창(Window) 없이 물리 루프를 고속 검증하는 C 언어 헤드리스(Headless) 시뮬레이터Headless C Physics Simulator for High-Speed Batch Verification

#include <stdio.h>
#include <stdbool.h>
#include <math.h>

#define FIXED_DT (1.0f / 60.0f)
#define GRAVITY  980.0f

typedef struct {
    float x, y;
    float vx, vy;
    bool grounded;
    bool reached_goal;
} SimState;

typedef struct {
    int trigger_frame;
    float jump_impulse;
} InputEvent;

// 창(Window)이나 GPU 컨텍스트에 전혀 의존하지 않는 순수 물리 스텝
void PhysicsStep(SimState *s, float dt, bool jump_pressed, float goal_x) {
    if (jump_pressed && s->grounded) {
        s->vy = -420.0f;
        s->grounded = false;
    }
    // Semi-implicit Euler 적분 (속도 먼저 갱신 후 위치 갱신)
    s->vy += GRAVITY * dt;
    s->x  += s->vx * dt;
    s->y  += s->vy * dt;

    // 바닥 충돌 판정 (y = 0 기준)
    if (s->y >= 0.0f) {
        s->y = 0.0f;
        s->vy = 0.0f;
        s->grounded = true;
    }
    if (s->x >= goal_x) {
        s->reached_goal = true;
    }
}

int main(void) {
    SimState state = { .x = 0.0f, .y = 0.0f, .vx = 180.0f, .vy = 0.0f, .grounded = true, .reached_goal = false };
    const int max_frames = 3600; // 60초 분량을 대기 시간 없이 즉시 시뮬레이션

    for (int frame = 0; frame < max_frames && !state.reached_goal; ++frame) {
        bool jump = (frame == 30 || frame == 120);
        PhysicsStep(&state, FIXED_DT, jump, 500.0f);

        // NaN 또는 비정상 좌표 발산(터널링) 검증
        if (isnan(state.x) || isnan(state.y) || fabs(state.y) > 10000.0f) {
            fprintf(stderr, "[FAIL] Frame %d: 수치 발산 감지 (x=%.2f, y=%.2f)\n", frame, state.x, state.y);
            return 1;
        }
    }

    printf("[PASS] Goal Reached: %s (Final X=%.2f)\n", state.reached_goal ? "YES" : "NO", state.x);
    return state.reached_goal ? 0 : 1;
}

#include <stdio.h>
#include <stdbool.h>
#include <math.h>

#define FIXED_DT (1.0f / 60.0f)
#define GRAVITY  980.0f

typedef struct {
    float x, y;
    float vx, vy;
    bool grounded;
    bool reached_goal;
} SimState;

typedef struct {
    int trigger_frame;
    float jump_impulse;
} InputEvent;

// Pure physics step with zero dependency on a Window or GPU context
void PhysicsStep(SimState *s, float dt, bool jump_pressed, float goal_x) {
    if (jump_pressed && s->grounded) {
        s->vy = -420.0f;
        s->grounded = false;
    }
    // Semi-implicit Euler integration (update velocity first, then position)
    s->vy += GRAVITY * dt;
    s->x  += s->vx * dt;
    s->y  += s->vy * dt;

    // Ground collision check (at y = 0)
    if (s->y >= 0.0f) {
        s->y = 0.0f;
        s->vy = 0.0f;
        s->grounded = true;
    }
    if (s->x >= goal_x) {
        s->reached_goal = true;
    }
}

int main(void) {
    SimState state = { .x = 0.0f, .y = 0.0f, .vx = 180.0f, .vy = 0.0f, .grounded = true, .reached_goal = false };
    const int max_frames = 3600; // Simulate 60 seconds of gameplay immediately without waiting

    for (int frame = 0; frame < max_frames && !state.reached_goal; ++frame) {
        bool jump = (frame == 30 || frame == 120);
        PhysicsStep(&state, FIXED_DT, jump, 500.0f);

        // Check for NaN or abnormal coordinate divergence (tunneling)
        if (isnan(state.x) || isnan(state.y) || fabs(state.y) > 10000.0f) {
            fprintf(stderr, "[FAIL] Frame %d: Numerical divergence detected (x=%.2f, y=%.2f)\n", frame, state.x, state.y);
            return 1;
        }
    }

    printf("[PASS] Goal Reached: %s (Final X=%.2f)\n", state.reached_goal ? "YES" : "NO", state.x);
    return state.reached_goal ? 0 : 1;
}