我试图在程序上产生一些河流.
我有一个平面(没有高程概念)方格作为基础,并希望在其上绘制一个分支结构,如图所示.
你能分享一下可以用来完成的步骤吗?
我不是在寻找最快的实现,因为没有实时生成,但更简单的实现将是首选. Lua是我的语言,但任何事都可以.
更多的东西:
>形状应该是算法生成的.
>形状应该是
使用种子值可控制.
解决方法
我认为生成河流是一种落后的方法,因为你需要根据它们的形状调整很多东西,这将很难.我会创建随机地形高度图并从中提取特征(如在现实世界中),这更容易且更接近现实.在最终地图中,您忽略高度并使用平面高度(如果您真的想要平面地图).以下是您可以从高度图中提取的一些内容:
>河流和湖泊
通过播种随机高海拔点并沿着它下坡到海平面或地图边缘.
>植被或地面
从坡度和高度,你可以确定地面是沙子,泥土,岩石.如果有树木,灌木丛,草地或其他什么.
在这里看看这个QA:random island generator
和一些河流概述:
种子也在为这种方法工作.
[Edit1]承诺C代码
这基本上生成随机高度图然后种子和下坡跟随河流(如果地形块下坡流动,湖泊会自动生成).地形类型也由坡度和高度确定.
- //---------------------------------------------------------------------------
- picture pic;
- //---------------------------------------------------------------------------
- void map_random(int _xs,int _ys)
- {
- // config
- int h0=-1000,h1=3000; // [m] terrain elevation range
- int h_water= 0; // [m] sea level
- int h_sand=15; // [m] sand level
- int h_evergreen=1500; // [m] evergreen level
- int h_snow=2000; // [m] snow level
- int h_rock=1800; // [m] mountine rock level
- float a_rock=60.0; // [deg] mountine rock slope
- float d_pixel=35.0; // [m] pixel size
- int d_river_w=5; // [pixel] river max width
- int d_river_l=150; // [pixel] river base length per width increase
- bool _island=true;
- // types
- enum _cover_enum
- {
- _cover_none=0,_cover_water,// sea
- _cover_snow,_covers,_cover_shift=0,_cover_mask=15,};
- DWORD _cover[_covers]=
- {
- // RRGGBB
- 0x00000000,// none
- 0x00003080,// watter (sea)
- 0x00EEEEEE,// snow
- };
- enum _terrain_enum
- {
- _terrain_dirt=0,_terrain_sand,_terrain_rock,_terrain_water,// streams,rivers,lakes
- _terrain_temp,// temp
- _terrains,_terrain_shift=4,_terrain_mask=15,};
- DWORD _terrain[_terrains]=
- {
- // RRGGBB
- 0x00301510,// dirt
- 0x00EEC49A,// sand
- 0x006F6F6F,// rock
- 0x00006080,// water (streams,lakes)
- 0x00006080,// temp
- };
- enum _flora_enum
- {
- _flora_none=0,_flora_grass,_flora_hardwood,_flora_evergreen,_flora_deadwood,_floras,_flora_shift=8,_flora_mask=15,};
- DWORD _flora[_floras]=
- {
- // RRGGBB
- 0x00000000,// none
- 0x007F7F3F,// grass
- 0x001FFF1F,// hardwood
- 0x00007F00,// evergreen
- 0x007F3F1F,// deadwood
- };
- // variables
- float a,b,da; int c,t,f;
- int x,y,z,xx,yy,mxs,mys,dx,dy,dx2,dy2,r,r2,ix,l;
- int xh1,yh1; // topest hill position
- int **ter=NULL,**typ=NULL;
- Randomize();
- // align resolution to power of 2
- for (mxs=1;mxs+1<_xs;mxs<<=1); if (mxs<3) mxs=3;
- for (mys=1;mys+1<_ys;mys<<=1); if (mys<3) mys=3;
- ter=new int*[mys+1]; for (y=0;y<=mys;y++) ter[y]=new int[mxs+1];
- typ=new int*[mys+1]; for (y=0;y<=mys;y++) typ[y]=new int[mxs+1];
- // [Terrain]
- for (;;)
- {
- // diamond & square random height map -> ter[][]
- dx=mxs; dx2=dx>>1; r=(mxs+mys)<<1; // init step,half step and randomness
- dy=mys; dy2=dy>>1; r2=r>>1;
- // set corners values
- if (_island)
- {
- t=-r2;
- ter[ 0][ 0]=t;
- ter[ 0][mxs]=t;
- ter[mys][ 0]=t;
- ter[mys][mxs]=t;
- ter[dy2][dx2]=r+r; // top of central hill
- }
- else{
- ter[ 0][ 0]=Random(r);
- ter[ 0][mxs]=Random(r);
- ter[mys][ 0]=Random(r);
- ter[mys][mxs]=Random(r);
- }
- for (;dx2|dy2;dx=dx2,dx2>>=1,dy=dy2,dy2>>=1) // subdivide step until full image is filled
- {
- if (!dx) dx=1;
- if (!dy) dy=1;
- // diamond (skip first one for islands)
- if ((!_island)||(dx!=mxs))
- for (y=dy2,yy=mys-dy2;y<=yy;y+=dy)
- for (x=dx2,xx=mxs-dx2;x<=xx;x+=dx)
- ter[y][x]=((ter[y-dy2][x-dx2]+ter[y-dy2][x+dx2]+ter[y+dy2][x-dx2]+ter[y+dy2][x+dx2])>>2)+Random(r)-r2;
- // square
- for (y=dy2,yy=mys-dy2;y<=yy;y+=dy)
- for (x=dx,xx=mxs-dx ;x<=xx;x+=dx)
- ter[y][x]=((ter[y][x-dx2]+ter[y][x+dx2]+ter[y-dy2][x]+ter[y+dy2][x])>>2)+Random(r)-r2;
- for (y=dy,yy=mys-dy ;y<=yy;y+=dy)
- for (x=dx2,xx=mxs-dx2;x<=xx;x+=dx)
- ter[y][x]=((ter[y][x-dx2]+ter[y][x+dx2]+ter[y-dy2][x]+ter[y+dy2][x])>>2)+Random(r)-r2;
- for (x=dx2,xx=mxs-dx2;x<=xx;x+=dx)
- {
- y= 0; ter[y][x]=((ter[y][x-dx2]+ter[y][x+dx2]+ter[y+dy2][x])/3)+Random(r)-r2;
- y=mys; ter[y][x]=((ter[y][x-dx2]+ter[y][x+dx2]+ter[y-dy2][x])/3)+Random(r)-r2;
- }
- for (y=dy2,yy=mys-dy2;y<=yy;y+=dy)
- {
- x= 0; ter[y][x]=((ter[y][x+dx2]+ter[y-dy2][x]+ter[y+dy2][x])/3)+Random(r)-r2;
- x=mxs; ter[y][x]=((ter[y][x-dx2]+ter[y-dy2][x]+ter[y+dy2][x])/3)+Random(r)-r2;
- }
- if (_island)
- {
- // recompute middle position after first pass so there can be more central hills
- if (dx==mxs) ter[dy2][dx2]=Random(r2);
- // adjust border to underwatter
- for (y=0;y<=mys;y+=dy2) { ter[y][0]=t; ter[y][mxs]=t; }
- for (x=0;x<=mxs;x+=dx2) { ter[0][x]=t; ter[mys][x]=t; }
- }
- // adjust randomness
- r>>=1; if (r<2) r=2; r2=r>>1;
- }
- // rescale to <h0,h1>
- xx=ter[0][0]; yy=xx;
- for (y=0;y<=mys;y++)
- for (x=0;x<=mxs;x++)
- {
- z=ter[y][x];
- if (xx>z) xx=z;
- if (yy<z){ yy=z; xh1=x; yh1=y; }
- }
- for (y=0;y<=mys;y++)
- for (x=0;x<=mxs;x++)
- ter[y][x]=h0+(((ter[y][x]-xx)*(h1-h0))/(yy-xx));
- // test for correctness
- if (_island)
- {
- l=0;
- for (x=0;x<=mxs;x++) { if (ter[0][x]>h_water) l++; if (ter[mys][x]>h_water) l++; }
- for (y=0;y<=mys;y++) { if (ter[y][0]>h_water) l++; if (ter[y][mxs]>h_water) l++; }
- if (l>1+((mxs+mys)>>3)) continue;
- }
- break;
- }
- // [Surface]
- for (y=0;y<mys;y++)
- for (x=0;x<mxs;x++)
- {
- z=ter[y][x];
- // max slope [deg]
- a=atan2(ter[y][x+1]-z,d_pixel);
- b=atan2(ter[y+1][x]-z,d_pixel);
- if (a<b) a=b; a*=180.0/M_PI;
- c=_cover_none;
- if (z<=h_water) c=_cover_water;
- if (z>=h_snow ) c=_cover_snow;
- t=_terrain_dirt;
- if (z<=h_sand) t=_terrain_sand;
- if (z>=h_rock) t=_terrain_rock;
- if (a>=a_rock) t=_terrain_rock;
- f=_flora_none;
- if (t==_terrain_dirt)
- {
- r=Random(100);
- if (r>10) f=_flora_grass;
- if (r>50)
- {
- if (z>h_evergreen) f=_flora_evergreen;
- else{
- r=Random(h_evergreen);
- if (r<=z) f=_flora_evergreen;
- else f=_flora_hardwood;
- }
- }
- if (r<5) f=_flora_deadwood;
- }
- typ[y][x]=(c<<_cover_shift)|(t<<_terrain_shift)|(f<<_flora_shift);
- }
- // [Rivers]
- for (ix=10+Random(5),a=0.0,da=2.0*M_PI/float(ix);ix;ix--)
- {
- // random start around topest hill
- a+=da*(0.75+(0.50*Random()));
- for (l=0;l<10;l++)
- {
- b=Random(mxs>>3);
- x=xh1; x+=float(b*cos(a));
- y=yh1; y+=float(b*sin(a));
- if ((x<1)||(x>=mxs)) continue;
- if ((y<1)||(y>=mys)) continue;
- if (typ[y][x]&0x00F==_cover_water) continue;
- l=-1;
- break;
- } if (l>=0) continue; // safety check
- for (l=0,r2=0;;)
- {
- // stop on map edge
- if ((x<=0)||(x>=mxs-1)||(y<=0)||(y>=mys-1)) break;
- // decode generated surface
- r=typ[y][x];
- c=(r>> _cover_shift)& _cover_mask;
- t=(r>>_terrain_shift)&_terrain_mask;
- f=(r>> _flora_shift)& _flora_mask;
- // stop if reached sea
- if (c==_cover_water) break;
- // insert river dot radius = r2
- dx=x-r2; if (dx<0) dx=0; dx2=x+r2; if (dx2>=mxs) dx2=mxs-1;
- dy=y-r2; if (dy<0) dy=0; dy2=y+r2; if (dy2>=mys) dy2=mys-1;
- for (yy=dy;yy<=dy2;yy++)
- for (xx=dx;xx<=dx2;xx++)
- if (((xx-x)*(xx-x))+((yy-y)*(yy-y))<=r2*r2)
- if (((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)
- typ[yy][xx]=(typ[yy][xx]&0x00F)|(_terrain_temp<<_terrain_shift);
- // step to smalest elevation neighbor
- dx=x; dy=y; z=h1; typ[y][x]=(typ[y][x]&0x00F)|(_terrain_water<<_terrain_shift); xx=x; yy=y;
- xx--; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- yy--; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- xx++; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- xx++; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- yy++; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- yy++; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- xx--; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- xx--; r=ter[yy][xx]; if ((z>=r)&&(((typ[yy][xx]>>_terrain_shift)&_terrain_mask)!=_terrain_water)) { z=r; dx=xx; dy=yy; }
- if ((dx==x)&&(dy==y))
- {
- // handle invalid path or need for a lake!!!
- if (dx>mxs>>1) dx++; else dx--;
- if (dy>mys>>1) dy++; else dy--;
- }
- x=dx; y=dy;
- // increase river volume with length
- l++; if (l>d_river_l*(r2+1)) { l=0; if (r2<d_river_w) r2++; }
- }
- // make merging of rivers possible
- for (y=0;y<=mys;y++)
- for (x=0;x<=mxs;x++)
- if (((typ[y][x]>>_terrain_shift)&_terrain_mask)==_terrain_water)
- typ[y][x]=(typ[y][x]&0x00F)|(_terrain_temp<<_terrain_shift);
- }
- for (y=0;y<=mys;y++)
- for (x=0;x<=mxs;x++)
- if (((typ[y][x]>>_terrain_shift)&_terrain_mask)==_terrain_temp)
- typ[y][x]=(typ[y][x]&0x00F)|(_terrain_water<<_terrain_shift);
- // [copy data] rewrite this part to suite your needs
- for (y=1;y<_ys;y++)
- for (x=1;x<_xs;x++)
- {
- float nx,ny,nz,x0,y0,z0,x1,y1,z1;
- // (nx,nz) = surface normal
- nx=0.0; ny=0.0; nz=ter[y][x];
- x0=-d_pixel; y0=0.0; z0=ter[y][x-1];
- x1=0.0; y1=-d_pixel; z1=ter[y-1][x];
- x0-=nx; x1-=nx;
- y0-=ny; y1-=ny;
- z0-=nz; z1-=nz;
- nx=(y0*z1)-(z0*y1);
- ny=(z0*x1)-(x0*z1);
- nz=(x0*y1)-(y0*x1);
- x0=1.0/sqrt((nx*nx)+(ny*ny)+(nz*nz));
- nx*=x0;
- ny*=x0;
- nz*=x0;
- // z = ambient light + normal shading
- nz=(+0.7*nx)+(-0.7*ny)+(+0.7*nz);
- if (nz<0.0) nz=0.0;
- nz=255.0*(0.2+(0.8*nz)); z=nz;
- // r = base color
- r=typ[y][x];
- c=(r>> _cover_shift)& _cover_mask;
- t=(r>>_terrain_shift)&_terrain_mask;
- f=(r>> _flora_shift)& _flora_mask;
- r=_terrain[t];
- if (c) r= _cover[c];
- if (f){ if (c) r|=_flora[f]; else r=_flora[f]; };
- // sea color is depending on depth not surface normal
- if (c==_cover_water) z=256-((ter[y][x]<<7)/h0);
- // apply lighting z to color r
- yy=int(r>>16)&255; yy=(yy*z)>>8; if (yy>255) yy=255; r=(r&0x0000FFFF)|(yy<<16);
- yy=int(r>> 8)&255; yy=(yy*z)>>8; if (yy>255) yy=255; r=(r&0x00FF00FF)|(yy<< 8);
- yy=int(r )&255; yy=(yy*z)>>8; if (yy>255) yy=255; r=(r&0x00FFFF00)|(yy );
- // set pixel to target image
- pic.p[y][x].dd=r;
- }
- // free ter[][],typ[][]
- for (y=0;y<=mys;y++) delete[] ter[y]; delete[] ter; ter=NULL;
- for (y=0;y<=mys;y++) delete[] typ[y]; delete[] typ; typ=NULL;
- }
- //---------------------------------------------------------------------------
该代码基于我所链接的答案中的代码,但具有附加功能(包括河流).我使用自己的图片类图片,所以一些成员是:
> xs,ys图像大小(以像素为单位)
> p [y] [x] .dd是(x,y)位置的像素,为32位整数类型
>清晰(颜色) – 清除整个图像
> resize(xs,ys) – 将图像调整为新分辨率
> bmp – VCL封装了带Canvas访问的GDI Bitmap
您可以调整Diamond& Square中的调整随机性以更改地形平滑度.高度限制和阈值也可以被篡改.
为了实现像河流这样的更多的增长,在群集中种植更多的起始点,以便它们能够及时合并到单个或更多的河流中.