InputAction.h

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#pragma once
 
// ---- Input Action System --------------------------------------------------
// Data-driven input-to-action mapping inspired by Game Engine Architecture
// (Gregory).  Raw inputs (mouse, keyboard) are resolved to logical actions
// via configurable bindings.  The resolved InputState is consumed by the
// ViewportController to manipulate the camera.
 
#include "imgui.h"
 
// ---------------------------------------------------------------------------
// Logical viewport actions
// ---------------------------------------------------------------------------
 
enum class ViewportAction
{
    Orbit,          // 2D mouse drag: yaw (from dx) + pitch (from dy)
    Pan,            // 2D mouse drag: lateral (from dx) + vertical (from dy)
    Zoom,           // 1D: scroll wheel or mouse-Y drag changes radius
    OrbitYaw,       // 1D key: yaw offset per frame
    OrbitPitch,     // 1D key: pitch offset per frame
    PanLateral,     // 1D key: pan along camera right vector
    PanVertical,    // 1D key: pan along world Z axis
    ResetCamera,    // Discrete one-shot trigger
};
 
// ---------------------------------------------------------------------------
// Trigger types
// ---------------------------------------------------------------------------
 
enum class TriggerType
{
    MouseDrag,      // Mouse button held + pointer movement
    MouseScroll,    // Mouse wheel rotation
    KeyHold,        // Key held down (continuous, per-frame)
    KeyPress,       // Key pressed (single trigger, edge-detected)
};
 
// ---------------------------------------------------------------------------
// Input binding — maps a raw input to a logical action
// ---------------------------------------------------------------------------
 
struct InputBinding
{
    ViewportAction   action      = ViewportAction::Orbit;
    TriggerType      trigger     = TriggerType::MouseDrag;
 
    ImGuiMouseButton mouseButton = ImGuiMouseButton_Left;
 
    ImGuiKey         key         = ImGuiKey_None;
 
    float            scaleX      = 1.0f;
 
    float            scaleY      = 1.0f;
 
    float            keyDelta    = 0.0f;
 
    float            shiftScale  = 0.1f;
};
 
// ---------------------------------------------------------------------------
// Resolved input state for one frame — consumed by ViewportController
// ---------------------------------------------------------------------------
 
struct InputState
{
    float orbitYaw   = 0.0f;    // Accumulated yaw delta
    float orbitPitch = 0.0f;    // Accumulated pitch delta
    float panX       = 0.0f;    // Lateral pan (camera-right units)
    float panZ       = 0.0f;    // Vertical pan (world-Z units)
    float zoom       = 0.0f;    // Radius delta (positive = further away)
    bool  resetCamera = false;  // One-shot trigger
};