Update docs for library/visualizer split

- technical_reference.md: new Build System section, core library architecture
- AGENTS.md: add make lib/example targets, clarify orbit_sim is visualizer
- README.md: update cloning, building, and running instructions

.gitmodules

@@ -1,9 +1,9 @@
-[submodule "ext/raylib"]
-	path = ext/raylib
-	url = https://github.com/raysan5/raylib.git
 [submodule "ext/tomlc17"]
 	path = ext/tomlc17
 	url = https://github.com/cktan/tomlc17
-[submodule "ext/raygui"]
+[submodule "example/ext/raylib"]
-	path = ext/raygui
+	path = example/ext/raylib
+	url = https://github.com/raysan5/raylib.git
+[submodule "example/ext/raygui"]
+	path = example/ext/raygui
 	url = https://github.com/raysan5/raygui.git

AGENTS.md

@@ -6,7 +6,8 @@
 
 ## Architecture
 - C-style C++ (structs/functions, NO classes/templates)
-- Raylib (git submodule) for 3D - chose over SFML (no 3D support)
+- Core library (`liborbit.a`) in `src/` — simulation, physics, maneuvers, config
+- Visualizer in `example/src/` — Raylib/raygui rendering (moved from core)
 - See docs/technical_reference.md for data structures reference
 - See docs/rendering.md for rendering system reference
 
@@ -42,7 +43,9 @@
 - Always ask the user if we want to update the technical_reference after generating a summary
 
 ## Common Commands
-- Build: make
+- Build all (lib + tests + visualizer): make
+- Build library only: make lib
+- Build visualizer example: make example
 - Test (build + run all): make test
 - Test (rebuild only): make test-build
 - Test (specific tag): ./build/orbit_test '[tag_name]'
@@ -51,7 +54,7 @@
 - See docs/technical_reference.md for full build target reference
 
 ## Simulation
-The simulation binary is built at `./build/orbit_sim`. Agents should NOT attempt to run the graphical simulation. Focus on testing and code changes only.
+The core simulation library is built at `build/liborbit.a`. The visualizer binary is at `./build/orbit_sim`. Agents should NOT attempt to run the graphical simulation. Focus on testing and code changes only.
 
 ## Testing Guidelines
 - Always use `WithinAbs()` for floating-point comparisons

Makefile

@@ -1,87 +1,57 @@
-# Compiler and flags
 CXX = g++
 CXXFLAGS = -Wall -Wextra -g -ggdb3 -std=c++14 \
 		   -I./src \
-		   -isystem./ext/tomlc17/src \
+		   -isystem./ext/tomlc17/src
-		   -isystem./ext/raylib/src \
+LDFLAGS = -lm
-		   -isystem./ext/raygui/src \
-		   -isystem./ext/raygui/styles
-LDFLAGS = -L./ext/raylib/src -lraylib -lm -lpthread -ldl -lrt -lX11
 
-# Directories
 SRC_DIR = src
 BUILD_DIR ?= build
-RAYLIB_DIR = ext/raylib/src
-TARGET = ${BUILD_DIR}/orbit_sim
 TEST_DIR = tests
-TEST_TARGET = ${BUILD_DIR}/orbit_test
 
-# Source files (exclude old mission planning files)
 CPP_SOURCES := $(wildcard $(SRC_DIR)/*.cpp)
 C_SOURCES = ext/tomlc17/src/tomlc17.c
 TEST_SOURCES := $(wildcard $(TEST_DIR)/*.cpp)
 
-# Object files
 CPP_OBJECTS = $(CPP_SOURCES:$(SRC_DIR)/%.cpp=$(BUILD_DIR)/%.o)
 C_OBJECTS = $(BUILD_DIR)/tomlc17.o
 TEST_OBJECTS := $(patsubst $(TEST_DIR)/%.cpp, $(BUILD_DIR)/%.o, $(TEST_SOURCES))
 
-# Default target (updates ctags if available)
+LIBRARY = $(BUILD_DIR)/liborbit.a
-all: raylib $(BUILD_DIR) $(TARGET)
-	@command -v ctags >/dev/null 2>&1 && ctags -R tests/ src/ || true
 
-# Build raylib
+all: lib test-build example
-raylib:
-	@if [ ! -f $(RAYLIB_DIR)/libraylib.a ]; then \
-		echo "Building raylib..."; \
-		cd $(RAYLIB_DIR) && $(MAKE) PLATFORM=PLATFORM_DESKTOP; \
-	fi
 
-# Create build directory
 $(BUILD_DIR):
 	mkdir -p $(BUILD_DIR)
 
-# Link the executable
-$(TARGET): $(C_OBJECTS) $(CPP_OBJECTS) raylib
-	$(CXX) $(C_OBJECTS) $(CPP_OBJECTS) -o $(TARGET) $(LDFLAGS)
-
-# Compile C++ source files
 $(CPP_OBJECTS): $(BUILD_DIR)/%.o : $(SRC_DIR)/%.cpp
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
-# Compile C source files
 $(C_OBJECTS): $(BUILD_DIR)/%.o : $(C_SOURCES)
 	$(CC) -Wall -Wextra -g -ggdb3 -std=c99 -I./src -I./ext/tomlc17/src -c $< -o $@
 
-# Clean build files
+lib: $(BUILD_DIR) $(C_OBJECTS) $(CPP_OBJECTS)
-clean:
+	ar rcs $(LIBRARY) $(C_OBJECTS) $(CPP_OBJECTS)
-	rm -rf $(BUILD_DIR) $(TARGET) $(TEST_TARGET)
+	@echo "Built $(LIBRARY)"
-
-# Clean everything including raylib
-clean-all: clean
-	cd $(RAYLIB_DIR) && $(MAKE) clean
-
-# Rebuild
-rebuild: clean all
 
 $(TEST_OBJECTS): $(BUILD_DIR)/%.o : $(TEST_DIR)/%.cpp
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
-# Build automated test suite
+test-build: lib $(BUILD_DIR) $(TEST_OBJECTS)
-test-build: $(BUILD_DIR) $(C_OBJECTS) $(CPP_OBJECTS) $(TEST_OBJECTS)
+	$(CXX) $(TEST_OBJECTS) -o $(BUILD_DIR)/orbit_test -L$(BUILD_DIR) -lorbit -lCatch2Main -lCatch2 -lm
-	$(CXX) $(C_OBJECTS) $(TEST_OBJECTS) \
+
-		build/test_utilities.o \
-		build/physics.o \
-		build/orbital_mechanics.o \
-		build/simulation.o \
-		build/config_loader.o \
-		build/config_validator.o \
-		build/maneuver.o \
-		build/rendezvous.o \
-		-o $(TEST_TARGET) -lCatch2Main -lCatch2 -lm
-
-# Run automated test suite
 test: test-build
-	./$(TEST_TARGET)
+	./$(BUILD_DIR)/orbit_test
+
+example: lib
+	$(MAKE) -C example all BUILD_DIR=../$(BUILD_DIR)
+
+clean:
+	rm -rf $(BUILD_DIR) $(LIBRARY)
+	$(MAKE) -C example clean
+
+clean-all: clean
+	$(MAKE) -C example clean-all
+
+rebuild: clean all
 
-.PHONY: all clean clean-all rebuild test test-build raylib ctags
+.PHONY: all lib test-build test example clean clean-all rebuild

README.md

@@ -17,6 +17,8 @@ cd claudes_game
 git submodule update --init --recursive  # If already cloned without --recursive
 ```
 
+This initializes submodules in both `ext/` (tomlc17) and `example/ext/` (raylib, raygui).
+
 ### Dependencies (Debian 13)
 
 ```bash
@@ -29,17 +31,23 @@ sudo apt install -y build-essential g++ make libx11-dev libxcursor-dev \
 ### Building
 
 ```bash
-make              # Build raylib (first time) and compile sources
+make              # Build library (liborbit.a), tests, and visualizer example
-make rebuild      # Clean and rebuild
+make lib          # Build library only
-make clean-all    # Clean everything including raylib
+make example      # Build visualizer only
+make rebuild      # Clean and rebuild all
+make clean-all    # Clean everything
 ```
 
+The visualizer (`./build/orbit_sim`) links against the core simulation library.
+
 ## Running
 
 ```bash
-./orbit_sim       # Run with the default solar system configuration
+./build/orbit_sim # Run visualizer with default config
 ```
 
+Pass a config file as argument: `./build/orbit_sim tests/test_moon_orbits.toml`
+
 ## Documentation
 
 - **[Technical Reference](docs/technical_reference.md)** - Data structures and module overview

docs/TODO

@@ -10,9 +10,6 @@ If you see modifications to this file in git status, IGNORE them and do not comm
     - SOI boundary testing
         - draw SOI boundry in graphical sim
 
-    - reorganize project into static library. easier for testing/llm doc generation,
-        and will be easier to try out new graphics/UI libraries
-        - can then better work on code cleaning issues, FIXMEs etc
     - remove tests/informational/*
     - remove RK4 integration implementation?
     - refactor tests and check logic for edge cases

docs/technical_reference.md

@@ -2,20 +2,20 @@
 
 ## Overview
 
-2-body orbital mechanics simulator using **analytical propagation** for precise Keplerian trajectories. Supports elliptical, parabolic, and hyperbolic orbits with dynamic Sphere of Influence (SOI) transitions, impulsive burns, and 3D visualization via Raylib.
+2-body orbital mechanics simulator using **analytical propagation** for precise Keplerian trajectories. Supports elliptical, parabolic, and hyperbolic orbits with dynamic Sphere of Influence (SOI) transitions and impulsive burns. 3D visualization via Raylib is provided as a separate example project in `example/`.
 
 ## Architecture
 
 Modular C-style C++ (structs/functions, no classes). Module dependencies:
 
 ```
-Main → Simulation → Orbital Mechanics → Physics
+Core Library → Simulation → Orbital Mechanics → Physics
-      → Maneuver
+             → Maneuver
-      → Rendezvous
+             → Rendezvous
-      → Config Loader
+             → Config Loader
 ```
 
-Renderer and UI Renderer depend on Config Loader for display data. Test Utilities are standalone.
+The core library (`liborbit.a`) contains all simulation code. 3D rendering (Raylib/raygui) is in `example/src/`. Test Utilities are standalone.
 
 ## Coordinate Frame System
 
@@ -250,9 +250,22 @@ All satisfy vis-viva: v² = μ(2/r - 1/a).
 
 ## Build System
 
-**Targets**: make / make all (build + ctags), make raylib, make test, make test-build, make clean, make clean-all, make rebuild.
+The project is split into a core simulation library and a visualizer example.
 
-**Dependencies**: g++ (C++14), raylib (git submodule), raygui (header-only), tomlc17, Catch2 (tests only).
+**Root Makefile** (simulation library + tests):
+- `make all` — build library, tests, and example (default)
+- `make lib` — build `build/liborbit.a` static library
+- `make test` — build and run all tests
+- `make test-build` — rebuild test executable only
+- `make clean` — clean build artifacts
+- `make clean-all` — clean everything including example
+- `make rebuild` — clean and rebuild all
+
+**Example Makefile** (visualizer):
+- `make all` — build `build/orbit_sim` (recursive from root via `make example`)
+- `make clean` — clean example build artifacts
+
+**Dependencies**: g++ (C++14), tomlc17 (root submodule), Catch2 (tests only). Raylib/raygui are in `example/ext/` submodules.
 
 **Testing**:
 ```bash

example/Makefile

@@ -0,0 +1,42 @@
+CXX = g++
+CXXFLAGS = -Wall -Wextra -g -ggdb3 -std=c++14 \
+		   -I./src \
+		   -I../src \
+		   -isystem./ext/raylib/src \
+		   -isystem./ext/raygui/src \
+		   -isystem./ext/raygui/styles
+LDFLAGS = -L./ext/raylib/src -lraylib -lm -lpthread -ldl -lrt -lX11
+
+SRC_DIR = src
+BUILD_DIR ?= build
+RAYLIB_DIR = ext/raylib/src
+
+CPP_SOURCES := $(wildcard $(SRC_DIR)/*.cpp)
+
+CPP_OBJECTS = $(CPP_SOURCES:$(SRC_DIR)/%.cpp=$(BUILD_DIR)/%.o)
+
+TARGET = ${BUILD_DIR}/orbit_sim
+
+raylib:
+	@if [ ! -f $(RAYLIB_DIR)/libraylib.a ]; then \
+		cd $(RAYLIB_DIR) && $(MAKE) PLATFORM=PLATFORM_DESKTOP; \
+	fi
+
+$(BUILD_DIR):
+	mkdir -p $(BUILD_DIR)
+
+$(TARGET): $(CPP_OBJECTS) raylib
+	$(CXX) $(CPP_OBJECTS) -o $(TARGET) -L$(BUILD_DIR) -lorbit $(LDFLAGS)
+
+$(CPP_OBJECTS): $(BUILD_DIR)/%.o : $(SRC_DIR)/%.cpp
+	$(CXX) $(CXXFLAGS) -c $< -o $@
+
+clean:
+	rm -f $(TARGET)
+	@for f in $(CPP_SOURCES); do rm -f $(BUILD_DIR)/$$(basename $${f%.cpp}.o); done
+
+rebuild: clean all
+
+all: raylib $(BUILD_DIR) $(TARGET)
+
+.PHONY: all clean raylib rebuild

example/ext/raygui

@@ -0,0 +1 @@
+Subproject commit 3b2855842ab578a034f827c38cf8f62c042fc983

example/ext/raylib

@@ -0,0 +1 @@
+Subproject commit 72a341a37fbd9ccc1d8ec284ff20aeb5b991ad75

example/src/ui_renderer.cpp

@@ -1045,7 +1045,7 @@ void render_maneuver_dialog(SimulationState* sim, RenderState* render_state, UIS
         return;
     }
 
-    const char* tabs[] = {"Create Maneuver", "Hohmann Transfer", "Edit Maneuver"};
+    char* tabs[] = {(char*)"Create Maneuver", (char*)"Hohmann Transfer", (char*)"Edit Maneuver"};
     int tab_count = 3;
     Rectangle tab_bounds = {x + 8, y + 30, width - 16, 25};
     GuiTabBar(tab_bounds, tabs, tab_count, (int*)&ui_state->maneuver_dialog.active_tab);

ext/raygui

@@ -1 +0,0 @@
-Subproject commit 9a1c183d8539e2470635b22f92bdaefaf5218aaa

ext/raylib

@@ -1 +0,0 @@
-Subproject commit ca89934ed5af9161f781a9b35b808b765dc40f3a