sparse array implementation with reduced updates

public/modules/ice.js

@@ -65,33 +65,41 @@ window.Ice = (function () {
     }
   }
 
-  // Add a new iceberg (manual editing)
   function addIceberg(cellId, size) {
     const [cx, cy] = grid.points[cellId];
     const points = getGridPolygon(cellId).map(([x, y]) => [
       rn(lerp(cx, x, size), 2),
       rn(lerp(cy, y, size), 2)
     ]);
-
-    pack.ice.icebergs.push({
-      cellId,
-      size,
-      points
-    });
-
-    return pack.ice.icebergs.length - 1; // return index
-  }
-
-  // Remove ice element by index
-  function removeIce(type, index) {
-    if (type === "glacier" && pack.ice.glaciers[index]) {
-      pack.ice.glaciers.splice(index, 1);
-    } else if (type === "iceberg" && pack.ice.icebergs[index]) {
-      pack.ice.icebergs.splice(index, 1);
+    //here we use the lose equality to find the first undefined or empty or null slot
+    const nextIndex = pack.ice.icebergs.findIndex(iceberg => iceberg == undefined);
+    if (nextIndex !== -1) {
+      pack.ice.icebergs[nextIndex] = {
+        cellId,
+        size,
+        points
+      };
+      redrawIceberg(nextIndex);
+    } else {
+      pack.ice.icebergs.push({
+        cellId,
+        size,
+        points
+      });
+      redrawIceberg(pack.ice.icebergs.length - 1);
+    }
+  }
+
+  function removeIce(type, index) {
+    if (type === "glacier" && pack.ice.glaciers[index]) {
+      delete pack.ice.glaciers[index];
+      redrawGlacier(index);
+    } else if (type === "iceberg" && pack.ice.icebergs[index]) {
+      delete pack.ice.icebergs[index];
+      redrawIceberg(index);
     }
   }
 
-  // Update iceberg points and size
   function updateIceberg(index, points, size) {
     if (pack.ice.icebergs[index]) {
       pack.ice.icebergs[index].points = points;
@@ -99,7 +107,6 @@ window.Ice = (function () {
     }
   }
 
-  // Randomize iceberg shape
   function randomizeIcebergShape(index) {
     const iceberg = pack.ice.icebergs[index];
     if (!iceberg) return;
@@ -120,7 +127,6 @@ window.Ice = (function () {
     iceberg.points = points;
   }
 
-  // Change iceberg size and recalculate points
   function changeIcebergSize(index, newSize) {
     const iceberg = pack.ice.icebergs[index];
     if (!iceberg) return;
@@ -129,7 +135,6 @@ window.Ice = (function () {
     const [cx, cy] = grid.points[cellId];
     const oldSize = iceberg.size;
 
-    // Recalculate points based on new size
     const flat = iceberg.points.flat();
     const pairs = [];
     while (flat.length) pairs.push(flat.splice(0, 2));
@@ -143,7 +148,6 @@ window.Ice = (function () {
     iceberg.size = newSize;
   }
 
-  // Get all ice data
   function getData() {
     return pack.ice;
   }

public/modules/renderers/draw-ice.js

@@ -11,17 +11,73 @@ function drawIce() {
 
   // Draw glaciers
   pack.ice.glaciers.forEach((glacier, index) => {
-    html += `<polygon points="${glacier.points}" type="iceShield" data-index="${index}" ${glacier.offset ? `transform="translate(${glacier.offset[0]},${glacier.offset[1]})"` : ""} class="glacier"/>`;
+    html += getGlacierHtml(glacier, index);
   });
 
   // Draw icebergs
   pack.ice.icebergs.forEach((iceberg, index) => {
-    html += `<polygon points="${iceberg.points}" cell="${iceberg.cellId}" size="${iceberg.size}" data-index="${index}" ${iceberg.offset ? `transform="translate(${iceberg.offset[0]},${iceberg.offset[1]})"` : ""} class="iceberg"/>`;
+    html += getIcebergHtml(iceberg, index);
   });
 
   ice.html(html);
 
   TIME && console.timeEnd("drawIce");
+
+  function getGlacierHtml(glacier, index) {
+    return `<polygon points="${glacier.points}" type="iceShield" data-index="${index}" ${glacier.offset ? `transform="translate(${glacier.offset[0]},${glacier.offset[1]})"` : ""} class="glacier"/>`;
+  }
+
+  function getIcebergHtml(iceberg, index) {
+    return `<polygon points="${iceberg.points}" cell="${iceberg.cellId}" size="${iceberg.size}" data-index="${index}" ${iceberg.offset ? `transform="translate(${iceberg.offset[0]},${iceberg.offset[1]})"` : ""} class="iceberg"/>`;
+  }
+}
+
+function redrawIceberg(index) {
+  TIME && console.time("redrawIceberg");
+  const iceberg = pack.ice.icebergs[index];
+  let el = ice.selectAll(`.iceberg[data-index="${index}"]`);
+  if (!iceberg && !el.empty()) {
+    el.remove();
+  } else {
+    if (el.empty()) {
+      // Create new element if it doesn't exist
+      const polygon = getIcebergHtml(iceberg, index);
+      ice.node().insertAdjacentHTML("beforeend", polygon);
+      el = ice.selectAll(`.iceberg[data-index="${index}"]`);
+    }
+    el.attr("points", iceberg.points);
+    el.attr("size", iceberg.size);
+    el.attr("cell", iceberg.cellId);
+    el.attr("transform", iceberg.offset ? `translate(${iceberg.offset[0]},${iceberg.offset[1]})` : null);
+  }
+  TIME && console.timeEnd("redrawIceberg");
+
+  function getIcebergHtml(iceberg, index) {
+    return `<polygon points="${iceberg.points}" cell="${iceberg.cellId}" size="${iceberg.size}" data-index="${index}" ${iceberg.offset ? `transform="translate(${iceberg.offset[0]},${iceberg.offset[1]})"` : ""} class="iceberg"/>`;
+  }
+}
+
+function redrawGlacier(index) {
+  TIME && console.time("redrawGlacier");
+  const glacier = pack.ice.glaciers[index];
+  let el = ice.selectAll(`.glacier[data-index="${index}"]`);
+  if (!glacier && !el.empty()) {
+    el.remove();
+  } else {
+    if (el.empty()) {
+      // Create new element if it doesn't exist
+      const polygon = getGlacierHtml(glacier, index);
+      ice.node().insertAdjacentHTML("beforeend", polygon);
+      el = ice.selectAll(`.glacier[data-index="${index}"]`);
+    }
+    el.attr("points", glacier.points);
+    el.attr("transform", glacier.offset ? `translate(${glacier.offset[0]},${glacier.offset[1]})` : null);
+  }
+  TIME && console.timeEnd("redrawGlacier");
+
+  function getGlacierHtml(glacier, index) {
+    return `<polygon points="${glacier.points}" type="iceShield" data-index="${index}" ${glacier.offset ? `transform="translate(${glacier.offset[0]},${glacier.offset[1]})"` : ""} class="glacier"/>`;
+  }
 }
 
 // Re-render ice layer from data model

public/modules/ui/ice-editor.js

@@ -23,7 +23,7 @@ function editIce() {
   });
 
   if (!modules.editIce) {
-    modules.editIce = {currentIndex: index};
+    modules.editIce = {currentIndex: index, isGlacier: isGlacier};
     // add listeners
     document.getElementById("iceEditStyle").addEventListener("click", () => editStyle("ice"));
     document.getElementById("iceRandomize").addEventListener("click", randomizeShape);
@@ -32,19 +32,20 @@ function editIce() {
     document.getElementById("iceRemove").addEventListener("click", removeIce);
   }
   modules.editIce.currentIndex = index;
+  modules.editIce.isGlacier = isGlacier;
 
 
   function randomizeShape() {
     const idx = modules.editIce.currentIndex;
     Ice.randomizeIcebergShape(idx);
-    redrawIce();
+    redrawIceberg(idx);
   }
 
   function changeSize() {
     const newSize = +this.value;
     const idx = modules.editIce.currentIndex;
     Ice.changeIcebergSize(idx, newSize);
-    redrawIce();
+    redrawIceberg(idx);
   }
 
   function toggleAdd() {
@@ -64,13 +65,12 @@ function editIce() {
     const size = +document.getElementById("iceSize")?.value || 1;
 
     Ice.addIceberg(i, size);
-    redrawIce();
 
     if (d3.event.shiftKey === false) toggleAdd();
   }
 
   function removeIce() {
-    const type = isGlacier ? "Glacier" : "Iceberg";
+    const type = modules.editIce.isGlacier ? "Glacier" : "Iceberg";
     alertMessage.innerHTML = /* html */ `Are you sure you want to remove the ${type}?`;
     $("#alert").dialog({
       resizable: false,
@@ -78,8 +78,7 @@ function editIce() {
       buttons: {
         Remove: function () {
           $(this).dialog("close");
-          Ice.removeIce(isGlacier ? "glacier" : "iceberg", index);
-          redrawIce();
+          Ice.removeIce(type.toLowerCase(), modules.editIce.currentIndex);
           $("#iceEditor").dialog("close");
         },
         Cancel: function () {