From 96a103376f55883009fe1f3d53d5d557225d482a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 09:05:12 +0000
Subject: [PATCH 1/3] Initial plan


From 62da4f8b53579e0f93e4f5aa68a1167fa64c8519 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 09:17:50 +0000
Subject: [PATCH 2/3] Add 'Change Only Ocean Cells' checkbox to heightmap
 editor

Agent-Logs-Url: https://github.com/Azgaar/Fantasy-Map-Generator/sessions/4011258c-2dd9-45c2-bec6-bd390cb8ca73

Co-authored-by: Azgaar <26469650+Azgaar@users.noreply.github.com>
---
 public/modules/ui/heightmap-editor.js | 50 ++++++++++++++++++++++-----
 src/index.html                        |  8 +++++
 2 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/public/modules/ui/heightmap-editor.js b/public/modules/ui/heightmap-editor.js
index 69be50591..9d2495212 100644
--- a/public/modules/ui/heightmap-editor.js
+++ b/public/modules/ui/heightmap-editor.js
@@ -71,14 +71,17 @@ function editHeightmap(options) {
     if (mode === "erase") {
       undraw();
       changeOnlyLand.checked = false;
+      changeOnlyOcean.checked = false;
     } else if (mode === "keep") {
       viewbox.selectAll("#landmass, #lakes").style("display", "none");
       changeOnlyLand.checked = true;
+      changeOnlyOcean.checked = false;
     } else if (mode === "risk") {
       defs.selectAll("#land, #water").selectAll("path").remove();
       defs.select("#featurePaths").selectAll("path").remove();
       viewbox.selectAll("#coastline use, #lakes path, #oceanLayers path").remove();
       changeOnlyLand.checked = false;
+      changeOnlyOcean.checked = false;
     }
 
     // show convert and template buttons for Erase mode only
@@ -488,6 +491,13 @@ function editHeightmap(options) {
       }
     }
 
+    // check land cells are not changed if only ocean edit is allowed
+    if (changeOnlyOcean.checked) {
+      for (const i of grid.cells.i) {
+        if (prev[i] >= 20 || grid.cells.h[i] >= 20) grid.cells.h[i] = prev[i];
+      }
+    }
+
     mockHeightmap();
     updateHistory();
   }
@@ -588,6 +598,7 @@ function editHeightmap(options) {
     // add listeners
     byId("brushesButtons").on("click", e => toggleBrushMode(e));
     byId("changeOnlyLand").on("click", e => changeOnlyLandClick(e));
+    byId("changeOnlyOcean").on("click", e => changeOnlyOceanClick(e));
     byId("undo").on("click", () => restoreHistory(edits.n - 1));
     byId("redo").on("click", () => restoreHistory(edits.n + 1));
     byId("rescaleShow").on("click", () => {
@@ -686,6 +697,7 @@ function editHeightmap(options) {
       for (let i = 0; i < heights.length; i++) {
         if (changedHeights[i] === heights[i]) continue;
         if (changeOnlyLand.checked && heights[i] < 20) continue;
+        if (changeOnlyOcean.checked && heights[i] >= 20) continue;
         heights[i] = changedHeights[i];
         selection.push(i);
       }
@@ -705,7 +717,9 @@ function editHeightmap(options) {
         if (~~d3.event.sourceEvent.timeStamp % 5 != 0) return; // slow down the edit
 
         const inRadius = findGridAll(p[0], p[1], r);
-        const selection = changeOnlyLand.checked ? inRadius.filter(i => grid.cells.h[i] >= 20) : inRadius;
+        let selection = inRadius;
+        if (changeOnlyLand.checked) selection = inRadius.filter(i => grid.cells.h[i] >= 20);
+        else if (changeOnlyOcean.checked) selection = inRadius.filter(i => grid.cells.h[i] < 20);
         if (selection && selection.length) changeHeightForSelection(selection, start);
       });
 
@@ -717,11 +731,12 @@ function editHeightmap(options) {
 
       const interpolate = d3.interpolateRound(power, 1);
       const land = changeOnlyLand.checked;
-      const lim = v => minmax(v, land ? 20 : 0, 100);
+      const ocean = changeOnlyOcean.checked;
+      const lim = v => minmax(v, land ? 20 : 0, ocean ? 19 : 100);
       const heights = grid.cells.h;
 
       const brush = document.querySelector("#brushesButtons > button.pressed").id;
-      if (brush === "brushRaise") selection.forEach(i => (heights[i] = heights[i] < 20 ? 20 : lim(heights[i] + power)));
+      if (brush === "brushRaise") selection.forEach(i => (heights[i] = !ocean && heights[i] < 20 ? 20 : lim(heights[i] + power)));
       else if (brush === "brushElevate")
         selection.forEach(
           (i, d) => (heights[i] = lim(heights[i] + interpolate(d / Math.max(selection.length - 1, 1))))
@@ -736,7 +751,7 @@ function editHeightmap(options) {
         selection.forEach(
           i =>
             (heights[i] = rn(
-              (d3.mean(grid.cells.c[i].filter(i => (land ? heights[i] >= 20 : 1)).map(c => heights[c])) +
+              (d3.mean(grid.cells.c[i].filter(c => (land ? heights[c] >= 20 : ocean ? heights[c] < 20 : 1)).map(c => heights[c])) +
                 heights[i] * (10 - power) +
                 0.6) /
                 (11 - power),
@@ -753,14 +768,32 @@ function editHeightmap(options) {
     }
 
     function changeOnlyLandClick(e) {
-      if (heightmapEditMode.innerHTML !== "keep") return;
-      e.preventDefault();
-      tip("You cannot change the coastline in 'Keep' edit mode", false, "error");
+      if (heightmapEditMode.innerHTML === "keep") {
+        e.preventDefault();
+        tip("You cannot change the coastline in 'Keep' edit mode", false, "error");
+        return;
+      }
+      if (changeOnlyLand.checked) changeOnlyOcean.checked = false;
+    }
+
+    function changeOnlyOceanClick(e) {
+      if (heightmapEditMode.innerHTML === "keep") {
+        e.preventDefault();
+        tip("You cannot change the coastline in 'Keep' edit mode", false, "error");
+        return;
+      }
+      if (changeOnlyOcean.checked) changeOnlyLand.checked = false;
     }
 
     function rescale(v) {
       const land = changeOnlyLand.checked;
-      grid.cells.h = grid.cells.h.map(h => (land && (h < 20 || h + v < 20) ? h : lim(h + v)));
+      const ocean = changeOnlyOcean.checked;
+      grid.cells.h = grid.cells.h.map(h => {
+        if (land && (h < 20 || h + v < 20)) return h;
+        if (ocean && h >= 20) return h;
+        const newH = lim(h + v);
+        return ocean ? Math.min(newH, 19) : newH;
+      });
       updateHeightmap();
       byId("rescaler").value = 0;
     }
@@ -799,6 +832,7 @@ function editHeightmap(options) {
 
     function startFromScratch() {
       if (changeOnlyLand.checked) return tip("Not allowed when 'Change only land cells' mode is set", false, "error");
+      if (changeOnlyOcean.checked) return tip("Not allowed when 'Change only ocean cells' mode is set", false, "error");
       const someHeights = grid.cells.h.some(h => h);
       if (!someHeights)
         return tip("Heightmap is already cleared, please do not click twice if not required", false, "error");
diff --git a/src/index.html b/src/index.html
index f721353b5..ac7d5ffc5 100644
--- a/src/index.html
+++ b/src/index.html
@@ -4199,6 +4199,14 @@
           <label for="changeOnlyLand" class="checkbox-label"><i>change only land cells</i></label>
         </div>
 
+        <div
+          data-tip="Allow brush to change only ocean cells and hence restrict land modification"
+          style="margin-bottom: 0.6em"
+        >
+          <input id="changeOnlyOcean" class="checkbox" type="checkbox" />
+          <label for="changeOnlyOcean" class="checkbox-label"><i>change only ocean cells</i></label>
+        </div>
+
         <div id="modifyButtons">
           <button id="undo" data-tip="Undo the latest action (Ctrl + Z)" class="icon-ccw" disabled></button>
           <button id="redo" data-tip="Redo the action (Ctrl + Y)" class="icon-cw" disabled></button>

From 1edb1e241580fca8850962802675380c7119cb53 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 22 Apr 2026 10:04:18 +0000
Subject: [PATCH 3/3] Replace land/ocean checkboxes with cellTypeFilter select
 dropdown

Agent-Logs-Url: https://github.com/Azgaar/Fantasy-Map-Generator/sessions/e456d324-554b-4ee5-98ae-3c28da95ecca

Co-authored-by: Azgaar <26469650+Azgaar@users.noreply.github.com>
---
 public/modules/ui/heightmap-editor.js | 57 ++++++++++-----------------
 src/index.html                        | 21 ++++------
 2 files changed, 28 insertions(+), 50 deletions(-)

diff --git a/public/modules/ui/heightmap-editor.js b/public/modules/ui/heightmap-editor.js
index 9d2495212..227c07920 100644
--- a/public/modules/ui/heightmap-editor.js
+++ b/public/modules/ui/heightmap-editor.js
@@ -70,18 +70,15 @@ function editHeightmap(options) {
 
     if (mode === "erase") {
       undraw();
-      changeOnlyLand.checked = false;
-      changeOnlyOcean.checked = false;
+      cellTypeFilter.value = "all";
     } else if (mode === "keep") {
       viewbox.selectAll("#landmass, #lakes").style("display", "none");
-      changeOnlyLand.checked = true;
-      changeOnlyOcean.checked = false;
+      cellTypeFilter.value = "land";
     } else if (mode === "risk") {
       defs.selectAll("#land, #water").selectAll("path").remove();
       defs.select("#featurePaths").selectAll("path").remove();
       viewbox.selectAll("#coastline use, #lakes path, #oceanLayers path").remove();
-      changeOnlyLand.checked = false;
-      changeOnlyOcean.checked = false;
+      cellTypeFilter.value = "all";
     }
 
     // show convert and template buttons for Erase mode only
@@ -484,15 +481,15 @@ function editHeightmap(options) {
     tip("Cells changed: " + changed);
     if (!changed) return;
 
-    // check ocean cells are not checged if olny land edit is allowed
-    if (changeOnlyLand.checked) {
+    // check ocean cells are not changed if only land edit is allowed
+    if (cellTypeFilter.value === "land") {
       for (const i of grid.cells.i) {
         if (prev[i] < 20 || grid.cells.h[i] < 20) grid.cells.h[i] = prev[i];
       }
     }
 
-    // check land cells are not changed if only ocean edit is allowed
-    if (changeOnlyOcean.checked) {
+    // check land cells are not changed if only water edit is allowed
+    if (cellTypeFilter.value === "water") {
       for (const i of grid.cells.i) {
         if (prev[i] >= 20 || grid.cells.h[i] >= 20) grid.cells.h[i] = prev[i];
       }
@@ -597,8 +594,7 @@ function editHeightmap(options) {
 
     // add listeners
     byId("brushesButtons").on("click", e => toggleBrushMode(e));
-    byId("changeOnlyLand").on("click", e => changeOnlyLandClick(e));
-    byId("changeOnlyOcean").on("click", e => changeOnlyOceanClick(e));
+    byId("cellTypeFilter").on("change", cellTypeFilterChange);
     byId("undo").on("click", () => restoreHistory(edits.n - 1));
     byId("redo").on("click", () => restoreHistory(edits.n + 1));
     byId("rescaleShow").on("click", () => {
@@ -696,8 +692,8 @@ function editHeightmap(options) {
       let selection = [];
       for (let i = 0; i < heights.length; i++) {
         if (changedHeights[i] === heights[i]) continue;
-        if (changeOnlyLand.checked && heights[i] < 20) continue;
-        if (changeOnlyOcean.checked && heights[i] >= 20) continue;
+        if (cellTypeFilter.value === "land" && heights[i] < 20) continue;
+        if (cellTypeFilter.value === "water" && heights[i] >= 20) continue;
         heights[i] = changedHeights[i];
         selection.push(i);
       }
@@ -718,8 +714,8 @@ function editHeightmap(options) {
 
         const inRadius = findGridAll(p[0], p[1], r);
         let selection = inRadius;
-        if (changeOnlyLand.checked) selection = inRadius.filter(i => grid.cells.h[i] >= 20);
-        else if (changeOnlyOcean.checked) selection = inRadius.filter(i => grid.cells.h[i] < 20);
+        if (cellTypeFilter.value === "land") selection = inRadius.filter(i => grid.cells.h[i] >= 20);
+        else if (cellTypeFilter.value === "water") selection = inRadius.filter(i => grid.cells.h[i] < 20);
         if (selection && selection.length) changeHeightForSelection(selection, start);
       });
 
@@ -730,8 +726,8 @@ function editHeightmap(options) {
       const power = heightmapBrushPower.valueAsNumber;
 
       const interpolate = d3.interpolateRound(power, 1);
-      const land = changeOnlyLand.checked;
-      const ocean = changeOnlyOcean.checked;
+      const land = cellTypeFilter.value === "land";
+      const ocean = cellTypeFilter.value === "water";
       const lim = v => minmax(v, land ? 20 : 0, ocean ? 19 : 100);
       const heights = grid.cells.h;
 
@@ -767,27 +763,16 @@ function editHeightmap(options) {
       // updateHistory(); uncomment to update history on every step
     }
 
-    function changeOnlyLandClick(e) {
-      if (heightmapEditMode.innerHTML === "keep") {
-        e.preventDefault();
+    function cellTypeFilterChange() {
+      if (cellTypeFilter.value === "land" && heightmapEditMode.innerHTML === "keep") {
         tip("You cannot change the coastline in 'Keep' edit mode", false, "error");
-        return;
-      }
-      if (changeOnlyLand.checked) changeOnlyOcean.checked = false;
-    }
-
-    function changeOnlyOceanClick(e) {
-      if (heightmapEditMode.innerHTML === "keep") {
-        e.preventDefault();
-        tip("You cannot change the coastline in 'Keep' edit mode", false, "error");
-        return;
+        cellTypeFilter.value = "all";
       }
-      if (changeOnlyOcean.checked) changeOnlyLand.checked = false;
     }
 
     function rescale(v) {
-      const land = changeOnlyLand.checked;
-      const ocean = changeOnlyOcean.checked;
+      const land = cellTypeFilter.value === "land";
+      const ocean = cellTypeFilter.value === "water";
       grid.cells.h = grid.cells.h.map(h => {
         if (land && (h < 20 || h + v < 20)) return h;
         if (ocean && h >= 20) return h;
@@ -831,8 +816,8 @@ function editHeightmap(options) {
     }
 
     function startFromScratch() {
-      if (changeOnlyLand.checked) return tip("Not allowed when 'Change only land cells' mode is set", false, "error");
-      if (changeOnlyOcean.checked) return tip("Not allowed when 'Change only ocean cells' mode is set", false, "error");
+      if (cellTypeFilter.value === "land") return tip("Not allowed when 'only land cells' filter is set", false, "error");
+      if (cellTypeFilter.value === "water") return tip("Not allowed when 'only water cells' filter is set", false, "error");
       const someHeights = grid.cells.h.some(h => h);
       if (!someHeights)
         return tip("Heightmap is already cleared, please do not click twice if not required", false, "error");
diff --git a/src/index.html b/src/index.html
index ac7d5ffc5..2ef9d95a5 100644
--- a/src/index.html
+++ b/src/index.html
@@ -4191,20 +4191,13 @@
           </div>
         </div>
 
-        <div
-          data-tip="Allow brush to change only land cells and hence restrict the coastline modification"
-          style="margin-bottom: 0.6em"
-        >
-          <input id="changeOnlyLand" class="checkbox" type="checkbox" />
-          <label for="changeOnlyLand" class="checkbox-label"><i>change only land cells</i></label>
-        </div>
-
-        <div
-          data-tip="Allow brush to change only ocean cells and hence restrict land modification"
-          style="margin-bottom: 0.6em"
-        >
-          <input id="changeOnlyOcean" class="checkbox" type="checkbox" />
-          <label for="changeOnlyOcean" class="checkbox-label"><i>change only ocean cells</i></label>
+        <div data-tip="Restrict brush to specific cell types" style="margin-bottom: 0.6em">
+          <label for="cellTypeFilter"><i>Cells to change:</i></label>
+          <select id="cellTypeFilter">
+            <option value="all" selected>all cells</option>
+            <option value="land">only land cells</option>
+            <option value="water">only water cells</option>
+          </select>
         </div>
 
         <div id="modifyButtons">