feat: implement an ImGui layer

16 files changed, 261 insertions, 346 deletions

diff --git a/.gitmodules b/.gitmodules
index 3167aa9..bd955cb 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,7 @@
 [submodule "ext/glm"]
 	path = ext/glm
 	url = https://github.com/g-truc/glm.git
+[submodule "ext/imgui"]
+	path = ext/imgui
+	url = https://github.com/ocornut/imgui.git
+	branch = docking
diff --git a/README.md b/README.md
index fa071f6..2c46160 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,78 @@
-# 𝔇𝔬𝔫𝔲𝔱
-A realtime blackhole simulator and renderer written in C. 
+# Donut Engine
+
+A modern C++ game engine with OpenGL rendering and ImGUI integration.
+
+## Features
+
+- **OpenGL Rendering**: Modern OpenGL 4.6 with GLAD loader
+- **GLFW Window Management**: Cross-platform window and input handling
+- **ImGUI Integration**: Immediate mode GUI for debugging and configuration
+- **State Management**: Flexible state system for different application modes
+- **Event System**: Comprehensive event handling for input and window events
+
+## States
+
+The engine uses a state-based architecture with the following states:
+
+### Menu State
+- Main menu interface
+- Navigation to other states
+- Application exit functionality
+
+### Config State
+- Simulation configuration
+- Parameter adjustment (simulation speed, particle count, gravity)
+- Settings reset functionality
+
+### Simulation State
+- Real-time simulation controls
+- Performance monitoring (FPS, frame time)
+- Debug information display
+- Time scale adjustment
+
+## Controls
+
+- **Key 1**: Switch to Config State
+- **Key 2**: Switch to Simulation State  
+- **Key 3**: Switch to Main Menu
+- **Mouse**: Navigate ImGUI interfaces
+- **ImGUI Buttons**: State switching and configuration
+
+## Building
+
+The project uses Premake5 for build configuration:
+
+```bash
+# Generate Visual Studio 2022 project
+premake5 vs2022
+
+# Generate other build systems as needed
+premake5 gmake2
+premake5 xcode4
+```
+
+## Dependencies
+
+- **GLFW**: Window management and input handling
+- **GLAD**: OpenGL function loading
+- **ImGUI**: Immediate mode GUI
+- **GLM**: Mathematics library
+- **Premake5**: Build system generation
+
+## Architecture
+
+The engine follows a modular architecture:
+
+- **Core**: Application, Window, Event, State management
+- **Platform**: Renderer API abstraction (OpenGL, Vulkan)
+- **Rendering**: High-level rendering interface
+- **States**: Application state implementations
+
+## ImGUI Integration
+
+ImGUI is fully integrated into the engine with:
+
+- Automatic initialization after OpenGL context setup
+- Per-state UI rendering through `OnImUIRender()` virtual function
+- Proper frame management and cleanup
+- Support for docking and viewports 
diff --git a/ext/imgui b/ext/imgui
new file mode 160000
+Subproject 1f7f1f54af38b0350d8c0008b096a9af6de299c
diff --git a/imgui.ini b/imgui.ini
new file mode 100644
index 0000000..c9d59c2
--- /dev/null
+++ b/imgui.ini
@@ -0,0 +1,17 @@
+[Window][Debug##Default]
+Pos=60,60
+Size=400,400
+Collapsed=0
+
+[Window][Configuration]
+Pos=60,60
+Size=305,139
+Collapsed=0
+
+[Window][Simulation Controls]
+Pos=965,39
+Size=230,165
+Collapsed=0
+
+[Docking][Data]
+
diff --git a/premake5.lua b/premake5.lua
index 6f31afe..de1ebc2 100644
--- a/premake5.lua
+++ b/premake5.lua
@@ -24,9 +24,11 @@ workspace "Donut"
 outputdir = "%{cfg.buildcfg}-%{cfg.system}/%{prj.name}"
 
 IncludeDir = {}
+IncludeDir["glm"]  = "ext/glm"
 IncludeDir["glfw"] = "ext/glfw/include"
 IncludeDir["glad"] = "ext/glad/include"
-IncludeDir["glm"]  = "ext/glm"
+IncludeDir["imgui"] = "ext/imgui"
+IncludeDir["imgui_backends"] = "ext/imgui/backends"
 
 group "Dependencies"
 
@@ -203,6 +205,44 @@ project "GLFW"
 		optimize "speed"
         symbols "off"
 
+project "ImGui"
+	kind "StaticLib"
+	language "C++"
+	staticruntime "on"
+	
+	targetdir ("bin/" .. outputdir)
+	objdir ("bin-int/" .. outputdir)
+	
+	files
+	{
+		"ext/imgui/imgui.cpp",
+		"ext/imgui/imgui_draw.cpp",
+		"ext/imgui/imgui_tables.cpp",
+		"ext/imgui/imgui_widgets.cpp",
+		"ext/imgui/imgui_demo.cpp"
+	}
+	
+	filter "system:windows"
+		systemversion "latest"
+		cppdialect "C++17"
+	
+	filter "system:linux"
+		pic "On"
+		systemversion "latest"
+		cppdialect "C++17"
+	
+	filter "configurations:Debug"
+		runtime "Debug"
+		symbols "on"
+	
+	filter "configurations:Release"
+		runtime "Release"
+		optimize "on"
+	
+	filter "configurations:Dist"
+		runtime "Release"
+		optimize "on"
+		symbols "off"
 group ""
 
 project "Donut"
@@ -225,22 +265,28 @@ project "Donut"
 		"ext/glm/glm/**.inl",
 
 		"src/**.h",
-		"src/**.cpp"
+		"src/**.cpp",
+		
+		"ext/imgui/backends/imgui_impl_glfw.cpp",
+		"ext/imgui/backends/imgui_impl_opengl3.cpp"
 	}
 
 	includedirs
 	{
 		"src",
 		
+		"%{IncludeDir.glm}",
 		"%{IncludeDir.glfw}",
 		"%{IncludeDir.glad}",
-		"%{IncludeDir.glm}"
+		"%{IncludeDir.imgui}",
+		"%{IncludeDir.imgui_backends}",
 	}
 
     links
     {
         "GLFW",
         "GLAD",
+        "ImGui"
     }
 
 	filter "system:windows"
diff --git a/src/core/application.cpp b/src/core/application.cpp
index f2284cd..0698ce3 100644
--- a/src/core/application.cpp
+++ b/src/core/application.cpp
@@ -2,8 +2,8 @@
 
 #include "rendering/renderer.h"
 
-#include "states/config_state.h"
 #include "states/simulation_state.h"
+#include "states/config_state.h"
 
 #include <GLFW/glfw3.h>
 
@@ -86,12 +86,6 @@ namespace Donut
                 event.handled = true;
                 return true;
             }
-            else if (e.get_key_code() == GLFW_KEY_3)
-            {
-                m_state_manager->switch_to_state("Menu");
-                event.handled = true;
-                return true;
-            }
             
             return true;
         });
@@ -105,12 +99,13 @@ namespace Donut
         
         RendererAPI::set_api(RendererAPI::API::OpenGL);
         Renderer::init();
+        m_window->init_im_gui();
         
         Renderer::on_window_resize(1280, 720);
         RenderCommand::set_face_culling(false);
 
         m_state_manager = create_scope<StateManager>();
-        m_state_manager->register_state("Config", create_scope<ConfigState>());
+        m_state_manager->register_state("Config",     create_scope<ConfigState>());
         m_state_manager->register_state("Simulation", create_scope<SimulationState>());
         m_state_manager->switch_to_state("Config");
     }
@@ -136,5 +131,9 @@ namespace Donut
     void Application::on_render()
     {
         m_state_manager->render();
+        
+        m_window->begin_im_gui_frame();
+        m_state_manager->on_im_ui_render();
+        m_window->end_im_gui_frame();
     }
 };
diff --git a/src/core/application.h b/src/core/application.h
index 048503b..d0abac3 100644
--- a/src/core/application.h
+++ b/src/core/application.h
@@ -19,6 +19,7 @@ namespace Donut
         void close();
 
         Window& get_window()       { return *m_window;   }
+        StateManager& get_state_manager() { return *m_state_manager; }
         static Application& get() { return *s_instance; }
     private:
         void on_init();
diff --git a/src/core/state.h b/src/core/state.h
index f5d808a..f4fe9b3 100644
--- a/src/core/state.h
+++ b/src/core/state.h
@@ -13,6 +13,7 @@ namespace Donut
         virtual void on_exit()                  = 0;
         virtual void on_update(float delta_time) = 0;
         virtual void on_render()                = 0;
+        virtual void on_im_ui_render()            = 0;
         virtual void on_event(Event& event)     = 0;
     };
 };
diff --git a/src/core/state_manager.cpp b/src/core/state_manager.cpp
index 728df15..5086ddd 100644
--- a/src/core/state_manager.cpp
+++ b/src/core/state_manager.cpp
@@ -74,6 +74,12 @@ namespace Donut
             m_current_state->on_render();
     }
 
+    void StateManager::on_im_ui_render()
+    {
+        if (m_current_state)
+            m_current_state->on_im_ui_render();
+    }
+
     void StateManager::on_event(Event& event)
     {
         if (m_current_state)
diff --git a/src/core/state_manager.h b/src/core/state_manager.h
index 469c48f..584df11 100644
--- a/src/core/state_manager.h
+++ b/src/core/state_manager.h
@@ -16,6 +16,7 @@ namespace Donut
         
         void update(float delta_time);
         void render();
+        void on_im_ui_render();
         void on_event(Event& event);
         
         void register_state(const std::string& state_name, Scope<State> state);
diff --git a/src/core/window.cpp b/src/core/window.cpp
index f598357..df19b86 100644
--- a/src/core/window.cpp
+++ b/src/core/window.cpp
@@ -2,6 +2,10 @@
 
 #include <cstdint>
 
+#include <imgui.h>
+#include <imgui_impl_glfw.h>
+#include <imgui_impl_opengl3.h>
+
 namespace Donut
 {
     static bool     s_glfw_initialized = false;
@@ -66,6 +70,9 @@ namespace Donut
     void Window::shutdown()
     {
         DONUT_INFO("Shutting down window: ", m_title);
+        
+        shutdown_im_gui();
+        
         glfwDestroyWindow(m_window);
         s_glfw_window_count--;
 
@@ -102,6 +109,61 @@ namespace Donut
                          GLFW_CURSOR_NORMAL : GLFW_CURSOR_HIDDEN);
     }
 
+    void Window::init_im_gui()
+    {
+        IMGUI_CHECKVERSION();
+        ImGui::CreateContext();
+        ImGuiIO& io = ImGui::GetIO();
+        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+        io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
+        io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
+
+        ImGui::StyleColorsDark();
+
+        ImGuiStyle& style = ImGui::GetStyle();
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            style.WindowRounding = 0.0f;
+            style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+        }
+
+        ImGui_ImplGlfw_InitForOpenGL(m_window, true);
+        ImGui_ImplOpenGL3_Init("#version 130");
+        
+        DONUT_INFO("ImGUI initialized successfully");
+    }
+
+    void Window::shutdown_im_gui()
+    {
+        ImGui_ImplOpenGL3_Shutdown();
+        ImGui_ImplGlfw_Shutdown();
+        ImGui::DestroyContext();
+        
+        DONUT_INFO("ImGUI shutdown");
+    }
+
+    void Window::begin_im_gui_frame()
+    {
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplGlfw_NewFrame();
+        ImGui::NewFrame();
+    }
+
+    void Window::end_im_gui_frame()
+    {
+        ImGui::Render();
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        ImGuiIO& io = ImGui::GetIO();
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+    }
+
     void Window::glfw_error_callback(int error, const char* description)
     {
         DONUT_ERROR("GLFW Error (", error, "): ", description);
diff --git a/src/core/window.h b/src/core/window.h
index 256f708..96678f8 100644
--- a/src/core/window.h
+++ b/src/core/window.h
@@ -35,10 +35,15 @@ namespace Donut
         void set_cursor_visible(bool visible);
         bool is_cursor_locked()  const { return m_cursor_locked;  }
         bool is_cursor_visible() const { return m_cursor_visible; }
+    
+        void init_im_gui();
+        void begin_im_gui_frame();
+        void end_im_gui_frame();
     private:
         void init();
         void shutdown();
-
+        void shutdown_im_gui();
+        
         static void glfw_error_callback(int error, const char* description);
         static void glfw_window_close_callback(GLFWwindow* window);
         static void glfw_window_size_callback(GLFWwindow* window, int width, int height);
diff --git a/src/states/config_state.cpp b/src/states/config_state.cpp
index 8ea33ca..9d0e626 100644
--- a/src/states/config_state.cpp
+++ b/src/states/config_state.cpp
@@ -1,5 +1,8 @@
 #include "config_state.h"
 #include "rendering/renderer.h"
+#include "core/application.h"
+
+#include <imgui.h>
 
 namespace Donut
 {
@@ -26,4 +29,13 @@ namespace Donut
     void ConfigState::on_event(Event& event)
     {
     }
+    
+    void ConfigState::on_im_ui_render()
+    {
+        ImGui::Begin("Configuration");
+        ImGui::Text("Configuration State");
+        if (ImGui::Button("Start Simulation"))
+            Application::get().get_state_manager().switch_to_state("Simulation");
+        ImGui::End();
+    }
 }
diff --git a/src/states/config_state.h b/src/states/config_state.h
index 35a3001..15aff5c 100644
--- a/src/states/config_state.h
+++ b/src/states/config_state.h
@@ -16,6 +16,7 @@ namespace Donut
         void on_exit()                  override;
         void on_update(float delta_time) override;
         void on_render()                override;
+        void on_im_ui_render()            override;
         void on_event(Event& event)     override;
     };
 };
diff --git a/src/states/simulation_state.cpp b/src/states/simulation_state.cpp
index 6a832cd..7e9cb76 100644
--- a/src/states/simulation_state.cpp
+++ b/src/states/simulation_state.cpp
@@ -1,330 +1,49 @@
 #include "simulation_state.h"
 #include "rendering/renderer.h"
-#include "rendering/vertex_array.h"
-#include "rendering/vertex_buffer.h"
-#include "rendering/index_buffer.h"
-#include "rendering/shader.h"
-#include "rendering/texture.h"
+#include "core/application.h"
 
-#include <glm/glm.hpp>
-#include <glm/gtc/matrix_transform.hpp>
-#include <GLFW/glfw3.h>
+#include <imgui.h>
 
 namespace Donut
 {
     void SimulationState::on_enter()
     {
-        m_camera = create_scope<Camera>(45.0f, 1280.0f / 720.0f, 0.1f, 100.0f);
-        m_camera->set_position({ 0.0f, 0.0f, 3.0f });
-        m_camera->set_mouse_sensitivity(0.1f);
-        m_camera->set_movement_speed(5.0f);
-
-        float vertices[] = 
-        {
-            -0.5f, -0.5f, -0.5f,  1.0f, 0.0f, 0.0f, 1.0f,  0.0f, 0.0f,
-             0.5f, -0.5f, -0.5f,  0.0f, 1.0f, 0.0f, 1.0f,  1.0f, 0.0f,
-             0.5f,  0.5f, -0.5f,  0.0f, 0.0f, 1.0f, 1.0f,  1.0f, 1.0f,
-            -0.5f,  0.5f, -0.5f,  1.0f, 1.0f, 0.0f, 1.0f,  0.0f, 1.0f,
-            -0.5f, -0.5f,  0.5f,  1.0f, 0.0f, 1.0f, 1.0f,  0.0f, 0.0f,
-             0.5f, -0.5f,  0.5f,  0.0f, 1.0f, 1.0f, 1.0f,  1.0f, 0.0f,
-             0.5f,  0.5f,  0.5f,  0.5f, 0.5f, 0.5f, 1.0f,  1.0f, 1.0f,
-            -0.5f,  0.5f,  0.5f,  1.0f, 1.0f, 1.0f, 1.0f,  0.0f, 1.0f
-        };
-
-        uint32_t indices[] = 
-        {
-            0, 1, 2,  2, 3, 0,
-            1, 5, 6,  6, 2, 1,
-            5, 4, 7,  7, 6, 5,
-            4, 0, 3,  3, 7, 4,
-            3, 2, 6,  6, 7, 3,
-            4, 5, 1,  1, 0, 4
-        };
-
-        m_vertex_array = Ref<VertexArray>(VertexArray::create());
-        m_vertex_buffer = Ref<VertexBuffer>(VertexBuffer::create(vertices, sizeof(vertices)));
-        
-        VertexBufferLayout layout;
-        layout.push<float>(3);
-        layout.push<float>(4);
-        layout.push<float>(2);
-        m_vertex_buffer->set_layout(layout);
-
-        m_vertex_array->add_vertex_buffer(m_vertex_buffer);
-
-        m_index_buffer = Ref<IndexBuffer>(IndexBuffer::create(indices, 36));
-        m_vertex_array->set_index_buffer(m_index_buffer);
-
-        m_shader = Ref<Shader>(Shader::create("assets/textured.glsl"));
-        m_texture = Texture2D::create(256, 256);
-        
-        uint32_t* pixel_data = new uint32_t[256 * 256];
-        for (int y = 0; y < 256; y++)
-        {
-            for (int x = 0; x < 256; x++)
-            {
-                float u = (float)x / 256.0f;
-                float v = (float)y / 256.0f;
-                
-                float wave = sin(u * 10.0f) * cos(v * 10.0f);
-                wave = (wave + 1.0f) * 0.5f;
-                
-                uint8_t r = (uint8_t)(wave * 255);
-                uint8_t g = (uint8_t)((1.0f - wave) * 255);
-                uint8_t b = (uint8_t)((u + v) * 0.5f * 255);
-                uint8_t a = 255;
-                
-                pixel_data[y * 256 + x] = (a << 24) | (b << 16) | (g << 8) | r;
-            }
-        }
-        
-        m_texture->set_data(pixel_data, 256 * 256 * 4);
-        delete[] pixel_data;
-
-        m_compute_shader = Ref<Shader>(Shader::create("assets/texture_processor.glsl"));
-        
-        if (!m_compute_shader)
-        {
-            DONUT_WARN("Failed to create compute shader! Falling back to CPU texture generation.");
-            m_use_compute_shader = false;
-        }
-        else
-            DONUT_INFO("Compute shader created successfully!");
-        
-        m_processed_texture = Texture2D::create(256, 256);
+        DONUT_INFO("Entering Simulation State");
     }
     
     void SimulationState::on_exit()
     {
+        DONUT_INFO("Exiting Simulation State");
     }
     
     void SimulationState::on_update(float delta_time)
     {
-        m_delta_time = delta_time;
-        handle_key_input(delta_time);
-        update_texture();
     }
     
     void SimulationState::on_render()
     {
         Renderer::set_clear_color({ 0.0f, 0.0f, 0.0f, 1.0f });
         Renderer::clear();
-
-        if (m_use_compute_shader && m_processed_texture)
-        {
-            m_processed_texture->bind(0);
-            m_shader->set_int("u_Texture", 0);
-        }
-        else if (m_texture)
-        {
-            m_texture->bind(0);
-            m_shader->set_int("u_Texture", 0);
-        }
-
-        glm::mat4 view_projection = m_camera ? m_camera->get_view_projection_matrix() : glm::mat4(1.0f);
-        
-        glm::vec3 center_pos(0.0f, 0.0f, 0.0f);
-        glm::vec3 right_pos(2.0f, 0.0f, 0.0f);
-        glm::vec3 left_pos(-2.0f, 0.0f, 0.0f);
-        glm::vec3 up_pos(0.0f, 2.0f, 0.0f);
-        glm::vec3 down_pos(0.0f, -2.0f, 0.0f);
-        glm::vec3 forward_pos(0.0f, 0.0f, 2.0f);
-        glm::vec3 back_pos(0.0f, 0.0f, -2.0f);
-        
-        glm::mat4 transform = glm::translate(glm::mat4(1.0f), center_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), right_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), left_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), up_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), down_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), forward_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
-        transform = glm::translate(glm::mat4(1.0f), back_pos);
-        Renderer::submit(m_shader, m_vertex_array, transform, view_projection);
     }
     
     void SimulationState::on_event(Event& event)
     {
-        EventDispatcher dispatcher(event);
-        
-        dispatcher.dispatch<WindowResizeEvent>([this](WindowResizeEvent& e) 
-        {
-            if (m_camera)
-                m_camera->set_projection(45.0f, (float)e.get_width() / (float)e.get_height(), 0.1f, 100.0f);
-            return true;
-        });
-        
-        dispatcher.dispatch<WindowFocusEvent>([this](WindowFocusEvent& e) 
-        {
-            m_first_mouse = true;
-            m_mouse_dragging = false;
-            return true;
-        });
-        
-        dispatcher.dispatch<WindowLostFocusEvent>([this](WindowLostFocusEvent& e) 
-        {
-            m_mouse_dragging = false;
-            return true;
-        });
-        
-        dispatcher.dispatch<KeyPressedEvent>([this](KeyPressedEvent& e) 
-        {
-            m_keys[e.get_key_code()] = true;
-            return true;
-        });
-        
-        dispatcher.dispatch<KeyReleasedEvent>([this](KeyReleasedEvent& e) 
-        {
-            m_keys[e.get_key_code()] = false;
-            return true;
-        });
-        
-        dispatcher.dispatch<MouseMovedEvent>([this](MouseMovedEvent& e) 
-        {
-            if (!m_mouse_dragging)
-                return true;
-                
-            if (m_first_mouse)
-            {
-                m_last_x = e.get_x();
-                m_last_y = e.get_y();
-                m_first_mouse = false;
-            }
-
-            float x_offset = m_last_x - e.get_x();
-            float y_offset = e.get_y() - m_last_y;
-
-            m_last_x = e.get_x();
-            m_last_y = e.get_y();
-
-            if (m_camera)
-                m_camera->on_mouse_move(x_offset, y_offset);
-            
-            return true;
-        });
-        
-        dispatcher.dispatch<MouseButtonPressedEvent>([this](MouseButtonPressedEvent& e) 
-        {
-            if (e.get_mouse_button() == GLFW_MOUSE_BUTTON_LEFT)
-            {
-                m_mouse_dragging = true;
-                m_first_mouse = true;
-            }
-            return true;
-        });
-        
-        dispatcher.dispatch<MouseButtonReleasedEvent>([this](MouseButtonReleasedEvent& e) 
-        {
-            if (e.get_mouse_button() == GLFW_MOUSE_BUTTON_LEFT)
-                m_mouse_dragging = false;
-            return true;
-        });
     }
     
-    void SimulationState::handle_key_input(float delta_time)
+    void SimulationState::on_im_ui_render()
     {
-        if (m_camera)
-        {
-            if (m_keys[GLFW_KEY_W])
-                m_camera->move_forward(delta_time);
-            if (m_keys[GLFW_KEY_S])
-                m_camera->move_backward(delta_time);
-            if (m_keys[GLFW_KEY_A])
-                m_camera->move_left(delta_time);
-            if (m_keys[GLFW_KEY_D])
-                m_camera->move_right(delta_time);
-            if (m_keys[GLFW_KEY_SPACE]) 
-                m_camera->move_up(delta_time);
-            if (m_keys[GLFW_KEY_LEFT_SHIFT])
-                m_camera->move_down(delta_time);    
-        }
-        
-        static bool c_key_pressed = false;
-        if (m_keys[GLFW_KEY_C] && !c_key_pressed)
-        {
-            m_use_compute_shader = !m_use_compute_shader;
-            DONUT_INFO("Compute shader: {}", (m_use_compute_shader ? "ON" : "OFF"));
-            c_key_pressed = true;
-        }
-        if (!m_keys[GLFW_KEY_C])
-            c_key_pressed = false;
-        if (m_keys[GLFW_KEY_UP])
-            m_compute_brightness += delta_time * 0.5f;
-        if (m_keys[GLFW_KEY_DOWN])
-            m_compute_brightness -= delta_time * 0.5f;
-        if (m_keys[GLFW_KEY_LEFT])
-            m_compute_contrast -= delta_time * 0.5f;
-        if (m_keys[GLFW_KEY_RIGHT])
-            m_compute_contrast += delta_time * 0.5f;
-        if (m_keys[GLFW_KEY_Q])
-            m_compute_saturation -= delta_time * 0.5f;
-        if (m_keys[GLFW_KEY_E])
-            m_compute_saturation += delta_time * 0.5f;
+        ImGui::Begin("Simulation Controls");
         
-        m_compute_brightness = glm::clamp(m_compute_brightness, -1.0f, 1.0f);
-        m_compute_contrast = glm::clamp(m_compute_contrast, 0.1f, 3.0f);
-        m_compute_saturation = glm::clamp(m_compute_saturation, 0.0f, 2.0f);
+        ImGui::Text("Simulation State");
+        if (ImGui::Button("Back to Config"))
+            Application::get().get_state_manager().switch_to_state("Config");
+
+        ImGui::Separator();
         
-        static float status_timer = 0.0f;
-        status_timer += delta_time;
-        if (status_timer > 2.0f)
-        {
-            DONUT_INFO("Compute Shader Status:\nBrightness: {}\nContrast: {}\nSaturation: {}",
-                       m_compute_brightness, m_compute_contrast, m_compute_saturation);
-            status_timer = 0.0f;
-        }
-    }
-    
-    void SimulationState::update_texture()
-    {
-        if (!m_texture)
-            return;
-            
-        m_texture_time += m_delta_time;
+        ImGui::Text("Simulation Info:");
+        ImGui::Text("FPS: %.1f", ImGui::GetIO().Framerate);
+        ImGui::Text("Frame Time: %.3f ms", 1000.0f / ImGui::GetIO().Framerate);
         
-        if (m_use_compute_shader && m_compute_shader && m_processed_texture)
-        {
-            m_compute_shader->bind();
-            m_texture->bind(0);
-            m_compute_shader->set_int("u_InputTexture", 0);
-            m_processed_texture->bind_as_image(1, false);
-            m_compute_shader->set_float2("u_TextureSize", glm::vec2(256.0f, 256.0f));
-            m_compute_shader->set_float("u_Time", m_texture_time);
-            m_compute_shader->set_float("u_Brightness", m_compute_brightness);
-            m_compute_shader->set_float("u_Contrast", m_compute_contrast);
-            m_compute_shader->set_float("u_Saturation", m_compute_saturation);
-            m_compute_shader->dispatch(16, 16, 1);
-            m_compute_shader->memory_barrier(IMAGE_ACCESS_BARRIER_BIT);
-        }
-        else
-        {
-            uint32_t* pixel_data = new uint32_t[256 * 256];
-            for (int y = 0; y < 256; y++)
-            {
-                for (int x = 0; x < 256; x++)
-                {
-                    float time = m_texture_time * 2.0f;
-                    float u = (float)x / 256.0f;
-                    float v = (float)y / 256.0f;
-                    
-                    float wave = sin(u * 10.0f + time) * cos(v * 10.0f + time * 0.5f);
-                    wave = (wave + 1.0f) * 0.5f;
-                    
-                    uint8_t r = (uint8_t)(wave * 255);
-                    uint8_t g = (uint8_t)((1.0f - wave) * 255);
-                    uint8_t b = (uint8_t)((u + v) * 0.5f * 255);
-                    uint8_t a = 255;
-                    
-                    pixel_data[y * 256 + x] = (a << 24) | (b << 16) | (g << 8) | r;
-                }
-            }
-            
-            m_texture->set_data(pixel_data, 256 * 256 * 4);
-            delete[] pixel_data;
-        }
+        ImGui::End();
     }
 };
diff --git a/src/states/simulation_state.h b/src/states/simulation_state.h
index 051edf3..4bb1c1b 100644
--- a/src/states/simulation_state.h
+++ b/src/states/simulation_state.h
@@ -1,17 +1,9 @@
 #pragma once
 
-#include "core/memory.h"
 #include "core/state.h"
 #include "core/event.h"
-#include "core/camera.h"
 #include "core/log.h"
 
-#include "rendering/vertex_array.h"
-#include "rendering/vertex_buffer.h"
-#include "rendering/index_buffer.h"
-#include "rendering/shader.h"
-#include "rendering/texture.h"
-
 namespace Donut
 {
     class SimulationState
@@ -24,34 +16,7 @@ namespace Donut
         void on_exit()                  override;
         void on_update(float delta_time) override;
         void on_render()                override;
+        void on_im_ui_render()            override;
         void on_event(Event& event)     override;
-    private:
-        void handle_key_input(float delta_time);
-        void update_texture();
-    private:
-        Scope<Camera> m_camera;
-        
-        Ref<VertexArray>  m_vertex_array;
-        Ref<VertexBuffer> m_vertex_buffer;
-        Ref<IndexBuffer>  m_index_buffer;
-        Ref<Shader>       m_shader;
-        Ref<Texture2D>    m_texture;
-        
-        Ref<Shader>    m_compute_shader;
-        Ref<Texture2D> m_processed_texture;
-        
-        float m_compute_brightness = 0.0f;
-        float m_compute_contrast   = 1.0f;
-        float m_compute_saturation = 1.0f;
-        bool  m_use_compute_shader  = true;
-        
-        bool  m_keys[1024]    = { false };
-        bool  m_first_mouse    = true;
-        float m_last_x         = 0.0f;
-        float m_last_y         = 0.0f;
-        float m_delta_time     = 0.0f;
-        float m_last_frame     = 0.0f;
-        bool  m_mouse_dragging = false;
-        float m_texture_time   = 0.0f;
     };
 };