Show how far away two characters can see each other

Only happens if both 'show ratios' and 'show horizon' are enabled

macrovision.js

@@ -566,6 +566,7 @@ function updateEntityElement(entity, element) {
     } else {
         topName.classList.remove("top-name-needed");
     }
+    updateRatios();
 }
 
 let ratioInfo
@@ -607,15 +608,35 @@ function updateRatios() {
 
     if (config.showHorizon) {
         if (selectedEntity !== null) {
+            const y = document.querySelector("#entity-" + selectedEntity.index).dataset.y;
             const R = math.unit(1.27560e+7, "meters")
-            const h = selectedEntity.currentView.height
+            const h = math.add(selectedEntity.currentView.height, math.unit(y, "meters"))
 
             const first = math.multiply(2, math.multiply(R, h))
             const second = math.multiply(h, h)
 
             const sightline = math.sqrt(math.add(first, second)).to(config.height.units[0].unit.name)
 
-            text += selectedEntity.name + " could see for " + math.format(sightline, { precision: 3 })
+            text += selectedEntity.name + " could see for " + math.format(sightline, { precision: 3 }) + "\n"
+        }
+    }
+
+    if (config.showRatios && config.showHorizon) {
+        if (selectedEntity !== null && prevSelectedEntity !== null && selectedEntity !== prevSelectedEntity) {
+            const y1 = document.querySelector("#entity-" + selectedEntity.index).dataset.y;
+            const y2 = document.querySelector("#entity-" + prevSelectedEntity.index).dataset.y;
+            const R = math.unit(1.27560e+7, "meters")
+            const R2 = math.subtract(math.subtract(R, prevSelectedEntity.currentView.height), math.unit(y2, "meters"))
+            const h = math.add(selectedEntity.currentView.height, math.unit(y1, "meters"))
+
+            console.log(R, R2, h)
+
+            const first = math.pow(math.add(R, h), 2)
+            const second = math.pow(R2, 2)
+
+            const sightline = math.sqrt(math.subtract(first, second)).to(config.height.units[0].unit.name)
+
+            text += selectedEntity.name + " could see " + prevSelectedEntity.name + " from " + math.format(sightline, { precision: 3 }) + " away\n"
         }
     }
 
@@ -2219,6 +2240,9 @@ function removeEntity(element) {
     topName.parentElement.removeChild(topName);
     element.parentElement.removeChild(element);
 
+    selectedEntity = null;
+    prevSelectedEntity = null;
+    updateRatios();
 }
 
 function checkEntity(entity) {