Add Dear ImGui

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "third-party/SDL"]
 	path = third-party/SDL
 	url = https://github.com/libsdl-org/SDL.git
+[submodule "third-party/imgui"]
+	path = third-party/imgui
+	url = https://github.com/ocornut/imgui.git

CMakeLists.txt

@@ -19,6 +19,24 @@ add_library(${PROJECT_NAME} STATIC ${SOURCES} ${HEADERS})
 
 add_library(glad STATIC third-party/glad/glad.c)
 
+# ImGui setup
+set(IMGUI_DIR ${CMAKE_CURRENT_SOURCE_DIR}/third-party/imgui)
+add_library(imgui STATIC
+    ${IMGUI_DIR}/imgui.cpp
+    ${IMGUI_DIR}/imgui_draw.cpp
+    ${IMGUI_DIR}/imgui_tables.cpp
+    ${IMGUI_DIR}/imgui_widgets.cpp
+    ${IMGUI_DIR}/imgui_demo.cpp
+    ${IMGUI_DIR}/backends/imgui_impl_sdl3.cpp
+    ${IMGUI_DIR}/backends/imgui_impl_opengl3.cpp
+)
+target_include_directories(imgui
+    PUBLIC
+        ${IMGUI_DIR}
+        ${IMGUI_DIR}/backends
+        ${CMAKE_CURRENT_SOURCE_DIR}/third-party/SDL/include
+)
+
 target_include_directories(${PROJECT_NAME} 
     PUBLIC 
         $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>
@@ -73,6 +91,7 @@ target_include_directories(glad
 # handles their include paths and other properties for you.
 target_link_libraries(${PROJECT_NAME} PUBLIC glad)
 target_link_libraries(${PROJECT_NAME} PUBLIC SDL3::SDL3)
+target_link_libraries(${PROJECT_NAME} PUBLIC imgui)
 
 
 # Shaders

include/weird-engine.h

@@ -4,6 +4,11 @@
 #define ENGINE_PATH "../weird-engine"
 #endif // !ENGINE_PATH
 
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_timer.h>
+#include <imgui.h>
+#include <imgui_impl_sdl3.h>
+
 #include "weird-engine/Input.h"
 #include "weird-engine/Profiler.h"
 #include "weird-engine/SceneManager.h"
@@ -79,6 +84,15 @@ namespace WeirdEngine
 			// Capture window input
 			Input::update(ctx.renderer.getWindow());
 
+			// Suppress game input when ImGui has focus
+			{
+				const ImGuiIO& io = ImGui::GetIO();
+				if (io.WantCaptureMouse)
+					Input::suppressMouseInput();
+				if (io.WantCaptureKeyboard)
+					Input::suppressKeyboardInput();
+			}
+
 			if (Input::GetKeyDown(Input::T))
 			{
 				WeirdEngine::Profiler::Get().startRecording();
@@ -91,6 +105,8 @@ namespace WeirdEngine
 			SDL_Event event;
 			while (SDL_PollEvent(&event))
 			{
+				ImGui_ImplSDL3_ProcessEvent(&event);
+
 				if (event.type == SDL_EVENT_QUIT)
 				{
 					ctx.quit = true;

include/weird-engine/Input.h

@@ -258,6 +258,32 @@ namespace WeirdEngine
 
 #pragma endregion
 
+		static void suppressMouseInput()
+		{
+			auto& instance = getInstance();
+			for (int i = 0; i < 5; ++i)
+			{
+				if (instance.m_mouseKeysTable[i] > NOT_PRESSED)           // IS_PRESSED or FIRST_PRESSED
+					instance.m_mouseKeysTable[i] = RELEASED_THIS_FRAME;    // fire key-up
+				else if (instance.m_mouseKeysTable[i] == RELEASED_THIS_FRAME)
+					instance.m_mouseKeysTable[i] = NOT_PRESSED;            // clear existing key-up
+				// NOT_PRESSED stays NOT_PRESSED — no spurious key-ups
+			}
+		}
+
+		static void suppressKeyboardInput()
+		{
+			auto& instance = getInstance();
+			for (int i = 0; i < SDL_SCANCODE_COUNT; ++i)
+			{
+				if (instance.m_keyTable[i] > NOT_PRESSED)                 // IS_PRESSED or FIRST_PRESSED
+					instance.m_keyTable[i] = RELEASED_THIS_FRAME;          // fire key-up
+				else if (instance.m_keyTable[i] == RELEASED_THIS_FRAME)
+					instance.m_keyTable[i] = NOT_PRESSED;                  // clear existing key-up
+				// NOT_PRESSED stays NOT_PRESSED — no spurious key-ups
+			}
+		}
+
 #pragma region Keyboard
 
 		static bool GetKey(KeyCode key)

include/weird-renderer/core/SDF2DRenderPipeline.h

@@ -49,6 +49,7 @@ namespace WeirdEngine
 							double delta, Texture* backgroundTexture = nullptr);
 			void resize(unsigned int newWidth, unsigned int newHeight);
 			void free();
+			void handleDebugInputs();
 
 		private:
 			Config m_config;
@@ -124,8 +125,6 @@ namespace WeirdEngine
 			void blendMaterials(double time);
 			void renderBackground(const Camera& camera, double time);
 			void applyLighting(const Camera& camera, double time, Texture* backgroundTexture);
-			void handleDebugInputs();
-
 			static int largestPowerOfTwoBelow(int n);
 		};
 	} // namespace WeirdRenderer

include/weird-renderer/core/SDLInitializer.h

@@ -1,8 +1,9 @@
 #pragma once
 
-#include "weird-renderer/audio/AudioEngine.h"
 #include <SDL3/SDL.h>
 
+#include "weird-renderer/audio/AudioEngine.h"
+
 namespace WeirdEngine
 {
 	namespace WeirdRenderer

src/weird-renderer/core/Renderer.cpp

@@ -1,9 +1,14 @@
 #include "weird-renderer/core/Renderer.h"
 
-#include "weird-engine/Profiler.h"
+#include <sys/stat.h>
+
 #include <SDL3/SDL.h>
 #include <SDL3/SDL_hints.h>
-#include <sys/stat.h>
+#include <imgui.h>
+#include <imgui_impl_sdl3.h>
+#include <imgui_impl_opengl3.h>
+
+#include "weird-engine/Profiler.h"
 
 namespace WeirdEngine
 {
@@ -117,6 +122,30 @@ namespace WeirdEngine
 			auto& result = renderScene(scene, time, clampedDelta);
 			output(scene, result, clampedDelta);
 
+			static bool showDebugUI = false;
+
+			if(Input::GetKeyDown(Input::F3))
+			{
+				showDebugUI = !showDebugUI;
+			}
+
+			if(showDebugUI)
+			{
+				ImGui_ImplOpenGL3_NewFrame();
+				ImGui_ImplSDL3_NewFrame();
+				ImGui::NewFrame();
+
+				ImGui::Begin("Renderer Settings");
+				m_worldPipeline->handleDebugInputs();
+				m_uiPipeline->handleDebugInputs();
+				ImGui::End();
+
+				ImGui::Render();
+				glBindFramebuffer(GL_FRAMEBUFFER, 0);
+				glViewport(0, 0, m_windowWidth, m_windowHeight);
+				ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+			}
+
 			{
 				PROFILE_SCOPE("Synchronization");
 				SDL_GL_SwapWindow(m_window);

src/weird-renderer/core/SDF2DRenderPipeline.cpp

@@ -1,7 +1,11 @@
 #include "weird-renderer/core/SDF2DRenderPipeline.h"
-#include "weird-engine/vec.h"
+
 #include <algorithm>
 
+#include <imgui.h>
+
+#include "weird-engine/vec.h"
+
 namespace WeirdEngine
 {
 	namespace WeirdRenderer
@@ -528,45 +532,62 @@ namespace WeirdEngine
 
 		void SDF2DRenderPipeline::handleDebugInputs()
 		{
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::L))
-			// {
-			// 	m_2DLightingShader.toggleDefine("SHADOWS_ENABLED");
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::D))
-			// {
-			// 	if (Input::GetKey(Input::LeftShift)) {
-			// 		m_finalUIShader.toggleDefine("DITHERING");
-			// 	} else {
-			// 		m_finalUIShader.toggleDefine("DEBUG_SHOW_DISTANCE");
-			// 	}
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::C))
-			// {
-			// 	m_2DLightingShader.toggleDefine("DEBUG_SHOW_COLORS");
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::A))
-			// {
-			// 	m_2DLightingShader.toggleDefine("ANTIALIASING");
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::B))
-			// {
-			// 	m_2DDistanceShader.toggleDefine("BLEND_SHAPES");
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::M))
-			// {
-			// 	m_2DDistanceShader.toggleDefine("MOTION_BLUR");
-			// 	m_uiDistanceShader.toggleDefine("MOTION_BLUR");
-			// }
-			//
-			// if (Input::GetKey(Input::LeftCtrl) && Input::GetKeyDown(Input::F))
-			// {
-			// 	USE_CORRECTED_DISTANCE_TEXTURE = !USE_CORRECTED_DISTANCE_TEXTURE;
-			// }
+			const char* label = m_config.isUI ? "UI Pipeline" : "World Pipeline";
+			if (!ImGui::CollapsingHeader(label))
+				return;
+
+			ImGui::PushID(label);
+
+			ImGui::SeparatorText("Shadows");
+			if (ImGui::Checkbox("Shadows", &m_config.enableShadows))
+			{
+				if (m_config.enableShadows) m_lightingShader.addDefine("SHADOWS_ENABLED");
+				else m_lightingShader.removeDefine("SHADOWS_ENABLED");
+			}
+			if (ImGui::Checkbox("Long Shadows", &m_config.enableLongShadows))
+			{
+				if (m_config.enableLongShadows) m_lightingShader.addDefine("LONG_SHADOWS");
+				else m_lightingShader.removeDefine("LONG_SHADOWS");
+			}
+
+			ImGui::SeparatorText("Rendering");
+			if (ImGui::Checkbox("Antialiasing", &m_config.enableAntialiasing))
+			{
+				if (m_config.enableAntialiasing) m_lightingShader.addDefine("ANTIALIASING");
+				else m_lightingShader.removeDefine("ANTIALIASING");
+			}
+			if (ImGui::Checkbox("Motion Blur", &m_config.enableMotionBlur))
+			{
+				if (m_config.enableMotionBlur) m_distanceShader.addDefine("MOTION_BLUR");
+				else m_distanceShader.removeDefine("MOTION_BLUR");
+			}
+			if (ImGui::Checkbox("Refraction", &m_config.enableRefraction))
+			{
+				if (m_config.enableRefraction) m_lightingShader.addDefine("REFRACTION");
+				else m_lightingShader.removeDefine("REFRACTION");
+			}
+
+			ImGui::SeparatorText("Debug");
+			if (ImGui::Checkbox("Show Distance Field", &m_config.debugDistanceField))
+			{
+				if (m_config.debugDistanceField) m_lightingShader.addDefine("DEBUG_SHOW_DISTANCE");
+				else m_lightingShader.removeDefine("DEBUG_SHOW_DISTANCE");
+			}
+			if (ImGui::Checkbox("Show Material Colors", &m_config.debugMaterialColors))
+			{
+				if (m_config.debugMaterialColors) m_lightingShader.addDefine("DEBUG_SHOW_COLORS");
+				else m_lightingShader.removeDefine("DEBUG_SHOW_COLORS");
+			}
+
+			ImGui::SeparatorText("Ambient Occlusion");
+			ImGui::SliderFloat("AO Radius", &m_config.ambienOcclusionRadius, 0.0f, 20.0f);
+			ImGui::SliderFloat("AO Strength", &m_config.ambienOcclusionStrength, 0.0f, 1.0f);
+
+			ImGui::SeparatorText("Materials");
+			ImGui::SliderFloat("Blend Speed", &m_config.materialBlendSpeed, 0.0f, 20.0f);
+			ImGui::SliderFloat("Smooth Factor (k)", &m_config.ballK, 0.0f, 50.0f);
+
+			ImGui::PopID();
 		}
 
 		Shader& SDF2DRenderPipeline::getDistanceShader()

src/weird-renderer/core/SDLInitializer.cpp

@@ -1,10 +1,14 @@
 #include "weird-renderer/core/SDLInitializer.h"
-#include "weird-renderer/audio/AudioEngine.h"
+
 #include <csignal>
-#include <glad/glad.h>
 #include <iostream>
 #include <stdexcept>
 
+#include <glad/glad.h>
+#include <imgui.h>
+#include <imgui_impl_sdl3.h>
+#include <imgui_impl_opengl3.h>
+
 namespace WeirdEngine
 {
 	namespace WeirdRenderer
@@ -91,6 +95,13 @@ namespace WeirdEngine
 				throw std::runtime_error("Failed to initialize GLAD.");
 			}
 
+			IMGUI_CHECKVERSION();
+			ImGui::CreateContext();
+			ImGui::StyleColorsDark();
+
+			ImGui_ImplSDL3_InitForOpenGL(m_window, m_glContext);
+			ImGui_ImplOpenGL3_Init("#version 300 es"); // matches your GL ES 3.0 context
+
 #ifndef NDEBUG
 			// Enable debug output via KHR_debug extension if supported
 			if (GLAD_GL_KHR_debug)
@@ -134,6 +145,10 @@ namespace WeirdEngine
 
 		SDLInitializer::~SDLInitializer()
 		{
+			ImGui_ImplOpenGL3_Shutdown();
+			ImGui_ImplSDL3_Shutdown();
+			ImGui::DestroyContext();
+
 			SDL_DestroyAudioStream(m_audioStream);
 			SDL_GL_DestroyContext(m_glContext);
 			SDL_DestroyWindow(m_window);