goldberg_emulator/overlay_experimental/OpenGLX_Hook.cpp

#include "OpenGLX_Hook.h"
#include "X11_Hook.h"
#include "Renderer_Detector.h"
#include "../dll/dll.h"

#ifndef NO_OVERLAY

#include <imgui.h>
#include <impls/imgui_impl_opengl3.h>

#include "steam_overlay.h"

OpenGLX_Hook* OpenGLX_Hook::_inst = nullptr;

bool OpenGLX_Hook::start_hook()
{
    bool res = true;
    if (!hooked)
    {
        if (!X11_Hook::Inst()->start_hook())
            return false;

        GLenum err = glewInit();

        if (err == GLEW_OK)
        {
            PRINT_DEBUG("Hooked OpenGLX\n");

            hooked = true;
            Renderer_Detector::Inst().renderer_found(this);

            UnhookAll();
            BeginHook();
            HookFuncs(
                std::make_pair<void**, void*>(&(void*&)_glXSwapBuffers, (void*)&OpenGLX_Hook::MyglXSwapBuffers)
            );
            EndHook();

            get_steam_client()->steam_overlay->HookReady();
        }
        else
        {
            PRINT_DEBUG("Failed to hook OpenGLX\n");
            /* Problem: glewInit failed, something is seriously wrong. */
            PRINT_DEBUG("Error: %s\n", glewGetErrorString(err));
            res = false;
        }
    }
    return true;
}

void OpenGLX_Hook::resetRenderState()
{
    if (initialized)
    {
        ImGui_ImplOpenGL3_Shutdown();
        //X11_Hook::Inst()->resetRenderState();
        ImGui::DestroyContext();

        initialized = false;
    }
}

// Try to make this function and overlay's proc as short as possible or it might affect game's fps.
void OpenGLX_Hook::prepareForOverlay(Display* display)
{
    PRINT_DEBUG("Called SwapBuffer hook");

    if( ! initialized )
    {
        ImGui::CreateContext();
        ImGuiIO& io = ImGui::GetIO();
        io.IniFilename = NULL;

        ImGui_ImplOpenGL3_Init();
        initialized = true;
    }

    if( initialized )
    {
        ImGuiIO& io = ImGui::GetIO();

        GLint m_viewport[4];
        glGetIntegerv( GL_VIEWPORT, m_viewport );
        int width = m_viewport[2];
        int height = m_viewport[3];

        ImGui_ImplOpenGL3_NewFrame();
        X11_Hook::Inst()->prepareForOverlay(display);

        ImGui::NewFrame();

        get_steam_client()->steam_overlay->OverlayProc(width, height);

        ImGui::EndFrame();

        ImGui::Render();

        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
    }
}

void OpenGLX_Hook::MyglXSwapBuffers(Display* display, GLXDrawable drawable)
{
    OpenGLX_Hook::Inst()->prepareForOverlay(display);
    OpenGLX_Hook::Inst()->_glXSwapBuffers(display, drawable);
}

OpenGLX_Hook::OpenGLX_Hook():
    initialized(false),
    hooked(false),
    _glXSwapBuffers(nullptr)
{
    //_library = dlopen(DLL_NAME);
}

OpenGLX_Hook::~OpenGLX_Hook()
{
    PRINT_DEBUG("OpenGLX Hook removed\n");

    if (initialized)
    {
        ImGui_ImplOpenGL3_Shutdown();
        ImGui::DestroyContext();
    }

    //dlclose(_library);

    _inst = nullptr;
}

OpenGLX_Hook* OpenGLX_Hook::Inst()
{
    if (_inst == nullptr)
        _inst = new OpenGLX_Hook;

    return _inst;
}

const char* OpenGLX_Hook::get_lib_name() const
{
    return DLL_NAME;
}

void OpenGLX_Hook::loadFunctions(decltype(glXSwapBuffers)* pfnglXSwapBuffers)
{
    _glXSwapBuffers = pfnglXSwapBuffers;
}

#endif//NO_OVERLAY