Settings panel (kke::DemoPanelModule)¶
A panel of sliders, choices, toggles, buttons and live text for a demo or a tool, drawn with RmlUi, that works the same with a controller, the keyboard and the mouse. Every demo's settings use it, so someone on a sofa with a pad can change everything a mouse user can.
The rule it follows (Kees, 2026-09-27): the engine's F1 panels are ImGui, for developers; everything a player sees, and every tool for making a game inside the game, is RmlUi.
Using it¶
// main.cpp
app.addModule<kke::InputModule>("my_demo_input.json");
app.addModule<kke::UiModule>();
app.addModule<MyDemoModule>();
app.addModule<kke::DemoPanelModule>("My demo"); // Side::Right for the right edge
// MyDemoModule::init()
auto& s = app.getModule<kke::DemoPanelModule>()->section("Waves");
s.hint("{mouse:left} throw", "{sea.throw} throw"); // keyboard+mouse / controller
s.slider("Wind", &m_wind, 0.0f, 14.0f, "%.1f m/s", [this] { applyWind(); }, 0.5f);
s.choice("Throw", &m_kind, { "Foam", "Wood", "Iron" });
s.toggle("Camera follows the boat", &m_follow);
s.button("Reset", [this] { reset(); });
s.text([this] { return "Speed " + std::to_string(speed()); });
s.note("Water is 1025 kg/m3: lighter things float.");
The values stay in the game. The panel reads them every frame (a key that
changes one shows up in the panel too), writes them when the player changes
a row and then calls the row's onChange.
{action}in any text becomes that action's button on the device the player holds (kke::ButtonPrompts);hint()picks a different line for keyboard and controller, since an action bound only to a pad shows nothing on the keyboard.- A row whose name changes (a slot for whichever player is in it):
.labelLive([this] { return "Mute " + name(); })after the row. - A row that belongs to one scene:
.showIf([this] { return m_scene == 1; }), or a whole section:sectionIf(...). - A value that moves (a setting of whichever character is selected): pass a
Ref(a function returning the pointer, or null to hide the row).
How the player drives it¶
| State | What shows | Controls |
|---|---|---|
| Open (start) | the panel; the game has the controls | the mouse clicks and drags anything |
| Active | a highlighted row | up/down picks a row, left/right changes it (hold to sweep), A presses, B or Esc goes back |
| Collapsed | only the title | the title or panel.toggle opens it |
panel.toggle is the View/Back button on a pad and F3 on the keyboard
(rebindable like any action). While the panel is Active, player 1's
game input context is off, so the stick that picks rows doesn't also
drive the boat. The last row, "Hide panel", collapses it.
In a game with the game shell (kke::GameShellModule, every demo now,
GAME_SHELL.md) the View/Back button and Esc open the
shell's pause menu instead, and its "Demo settings" row makes the panel
Active; panel.toggle is then F3 only and the panel has no Quit row (the
pause menu has it). Without the shell:
Esc works like a pause menu: it opens the panel with the keyboard on it,
and Esc again goes back to the game. Because of that the panel turns the
window's quit-on-Esc off and adds a "Quit" row above "Hide panel", so
nobody is stuck in a game with no way out. A game that wants Esc for
itself calls setEscapeMenu(false) before init.
With a DemoPanelModule the engine's ImGui windows (Performance, Camera,
Physics...) start hidden: F1 shows them, in developer builds only
(setDeveloperPanelsKey(false) for a game that handles F1 itself).
A camera for the controller¶
OrbitCameraModule::setPadControls(true) turns the view with the right
stick (camera.orbit) and zooms with the d-pad (camera.zoom). Both are
game actions, so they rest while the panel has the controller.
Checking it headless¶
opens the panel with the virtual pad's View button 8 s in, moves down a row and turns it up one step (docs/INPUT.md "Testing without hardware").