Convert to ObjC++

FossilOrigin-Name: 7c2704b3d77d6e63d960e315bfb601fddbf6fce538b7c5db6da664e04fbce4c2

src/rndmap.mm

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+// 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;
+		};
+};