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authorPaweł Redman <pawel.redman@gmail.com>2017-10-09 19:24:08 +0200
committerPaweł Redman <pawel.redman@gmail.com>2017-10-09 19:24:08 +0200
commit8d6cb03cd83b9f6576909058601af54f16c8acfe (patch)
tree1aae264859680e888c5801f279b638cefa137fb9 /src/procgen.cpp
parent9e7d64d052eabcf40d85c3e903aaba44903a380a (diff)
Refactoring and basic map generation.
Diffstat (limited to 'src/procgen.cpp')
-rw-r--r--src/procgen.cpp87
1 files changed, 87 insertions, 0 deletions
diff --git a/src/procgen.cpp b/src/procgen.cpp
new file mode 100644
index 0000000..09ccae5
--- /dev/null
+++ b/src/procgen.cpp
@@ -0,0 +1,87 @@
+#include "common.hpp"
+#include <cmath>
+
+namespace procgen {
+
+void prng_t::seed(uint32_t seed)
+{
+ state = seed;
+ next();
+ next();
+}
+
+uint32_t prng_t::next(void)
+{
+ // glibc's LCG parameters (with m = 2^32 - 1).
+ state *= 1103515245;
+ state += 12345;
+ return state;
+}
+
+float prng_t::next_float(void)
+{
+ return (float)next() / 4294967295.0f;
+}
+
+void prng_t::unit_vec(float out[2])
+{
+ float t;
+
+ t = next_float() * 2.0f * M_PI;
+ out[0] = cos(t);
+ out[1] = sin(t);
+}
+
+void perlin_noise_t::generate(prng_t *prng, size_t size_)
+{
+ if (table)
+ delete table;
+
+ size = size_;
+ table = new float[size * size][2];
+
+ for (size_t y = 0; y < size; y++)
+ for (size_t x = 0; x < size; x++)
+ prng->unit_vec(table[y * size + x]);
+}
+
+float perlin_noise_t::table_dot(size_t nx, size_t ny, float dx, float dy)
+{
+ return table[ny * size + nx][0] * dx + table[ny * size + nx][1] * dy;
+}
+
+static float smooth_step(float x)
+{
+ return 3 * x * x - 2 * x * x * x;
+}
+
+float perlin_noise_t::get(float x, float y, float scale)
+{
+ size_t nx, ny, nx1, ny1;
+ float s, t, a, b, c, d;
+
+ x /= scale;
+ y /= scale;
+
+ nx = mod<ssize_t>(floor(x), size);
+ ny = mod<ssize_t>(floor(y), size);
+ nx1 = (nx == size - 1 ? 0 : nx + 1);
+ ny1 = (ny == size - 1 ? 0 : ny + 1);
+
+ s = smooth_step(x - floor(x));
+ t = smooth_step(y - floor(y));
+
+ a = table_dot(nx, ny, -s, -t);
+ b = table_dot(nx1, ny, -s + 1.0f, -t);
+ c = table_dot(nx, ny1, -s, -t + 1.0f);
+ d = table_dot(nx1, ny1, -s + 1.0f, -t + 1.0f);
+
+ return bilerp(a, b, c, d, s, t);
+}
+
+perlin_noise_t::~perlin_noise_t()
+{
+ delete table;
+}
+
+} // namespace procgen