모션 블러(Motion Blur)

Ray.h — time 필드 추가 // 변경: 생성자에 time 파라미터 추가 __device__ Ray(const Point3& origin, const Vector3& direction, double time = 0.0) : mOrig(origin), mDir(direction), mTime(time) {} // 변경: 복사 생성자에 mTime 추가 __device__ Ray(const Ray& other) : mOrig(other.mOrig), mDir(other.mDir), mTime(other.mTime) {} // 추가: time 접근자 __device__ double Time() const { return mTime; } // 추가: private 멤버 double mTime; // 레이가 발사된 시각 ---

Camera.h — 셔터 시간 추가 // 변경: 생성자에 time0, time1 파라미터 추가 __device__ Camera( Point3 lookfrom, Point3 lookat, Vector3 vup, double vfov, double aspect, double aperture, double focusDist, double time0 = 0.0, // 추가 double time1 = 0.0) // 추가 { mTime0 = time0; // 추가 mTime1 = time1; // 추가 // ... 나머지 기존 코드 동일 } // 변경: GetRay()에서 랜덤 time 생성 후 Ray에 전달 __device__ Ray GetRay(double s, double t, curandState* randState) const { Vector3 rd = mLensRadius * RandomInUnitDisk(randState); Vector3 offset = mU * rd.X() + mV * rd.Y(); double time = mTime0 + curand_uniform(randState) * (mTime1 - mTime0); // 추가 return Ray( mOrigin + offset, mLowerLeftCorner + s * mHorizontal + t * mVertical - mOrigin - offset, time); // 추가 } // 추가: private 멤버 double mTime0; double mTime1;

MovingSphere.h — 신규 파일 #pragma once #ifndef MOVING_SPHERE_H #define MOVING_SPHERE_H #include "Hittable.h" class MovingSphere : public Hittable { public: __device__ MovingSphere() {} __device__ MovingSphere( Point3 center0, Point3 center1, double time0, double time1, double radius, Material* material) : mCenter0(center0), mCenter1(center1) , mTime0(time0), mTime1(time1) , mRadius(radius), mMaterial(material) {} __device__ Point3 Center(double time) const { return mCenter0 + ((time - mTime0) / (mTime1 - mTime0)) * (mCenter1 - mCenter0); } __device__ bool Hit( const Ray& ray, double tMin, double tMax, HitRecord& hitRecord) const override { // 레이 시각에 따라 중심 위치 보간 double frac = (ray.Time() - mTime0) / (mTime1 - mTime0); Point3 currentCenter = mCenter0 + frac * (mCenter1 - mCenter0); Vector3 oc = ray.Origin() - currentCenter; double a = Dot(ray.Direction(), ray.Direction()); double b = Dot(oc, ray.Direction()); double c = Dot(oc, oc) - mRadius * mRadius; double discriminant = b * b - a * c; if (discriminant > 0.0) { double temp = (-b - sqrt(discriminant)) / a; if (temp < tMax && temp > tMin) { hitRecord.T = temp; hitRecord.P = ray.At(hitRecord.T); Vector3 outwardNormal = (hitRecord.P - currentCenter) / mRadius; hitRecord.SetFaceNormal(ray, outwardNormal); hitRecord.MaterialPtr = mMaterial; return true; } temp = (-b + sqrt(discriminant)) / a; if (temp < tMax && temp > tMin) { hitRecord.T = temp; hitRecord.P = ray.At(hitRecord.T); Vector3 outwardNormal = (hitRecord.P - currentCenter) / mRadius; hitRecord.SetFaceNormal(ray, outwardNormal); hitRecord.MaterialPtr = mMaterial; return true; } } return false; } private: Point3 mCenter0, mCenter1; double mTime0, mTime1; double mRadius; Material* mMaterial; }; #endif

// Listing 4: sphere.h - 이동하는 구의 hit 함수(핵심 부분) class sphere : public hittable { public: ... bool hit(const ray& r, interval ray_t, hit_record& rec) const override { point3 current_center = center.at(r.time()); vec3 oc = current_center - r.origin(); auto a = r.direction().length_squared(); auto h = dot(r.direction(), oc); auto c = oc.length_squared() - radius * radius; ... rec.t = root; rec.p = r.at(rec.t); vec3 outward_normal = (rec.p - current_center) / radius; rec.set_face_normal(r, outward_normal); get_sphere_uv(outward_normal, rec.u, rec.v); rec.mat = mat; return true; } ... };

Material.h — Lambertian Scatter 수정 // 변경: scatter direction 계산 방식 + NearZero 처리 + time 전달 __device__ bool Scatter(...) const override { Vector3 scatterDirection = rec.Normal + RandomInUnitSphere(randState); // 추가: 산란 방향 퇴화 방지 if (scatterDirection.NearZero()) scatterDirection = rec.Normal; // 변경: rayIn.Time() 전달 scattered = Ray(rec.P, scatterDirection, rayIn.Time()); attenuation = mAlbedo; return true; } --- Metal.h — Scatter 수정 // 변경: rayIn.Time() 전달 scattered = Ray(rec.P, reflected + mFuzz * RandomInUnitSphere(randState), rayIn.Time()); --- Dielectric.h — Scatter 수정 // 변경: rayIn.Time() 전달 scattered = Ray(rec.P, direction, rayIn.Time());

kernel.cu — CreateWorld 수정 // 추가: include #include "MovingSphere.h" // 변경: CreateWorld 시그니처에 outCount 추가 __global__ void CreateWorld(..., int* outCount) // 변경: Lambertian 소형 구체 → MovingSphere로 교체 if (chooseMat < 0.8) { Vector3 center2 = center + Vector3(0.0, 0.5 * RND, 0.0); // 추가: 이동 목표점 list[i++] = new MovingSphere( center, center2, 0.0, 1.0, 0.2, new Lambertian(Color(RND * RND, RND * RND, RND * RND))); } // 추가: 대형 구체 근처 겹침 방지 Vector3 diff = center - Vector3(4.0, 0.2, 0.0); if (diff.Length() <= 0.9) continue; // 변경: 실제 배치된 수로 HittableList 생성 *world = new HittableList(list, i); *outCount = i; // 변경: 카메라에 셔터 시간 추가 *camera = new Camera(lookfrom, lookat, ..., 0.0, 1.0); // time0=0, time1=1 // 추가: main()에서 실제 count 추적 int* d_numHittables; cudaMallocManaged((void**)&d_numHittables, sizeof(int)); CreateWorld<<<1,1>>>(..., d_numHittables); int numHittables = *d_numHittables; // 변경: 스택 크기 cudaDeviceSetLimit(cudaLimitStackSize, 32768);