08_게임 물리 프로그래밍 가이드
- 1. 물리 엔진 사용을 위한 게임 물리 프로그래밍 가이드 김성익(noerror@hitel.net) 2008/06/22
- 2. Overview • 물리 엔진 사용을 위한 백그라운드 정보 – 개념들 소개/정리 – 구현을 다루지 않음 – Box2D 소개 • PhysX 소개
- 3. Box2D • Erin Catto씨 개인 프로젝트 • 2D 오픈 소스 물리 엔진 • 사용한 프로젝트 : Crayon Physics • http://www.box2d.org • 최적의 물리 처리 레퍼런스
- 4. Kinematics • Newtonian Physics – F = ma • Spring (F=-kx) • Drag Force (F=-mpv) • Gravity – F = dp/dt, P = mv – a = dV/dt – V = dX/dt
- 5. Calculus • Position • Velocity • Acceleration
- 6. Solution • Analytic Solution • Numeric Solution – Euler Method – Midpoint Method – Runge Kutta – Implicit Method – Verlet
- 7. Solution • Analytic Solution • Numeric Solution – Euler Method – Midpoint Method – Runge Kutta – Implicit Method – Verlet
- 8. Solution • Analytic Solution • Numeric Solution – Euler Method – Midpoint Method – Runge Kutta – Implicit Method – Verlet
- 9. Solution • Analytic Solution • Numeric Solution – Euler Method – Midpoint Method – Runge Kutta – Implicit Method – Verlet
- 10. Solution • Analytic Solution • Numeric Solution – Euler Method – Midpoint Method – Runge Kutta – Implicit Method – Verlet
- 11. Rotational Dynamics • Center of Mass • Linear vs Angular – Force vs Torque – Mass vs Moment of inertia – Momentum vs Angular Momentum – Velocity vs Angular Velocity – Position vs Orientation
- 12. Box2d CodeReview(1) • Simulation iteration step – broadphase • 충돌검사 (충돌정보 Arbiter 개체로 저장) – force 적용 • force->velocity • torque->angular velocity – prestep • 충돌 포인트에 대해서 massnormal, masstangent, bias 계산
- 13. Box2d CodeReview(2) – 충돌에 의한 impulse • 충돌체에 impulse – velocity, angular velocity 적용 • Joint 에 의한 impulse – 양 joint에 충돌체에 impulse – 위치 및 회전에 적용 • velocity => position • Angular velocity => rotation
- 14. PhysX(1) • NVidia (http://www.ageia.com) • 무료 (일부 플렛폼 및 소스코드 라이센스는 유료) • 충실한 튜터리얼 셈플 제공 • 메인스트림 물리 엔진 • 사용 프로젝트 : 언리얼3, 외 다수
- 15. PhysX(2) • 기능 – 복잡한 강체 물리 시스템 – 캐릭터 컨트롤 – 탈 것 다이나믹스 – 멀티쓰레드/멀티 플렛폼/PPU지원 – 유체 시뮬레이션 – 옷, 깃발등의 천 시뮬레이션 – 소프트 바디 – 역장(forcefield) 시뮬레이션
- 17. Shape • Shape – Sphere – Capsule – BoundBox • AABB (Axis Aligned Bound Box) • OBB (Object Oriented Box) – Convex – (height field)
- 18. PhysX-Shape • Sphere • Box • Capsule • Plane • Height field • Convex meshes • Triangle meshes
- 19. PhysX-Actor
- 20. Collision Detection(1) • Distance Test – Point-point distance – Line-point distance – Line-line distance – Segment-segment distance • Rough Bounding – Sweep and prune
- 21. Collision Detection(1) • Distance Test – Point-point distance – Line-point distance – Line-line distance – Segment-segment distance • Rough Bounding – Sweep and prune
- 22. Collision Detection(2) • SAT(separation axis test) • Lin Canny • Minkowski Diffrence
- 23. Collision Detection(2) • SAT(separation axis test) • Lin Canny • Minkowski Diffrence
- 24. Collision Detection(2) • SAT(separation axis test) • Lin Canny • Minkowski Sum/Diffrence
- 25. Collistion Detection(3) • Determine Collision Time – Time of impact • Tunnelling (CCD)
- 26. Collistion Detection(3) • Determine Collision Time – Time of impact • Tunnelling
- 27. PhysX - CCD • Continuous Collision Detection
- 28. Collision Detection(4) • Spatial Subdivision – Bsp, k-d tree – Portal – Quad tree / octree • Grouping – Sleeping
- 29. Collision Detection(4) • Spatial Subdivision – Bsp, k-d tree – Portal – Quad tree / octree • Grouping – Sleeping
- 30. Collision Detection(4) • Spatial Subdivision – Bsp, k-d tree – Portal – Quad tree / octree • Grouping – Sleeping
- 31. Collision Detection(4) • Spatial Subdivision – Bsp, k-d tree – Portal – Quad tree / octree • Grouping – Sleeping
- 32. Collision Detection(4) • Spatial Subdivision – Bsp, k-d tree – Portal – Quad tree / octree • Grouping – Sleeping
- 33. PhysX-Collision Detection • Contact Filtering • Triggers • CCD • Dominance Grioup • Overlap Testing
- 34. Collision Response(1) • Contact Point – EE (Edge-Edge) – FV (Face-Vertex) – GJK • Normal • Penetration
- 35. Collision Response(1) • Contact Point – EE (Edge-Edge) – FV (Face-Vertex) – GJK • Normal • Pentration
- 36. Collision Response(2) • Colliding – Bouncing • Resting – Rolling – Sliding
- 37. Collision Response(2) • Colliding – Bouncing • Resting – Rolling – Sliding
- 38. Constraint • Joint – Pin Joints – Hinge • Angular Constraints • Distance Constraints, ...
- 39. PhysX-Joint • spherical joint • revolute joint • prismatic joint • cylindrical joint • fixed joint • distance joint • point in plane joint / point on line joint • pulley joint • d6
- 40. PhysX-Joint • spherical joint • revolute joint • prismatic joint • cylindrical joint • fixed joint • distance joint • point in plane joint / point on line joint • pulley joint • d6
- 41. PhysX-Joint • spherical joint • revolute joint • prismatic joint • cylindrical joint • fixed joint • distance joint • point in plane joint / point on line joint • pulley joint • d6
- 42. PhysX-Example Review • 예제 : SampleBoxes • InitNx – Initialize PhysicsScene => gPhysicsSDK – CreateScene => gScene – Create Ground => gScene->createActor • RenderCallback – Simulate – GetResult/Render All actors => actor->getGlobalPos – FetchSimulation => flushScream, fetchResult • CreateCube – shapes.pushBack – gScene->createActor
- 43. More • Breaking • Force Field • Character Controller • Raycast/SweepTest • Multithreading Model
- 44. Reference • http://www.essentialmath.com • 게임물리바이블,David H Everly, 사이텍미디어