127 lines
2.4 KiB
C++
127 lines
2.4 KiB
C++
#include <sprstk/sprstk.h>
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#include <simplexnoise1234.h>
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#include <cmath>
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namespace
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{
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constexpr int SIZE = 256;
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double octaves(SimplexNoise1234& simplex, double x, double y, int layers, double persistence, double frequency)
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{
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double ampl = 1;
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double maxval = 0;
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double val = 0;
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for (int i = 0; i < layers; i++)
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{
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val += simplex.noise(x * frequency, y * frequency) * ampl;
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maxval += ampl;
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ampl *= persistence;
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frequency *= 2;
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}
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return val / maxval;
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}
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uint8_t data[SIZE * SIZE];
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double ease(double n)
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{
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return pow(n, 1.5);
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}
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uint32_t color(uint8_t r, uint8_t g, uint8_t b, uint8_t a)
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{
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return (r << 24) | (g << 16) | (b << 8) | a;
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}
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int pick_pal(uint8_t height)
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{
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if (height > 20) { return 0; }
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if (height > 8) { return 1; }
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return 2;
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}
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void init(sprstk* instance, void* userdata)
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{
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sprstk_palette pal = {};
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for (int i = 0; i < 24; i++)
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{
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uint8_t val = 0x33 / (12 - i / 2.0f) + 0x33;
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pal.colors[i] = color(val, val, val, 0x7F);
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}
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for (int i = 24; i < 32; i++)
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{
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uint8_t val = 0x55 / (16 - i / 2.0f) + 0xAA;
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pal.colors[i] = color(val, val, val, 0x7F);
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}
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sprstk_set_palette(instance, 0, &pal);
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for (int i = 0; i < 16; i++)
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{
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pal.colors[i] = color(0x70 / (5.0f - i / 4.0f), 0x35 / (5.0f - i / 4.0f), 0, 0x7F);
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}
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for (int i = 16; i < 32; i++)
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{
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pal.colors[i] = color(0x05 / (8.5f - i / 2.5f) + 0x15, 0x40 / (8.5f - i / 2.5f) + 0x0, 0, 0x7F);
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}
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sprstk_set_palette(instance, 1, &pal);
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for (int i = 0; i < 8; i++)
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{
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pal.colors[i] = color(0x20 / (8 - i) + 0x20, 0x40 / (8 - i) + 0x40, 0x90 / (8 - i) + 0x40, 0x7F);
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}
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sprstk_set_palette(instance, 2, &pal);
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sprstk_set_scale(instance, 0.4f);
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SimplexNoise1234 simplex;
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for (int i = 0; i < SIZE; i++)
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{
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for (int j = 0; j < SIZE; j++)
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{
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double value = octaves(simplex, i, j, 6, 0.4, 1.0 / 128.0);
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data[i + j * SIZE] = 28 * ease((value + 1) / 2) + 3;
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}
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}
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for (int i = 0; i < SIZE; i++)
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{
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for (int j = 0; j < SIZE; j++)
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{
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sprstk_put(instance, i - SIZE / 2, j - SIZE / 2, data[i + SIZE * j], pick_pal(data[i + SIZE * j]));
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}
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}
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}
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void update(sprstk* instance, float dt, float* userdata)
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{
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*userdata += dt / 2;
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sprstk_set_angle(instance, *userdata);
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}
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}
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int main()
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{
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float data = 0;
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sprstk* instance = sprstk_new({.init = init, .update = (sprstk_update_fn)update}, &data);
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sprstk_run(instance);
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sprstk_stop(instance);
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return 0;
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}
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