chore: modularize main.js

src/modules/temperature.js

@@ -0,0 +1,33 @@
+import {TIME} from "config/logging";
+import {minmax, rn} from "utils/numberUtils";
+
+// temperature model
+export function calculateTemperatures() {
+  TIME && console.time("calculateTemperatures");
+  const cells = grid.cells;
+  cells.temp = new Int8Array(cells.i.length); // temperature array
+
+  const tEq = +temperatureEquatorInput.value;
+  const tPole = +temperaturePoleInput.value;
+  const tDelta = tEq - tPole;
+  const int = d3.easePolyInOut.exponent(0.5); // interpolation function
+
+  d3.range(0, cells.i.length, grid.cellsX).forEach(function (r) {
+    const y = grid.points[r][1];
+    const lat = Math.abs(mapCoordinates.latN - (y / graphHeight) * mapCoordinates.latT); // [0; 90]
+    const initTemp = tEq - int(lat / 90) * tDelta;
+    for (let i = r; i < r + grid.cellsX; i++) {
+      cells.temp[i] = minmax(initTemp - convertToFriendly(cells.h[i]), -128, 127);
+    }
+  });
+
+  // temperature decreases by 6.5 degree C per 1km
+  function convertToFriendly(h) {
+    if (h < 20) return 0;
+    const exponent = +heightExponentInput.value;
+    const height = Math.pow(h - 18, exponent);
+    return rn((height / 1000) * 6.5);
+  }
+
+  TIME && console.timeEnd("calculateTemperatures");
+}