live_constant_editor.hpp

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#pragma once
 
// LiveConstantEditor — debug overlay for tweaking numeric constants at runtime.
// Register constants with PULP_LIVE_CONSTANT(value, min, max), then open the
// editor overlay to adjust them without recompiling.
 
#include <pulp/view/view.hpp>
#include <string>
#include <vector>
#include <map>
#include <functional>
#include <mutex>
 
namespace pulp::view {

struct LiveConstant {
    std::string name;
    std::string file;
    int line = 0;
    float value = 0;
    float min_value = 0;
    float max_value = 1;
    float default_value = 0;
};

class LiveConstantRegistry {
public:
    static LiveConstantRegistry& instance();

    float& register_constant(std::string_view name, std::string_view file, int line,
                              float default_value, float min_val, float max_val);

    std::vector<LiveConstant> all() const;

    void reset_all();

    void reset(std::string_view name);

    void set(std::string_view name, float value);

    float get(std::string_view name) const;

    int count() const;

    std::function<void(const LiveConstant&)> on_change;
 
private:
    LiveConstantRegistry() = default;
    mutable std::mutex mutex_;
    std::map<std::string, LiveConstant, std::less<>> constants_;
};

class LiveConstantEditor : public View {
public:
    LiveConstantEditor();

    void toggle() { set_visible(!visible()); }

    bool is_showing() const { return visible(); }

    void set_row_height(float h) { row_height_ = h; }
 
    void paint(canvas::Canvas& canvas) override;
    void on_mouse_down(Point pos) override;
    void on_mouse_drag(Point pos) override;
    bool wants_mouse_input() const override { return true; }
 
private:
    float row_height_ = 28.0f;
    int dragging_index_ = -1;
 
    int hit_test_row(float y) const;
};
 
}  // namespace pulp::view
 
// Macro for declaring live constants
// Usage: float radius = PULP_LIVE_CONSTANT(8.0f, 0.0f, 50.0f);
#define PULP_LIVE_CONSTANT(default_val, min_val, max_val) \
    (::pulp::view::LiveConstantRegistry::instance().register_constant( \
        #default_val, __FILE__, __LINE__, default_val, min_val, max_val))