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UIManager

UIManager owns the top-level UI element list and drives UI command submission each frame.

You access it through:

UI().setElements(uiElements);

The element list is a fixed-size UIElementRef[] array. nullptr entries are not allowed.

static UIElementRef uiElements[] = { scoreLabel, healthLabel };

Setup

Register UI elements after StartEngine() and before StartGame().

#include "WolfEngine/WolfEngine.hpp"
#include "WolfEngine/Graphics/UserInterface/UIElements/WE_UIElements.hpp"

static UILabel scoreLabel(4, 4, 96, 7, "Score: 0", PL_GS_White, PALETTE_GRAYSCALE, 0, UIAnchor::TopLeft);
static UILabel healthLabel(4, 16, 96, 7, "HP: 100", PL_GS_White, PALETTE_GRAYSCALE, 0, UIAnchor::TopLeft);

static UIElementRef uiElements[] = { scoreLabel, healthLabel };

extern "C" void app_main() {
    Engine().StartEngine();
    UI().setElements(uiElements);
    Engine().StartGame();
}

setElements

template <size_t N>
UI().setElements(const UIElementRef (&elements)[N]);

What it does:

  1. Copies the list into internal fixed storage using the compile-time array size N
  2. Wires each element to the manager pointer
  3. Assigns each element draw metadata (m_drawOrder, m_layer)
  4. Marks UI dirty if renderer/framebuffer has already been initialized

Bound rule:

  • N must be <= Settings.limits.maxUIElements (compile-time checked)
  • Use UI().clearElements() to unregister everything

Dirty Behavior

BaseUIElement::markDirty() sets a manager-level dirty flag.

At render time:

  • Renderer currently calls UI().render() every frame.
  • UIManager::render() iterates all registered elements and calls draw(...) on each.
  • Elements submit DrawCommand objects (FillRect, Line, Circle, TextRun) via RenderSys().submitDrawCommand(...).

The dirty flag still exists and is useful for future optimization/caching, but it no longer gates whether UI render is invoked.

Layout Notes

Game code sets UI layout through constructor arguments (x, y, w, h, layer, anchor).

Use anchors (TopLeft, BotCenter, Center, etc.) to place elements relative to screen edges or center. The engine still resolves final screen rectangles with UITransform internally in BaseUIElement::resolveRect().

Note: UILabel, UIShape, and UIPanel are not aggregates (virtual base methods), so use constructors for initialization.