skate3recomp-multiplayer/src/native/skate3_native_ghost.h

#pragma once

// Ghost multiplayer module (bolt-on, hand-written, confined to src/native):
// a from-scratch "ghost player" layer that relays each player's world
// transform (position + rotation) through a small UDP relay so other players
// see a placeholder marker at the same spot. It deliberately does NOT touch
// the game's own netcode, animation, physics or any codegen'd logic.
//
// Topology (automatic, zero client-side setup):
//   1. Every client connects OUTBOUND to the default public relay
//      (kGhostDefaultServer / skate3_ghost_server cvar) and joins a room
//      code. No port forwarding on any client.
//   2. If the public relay is unreachable, the game automatically becomes a
//      LAN host (GhostRelay in-process) and LAN peers auto-discover it via
//      UDP broadcast PING/HELLO.
//
// Local-player capture: at Sk8::UpdateBoneTransforms exit (the documented
// player-only hook) the pack-owner entity is the player's SkaterPresEntity;
// its verified world matrix lives at entity+416 (m_MatLtoWTrans). The
// capture runs on the sim thread and copies HOST floats under a mutex; the
// network thread never reads guest memory.

#include <cstdint>
#include <filesystem>

#include "skate3_native_ghost_proto.h"

namespace skate3::native_scene {
struct FrameScene;
}  // namespace skate3::native_scene

namespace skate3::native_ghost {

// ---- host-side capture (called from skate3_native_render.cpp) -------------
void OnLocalSkaterTick(uint8_t* base);

// ---- host-side pose capture (called from BuildFrameScene pre-publish) -----
// Snapshot the local player's skater skeleton (the highest-bone-count
// skinned non-ropa character item near the camera) as the pose this client
// broadcasts. Called every built frame; gated internally on the enable cvar.
void OnFrameSceneBuilt(uint8_t* base, const skate3::native_scene::FrameScene& scene);

// ---- network thread lifecycle -------------------------------------------------
void EnsureNetworkThread();
void Shutdown();

// Persist the multiplayer cvars (server/room/name/port/rate) into the app's
// cvar config file whenever they change, so a player's settings survive a
// restart. config_path is the same file the SDK loads at startup. Safe to
// call once at startup.
void InstallSettingsPersistence(const std::filesystem::path& config_path);

// ---- status (UI / debug) --------------------------------------------------------
struct Status {
  bool enabled = false;
  bool connected = false;  // joined to a relay (public or LAN)
  bool hosting = false;    // this game is relaying a LAN room
  bool refused = false;    // the relay refused us (protocol version mismatch)
  uint32_t session_id = 0;
  char room[kGhostMaxRoomLen] = {};
  uint8_t room_len = 0;
  size_t roster = 0;  // other members in our room
  size_t ghosts = 0;  // remote ghosts currently drawn
  char peer[96] = {}; // active relay "ip:port"
  char last_error[160] = {};  // last non-fatal error, for the menu
};
bool GetStatus(Status* out);

// ---- render query (called from RenderScene, render thread) ---------------------
size_t GhostCount();
// Row-vector world matrix (translation in row 3) + a stable color per ghost.
bool GetGhost(uint32_t index, float world[16], float color[3]);
// Full-pose variant: additionally copies up to max_bones 12-float skeleton
// rows (the exact layout DrawItem::bones uses) so the renderer can drive a
// real character mesh. bone_count receives the copied row count (0 = the
// sender had no pose available; the caller should use the cube fallback).
bool GetGhostPose(uint32_t index, float world[16], float color[3],
                  uint16_t max_bones, float* bones, uint16_t* bone_count);
// Self-check cube at the local captured pose (skate3_ghost_draw_local).
bool GetLocalWorld(float world[16]);

// Lightweight per-ghost query for the nameplate overlay: the ghost's world
// position (entity world), marker color, and display name (from the room
// roster, or a session fallback). Returns false if the ghost is gone.
bool GetGhostLabel(uint32_t index, float pos[3], float color[3], char* name,
                   size_t name_max);

// ---- lobby browser ------------------------------------------------------------
// Ask the network thread to fetch the relay's room list (non-blocking; the
// reply updates GetRooms asynchronously, a second or two later).
void RequestRooms();

// Latest room list snapshot. count == 0 before the first ROOMS reply.
struct RoomList {
  uint8_t version = 0;
  uint8_t count = 0;
  RoomEntry rooms[kGhostMaxRooms];
  double received = 0.0;  // steady seconds of the reply (0 = none yet)
};
bool GetRooms(RoomList* out);

// ---- cube geometry (56-byte records matching kSceneInputLayout) -----------------
struct GhostCubeVertex {
  float pos[3];
  float uv[2];
  float uv2[2];
  uint8_t bw[4];
  uint8_t bi[4];
  float normal[3];
  float uv3[2];
};
const GhostCubeVertex* CubeVertices();
uint32_t CubeVertexCount();  // 36 (12 triangles, non-indexed)

}  // namespace skate3::native_ghost