An interactive, grid-based visualiser for the Bug0, Bug1, and Bug2 path-planning algorithms, built with C++17 and SDL2.
- Paint obstacle walls, set a start and goal, and optionally add ordered checkpoints.
- Watch the robot navigate in real time at three configurable speeds (15 ms / 60 ms / 200 ms).
- Step forward and backward through the simulation one tick at a time.
- Switch between Bug0 / Bug1 / Bug2 without rebuilding - sidebar buttons or keys
0/1/2. - Save and load maps as plain-text
.mapfiles via a native file dialog (zenity). - Five built-in example maps loadable from the sidebar.
- Bug2 M-line overlay rendered on the grid.
- Bug1 hit-point (magenta) and closest-point (teal) debug markers rendered on the grid.
- Full path painted on completion; visited cells shown in a distinct colour during traversal.
- Checkpoint support: add ordered waypoints the robot must visit before the goal.
Greedy move directly toward the goal. On hitting an obstacle, enter left-hand wall-follow. Exit wall-follow only after making net progress past the wall-follow entry point (current distance to goal < entry distance) and a direction with positive goal-progress is free (one-step lookahead). This prevents oscillation inside concave obstacles such as U-shapes.
On hitting an obstacle, fully circumnavigate it while recording the closest cell to the goal (closePt). After the full circuit, retrace the boundary back to closePt and resume direct travel toward the goal. Guaranteed to find a path if one exists, at the cost of more steps than Bug0/Bug2.
Defines an M-line - the straight line from the current segment start to the goal. On hitting an obstacle, follow the wall and exit as soon as the robot crosses the M-line at a point closer to the goal than the hit point. If the robot returns to the hit point without such a crossing, the goal is declared unreachable.
| Library | Ubuntu / Debian package |
|---|---|
| SDL2 | libsdl2-dev |
| SDL2_ttf | libsdl2-ttf-dev |
| CMake ≥ 3.16 | cmake |
| zenity | zenity |
sudo apt install libsdl2-dev libsdl2-ttf-dev cmake zenitymkdir build && cd build
cmake ..
make -j$(nproc)
./bug_plannerExample maps are automatically copied into build/maps/ by the CMake post-build step.
| Action | Effect |
|---|---|
| Left-click / drag on grid | Apply the selected draw mode |
| Right-click / drag on grid | Erase cell |
| Click a sidebar button | Activate that mode or action |
| Key | Action |
|---|---|
R |
Run simulation |
Esc |
Reset simulation |
C |
Clear all |
Space |
Pause / resume |
<- / -> |
Step backward / forward |
0 / 1 / 2 |
Select Bug0 / Bug1 / Bug2 |
Ctrl+S |
Save map |
Ctrl+L |
Load map |
| Mode | Effect |
|---|---|
| Draw Obstacle | Paint obstacle cells |
| Erase | Remove any cell (obstacle, start, goal, checkpoint) |
| Set Start | Place the robot's start position (one per map) |
| Set Goal | Place the goal position (one per map) |
| Add Checkpoint | Append an ordered waypoint the robot must visit first |
Plain-text, one record per line:
# comment
S x y # start position
G x y # goal position
K x y # checkpoint (ordered, may repeat)
O x y # obstacle cell
bug-nav-cpp-sim/
├── include/
│ ├── constants.hpp
│ ├── direction.hpp
│ ├── button.hpp
│ ├── grid.hpp
│ ├── robot.hpp
│ ├── mapfile.hpp
│ ├── theme.hpp
│ └── app.hpp
├── src/
│ ├── main.cpp # Entry point
│ ├── grid.cpp
│ ├── mapfile.cpp
│ ├── robot.cpp
│ ├── bug0.cpp
│ ├── bug1.cpp
│ ├── bug2.cpp
│ ├── app.cpp
│ ├── app_events.cpp
│ ├── app_editor.cpp
│ ├── app_ui.cpp
│ ├── app_sim.cpp
│ ├── app_map.cpp
│ └── app_render.cpp
├── maps/
│ ├── vertical_wall.map
│ ├── u_shape.map
│ ├── double_wall.map
│ ├── corridor.map
│ ├── zigzag.map
│ └── mirror_step.map
├── assets/
│ ├── wall.png
│ ├── wall_b0.png
│ ├── wall_b1.png
│ └── wall_b2.png
├── docs/
│ ├── Doxyfile
│ └── DoxygenLayout.xml
├── CMakeLists.txt
└── README.md
doxygen docs/DoxyfileHTML output is written to docs/html/index.html.