This code was written by ChatGPT

opengl_vr_from_chatgpt.c

#include <Windows.h>
#include <MinHook.h>
#include <GL/gl.h>
#include <GL/glext.h>
#include <OVR_CAPI_GL.h>

// Declaration of the original function.
typedef void (__stdcall *glBegin_t)(GLenum);
glBegin_t original_glBegin;

// Replacement function that adds VR support.
void __stdcall VR_glBegin(GLenum mode)
{
    // Get the current VR pose.
    ovrPosef pose = ovrHmd_BeginEyeRender(hmd, ovrEye_Left);

    // Set up the projection and modelview matrices for the left eye.
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glMultMatrixf(pose.ProjectionDesc.LeftProjection.M[0]);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glMultMatrixf(pose.LeftView.M[0]);

    // Call the original glBegin function.
    original_glBegin(mode);

    // Set up the projection and modelview matrices for the right eye.
    pose = ovrHmd_BeginEyeRender(hmd, ovrEye_Right);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glMultMatrixf(pose.ProjectionDesc.RightProjection.M[0]);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glMultMatrixf(pose.RightView.M[0]);

    // Call the original glBegin function again.
    original_glBegin(mode);
}

int main(int argc, char** argv)
{
    // Initialize the VR system.
    ovr_Initialize();
    hmd = ovrHmd_Create(0);
    ovrHmd_ConfigureTracking(hmd, ovrTrackingCap_Orientation |
        ovrTrackingCap_Position, 0);

    // Install the hook for the glBegin function.
    MH_Initialize();
    MH_CreateHook(&glBegin, &VR_glBegin, (void**)&original_glBegin);
    MH_EnableHook(&glBegin);

    // Run the game loop.
    while (true)
    {
        // Get the VR pose and update the game state.
        ovrTrackingState state = ovrHmd_GetTrackingState(hmd, 0.0);
        UpdateGameState(state.HeadPose.ThePose);

        // Render the game world.
        ovrHmd_BeginFrame(hmd, 0);
        RenderGame();
        ovrHmd_EndFrame(hmd);
    }

    // Uninstall the hook and shutdown the VR system.
    MH_DisableHook(&glBegin);
    MH_RemoveHook(&glBegin);
    MH_Uninitialize();
    ovrHmd_Destroy(hmd);
    ovr_Shutdown();

    return 0;
}