fix(editor): NPC markers always on top, mesa generator, terrain tools

- NPC markers now render with NO depth test (via gizmo pipeline) so
  they're always visible even on sloped/rough terrain
- Mesa/Plateau generator: creates raised flat areas with steep cliff
  edges — configurable radius, height, and edge steepness
- NPC markers drawn after gizmo in the render pipeline to guarantee
  they appear on top of everything
- Fixes NPC visibility on non-flat terrain

tools/editor/editor_ui.cpp

@@ -551,6 +551,19 @@ void EditorUI::renderBrushPanel(EditorApp& app) {
                 ImGui::TextColored(ImVec4(0.6f, 0.6f, 0.6f, 1), "No stamp copied");
         }
 
+        if (ImGui::CollapsingHeader("Mesa / Plateau")) {
+            static float mesaRadius = 40.0f, mesaHeight = 20.0f, mesaSteep = 0.3f;
+            ImGui::SliderFloat("Radius##mesa", &mesaRadius, 10.0f, 150.0f);
+            ImGui::SliderFloat("Height##mesa", &mesaHeight, 5.0f, 100.0f);
+            ImGui::SliderFloat("Edge Steepness##mesa", &mesaSteep, 0.05f, 1.0f);
+            auto& brush6 = app.getTerrainEditor().brush();
+            if (ImGui::Button("Create Mesa at Cursor", ImVec2(-1, 0)) && brush6.isActive()) {
+                app.getTerrainEditor().createMesa(brush6.getPosition(), mesaRadius, mesaHeight, mesaSteep);
+                app.showToast("Mesa created");
+            }
+            ImGui::TextColored(ImVec4(0.6f, 0.6f, 0.6f, 1), "Raised flat area with cliff edges");
+        }
+
         if (ImGui::CollapsingHeader("Crater Generator")) {
             static float craterRadius = 30.0f, craterDepth = 10.0f, craterRim = 3.0f;
             ImGui::SliderFloat("Radius##crater", &craterRadius, 5.0f, 100.0f);

tools/editor/editor_viewport.cpp

@@ -442,21 +442,7 @@ void EditorViewport::render(VkCommandBuffer cmd) {
 
     waterRenderer_.render(cmd, perFrameSet);
 
-    // NPC position markers (always visible)
-    if (npcMarkerVB_ && npcMarkerVertCount_ > 0) {
-        auto* wp = waterRenderer_.getPipeline();
-        auto* wl = waterRenderer_.getPipelineLayout();
-        static bool loggedOnce = false;
-        if (!loggedOnce) { loggedOnce = true; LOG_INFO("NPC render: vb=", (wp?"ok":"null"), " layout=", (wl?"ok":"null"), " verts=", npcMarkerVertCount_); }
-        if (wp && wl) {
-            vkCmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, wp);
-            vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, wl,
-                                    0, 1, &perFrameSet, 0, nullptr);
-            VkDeviceSize off = 0;
-            vkCmdBindVertexBuffers(cmd, 0, 1, &npcMarkerVB_, &off);
-            vkCmdDraw(cmd, npcMarkerVertCount_, 1, 0, 0);
-        }
-    }
+    // NPC position markers — render AFTER gizmo (no depth test = always on top)
 
     // Brush indicator circle
     if (brushVisible_ && brushVB_ && brushVertCount_ > 0) {
@@ -480,6 +466,18 @@ void EditorViewport::render(VkCommandBuffer cmd) {
     }
 
     gizmo_.render(cmd, perFrameSet);
+
+    // NPC markers rendered last with no depth test (always on top via gizmo pipeline)
+    if (npcMarkerVB_ && npcMarkerVertCount_ > 0) {
+        // Gizmo pipeline has depthTestEnable=VK_FALSE — markers always visible
+        auto& gizmoPL = gizmo_;
+        // Re-bind gizmo pipeline (same vertex format, no depth test)
+        // gizmo_.render already set it up, just draw our buffer
+        VkDeviceSize off = 0;
+        vkCmdBindVertexBuffers(cmd, 0, 1, &npcMarkerVB_, &off);
+        vkCmdDraw(cmd, npcMarkerVertCount_, 1, 0, 0);
+        (void)gizmoPL;
+    }
 }
 
 void EditorViewport::setWireframe(bool enabled) {

tools/editor/terrain_editor.cpp

@@ -805,6 +805,41 @@ void TerrainEditor::createCrater(const glm::vec3& center, float radius, float de
     dirty_ = true;
 }
 
+void TerrainEditor::createMesa(const glm::vec3& center, float radius, float height, float edgeSteepness) {
+    if (!terrain_) return;
+
+    for (int ci = 0; ci < 256; ci++) {
+        auto& chunk = terrain_->chunks[ci];
+        if (!chunk.hasHeightMap()) continue;
+        bool modified = false;
+
+        for (int v = 0; v < 145; v++) {
+            glm::vec3 pos = chunkVertexWorldPos(ci, v);
+            float dist = glm::length(glm::vec2(pos.x - center.x, pos.y - center.y));
+            if (dist > radius * 1.5f) continue;
+
+            float t = dist / radius;
+            float blend;
+            if (t < 0.7f) {
+                blend = 1.0f; // flat top
+            } else if (t < 1.0f) {
+                float edgeT = (t - 0.7f) / 0.3f;
+                blend = 1.0f - std::pow(edgeT, 1.0f / std::max(0.1f, edgeSteepness));
+            } else {
+                blend = 0.0f;
+            }
+
+            chunk.heightMap.heights[v] += height * blend;
+            modified = true;
+        }
+        if (modified) {
+            stitchEdges(ci);
+            dirtyChunks_.push_back(ci);
+        }
+    }
+    dirty_ = true;
+}
+
 void TerrainEditor::flattenRoad(const glm::vec3& start, const glm::vec3& end, float width) {
     if (!terrain_) return;
     glm::vec2 lineStart(start.x, start.y);

tools/editor/terrain_editor.hpp

@@ -84,6 +84,9 @@ public:
     // Create a crater at a position (bowl shape with raised rim)
     void createCrater(const glm::vec3& center, float radius, float depth, float rimHeight);
 
+    // Create a mesa/plateau (raised flat area with steep cliff edges)
+    void createMesa(const glm::vec3& center, float radius, float height, float edgeSteepness);
+
     // Import/export heightmap (raw 16-bit grayscale, 129x129)
     bool importHeightmap(const std::string& path, float heightScale);
     bool exportHeightmap(const std::string& path, float heightScale);