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   /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__memory/uses_allocator_construction.h \
+  /opt/homebrew/include/glm/gtc/matrix_access.hpp \
+  /opt/homebrew/include/glm/gtc/../detail/setup.hpp \
+  /opt/homebrew/include/glm/gtc/matrix_access.inl \
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   /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/v1/__exception/exception_ptr.h \
+  /opt/homebrew/include/glm/gtc/matrix_access.hpp \
+  /opt/homebrew/include/glm/gtc/../detail/setup.hpp \
+  /opt/homebrew/include/glm/gtc/matrix_access.inl \
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+  /opt/homebrew/include/glm/gtc/matrix_access.hpp \
+  /opt/homebrew/include/glm/gtc/../detail/setup.hpp \
+  /opt/homebrew/include/glm/gtc/matrix_access.inl \
   /Users/will/Documents/zoomengine/src/OBJLoader.h \
   /Users/will/Documents/zoomengine/src/SimpleTextureLoader.h \
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+  /opt/homebrew/include/glm/gtc/matrix_access.hpp \
+  /opt/homebrew/include/glm/gtc/../detail/setup.hpp \
+  /opt/homebrew/include/glm/gtc/matrix_access.inl \
   /Users/will/Documents/zoomengine/src/LevelEditor.cpp \
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src/Engine.cpp

@@ -522,6 +522,46 @@ Engine::Engine(int w, int h, const char* title)
     InitOverlay();
 }
 
+// -------------------------------------------------------------
+// CullSphere — Gribb/Hartmann frustum plane extraction
+//
+// Extracts 6 frustum planes directly from the view-projection
+// matrix by combining its rows. [web:72][web:76]
+// Returns TRUE if the sphere is fully OUTSIDE any plane
+// (i.e. should be culled — skip rendering).
+// -------------------------------------------------------------
+bool Engine::CullSphere(const glm::mat4& vp,
+                        const glm::vec3& center,
+                        float radius)
+{
+    // GLM stores matrices column-major, so row(vp, n) extracts row n.
+    // Each frustum plane = combination of row 3 ± row n. [web:75][web:76]
+    const glm::vec4 row0 = glm::row(vp, 0);
+    const glm::vec4 row1 = glm::row(vp, 1);
+    const glm::vec4 row2 = glm::row(vp, 2);
+    const glm::vec4 row3 = glm::row(vp, 3);
+
+    const glm::vec4 planes[6] = {
+        row3 + row0,   // Left
+        row3 - row0,   // Right
+        row3 + row1,   // Bottom
+        row3 - row1,   // Top
+        row3 + row2,   // Near
+        row3 - row2,   // Far
+    };
+
+    const glm::vec4 pt(center, 1.0f);
+
+    for (const auto& plane : planes) {
+        // Signed distance from sphere centre to plane.
+        // If distance < -radius, sphere is fully on the outside. [web:73]
+        if (glm::dot(plane, pt) < -radius) {
+            return true;   // Cull — outside this plane
+        }
+    }
+    return false;   // Inside or intersecting all 6 planes — keep
+}
+
 // Culling subset method
 Engine::CullingResult Engine::CullObjectsSubset(
     const std::vector<GameObject*>& objects,
@@ -1003,9 +1043,17 @@ void Engine::RenderSceneInstanced() {
 
     // MULTITHREADED CULLING SECTION
     glm::mat4 vp = proj * view;
-    
+   
+    std::vector<GameObject*> raw_objects;
+    raw_objects.reserve(game_objects_.size());
+    for (const auto& sp : game_objects_)
+        raw_objects.push_back(sp.get());
+
+    if (raw_objects.empty()) return;
+
     // Determine number of threads and chunk size
-    size_t numThreads = std::min(threadPool_.getNumThreads(), game_objects_.size());
+    size_t numThreads = std::min(threadPool_.size(), game_objects_.size());
+    numThreads = std::max(numThreads, static_cast<size_t>(1));
     size_t objectsPerThread = (game_objects_.size() + numThreads - 1) / numThreads;
     
     // Launch culling tasks
@@ -1018,9 +1066,11 @@ void Engine::RenderSceneInstanced() {
         
         if (startIdx >= game_objects_.size()) break;
         
-        futures.push_back(threadPool_.enqueue([this, startIdx, endIdx, vp]() {
+        futures.push_back(threadPool_.enqueue(
-            return CullObjectsSubset(game_objects_, startIdx, endIdx, vp);
+            [this, &raw_objects, startIdx, endIdx, vp]() -> CullingResult {
-        }));
+        return CullObjectsSubset(raw_objects, startIdx, endIdx, vp);
+        }
+    ));
     }
     
     // Collect results

src/Engine.h

@@ -6,7 +6,8 @@
 #include <vector>
 #include <memory>
 #include <functional>
-#include "ThreadPool.h" 
+#include "ThreadPool.h"
+#include <glm/gtc/matrix_access.hpp>
 
 
 // Forward declarations
@@ -80,6 +81,10 @@ private:
         std::unordered_map<Primitive*, std::vector<glm::mat4>>& outBatches
     );
 
+    static bool CullSphere(const glm::mat4& vp,
+                           const glm::vec3& center,
+                           float radius);
+
 
 
    
@@ -177,4 +182,4 @@ private:
     glm::vec3 position_;
     glm::vec3 rotation_;
     glm::vec3 scale_{1.0f};
-};
+};

src/LevelEditor.cpp

@@ -1,53 +1,65 @@
-// LevelEditor.cpp
+// LevelEditor.cpp — FIXED
 
 #include "Engine.h"
 #include <GLFW/glfw3.h>
 #include <iostream>
 #include <vector>
 #include <cmath>
+#include <cstring>
 
-// ---------------------------------------------
-// LevelEditor: free camera, object placement, light sliders, stats
-// ---------------------------------------------
 class LevelEditor : public Engine {
 private:
     std::vector<std::shared_ptr<GameObject>> objects_;
-    std::shared_ptr<Primitive> monkeyPrim_;
+    std::shared_ptr<Primitive>  monkeyPrim_;
     std::shared_ptr<GameObject> selected_;
 
-
+    // FIX: Button stores its own pressed state so DrawButton can be
+    //      called for multiple buttons without a shared static variable
     struct Button {
         float x, y, w, h;
-        bool pressed;
+        bool  pressed = false;
     };
 
+    // Free-cam state
+    bool   firstMouse_ = true;
+    double lastX_ = 0.0, lastY_ = 0.0;
+    float  yaw_ = -90.0f, pitch_ = 0.0f;
+    float  camSpeed_ = 10.0f, mouseSens_ = 0.1f;
 
-    // Free cam state
+    // Light sliders
-    bool firstMouse_ = true;
+    float lightR = 1.0f, lightG = 1.0f, lightB = 1.0f, lightI = 1.0f;
-    double lastX_, lastY_;
+    bool  dragR = false, dragG = false, dragB = false, dragI = false;
-    float yaw_ = -90.0f, pitch_ = 0.0f;
-    float camSpeed_ = 10.0f, mouseSens_ = 0.1f;
 
-    // Light control state
+    Button btnOrtho{ 560.0f, 150.0f, 80.0f, 20.0f, false };
-    float lightR = 1, lightG = 1, lightB = 1, lightI = 1;
+    bool   useOrtho_ = false;
-    bool dragR = false, dragG = false, dragB = false, dragI = false;
 
+    // FIX: per-key previous-state for edge detection (one-shot placement)
+    bool prevKey1_ = false, prevKey2_ = false, prevKey3_ = false,
+         prevKey4_ = false, prevKey5_ = false;
 
-    Button btnOrtho { 560, 150, 80, 20, false };
+    // ---------------------------------------------------------------
-    bool useOrtho_ = false;
+    // Input helpers
-
+    // ---------------------------------------------------------------
-    // Helpers
     bool KeyDown(int k) const { return glfwGetKey(window_, k) == GLFW_PRESS; }
 
+    // Returns true only on the frame the key transitions low→high [web:61]
+    bool KeyJustPressed(int k, bool& prev) const {
+        bool cur  = KeyDown(k);
+        bool just = cur && !prev;
+        prev = cur;
+        return just;
+    }
+
     void ProcessMouse(double xpos, double ypos) {
         if (firstMouse_) {
             lastX_ = xpos; lastY_ = ypos;
             firstMouse_ = false;
+            return; // FIX: skip first frame to avoid a jump
         }
-        float xoff = (xpos - lastX_) * mouseSens_;
+        float xoff = static_cast<float>(xpos - lastX_) * mouseSens_;
-        float yoff = (lastY_ - ypos) * mouseSens_;
+        float yoff = static_cast<float>(lastY_ - ypos) * mouseSens_;
         lastX_ = xpos; lastY_ = ypos;
-        yaw_   += xoff;
+        yaw_  += xoff;
         pitch_ = glm::clamp(pitch_ + yoff, -89.0f, 89.0f);
         glm::vec3 front;
         front.x = cos(glm::radians(yaw_)) * cos(glm::radians(pitch_));
@@ -56,266 +68,268 @@ private:
         camera_target_ = camera_position_ + glm::normalize(front);
     }
 
-    // Place primitive at camera target
+    // FIX: overload — explicit position for use before camera is set up
-    void Place(std::shared_ptr<Primitive> prim) {
+    void Place(std::shared_ptr<Primitive> prim, const glm::vec3& pos) {
-        glm::vec3 pos = camera_target_;
         auto go = CreateGameObject(prim, pos);
         objects_.push_back(go);
         AddGameObject(go);
     }
+    void Place(std::shared_ptr<Primitive> prim) { Place(prim, camera_target_); }
 
-    // Raycast pick uses bounding spheres
     std::shared_ptr<GameObject> Pick(double mx, double my) {
-        int w,h; glfwGetWindowSize(window_,&w,&h);
+        int w, h; glfwGetWindowSize(window_, &w, &h);
-        float x = (2.0f*mx)/w -1.0f, y=1.0f-(2.0f*my)/h;
+        float nx =  (2.0f * mx) / w - 1.0f;
-        glm::vec4 ray_clip{x,y,-1,1};
+        float ny = 1.0f - (2.0f * my) / h;
-        
+        glm::vec4 ray_clip{ nx, ny, -1.0f, 1.0f };
-        // Create projection and view matrices locally
         glm::mat4 proj = glm::perspective(glm::radians(60.0f), float(w)/h, 0.1f, 1000.0f);
         glm::mat4 view = glm::lookAt(camera_position_, camera_target_, camera_up_);
-        
+        glm::vec4 ray_eye = glm::inverse(proj) * ray_clip;
-        glm::vec4 ray_eye = glm::inverse(proj)*ray_clip; ray_eye.z=-1; ray_eye.w=0;
+        ray_eye.z = -1.0f; ray_eye.w = 0.0f;
-        glm::vec3 dir = glm::normalize(glm::vec3(glm::inverse(view)*ray_eye));
+        glm::vec3 dir = glm::normalize(glm::vec3(glm::inverse(view) * ray_eye));
-        
+
-        std::shared_ptr<GameObject> best; float bd=FLT_MAX;
+        std::shared_ptr<GameObject> best; float bd = FLT_MAX;
-        for(auto& obj:objects_){
+        for (auto& obj : objects_) {
             glm::vec3 oc = camera_position_ - obj->GetPosition();
-            float b = glm::dot(oc,dir);
+            float b    = glm::dot(oc, dir);
-            float c = glm::dot(oc,oc) - obj->GetBoundingRadius()*obj->GetBoundingRadius();
+            float c    = glm::dot(oc, oc)
-            float disc = b*b - c;
+                       - obj->GetBoundingRadius() * obj->GetBoundingRadius();
-            if(disc<0) continue;
+            float disc = b * b - c;
-            float t = -b - sqrt(disc);
+            if (disc < 0.0f) continue;
-            if(t>0 && t<bd){ bd=t; best=obj; }
+            float t = -b - std::sqrt(disc);
+            if (t > 0.0f && t < bd) { bd = t; best = obj; }
         }
         return best;
     }
 
-    void DrawChar(char c, float x, float y, float s) {
+    // ---------------------------------------------------------------
-        static const std::vector<std::vector<std::pair<float,float>>> strokes = {
+    // 2D drawing — unified vertex type + helper to avoid repeating
-            {{0,0},{1,0},{1,1},{0,1},{0,0}},{{0.5f,0},{0.5f,1}},
+    // glBufferData / glVertexAttribPointer for every draw call
-            {{0,1},{1,1},{1,0.5f},{0,0.5f},{0,0},{1,0}},
+    // ---------------------------------------------------------------
-            {{0,1},{1,1},{1,0},{0,0},{1,0.5f}},
+    struct V2D { float x, y, r, g, b; };
-            {{0,1},{0,0.5f},{1,0.5f},{1,1},{1,0}},
+
-            {{1,1},{0,1},{0,0.5f},{1,0.5f},{1,0},{0,0}},
+    // FIX: single upload-and-draw helper used everywhere — the original
-            {{1,1},{0,1},{0,0},{1,0},{1,0.5f},{0,0.5f}},
+    //      code was missing glVertexAttribPointer calls before several
-            {{0,1},{1,1},{0.5f,0}},
+    //      glDrawArrays calls (e.g. the button fill triangles)
-            {{0,0},{0,1},{1,1},{1,0},{0,0},{0,0.5f},{1,0.5f}},
+    void UploadAndDraw(const std::vector<V2D>& v, GLenum mode) {
-            {{1,0},{1,1},{0,1},{0,0.5f},{1,0.5f}}
+        if (v.empty()) return;
-        };
+        glBufferData(GL_ARRAY_BUFFER,
-        std::vector<float> v;
+                     static_cast<GLsizeiptr>(v.size() * sizeof(V2D)),
-        if(c>='0'&&c<='9'){
+                     v.data(), GL_DYNAMIC_DRAW);
-            for(auto&p:strokes[c-'0']){
+        glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
-                v.push_back(x+p.first*s);
+                              sizeof(V2D), reinterpret_cast<void*>(0));
-                v.push_back(y+p.second*s);
+        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE,
-                v.push_back(1);v.push_back(1);v.push_back(1);
+                              sizeof(V2D), reinterpret_cast<void*>(2 * sizeof(float)));
+        glDrawArrays(mode, 0, static_cast<GLsizei>(v.size()));
+    }
+
+    // ---------------------------------------------------------------
+    // Segment-display font — digits AND letters
+    // FIX: original DrawChar only handled '0'–'9'; calling it with
+    //      'R','G','B','I' (and button labels) produced no output.
+    //      Merged into one function covering A–Z and 0–9.
+    // ---------------------------------------------------------------
+    void DrawChar(char c, float x, float y, float s,
+                  float r = 1.0f, float g = 1.0f, float b = 1.0f)
+    {
+        using P = std::pair<float,float>;
+        std::vector<P> pts;
+
+        if (c >= '0' && c <= '9') {
+            static const std::vector<std::vector<P>> D = {
+                {{0,0},{1,0},{1,1},{0,1},{0,0}},
+                {{0.5f,0},{0.5f,1}},
+                {{0,1},{1,1},{1,0.5f},{0,0.5f},{0,0},{1,0}},
+                {{0,1},{1,1},{1,0},{0,0},{1,0.5f}},
+                {{0,1},{0,0.5f},{1,0.5f},{1,1},{1,0}},
+                {{1,1},{0,1},{0,0.5f},{1,0.5f},{1,0},{0,0}},
+                {{1,1},{0,1},{0,0},{1,0},{1,0.5f},{0,0.5f}},
+                {{0,1},{1,1},{0.5f,0}},
+                {{0,0},{0,1},{1,1},{1,0},{0,0},{0,0.5f},{1,0.5f}},
+                {{1,0},{1,1},{0,1},{0,0.5f},{1,0.5f}}
+            };
+            pts = D[c - '0'];
+        } else {
+            switch (c) {
+            case 'A': pts={{0,0},{0.5f,1},{1,0},{0.25f,0.5f},{0.75f,0.5f}};            break;
+            case 'B': pts={{0,0},{0,1},{0.7f,1},{0.7f,0.5f},{0,0.5f},{0.7f,0.5f},{0.7f,0},{0,0}};  break;
+            case 'C': pts={{1,1},{0,1},{0,0},{1,0}};                                  break;
+            case 'D': pts={{0,0},{0,1},{0.7f,0.8f},{0.7f,0.2f},{0,0}};               break;
+            case 'E': pts={{1,1},{0,1},{0,0.5f},{0.7f,0.5f},{0,0.5f},{0,0},{1,0}};   break;
+            case 'F': pts={{0,0},{0,1},{1,1},{0,1},{0,0.5f},{0.7f,0.5f}};            break;
+            case 'G': pts={{1,1},{0,1},{0,0},{1,0},{1,0.5f},{0.5f,0.5f}};            break;
+            case 'H': pts={{0,0},{0,1},{0,0.5f},{1,0.5f},{1,1},{1,0}};               break;
+            case 'I': pts={{0,1},{1,1},{0.5f,1},{0.5f,0},{0,0},{1,0}};               break;
+            case 'J': pts={{0,1},{1,1},{1,0},{0,0},{0,0.3f}};                        break;
+            case 'K': pts={{0,0},{0,1},{0,0.5f},{1,1},{0,0.5f},{1,0}};               break;
+            case 'L': pts={{0,1},{0,0},{1,0}};                                        break;
+            case 'M': pts={{0,0},{0,1},{0.5f,0.5f},{1,1},{1,0}};                     break;
+            case 'N': pts={{0,0},{0,1},{1,0},{1,1}};                                  break;
+            case 'O': pts={{0,0},{0,1},{1,1},{1,0},{0,0}};                            break;
+            case 'P': pts={{0,0},{0,1},{1,1},{1,0.5f},{0,0.5f}};                     break;
+            case 'Q': pts={{1,0},{0,0},{0,1},{1,1},{1,0},{0.6f,0.2f}};               break;
+            case 'R': pts={{0,0},{0,1},{1,1},{1,0.5f},{0,0.5f},{1,0}};               break;
+            case 'S': pts={{1,1},{0,1},{0,0.5f},{1,0.5f},{1,0},{0,0}};               break;
+            case 'T': pts={{0,1},{1,1},{0.5f,1},{0.5f,0}};                           break;
+            case 'U': pts={{0,1},{0,0},{1,0},{1,1}};                                  break;
+            case 'V': pts={{0,1},{0.5f,0},{1,1}};                                     break;
+            case 'W': pts={{0,1},{0.25f,0},{0.5f,0.5f},{0.75f,0},{1,1}};             break;
+            case 'X': pts={{0,0},{1,1},{0.5f,0.5f},{0,1},{1,0}};                     break;
+            case 'Y': pts={{0,1},{0.5f,0.5f},{1,1},{0.5f,0.5f},{0.5f,0}};           break;
+            case 'Z': pts={{0,1},{1,1},{0,0},{1,0}};                                  break;
+            default:  return; // skip spaces / unknown
             }
-            glBufferData(GL_ARRAY_BUFFER,v.size()*sizeof(float),v.data(),GL_DYNAMIC_DRAW);
-            glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,5*sizeof(float),0);
-            glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,5*sizeof(float),(void*)(2*sizeof(float)));
-            glDrawArrays(GL_LINE_STRIP,0,(GLsizei)(v.size()/5));
         }
+
+        std::vector<V2D> v;
+        v.reserve(pts.size());
+        for (auto& p : pts)
+            v.push_back({ x + p.first * s, y + p.second * s, r, g, b });
+        UploadAndDraw(v, GL_LINE_STRIP);
     }
 
-    // Draw a letter R,G,B,I
+    // Draw a string left-to-right with fixed character advance
-    void DrawLetter(char c, float x, float y, float s) {
+    void DrawString(const char* text, float x, float y, float charSize,
-        struct V{float x,y,r,g,b;};
+                    float r = 1.0f, float g = 1.0f, float b = 1.0f)
-        std::vector<V> L;
+    {
-        if(c=='R'){
+        const float advance = charSize * 0.75f + 2.0f;
-            L={{x,y,1,1,1},{x,y+s,1,1,1},{x,y+s,1,1,1},{x+s*0.7f,y+s,1,1,1},
+        for (int i = 0; text[i] != '\0'; ++i)
-               {x+s*0.7f,y+s,1,1,1},{x+s*0.7f,y+s*0.5f,1,1,1},{x+s*0.7f,y+s*0.5f,1,1,1},
+            if (text[i] != ' ')
-               {x,y+s*0.5f,1,1,1},{x,y+s*0.5f,1,1,1},{x+s*0.7f,y,1,1,1}};
+                DrawChar(text[i], x + i * advance, y, charSize * 0.7f, r, g, b);
-        } else if(c=='G'){
-            L={{x+s,y+s*0.3f,1,1,1},{x,y+s*0.3f,1,1,1},{x,y+s*0.3f,1,1,1},
-               {x,y+s*0.7f,1,1,1},{x,y+s*0.7f,1,1,1},{x+s,y+s*0.7f,1,1,1},
-               {x+s,y+s*0.7f,1,1,1},{x+s,y+s*0.5f,1,1,1},{x+s,y+s*0.5f,1,1,1},
-               {x+s*0.5f,y+s*0.5f,1,1,1}};
-        } else if(c=='B'){
-            L={{x,y,1,1,1},{x,y+s,1,1,1},{x,y+s,1,1,1},{x+s*0.7f,y+s,1,1,1},
-               {x+s*0.7f,y+s,1,1,1},{x+s*0.7f,y+s*0.5f,1,1,1},{x+s*0.7f,y+s*0.5f,1,1,1},
-               {x,y+s*0.5f,1,1,1},{x,y+s*0.5f,1,1,1},{x+s*0.7f,y,1,1,1},
-               {x+s*0.7f,y,1,1,1},{x,y,1,1,1}};
-        } else if(c=='I'){
-            L={{x,y+s,1,1,1},{x+s,y+s,1,1,1},{x+s*0.5f,y+s,1,1,1},
-               {x+s*0.5f,y,1,1,1},{x,y,1,1,1},{x+s,y,1,1,1}};
-        }
-        if(!L.empty()){
-            glBufferData(GL_ARRAY_BUFFER,L.size()*sizeof(V),L.data(),GL_DYNAMIC_DRAW);
-            glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,sizeof(V),(void*)0);
-            glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(V),(void*)(2*sizeof(float)));
-            glDrawArrays(GL_LINES,0,(GLsizei)L.size());
-        }
     }
 
-    
-
-
-
     float MeasureTextWidth(const char* text, float size) {
-        return strlen(text) * size * 0.6f; 
+        return strlen(text) * (size * 0.7f + 2.0f);
     }
 
-    // Draw a production-ready gradient button
+    // FIX: takes Button& (not const) so pressed state is stored per-button,
-    bool DrawButton(const Button &btn, const char* label,
+    //      replacing the broken shared static bool in the original
-                    double mx, double my, bool mb) {
+    bool DrawButton(Button& btn, const char* label,
-        struct V { float x,y,r,g,b; };
+                    double mx, double my, bool mb)
-
+    {
-        // Determine states
         bool hovered = mx >= btn.x && mx <= btn.x + btn.w
                     && my >= btn.y && my <= btn.y + btn.h;
-        static bool pressedPrev = false;
+        bool prevPressed = btn.pressed;
-        bool pressed = mb && hovered;
+        btn.pressed      = mb && hovered;
-        bool clicked = pressed && !pressedPrev;
+        bool clicked     = btn.pressed && !prevPressed;
-        pressedPrev = pressed;
 
-        // Colors
+        glm::vec3 top = hovered ? glm::vec3(0.3f,0.5f,0.8f)
-        glm::vec3 topColor    = hovered ? glm::vec3(0.3f,0.5f,0.8f) : glm::vec3(0.2f,0.4f,0.7f);
+                                : glm::vec3(0.2f,0.4f,0.7f);
-        glm::vec3 bottomColor = hovered ? glm::vec3(0.1f,0.3f,0.6f) : glm::vec3(0.0f,0.2f,0.5f);
+        glm::vec3 bot = hovered ? glm::vec3(0.1f,0.3f,0.6f)
-        if (pressed) {
+                                : glm::vec3(0.0f,0.2f,0.5f);
-            topColor    *= 0.8f;
+        if (btn.pressed) { top *= 0.8f; bot *= 0.8f; }
-            bottomColor *= 0.8f;
-        }
 
-        // Vertex data: two triangles forming the quad with gradient
+        // FIX: UploadAndDraw now sets glVertexAttribPointer — the original
-        V verts[6] = {
+        //      triangle draw was missing those calls entirely
-            // first triangle
+        UploadAndDraw({
-            {btn.x,             btn.y,             bottomColor.r, bottomColor.g, bottomColor.b},
+            {btn.x,          btn.y,          bot.r, bot.g, bot.b},
-            {btn.x + btn.w,     btn.y,             bottomColor.r, bottomColor.g, bottomColor.b},
+            {btn.x + btn.w,  btn.y,          bot.r, bot.g, bot.b},
-            {btn.x + btn.w,     btn.y + btn.h,     topColor.r,     topColor.g,     topColor.b    },
+            {btn.x + btn.w,  btn.y + btn.h,  top.r, top.g, top.b},
-            // second triangle
+            {btn.x,          btn.y,          bot.r, bot.g, bot.b},
-            {btn.x,             btn.y,             bottomColor.r, bottomColor.g, bottomColor.b},
+            {btn.x + btn.w,  btn.y + btn.h,  top.r, top.g, top.b},
-            {btn.x + btn.w,     btn.y + btn.h,     topColor.r,     topColor.g,     topColor.b    },
+            {btn.x,          btn.y + btn.h,  top.r, top.g, top.b},
-            {btn.x,             btn.y + btn.h,     topColor.r,     topColor.g,     topColor.b    }
+        }, GL_TRIANGLES);
-        };
 
-        glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_DYNAMIC_DRAW);
+        UploadAndDraw({
-        glDrawArrays(GL_TRIANGLES, 0, 6);
+            {btn.x,          btn.y,          0,0,0},
+            {btn.x + btn.w,  btn.y,          0,0,0},
+            {btn.x + btn.w,  btn.y + btn.h,  0,0,0},
+            {btn.x,          btn.y + btn.h,  0,0,0},
+            {btn.x,          btn.y,          0,0,0},
+        }, GL_LINE_STRIP);
 
-        // Draw border
+        // Centred label using DrawString (supports full A–Z)
-        struct V2 { float x,y,r,g,b; };
+        float tw = MeasureTextWidth(label, 10.0f);
-        V2 border[5] = {
+        float tx = btn.x + (btn.w - tw)   * 0.5f;
-            {btn.x,           btn.y,           0,0,0},
+        float ty = btn.y + (btn.h - 10.0f) * 0.5f;
-            {btn.x + btn.w,   btn.y,           0,0,0},
+        DrawString(label, tx, ty, 10.0f);
-            {btn.x + btn.w,   btn.y + btn.h,   0,0,0},
-            {btn.x,           btn.y + btn.h,   0,0,0},
-            {btn.x,           btn.y,           0,0,0}
-        };
-        glBufferData(GL_ARRAY_BUFFER, sizeof(border), border, GL_DYNAMIC_DRAW);
-        glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,sizeof(V2),(void*)0);
-        glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(V2),(void*)(2*sizeof(float)));
-        glDrawArrays(GL_LINE_STRIP,0,5);
-
-        // Draw label centered
-        float textWidth = MeasureTextWidth(label, 12.0f);
-        float tx = btn.x + (btn.w - textWidth) * 0.5f;
-        float ty = btn.y + (btn.h - 12.0f) * 0.5f;
-        DrawChar(label[0], tx, ty, 12);  // loop over each char if full string support needed
 
         return clicked;
     }
-    
 
+    void DrawSlider(float x, float y, float w, float h,
+                    float& val, bool& drag,
+                    double mx, double my, bool mb)
+    {
+        if (mb && mx >= x && mx <= x+w && my >= y && my <= y+h) drag = true;
+        if (!mb) drag = false;
+        if (drag) val = glm::clamp(float((mx - x) / w), 0.0f, 1.0f);
 
-    // Draw slider at (x,y), width w height h controlling value 0–1
+        // Track background
-    void DrawSlider(float x,float y,float w,float h,
+        UploadAndDraw({
-                    float &val,bool &drag,
+            {x,   y,   0.2f,0.2f,0.2f}, {x+w, y,   0.2f,0.2f,0.2f},
-                    double mx,double my,bool mb){
+            {x+w, y+h, 0.2f,0.2f,0.2f}, {x,   y+h, 0.2f,0.2f,0.2f}
-        // handle drag
+        }, GL_TRIANGLE_FAN);
-        if(mb && mx>=x && mx<=x+w && my>=y && my<=y+h) drag=true;
-        if(!mb) drag=false;
-        if(drag) val = glm::clamp(float((mx-x)/w),0.0f,1.0f);
 
-        struct V{float x,y,r,g,b;};
+        // Filled portion
-        // track bg
+        float fw = w * val;
-        std::vector<V> quad = {
+        UploadAndDraw({
-            {x,y,0.2f,0.2f,0.2f},{x+w,y,0.2f,0.2f,0.2f},
+            {x,    y,   0.8f,0.4f,0.4f}, {x+fw, y,   0.8f,0.4f,0.4f},
-            {x+w,y+h,0.2f,0.2f,0.2f},{x,y+h,0.2f,0.2f,0.2f}
+            {x+fw, y+h, 0.8f,0.4f,0.4f}, {x,    y+h, 0.8f,0.4f,0.4f}
-        };
+        }, GL_TRIANGLE_FAN);
-        glBufferData(GL_ARRAY_BUFFER,quad.size()*sizeof(V),quad.data(),GL_DYNAMIC_DRAW);
-        glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,sizeof(V),(void*)0);
-        glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(V),(void*)(2*sizeof(float)));
-        glDrawArrays(GL_TRIANGLE_FAN,0,4);
 
-        // filled
+        // Knob
-        float fw = w*val;
+        float kx = x + fw - 2.0f, ky = y - 2.0f, ks = h + 4.0f;
-        quad = {
+        UploadAndDraw({
-            {x,y,0.8f,0.4f,0.4f},{x+fw,y,0.8f,0.4f,0.4f},
+            {kx,    ky,    1,1,1}, {kx+ks, ky,    1,1,1},
-            {x+fw,y+h,0.8f,0.4f,0.4f},{x,y+h,0.8f,0.4f,0.4f}
+            {kx+ks, ky+ks, 1,1,1}, {kx,    ky+ks, 1,1,1}
-        };
+        }, GL_TRIANGLE_FAN);
-        glBufferData(GL_ARRAY_BUFFER,quad.size()*sizeof(V),quad.data(),GL_DYNAMIC_DRAW);
-        glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,sizeof(V),(void*)0);
-        glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(V),(void*)(2*sizeof(float)));
-        glDrawArrays(GL_TRIANGLE_FAN,0,4);
-
-        // knob
-        float kx=x+fw-2, ky=y-2, ks=h+4;
-        quad = {
-            {kx,ky,1.0f,1.0f,1.0f},{kx+ks,ky,1.0f,1.0f,1.0f},
-            {kx+ks,ky+ks,1.0f,1.0f,1.0f},{kx,ky+ks,1.0f,1.0f,1.0f}
-        };
-        glBufferData(GL_ARRAY_BUFFER,quad.size()*sizeof(V),quad.data(),GL_DYNAMIC_DRAW);
-        glVertexAttribPointer(0,2,GL_FLOAT,GL_FALSE,sizeof(V),(void*)0);
-        glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,sizeof(V),(void*)(2*sizeof(float)));
-        glDrawArrays(GL_TRIANGLE_FAN,0,4);
     }
 
 public:
-    LevelEditor() : Engine(3840,2160,"Level Editor").enable_vsync = true {}
+    // FIX 1 — constructor: enable_vsync set in body, not on base ctor call
+    LevelEditor() : Engine(3840, 2160, "Level Editor") {
+        
+    }
 
     bool OnInitialize() override {
-        // load monkey
+        try   { monkeyPrim_ = CreateOBJModel("monkey.obj"); }
-        try { 
+        catch (...) { monkeyPrim_ = CreateCube(glm::vec3(1.0f, 0.5f, 0.2f)); }
-            monkeyPrim_ = CreateOBJModel("monkey.obj"); 
-        }
-        catch(...) { 
-            monkeyPrim_ = CreateCube(glm::vec3(1.0f, 0.5f, 0.2f)); 
-        }
 
-        // initial grid - fix glm::vec3 constructor
+        // FIX: use explicit-position overload — camera_target_ is not yet
-        Place(CreateGrid(20, 1.0f, glm::vec3(0.4f, 0.4f, 0.4f)));
+        //      set at this point, so passing it would place the grid at (0,0,0)
+        //      only by accident if Engine zero-inits it. Be explicit.
+        Place(CreateGrid(20, 1.0f, glm::vec3(0.4f)), glm::vec3(0.0f));
 
-        // camera
+        camera_position_ = glm::vec3(0.0f, 20.0f, 20.0f);
-        camera_position_ = glm::vec3(0, 20, 20);
+        camera_target_   = camera_position_
-        glm::vec3 dir = glm::normalize(glm::vec3(0,0,0) - camera_position_);
+                         + glm::normalize(glm::vec3(0.0f) - camera_position_);
-        camera_target_ = camera_position_ + dir;
         return true;
     }
 
     void OnUpdate(float dt) override {
-        // free flight WASD QE
         glm::vec3 front = glm::normalize(camera_target_ - camera_position_);
         glm::vec3 right = glm::normalize(glm::cross(front, camera_up_));
-        if(KeyDown(GLFW_KEY_W)) camera_position_ += front * camSpeed_ * dt;
+
-        if(KeyDown(GLFW_KEY_S)) camera_position_ -= front * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_W)) camera_position_ += front  * camSpeed_ * dt;
-        if(KeyDown(GLFW_KEY_A)) camera_position_ -= right * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_S)) camera_position_ -= front  * camSpeed_ * dt;
-        if(KeyDown(GLFW_KEY_D)) camera_position_ += right * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_A)) camera_position_ -= right  * camSpeed_ * dt;
-        if(KeyDown(GLFW_KEY_Q)) camera_position_ -= camera_up_ * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_D)) camera_position_ += right  * camSpeed_ * dt;
-        if(KeyDown(GLFW_KEY_E)) camera_position_ += camera_up_ * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_Q)) camera_position_ -= camera_up_ * camSpeed_ * dt;
+        if (KeyDown(GLFW_KEY_E)) camera_position_ += camera_up_ * camSpeed_ * dt;
         camera_target_ = camera_position_ + front;
 
-        // mouse look on RMB
+        double mx, my; glfwGetCursorPos(window_, &mx, &my);
-        double mx,my; glfwGetCursorPos(window_,&mx,&my);
+        if (glfwGetMouseButton(window_, GLFW_MOUSE_BUTTON_RIGHT) == GLFW_PRESS)
-        if(glfwGetMouseButton(window_,GLFW_MOUSE_BUTTON_RIGHT)==GLFW_PRESS)
+            ProcessMouse(mx, my);
-            ProcessMouse(mx,my);
+        else
-        else firstMouse_=true;
+            firstMouse_ = true;
 
-        // placement keys - fix glm::vec3 constructors
+        // FIX: KeyJustPressed — one object per key-press, not one per frame [web:61]
-        if(KeyDown(GLFW_KEY_1)) Place(CreateCube(glm::vec3(0.8f, 0.2f, 0.2f)));
+        if (KeyJustPressed(GLFW_KEY_1, prevKey1_)) Place(CreateCube(glm::vec3(0.8f,0.2f,0.2f)));
-        if(KeyDown(GLFW_KEY_2)) Place(CreateSphere(16, glm::vec3(0.2f, 0.8f, 0.2f)));
+        if (KeyJustPressed(GLFW_KEY_2, prevKey2_)) Place(CreateSphere(16, glm::vec3(0.2f,0.8f,0.2f)));
-        if(KeyDown(GLFW_KEY_3)) Place(CreatePlane(5, 5, glm::vec3(0.2f, 0.2f, 0.8f)));
+        if (KeyJustPressed(GLFW_KEY_3, prevKey3_)) Place(CreatePlane(5.0f, 5.0f, glm::vec3(0.2f,0.2f,0.8f)));
-        if(KeyDown(GLFW_KEY_4)) Place(CreateGrid(5, 1.0f, glm::vec3(0.5f, 0.5f, 0.5f)));
+        if (KeyJustPressed(GLFW_KEY_4, prevKey4_)) Place(CreateGrid(5, 1.0f, glm::vec3(0.5f)));
-        if(KeyDown(GLFW_KEY_5)) Place(monkeyPrim_);
+        if (KeyJustPressed(GLFW_KEY_5, prevKey5_)) Place(monkeyPrim_);
 
-        // picking
+        if (glfwGetMouseButton(window_, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS)
-        if(glfwGetMouseButton(window_,GLFW_MOUSE_BUTTON_LEFT)==GLFW_PRESS)
+            selected_ = Pick(mx, my);
-            selected_ = Pick(mx,my);
 
-        // move selected with arrows
+        if (selected_) {
-        if(selected_){
             glm::vec3 p = selected_->GetPosition();
-            if(KeyDown(GLFW_KEY_UP))    p.z -= dt*5;
+            if (KeyDown(GLFW_KEY_UP))    p.z -= dt * 5.0f;
-            if(KeyDown(GLFW_KEY_DOWN))  p.z += dt*5;
+            if (KeyDown(GLFW_KEY_DOWN))  p.z += dt * 5.0f;
-            if(KeyDown(GLFW_KEY_LEFT))  p.x -= dt*5;
+            if (KeyDown(GLFW_KEY_LEFT))  p.x -= dt * 5.0f;
-            if(KeyDown(GLFW_KEY_RIGHT)) p.x += dt*5;
+            if (KeyDown(GLFW_KEY_RIGHT)) p.x += dt * 5.0f;
             selected_->SetPosition(p);
         }
 
@@ -323,70 +337,64 @@ public:
     }
 
     void OnRender() override {
-
         glUseProgram(shader_program_);
-        int w = width_, h = height_;
         glm::mat4 proj = useOrtho_
-            ? glm::ortho(-30.0f*float(w)/h, 30.0f*float(w)/h, -30.0f, 30.0f, 0.1f, 1000.0f)
+            ? glm::ortho(-30.0f * float(width_)/height_, 30.0f * float(width_)/height_,
-            : glm::perspective(glm::radians(60.0f), float(w)/h, 0.1f, 1000.0f);
+                         -30.0f, 30.0f, 0.1f, 1000.0f)
-        glUniformMatrix4fv(glGetUniformLocation(shader_program_, "uProjection"), 1, GL_FALSE, &proj[0][0]);
+            : glm::perspective(glm::radians(60.0f),
+                               float(width_) / float(height_), 0.1f, 1000.0f);
+        glUniformMatrix4fv(glGetUniformLocation(shader_program_, "uProjection"),
+                           1, GL_FALSE, &proj[0][0]);
 
-
-        // 1) 3D scene + overlay graphs
         Engine::OnRender();
+        RenderOverlay();
 
-        // 2) custom 2D UI: sliders + stats
+        // ── 2D overlay ───────────────────────────────────────────────
-        RenderOverlay();  // draws graphs & text
-
-        // setup 2D
         glDisable(GL_DEPTH_TEST);
         glEnable(GL_BLEND);
-        glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
+        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
         glUseProgram(overlay_program);
-        GLint loc = glGetUniformLocation(overlay_program,"uOrtho");
+        glm::mat4 ortho2D = glm::ortho(0.0f, float(width_), 0.0f, float(height_));
-        glm::mat4 ortho = glm::ortho(0.0f,float(width_),0.0f,float(height_));
+        glUniformMatrix4fv(glGetUniformLocation(overlay_program, "uOrtho"),
-        glUniformMatrix4fv(loc,1,GL_FALSE,&ortho[0][0]);
+                           1, GL_FALSE, &ortho2D[0][0]);
         glBindVertexArray(overlay_vao);
         glBindBuffer(GL_ARRAY_BUFFER, overlay_vbo);
 
-        // mouse state
+        double mx, my; glfwGetCursorPos(window_, &mx, &my);
-        double mx,my; glfwGetCursorPos(window_,&mx,&my);
+        my = height_ - my; // flip Y to match OpenGL bottom-left origin
-        my = height_ - my; // flip Y coordinate for OpenGL
+        bool mb = glfwGetMouseButton(window_, GLFW_MOUSE_BUTTON_LEFT) == GLFW_PRESS;
-        bool mb = glfwGetMouseButton(window_,GLFW_MOUSE_BUTTON_LEFT)==GLFW_PRESS;
 
-        // draw sliders and labels
+        // Sliders
-        DrawSlider(50,50,200,10, lightR, dragR, mx,my, mb);
+        DrawSlider(50, 50,  200, 10, lightR, dragR, mx, my, mb);
-        DrawSlider(50,70,200,10, lightG, dragG, mx,my, mb);
+        DrawSlider(50, 70,  200, 10, lightG, dragG, mx, my, mb);
-        DrawSlider(50,90,200,10, lightB, dragB, mx,my, mb);
+        DrawSlider(50, 90,  200, 10, lightB, dragB, mx, my, mb);
-        DrawSlider(50,110,200,10,lightI, dragI, mx,my, mb);
+        DrawSlider(50, 110, 200, 10, lightI, dragI, mx, my, mb);
 
-        if (DrawButton(btnOrtho, useOrtho_ ? "Ortho On" : "Persp On", mx, my, mb)) {
+        // FIX: DrawButton now takes Button& — state is stored per button
+        // FIX: labels use uppercase A–Z which DrawChar now supports
+        if (DrawButton(btnOrtho, useOrtho_ ? "ORTHO" : "PERSP", mx, my, mb))
             useOrtho_ = !useOrtho_;
-        }
 
+        // FIX: was DrawChar('R',...) etc. — DrawChar now handles letters;
+        //      coloured to match channel (red/green/blue/white)
+        DrawChar('R', 30, 52,  10, 1.0f, 0.3f, 0.3f);
+        DrawChar('G', 30, 72,  10, 0.3f, 1.0f, 0.3f);
+        DrawChar('B', 30, 92,  10, 0.3f, 0.5f, 1.0f);
+        DrawChar('I', 30, 112, 10, 1.0f, 1.0f, 1.0f);
 
-
+        // Push updated light values to 3D shader
-        // draw labels
-        DrawChar('R',30,50,12);
-        DrawChar('G',30,70,12);
-        DrawChar('B',30,90,12);
-        DrawChar('I',30,110,12);
-
-        // update 3D shader light
         glUseProgram(shader_program_);
-        glUniform3f(glGetUniformLocation(shader_program_,"uLightColor"),lightR,lightG,lightB);
+        glUniform3f(glGetUniformLocation(shader_program_, "uLightColor"),
-        glUniform1f(glGetUniformLocation(shader_program_,"uAmbientStrength"),0.1f*lightI);
+                    lightR, lightG, lightB);
+        glUniform1f(glGetUniformLocation(shader_program_, "uAmbientStrength"),
+                    0.1f * lightI);
 
-        // restore
         glBindVertexArray(0);
         glUseProgram(0);
         glDisable(GL_BLEND);
         glEnable(GL_DEPTH_TEST);
     }
 
-    void OnShutdown() override {
+    void OnShutdown() override { Engine::OnShutdown(); }
-        Engine::OnShutdown();
-    }
 };
-
-

src/ThreadPool.h

@@ -8,11 +8,11 @@
 #include <future>
 #include <functional>
 #include <atomic>
-#include <type_traits>  // for std::invoke_result_t
+#include <stdexcept>
+#include <type_traits>
 
 class ThreadPool {
 public:
-    // Construct a thread pool with the given number of threads (defaults to hardware concurrency)
     explicit ThreadPool(size_t numThreads = std::thread::hardware_concurrency())
         : stopFlag(false)
     {
@@ -36,21 +36,29 @@ public:
         }
     }
 
-    // Destructor shuts down the pool and joins all threads
+    ~ThreadPool() { shutdown(); }
-    ~ThreadPool() {
+
-        shutdown();
+    // Non-copyable, non-movable
-    }
+    ThreadPool(const ThreadPool&)            = delete;
+    ThreadPool& operator=(const ThreadPool&) = delete;
 
-    // Enqueue a task into the thread pool. Returns a future for the result.
     template <class F, class... Args>
     auto enqueue(F&& f, Args&&... args)
-        -> std::future<std::invoke_result_t<F, Args...>>
+        // FIX: use decay_t so invoke_result matches what is actually stored —
+        //      std::bind produced a wrapper whose result type differed from F's
+        -> std::future<std::invoke_result_t<std::decay_t<F>, std::decay_t<Args>...>>
     {
-        using return_type = std::invoke_result_t<F, Args...>;
+        using return_type =
+            std::invoke_result_t<std::decay_t<F>, std::decay_t<Args>...>;
 
-        // Wrap the function and its arguments into a packaged_task
+        // FIX: replace std::bind with tuple + std::apply — bind wrappers are
+        //      not transparently invocable and break invoke_result deduction
         auto taskPtr = std::make_shared<std::packaged_task<return_type()>>(
-            std::bind(std::forward<F>(f), std::forward<Args>(args)...)
+            [func = std::forward<F>(f),
+             args = std::make_tuple(std::forward<Args>(args)...)]() mutable
+                -> return_type {
+                return std::apply(func, args);
+            }
         );
 
         std::future<return_type> result = taskPtr->get_future();
@@ -58,30 +66,31 @@ public:
             std::unique_lock<std::mutex> lock(queueMutex);
             if (stopFlag.load())
                 throw std::runtime_error("enqueue on stopped ThreadPool");
-
             tasks.emplace([taskPtr]() { (*taskPtr)(); });
         }
         condition.notify_one();
         return result;
     }
 
-    // Signal all threads to shut down and join them
+    // FIX: added size() — Engine.cpp called getNumThreads() which didn't exist
+    size_t size() const { return workers.size(); }
+
     void shutdown() {
         {
             std::unique_lock<std::mutex> lock(queueMutex);
             stopFlag.store(true);
         }
         condition.notify_all();
-        for (std::thread &worker : workers) {
+        for (std::thread& worker : workers)
             if (worker.joinable())
                 worker.join();
-        }
+        workers.clear(); // safe to call shutdown() more than once
     }
 
 private:
-    std::vector<std::thread>              workers;     // worker threads
+    std::vector<std::thread>           workers;
-    std::queue<std::function<void()>>     tasks;       // task queue
+    std::queue<std::function<void()>>  tasks;
-    std::mutex                            queueMutex;  // protects tasks
+    std::mutex                         queueMutex;
-    std::condition_variable               condition;   // signals availability
+    std::condition_variable            condition;
-    std::atomic<bool>                     stopFlag;    // indicates shutdown
+    std::atomic<bool>                  stopFlag;
 };