/*
title: Flow on the cartesian
category: flowGL
titleCN: 直角坐标系上的向量场
theme: dark
videoStart: 2000
videoEnd: 10000
*/

$.getScript(
  'https://fastly.jsdelivr.net/npm/simplex-noise@2.4.0/simplex-noise.js'
).done(function () {
  var noise = new SimplexNoise(Math.random);
  var noise2 = new SimplexNoise(Math.random);
  function generateData() {
    var data = [];
    for (var i = 0; i <= 50; i++) {
      for (var j = 0; j <= 50; j++) {
        var dx = noise.noise2D(i / 30, j / 30);
        var dy = noise2.noise2D(i / 30, j / 30);
        var mag = Math.sqrt(dx * dx + dy * dy);
        valMax = Math.max(valMax, mag);
        valMin = Math.min(valMin, mag);
        data.push([i, j, dx, dy, mag]);
      }
    }
    return data;
  }
  var valMin = Infinity;
  var valMax = -Infinity;
  var data = generateData();

  myChart.setOption({
    visualMap: {
      show: false,
      min: valMin,
      max: valMax,
      dimension: 4,
      inRange: {
        color: [
          '#313695',
          '#4575b4',
          '#74add1',
          '#abd9e9',
          '#e0f3f8',
          '#ffffbf',
          '#fee090',
          '#fdae61',
          '#f46d43',
          '#d73027',
          '#a50026'
        ]
      }
    },
    xAxis: {
      type: 'value',
      axisLine: {
        lineStyle: {
          color: '#fff'
        }
      },
      splitLine: {
        show: false,
        lineStyle: {
          color: 'rgba(255,255,255,0.2)'
        }
      }
    },
    yAxis: {
      type: 'value',
      axisLine: {
        lineStyle: {
          color: '#fff'
        }
      },
      splitLine: {
        show: false,
        lineStyle: {
          color: 'rgba(255,255,255,0.2)'
        }
      }
    },
    series: [
      {
        type: 'flowGL',
        data: data,
        particleDensity: 64,
        particleSize: 5,
        itemStyle: {
          opacity: 0.5
        }
      },
      {
        type: 'custom',
        data: data,
        encode: {
          x: 0,
          y: 0
        },
        renderItem: function (params, api) {
          var x = api.value(0),
            y = api.value(1),
            dx = api.value(2),
            dy = api.value(3);
          var start = api.coord([x - dx / 2, y - dy / 2]);
          var end = api.coord([x + dx / 2, y + dy / 2]);
          return {
            type: 'line',
            shape: {
              x1: start[0],
              y1: start[1],
              x2: end[0],
              y2: end[1]
            },
            style: {
              lineWidth: 2,
              stroke: '#fff',
              opacity: 0.2
            }
          };
        }
      }
    ]
  });
});