ImGuiLayer.h

Go to the documentation of this file.

#pragma once
 
// ---- ImGuiLayer (GUI subsystem lifecycle) ----------------------------------
// Manages the Dear ImGui context, GLFW/OpenGL3 backends, DPI scaling,
// font discovery, and font-atlas building/rebuilding.
//
// Following the Gregory "Engine Support" pattern this class encapsulates
// the entire ImGui lifecycle with explicit init / shutdown phases.
 
#include <vector>
#include <string>
 
struct GLFWwindow;
struct FontEntry;
struct UIState;
class AppWindow;
 
class ImGuiLayer
{
public:
    ImGuiLayer() = default;
    ~ImGuiLayer() = default;
 
    ImGuiLayer(const ImGuiLayer&)            = delete;
    ImGuiLayer& operator=(const ImGuiLayer&) = delete;
 
    bool init(GLFWwindow* window, float dpiScale, UIState* uiState);
 
    void discoverFonts(std::vector<FontEntry>& fonts, int& selectedFont);
 
    void buildFontAtlas(const std::vector<FontEntry>& fonts,
                        int selectedFont,
                        float fontSize,
                        float dpiScale);
 
    void rebuildFontAtlasIfDirty(bool& fontsDirty,
                                 const std::vector<FontEntry>& fonts,
                                 int selectedFont,
                                 float fontSize,
                                 float dpiScale);
 
    void beginFrame();
 
    void endFrame(const AppWindow& window);
 
    void shutdown();
};