<meta charset="utf-8" />
<script src="http://spelprogrammering.nu/simple.js">
function start()
{
  g      = 9.82;
  l      = 2.5;
  m      = 1;
  theta0 = pi/4;
  theta  = 0;
  phi    = pi/2;

  omega  = sqrt(g/l);
  SMax   = m*g*(3*cos(0)-2*cos(theta0));
  vMax   = sqrt(2*g*l*(cos(0)-cos(theta0)));
  T      = 2*pi*sqrt(l/g);
  t      = 0;
  
  updatesPerSecond = 50;
}

function update()
{
  clearScreen();

  S     = m*g*(3*cos(theta)-2*cos(theta0));
  v     = sqrt(2*g*l*(cos(theta)-cos(theta0)));
  theta = theta0*sin(omega*t + phi);

  math.polarLine(0, 0, theta + 3*pi/2, l, mixColor(floor(255*S/SMax), 0, 0));
  math.polarPoint(theta + 3*pi/2, l, 20, "black");

  t += 1/updatesPerSecond;

  math.text(-2.7, 2.5, 12, "Snörets längd: " + floor(l*100)/100+"m");
  math.text(-2.7, 2,   12, "Pendelns massa: " + floor(m*100)/100+"kg");
  math.text(-2.7, 1.5, 12, "Startvinkel: " + floor(theta0*100)/100+" radianer");
  math.text(-2.7, 1,   12, "Snöret utsätts för maximalt: "+floor(SMax*100)/100+"N");
  math.text(-2.7, 0.5, 12, "Pendelns maximala hastighet: "+floor(vMax*100)/100+"m/s");
  math.text(-2.7, 0,   12, "Period: "+floor(T*100)/100+"s");
  math.text(0,    2.5, 12, "Nuvarande tid: " + floor(t*100)/100+"s");
  math.text(0,    2,   12, "Nuvarande vinkel: "+floor(theta*100)/100+" radianer");
  math.text(0,    1.5, 12, "Nuvarande kraft i snöret: "+floor(S*100)/100+"N");
  math.text(0,    1,   12, "Pendelns hastighet: "+floor(v*100)/100+"m/s");
}
</script>