistance,Frequency,Octaves)*255);
        neighbors[2]:=Trunc(PerlinGenerator.PerlinNoise2d((cx*chunksize)+x,((cy*chunksize)+y)-1,Persistance,Frequency,Octaves)*255);
        neighbors[3]:=Trunc(PerlinGenerator.PerlinNoise2d((cx*chunksize)+x,((cy*chunksize)+y)+1,Persistance,Frequency,Octaves)*255);
        neighbors[4]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)-1,((cy*chunksize)+y)-1,Persistance,Frequency,Octaves)*255);
        neighbors[5]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)+1,((cy*chunksize)+y)-1,Persistance,Frequency,Octaves)*255);
        neighbors[6]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)+1,((cy*chunksize)+y)+1,Persistance,Frequency,Octaves)*255);
        neighbors[7]:=Trunc(PerlinGenerator.PerlinNoise2d(((cx*chunksize)+x)-1,((cy*chunksize)+y)+1,Persistance,Frequency,Octaves)*255);
        temp:= perlinresult div 2;
        for i:=0 to 7 do begin
          temp:= temp + (neighbors[i] div 12);
        end;
        if temp>255 then temp:=255;
        perlinresult:=temp;
        //standard ground
        if Between(perlinresult,90,256) then chunk[x][y]:=GROUNDID
        else chunk[x][y]:= AIRID;
      end;
    end;
    result:=Chunk;
end;

function TWorldGenerator._genStepGround(Chunk: TChunk): TChunk;
var chunksize,x,y:Integer;

begin
  chunksize:=Length(Chunk);
  for x:=0 to chunksize-1 do begin
    for y:=1 to chunksize-2 do begin
      //we start at Y=1 and end one index before end of chunk as we need to test block before that for being
      //air and if there is something under.
      if ((Chunk[x][y]=AIRID) and (Chunk[x][y-1]=AIRID) and (Chunk[x][y+1]=GROUNDID))
         then Chunk[x][y]:=INVINCIBLEBLOCKID;
    end;
  end;
  result:=Chunk;
end;

function TWorldGenerator._genStepCarve(Chunk: TChunk): TChunk;
var x,chunksize:Integer;
begin
  chunksize:=Length(Chunk);
  for x:=0 to Random(chunksize+(chunksize div 5)) do begin
          //al_circlefill(perlin,random(100),random(25)+25,Random(12),al_makecol(255,0,255)); //putting some random magenta circlesin middle co carve way a bit.
          ChunkCircle(Chunk,random(chunksize),random(chunksize div 2)+chunksize div 5,random(chunksize div 5),-1,true);
      end;
  result:=chunk;
end;

function TWorldGenerator._genStepTraps(Chunk: TChunk): TChunk;
var chunksize,x,y:Integer;

begin
  chunksize:=Length(Chunk);
  for x:=0 to chunksize-1 do begin
    for y:=1 to chunksize-2 do begin
      //we start at Y=1 and end one index before end of chunk as we need to test block before that for being
      //air and if there is something under.
      if ((Chunk[x][y]=AIRID) and (Chunk[x][y-1]=AIRID) and ((Chunk[x][y+1]=GROUNDID) or
         (Chunk[x][y+1]=INVINCIBLEBLOCKID)) and (Random(101)<TrapChance)) then Chunk[x][y]:=SPIKEID;
         //randomizing above is so whole ground won't be in traps.
    end;
  end;
  result:=Chunk;

end;

function TWorldGenerator._genStepBlocks(Chunk: TChunk): TChunk;
begin
  result:=Chunk;
end;

function TWorldGenerator.GetTrapSprite(Chunk: TChunk; Tileset: TTileset
  ): TSprite;
begin

end;

function TWorldGenerator.GetChunkSprite(Chunk: TChunk; Tileset: TTileset
  ): TSprite;
begin

end;

function TWorldGenerator.GetChunkWithBlocks(Chunk: TChunk): TChunk;
begin

end;

end.