Add buildsys

FossilOrigin-Name: e5461ff8527693d6fead8581236f625852d55c2a3d7577e4eac219c7031e774f

src/rndmap.cxx

@@ -0,0 +1,70 @@
+// rndmap.cpp: perlin noise landscape generation and some experimental random map stuff, currently not used
+
+#include "cube.h"
+
+float noise(int x, int y, int seed)
+{
+    int n = x+y*57;
+    n = (n<<13)^n;
+    return 1.0f-((n*(n*n*15731+789221)+1376312589)&0x7fffffff)/1073741824.0f;
+}
+
+float smoothednoise(int x, int y, int seed)
+{
+    float corners = (noise(x-1, y-1, seed)+noise(x+1, y-1, seed)+noise(x-1, y+1, seed)+noise(x+1, y+1, seed))/16;
+    float sides = (noise(x-1, y, seed)+noise(x+1, y, seed)+noise(x, y-1, seed)+noise(x, y+1, seed))/8;
+    float center = noise(x, y, seed)/4;
+    return corners+sides+center;
+}
+
+float interpolate(float a, float b, float x)
+{
+    float ft = x*3.1415927f;
+    float f = (1.0f-(float)cos(ft))*0.5f;
+    return a*(1-f)+b*f;
+}
+
+float interpolatednoise(float x, float y, int seed)
+{
+    int ix = (int)x;
+    float fx = x-ix;
+    int iy = (int)y;
+    float fy = y-iy;
+    float v1 = smoothednoise(ix,   iy,   seed);
+    float v2 = smoothednoise(ix+1, iy,   seed);
+    float v3 = smoothednoise(ix,   iy+1, seed);
+    float v4 = smoothednoise(ix+1, iy+1, seed);
+    float i1 = interpolate(v1, v2, fx);
+    float i2 = interpolate(v3, v4, fy);
+    return interpolate(i1, i2, fy);
+}
+
+float perlinnoise_2D(float x, float y, int seedstep, float pers)
+{
+    float total = 0;
+    int seed = 0;
+    for(int i = 0; i<7; i++)
+    {
+        float frequency = (float)(2^i);
+        float amplitude = (float)pow(pers, i);
+        total += interpolatednoise(x*frequency, y*frequency, seed)*amplitude;
+        seed += seedstep;
+    }
+    return total;
+}
+
+void perlinarea(block &b, int scale, int seed, int psize)
+{
+    srand(seed);
+    seed = rnd(10000);
+    if(!scale) scale = 10;
+    for(int x = b.x; x<=b.x+b.xs; x++) for(int y = b.y; y<=b.y+b.ys; y++)
+    {
+        sqr *s = S(x,y);
+        if(!SOLID(s) && x!=b.x+b.xs && y!=b.y+b.ys) s->type = FHF; 
+        s->vdelta = (int)(perlinnoise_2D(x/((float)scale)+seed, y/((float)scale)+seed, 1000, 0.01f)*50+25);
+        if(s->vdelta>128) s->vdelta = 0;
+    };
+};
+
+