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Prey (2017) internals - notes from three Chairloader DLL mods

Written for the PreyVR / motion-controls effort by Vittorio "Vee" Romeo, September 2026. Everything below was learned while building three DLL mods on the Chairloader framework and is offered freely (the mods are MIT):

• Viewmodel Tweaks & Ironsights - https://github.com/vittorioromeo/Vee.ViewmodelTweaks - moves the weapon and first-person arms to arbitrary camera-relative poses (hip offsets, ironsights lock, sway, recoil, FOV control). The most VR-relevant one: it is, in effect, "place the weapon and hands where I say, every frame".
• Mediumcore Death - https://github.com/vittorioromeo/Vee.Mediumcore - death rework, inventory, saves, traumas, signals.

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////////////////////////////////////////////////////////////
// Scenario 5: nested coroutines with per-layer state (16 doubles)
//
// Highlights one of SFEX's costs: every top-level resume re-walks the
// entire C++ call chain from the outermost coroutine down to the leaf.
// At depth 64 with non-trivial per-layer state, each level pays for a
// real function call and an actual touch of its members on every
// resume.
//

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#pragma once
// LICENSE AND COPYRIGHT (C) INFORMATION
// https://github.com/vittorioromeo/VRSFML/blob/master/license.md


////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include "SFML/System/Clock.hpp"
#include "SFML/System/Time.hpp"

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#include <benchmark/benchmark.h>

#include <cstdint>

enum class EDS_ScreenHuggingIconCorner : uint8_t
{
    TopLeft,
    TopRight,
    BottomLeft,
    BottomRight,

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// Compile on MSYS2 with:
// gcc ./fboBug.c -lSDL3 -lopengl32

#include <SDL3/SDL.h>
#include <SDL3/SDL_opengl.h>

#include <assert.h>
#include <stdio.h>

#define glCheck(...)                                                         \

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int main()
{
    //
    //
    // Setup globals and hidden shared OpenGL context (for resource sharing)
    // (uses `SDL_GLContext` internally)
    auto                 graphicsContext = sf::GraphicsContext::create().value();
    sf::priv::GlContext& sharedCtxPtr    = sf::WindowContext::getSharedGlContextPtr();

    //

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Analyzing build trace from 'out.bin'...
**** Time summary:
Compilation (94 times):
  Parsing (frontend):          360.0 s
  Codegen & opts (backend):     81.0 s

**** Files that took longest to parse (compiler frontend):
  9161 ms: .//tests/CMakeFiles/test-conversions_cpp17.dir/src/unit-conversions.cpp.obj
  9097 ms: .//tests/CMakeFiles/test-regression1_cpp17.dir/src/unit-regression1.cpp.obj
  8787 ms: .//tests/CMakeFiles/test-conversions_cpp14.dir/src/unit-conversions.cpp.obj

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// TODO P0: cleanup, add error handling, add missing events, etc...

#include <SFML/Copyright.hpp> // LICENSE AND COPYRIGHT (C) INFORMATION


////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include "SFML/Window/Mouse.hpp"
#include "SFML/Window/WindowImpl.hpp"

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using mode_t = unsigned int;
using size_t = decltype(sizeof(int));

namespace detail
{
    struct invalid_permission_character {};
    struct invalid_permission_string_length {};

    consteval mode_t from_readable_mode_string(const char * const s)
    {

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#include <boost/pfr.hpp>
#include <vector>
#include <tuple>
#include <type_traits>
#include <cassert>
#include <array>

namespace storage_policy
{
    struct aos;