refactor: rankCells

src/scripts/rankCells.ts

@@ -1,9 +1,13 @@
 import * as d3 from "d3";
 
 import {TIME} from "config/logging";
-import {normalize} from "utils/numberUtils";
+import {normalize, rn} from "utils/numberUtils";
+import {isWater, isCoastal} from "utils/graphUtils";
 
-// assess cells suitability to calculate population and rand cells for culture center and burgs placement
+const FLUX_MAX_BONUS = 250;
+const SUITABILITY_FACTOR = 5;
+
+// assess cells suitability for population and rank cells for culture centers and burgs placement
 export function rankCells() {
   TIME && console.time("rankCells");
   const {cells, features} = pack;
@@ -11,36 +15,66 @@ export function rankCells() {
   cells.s = new Int16Array(cells.i.length); // cell suitability array
   cells.pop = new Float32Array(cells.i.length); // cell population array
 
-  const flMean = d3.median(cells.fl.filter(f => f)) || 0;
-  const flMax = d3.max(cells.fl) + d3.max(cells.conf); // to normalize flux
-  const areaMean = d3.mean(cells.area); // to adjust population by cell area
+  const meanFlux = d3.median(cells.fl.filter(f => f)) || 0;
+  const maxFlux = (d3.max(cells.fl) || 0) + (d3.max(cells.conf) || 0); // to normalize flux
+  const meanArea = d3.mean(cells.area) || 0; // to adjust population by cell area
 
-  for (const i of cells.i) {
-    if (cells.h[i] < 20) continue; // no population in water
-    let s = +biomesData.habitability[cells.biome[i]]; // base suitability derived from biome habitability
-    if (!s) continue; // uninhabitable biomes has 0 suitability
-    if (flMean) s += normalize(cells.fl[i] + cells.conf[i], flMean, flMax) * 250; // big rivers and confluences are valued
-    s -= (cells.h[i] - 50) / 5; // low elevation is valued, high is not;
+  for (const cellId of cells.i) {
+    if (isWater(cellId)) continue; // no population in water
 
-    if (cells.t[i] === 1) {
-      if (cells.r[i]) s += 15; // estuary is valued
-      const feature = features[cells.f[cells.haven[i]]];
-      if (feature.type === "lake") {
-        if (feature.group === "freshwater") s += 30;
-        else if (feature.group == "salt") s += 10;
-        else if (feature.group == "frozen") s += 1;
-        else if (feature.group == "dry") s -= 5;
-        else if (feature.group == "sinkhole") s -= 5;
-        else if (feature.group == "lava") s -= 30;
-      } else {
-        s += 5; // ocean coast is valued
-        if (cells.harbor[i] === 1) s += 20; // safe sea harbor is valued
-      }
-    }
+    const habitabilityBonus = getHabitabilityBonus(cellId); // [0, 100]
+    if (!habitabilityBonus) continue; // uninhabitable biomes are excluded
+
+    const riverBonus = getFluxBonus(cellId); // [0, 250]
+    const elevationBonus = getElevationBonus(cellId); // [-10, 6]
+    const coastBonus = getCoastBonus(cellId); // [-30, 30]
+    const estuaryBonus = getEstuaryBonus(cellId); // [0, 15]
+
+    const suitability =
+      (habitabilityBonus + riverBonus + elevationBonus + coastBonus + estuaryBonus) / SUITABILITY_FACTOR; // [-30, 311]
 
-    cells.s[i] = s / 5; // general population rate
     // cell rural population is suitability adjusted by cell area
-    cells.pop[i] = cells.s[i] > 0 ? (cells.s[i] * cells.area[i]) / areaMean : 0;
+    const population = suitability > 0 ? suitability * (cells.area[cellId] / meanArea) : 0;
+
+    cells.pop[cellId] = population;
+    cells.s[cellId] = suitability;
+  }
+
+  function getHabitabilityBonus(cellId: number) {
+    return biomesData.habitability[cells.biome[cellId]];
+  }
+
+  function getFluxBonus(cellId: number) {
+    if (!cells.fl[cellId]) return 0;
+    return normalize(cells.fl[cellId] + cells.conf[cellId], meanFlux, maxFlux) * FLUX_MAX_BONUS;
+  }
+
+  function getElevationBonus(cellId: number) {
+    return (50 - cells.h[cellId]) / 5;
+  }
+
+  function getCoastBonus(cellId: number) {
+    if (!isCoastal(cellId)) return 0;
+
+    const havenCell = cells.haven[cellId];
+    const {group} = features[cells.f[havenCell]];
+
+    // lake coast
+    if (group === "freshwater") return 30;
+    if (group == "salt") return 10;
+    if (group == "frozen") return 1;
+    if (group == "dry") return 1;
+    if (group == "sinkhole") return 3;
+    if (group == "lava") return -30;
+
+    // ocean coast
+    if (cells.harbor[cellId] === 1) return 25; // safe harbor
+    return 5; // unsafe harbor
+  }
+
+  // estuary bonus is [0, 15]
+  function getEstuaryBonus(cellId: number) {
+    return cells.r[cellId] && isCoastal(cellId) ? 15 : 0;
   }
 
   TIME && console.timeEnd("rankCells");