tiny_donut/code.cpp at main · fivawyr/tiny_donut · GitHub

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#include <chrono>
#include <cstdint>
#include <cstring>
#include <iostream>
#include <stdio.h>
#include <cmath>
#include <array>
#include <thread>

typedef int32_t i32;
typedef float f32;
typedef double f64;

constexpr i32 WIDTH = 82;
constexpr i32 HEIGHT = 25;
constexpr i32 BUFFER_SIZE = WIDTH * HEIGHT;

using namespace std;

int main() {
  f32 rotationA = 0.0f;
  f32 rotationB = 0.0f;
  array<char, BUFFER_SIZE> screen;
  array<f32, BUFFER_SIZE> depthBuffer;
  for (;;) {
      screen.fill(' ');
      depthBuffer.fill(0.0f);
      // cos, sin(theta) for getting the right transformation, please take a look at the README notes for a better understanding -> 6.28 ~ 2pi (90° rotation!). Phi for torsus
      for (f32 theta = 0.0f; theta < 6.28f; theta += 0.07f)
          for (f32 phi = 0.0f; phi < 6.28f; phi += 0.02f) {
              f32 sinTheta = sin(theta);
              f32 cosTheta = cos(theta);
              f32 sinPhi = sin(phi);
              f32 cosPhi = cos(phi);
              f32 sinA = sin(rotationA);
              f32 cosA = cos(rotationA);
              f32 sinB = sin(rotationB);
              f32 cosB = cos(rotationB); // -> now comes the torus geo (https://en.wikipedia.org/wiki/Torus)
              f32 circleX = cosPhi * 2.0f;
              f32 inverseDepth = 1.0f / (sinTheta * circleX * sinA + sinPhi * cosA + 5.0f);
              f32 projX = sinTheta * circleX * cosA - sinPhi * sinA;
              i32 x = static_cast<int>( WIDTH / 2.0f + 30 * inverseDepth * (cosTheta * circleX * cosB - projX * sinB));
              i32 y = static_cast<int>( HEIGHT / 2.0f + 15 * inverseDepth * (cosTheta * circleX * sinB +projX * cosB));
              if(x < 0 || x >= WIDTH || y < 0 || y >= HEIGHT) continue;
              i32 idx = x + WIDTH * y;
              int luminance = static_cast<i32>(8 * ((sinPhi * sinA - sinTheta * cosPhi * cosA) * cosB -
              sinTheta * cosPhi * sinA - sinPhi * cosA - cosTheta * cosPhi * sinB));
              constexpr char shades[] = ".,-~:;=!*#@";
              if (inverseDepth > depthBuffer[idx]) {
                  depthBuffer[idx] = inverseDepth;
                  if (luminance < 0) luminance = 0;
                  if (luminance > 11) luminance = 11;
                  screen[idx] = shades[luminance];
            }
          }
        cout << "\x1b[H";
        for (int i = 0; i < BUFFER_SIZE; ++i) {
            if (i % WIDTH == 0) cout << '\n';
            cout << screen[i];
        }
            cout.flush();
            rotationA += 0.04f;
            rotationB += 0.02f;
            this_thread::sleep_for(chrono::milliseconds(30));
    }
}