#include <math.h></math.h>

#include <helianthus.h></helianthus.h>

#define COUNT 9

unsigned int colors[3] = { COLOR_RED, COLOR_BLUE, COLOR_YELLOW };

void drawTriangle(double x, double y, double radius, double angle, unsigned int color, int level) {

  if (level <= 0) {

    saveState();

    strokeWidth(radius * 0.1);

    fill(color);

    regularPolygon(x, y, 3, radius, angle);

    restoreState();

  } else {

    --level;

    double r = radius/((COUNT + 3)/2);

    radius -= r;

    saveState();

    noStroke();

    fill(colorWithAlpha(color, 0.5));

    regularPolygon(x, y, 3, radius - r - r, angle);

    restoreState();

    double a0 = angle*PI/180;

    double da = 2*PI/3;

    for(int i = 0; i < 3; ++i) {

      double x0 = x + radius*cos(a0 + i*da);

      double y0 = y + radius*sin(a0 + i*da);

      double x1 = x + radius*cos(a0 + i*da + da);

      double y1 = y + radius*sin(a0 + i*da + da);

      double dx = cos(a0 + i*da + da/2)*r/2;

      double dy = sin(a0 + i*da + da/2)*r/2;

      for(int j = 0; j < COUNT; ++j) {

        double k = (double)j/(COUNT + 1);

        double xx = x0*(1 - k) + x1*k;

        double yy = y0*(1 - k) + y1*k;

        if (j % 2) { xx -= dx; yy -= dy; }

        double a = angle + j*180;

        drawTriangle(xx, yy, r, a, colors[i], level);

      }

    }

  }

}

void init() {

}

void draw() {

  double w = windowGetWidth();

  double h = windowGetHeight();

  saveState();

  translate(w/2, h/2);

  drawTriangle(0, 0, 400, 0, colors[0], 2);

  restoreState();

}

int main() {

  windowSetResizable(TRUE);

  windowSetVariableFrameRate();

  windowSetInit(&init);

  windowSetDraw(&draw);

  windowRun();

}