TurntableCameraController.h

//
//  TurntableCameraController.h
//  avara3d
//
//  Created by Morgan Davis on 8/9/26.
//  Copyright © 2026 Morgan K Davis. All rights reserved.
//
 
#ifndef AVARA3D_EXTENSION_CAMERA_TURNTABLECAMERACONTROLLER_H
#define AVARA3D_EXTENSION_CAMERA_TURNTABLECAMERACONTROLLER_H
 
#include <memory>
#include <optional>
#include <variant>
 
#include "a3d/Math.h"
#include "a3d/input/DesktopInputContext.h"
 
namespace a3d {
 
    class Node;
 
}
 
namespace a3d::ext {
 
    class TurntableCameraController {
 
    public:
        // [Public Types]
 
        struct NodeTarget {
 
            std::weak_ptr<Node> node; 
            math::vec3          localPosition {0.0f}; 
        };
 
        using Target = std::variant<math::vec3, NodeTarget>;
 
        struct View {
 
            Target target {math::vec3 {0.0f}}; 
            float  yaw {0.0f}; 
            float  pitch {0.0f}; 
            float  distance {10.0f}; 
        };
 
        struct Controls {
 
            DesktopInputContext::MouseButton orbitButton {
                DesktopInputContext::MouseButton::One}; 
            DesktopInputContext::MouseButton panButton {
                DesktopInputContext::MouseButton::Two}; 
            DesktopInputContext::Key panModifier {
                DesktopInputContext::Key::LeftShift}; 
            DesktopInputContext::Key dollyModifier {
                DesktopInputContext::Key::LeftControl}; 
        };
 
        struct PointerClick {
 
            math::vec2 position; 
        };
 
        struct Config {
 
            float minPitch {
                -math::radians(85.0f)}; 
            float maxPitch {math::radians(85.0f)}; 
 
            float minDistance {0.01f}; 
            float maxDistance {math::F32_MAX}; 
 
            float orbitSensitivity {0.004f}; 
            float dollySensitivity {0.01f}; 
            float scrollDollySensitivity {0.15f}; 
            float dragThreshold {
                4.0f}; 
            bool     invertPitch {false}; 
 
            Controls controls; 
        };
 
        struct UpdateResult {
 
            bool cameraChanged {false}; 
            bool pointerDragging {false}; 
            std::optional<PointerClick>
                orbitButtonClick; 
            std::optional<PointerClick>
                panButtonClick; 
        };
 
        // [Public Lifecycle Functions]
 
        TurntableCameraController();
 
        explicit TurntableCameraController(const Config& config);
 
        // [Public Member Functions]
 
        const Config& config() const;
 
        void          config(const Config& config);
 
        const View&   view() const;
 
        void          view(const View& view);
 
        void          target(const math::vec3& worldPosition);
 
        void          target(const std::shared_ptr<Node>& node);
 
        void          target(const std::shared_ptr<Node>& node, const math::vec3& localPosition);
 
        UpdateResult  update(DesktopInputContext& input, float vFov, float viewportHeight);
 
        void          apply(Node& pov);
 
    private:
        // [Private Types]
 
        enum class DragMode {
            Orbit,
            Pan,
            Dolly
        };
 
        // [Private Member Functions]
 
        math::vec3 resolveTarget();
        void       translateTarget(const math::vec3& worldTranslation);
 
        // [Private Member Variables]
 
        Config     _config;
        View       _view;
        math::vec3 _resolvedTarget;
        bool       _orbitButtonActive;
        bool       _orbitButtonDragging;
        DragMode   _orbitButtonDragMode;
        math::vec2 _orbitButtonPressPosition;
        bool       _panButtonActive;
        bool       _panButtonDragging;
        math::vec2 _panButtonPressPosition;
    };
 
}
 
#endif // AVARA3D_EXTENSION_CAMERA_TURNTABLECAMERACONTROLLER_H