PhysX官方手册翻译（二）

Basics:

Math Classes

4种数据结构：

NxVec3

NxQuat

NxMat33

NxMat34

 

Simple Shapes

7种基本物理模型：

NxBounds3           轴对称边界盒

NxBox                  对象边界盒

NxCapsule            交囊

NxPlane                任意的面

NxRay                  无限射线/直线

NxSegment           有限射线/线段

NxSphere             球

(事实上还有多边形，不过它应该不能称为简单)

SDK Initialization

NxCreatePhysicsSDK: 创建接口指针。

参数一：接口版本

参数二：内存管理类实体

参数三：用于输出的流

 

要点一：SDK版本要和驱动版本匹配

要点二：可以多次调用NxCreatePhysicsSDK,但是都将得到同一个实体，就象单件模式一样。但是存在引用计数，因此需要严格匹配 call 和 release 的次数。

要点三：多次调用的时候，后设置的内存管理类将被忽略，但是输出流对象则会被覆盖。

 

Casting and Instancing

创建实例：

1、声明描述符

2、调用PhysX接口创建该实例

 

释放：

父对象的释放会引起子对象的自动释放。

 

转换：

NxShape / NxSphereShape / NxMoxsSs

向下转换

Shape->isSphere() shape->isBox()

失败返回NULL。

 

Memory Management

虽然不是必须的，但是PhysX提供了内存管理接口。（继承NxUserAllocator）

重载了 malloc / realloc / free。

一旦被设置，就不能更改。

该类提供的内存管理函数必须保证是“线程安全的”。

 

Debug Rendering

不能使对象之间的间距可视化

Debug Information通过 gScene->getDebugRenderable() 返回的 NxDebugRenderable得到。

PhysX不是图象库，使用者需要自己绘制这些信息。

 

User Data

可以给对象(Actor)关联数据。

如  myShape->userData = ***;

 

User Defined Classes

8个需要用户自己实现的类：

NxUserAllocator 内存管理 NxUserOutputStream 错误信息 NxUserContactReport 反射（接触）通知 NxUserNotify 事件通知 NxUserRaycastReport  射线查询回调 NxUserTriggerReport 触发器回调 NxUserEntityReport 实体回调？？ NxStream 串行化（用于数据IO）

 

Error Reporting

使用NxUserOutputStream

 

Saving the Simulation State

所有通过描述符创建的对象都有2个方法：saveToDesc() 和 loadFromDesc()

可以用于保存对象当前的状态，这个特性可以应用于保存游戏，或者其他目的。

SDK Parameters

PhysX有一套集中管理的全局变量，85个定义,其中变量83个，哑元1个，记录数量1个)

使用者可以通过 setParameters() / getParameters() 来修改他们。

大多数变量的默认值是不需要更改的。

 

Parameter Summary

Parameter	Default Value	Description
NX_PENALTY_FORCE		DEPRECATED
NX_SKIN_WIDTH	0.025	皮肤厚度 (range: [0, inf) Unit: distance.
NX_DEFAULT_SLEEP_LIN_VEL_SQUARED	(0.15*0.15)	The default linear velocity, squared, below which objects start going to sleep. (range: [0, inf))
NX_DEFAULT_SLEEP_ANG_VEL_SQUARED	(0.14*0.14)	The default angular velocity, squared, below which objects start going to sleep. (range: [0, inf))
NX_BOUNCE_TRESHOLD	-2	A contact with a relative velocity below this will not bounce. (range: (-inf, 0])
NX_DYN_FRICT_SCALING	1	This lets the user scale the magnitude of the dynamic friction applied to all objects. (range: [0, inf))
NX_STA_FRICT_SCALING	1	This lets the user scale the magnitude of the static friction applied to all objects. (range: [0, inf))
NX_MAX_ANGULAR_VELOCITY	7	See API Reference for NxBody::setMaxAngularVelocity() for details.
NX_CONTINUOUS_CD	0	Enable/disable continuous collision detection ( 0.0f to disable)
NX_VISUALIZATION_SCALE	0	This overall visualization scale gets multiplied with the individual scales. Setting to zero turns off debug visualizations.
NX_VISUALIZE_WORLD_AXES	0	Visualize the world axes.
NX_VISUALIZE_BODY_AXES	0	Visualize a body's axes.
NX_VISUALIZE_BODY_MASS_AXES	0	Visualize a body's mass axes.
NX_VISUALIZE_BODY_LIN_VELOCITY	0	Visualize the bodies' linear velocity.
NX_VISUALIZE_BODY_ANG_VELOCITY	0	Visualize the bodies' angular velocity.
NX_VISUALIZE_BODY_JOINT_GROUPS	0	Visualize joint groups.
NX_VISUALIZE_JOINT_LOCAL_AXES	0	Visualize local joint axes.
NX_VISUALIZE_JOINT_WORLD_AXES	0	Visualize joint world axes.
NX_VISUALIZE_JOINT_LIMITS	0	Visualize joint limits.
NX_VISUALIZE_CONTACT_POINT	0	Visualize contact points.
NX_VISUALIZE_CONTACT_NORMAL	0	Visualize contact normals.
NX_VISUALIZE_CONTACT_ERROR	0	Visualize contact errors.
NX_VISUALIZE_CONTACT_FORCE	0	Visualize contact forces.
NX_VISUALIZE_ACTOR_AXES	0	Visualize actor axes.
NX_VISUALIZE_COLLISION_AABBS	0	Visualize bounds (AABBs in world space).
NX_VISUALIZE_COLLISION_SHAPES	0	Visualize shape.
NX_VISUALIZE_COLLISION_AXES	0	Visualize shape axes.
NX_VISUALIZE_COLLISION_COMPOUNDS	0	Visualize compound (compound AABBs in world space).
NX_VISUALIZE_COLLISION_VNORMALS	0	Visualize mesh & convex vertex normals.
NX_VISUALIZE_COLLISION_FNORMALS	0	Visualize mesh & convex face normals.
NX_VISUALIZE_COLLISION_EDGES	0	Visualize active edges for meshes.
NX_VISUALIZE_COLLISION_SPHERES	0	Visualize bounding spheres.
NX_VISUALIZE_COLLISION_STATIC	0	Visualize static pruning structures.
NX_VISUALIZE_COLLISION_DYNAMIC	0	Visualize dynamic pruning structures.
NX_VISUALIZE_COLLISION_FREE	0	Visualize "free" pruning structures.
NX_VISUALIZE_COLLISION_CCD	0	Visualize CCD tests.
NX_VISUALIZE_COLLISION_SKELETONS	0	Visualize CCD skeletons.
NX_VISUALIZE_FLUID_EMITTERS	0	Visualize emitter.
NX_VISUALIZE_FLUID_POSITION	0	Visualize particle position.
NX_VISUALIZE_FLUID_VELOCITY	0	Visualize particle velocity.
NX_VISUALIZE_FLUID_KERNEL_RADIUS	0	Visualize particle kernel radius.
NX_VISUALIZE_FLUID_BOUNDS	0	Visualize fluid AABB.
NX_VISUALIZE_FLUID_PACKETS	0	Visualize fluid packets.
NX_VISUALIZE_FLUID_MOTION_LIMIT	0	Visualize fluid motion limits.
NX_VISUALIZE_FLUID_DYN_COLLISION	0	Visualize fluid dynamic mesh collision.
NX_VISUALIZE_FLUID_STC_COLLISION	0	Not implemented: Visualize fluid static collision.
NX_VISUALIZE_FLUID_MESH_PACKETS	0	Visualize available fluid mesh packets.
NX_VISUALIZE_FLUID_DRAINS	0	Visualize fluid drain shapes.
NX_VISUALIZE_FLUID_PACKET_DATA	0	Visualize fluid data packets.
NX_VISUALIZE_CLOTH_MESH	0	Visualize cloth meshes.
NX_VISUALIZE_CLOTH_COLLISIONS	0	Visualize cloth rigid body collision.
NX_VISUALIZE_CLOTH_SELFCOLLISIONS	0	Visualize cloth self collision.
NX_VISUALIZE_CLOTH_WORKPACKETS	0	Visualize cloth clustering for the PPU.
NX_VISUALIZE_CLOTH_SLEEP	0	Visualize cloth sleeping.
NX_VISUALIZE_CLOTH_SLEEP_VERTEX	0	Visualize cloth sleeping with full per-vertex information.
NX_VISUALIZE_CLOTH_TEARABLE_VERTICES	0	Visualize tearable cloth vertices.
NX_VISUALIZE_CLOTH_TEARING	0	Visualize cloth tearing.
NX_VISUALIZE_CLOTH_ATTACHMENT	0	Visualize cloth attachments.
NX_VISUALIZE_CLOTH_VALIDBOUNDS	0	Visualize cloth valid bounds.
NX_VISUALIZE_SOFTBODY_MESH	0	Visualize soft body meshes.
NX_VISUALIZE_SOFTBODY_COLLISIONS	0	Visualize soft body collisions with rigid bodies.
NX_VISUALIZE_SOFTBODY_WORKPACKETS	0	Visualize soft body clustering for simulation on the PPU.
NX_VISUALIZE_SOFTBODY_SLEEP	0	Visualize soft body sleeping.
NX_VISUALIZE_SOFTBODY_SLEEP_VERTEX	0	Visualize soft body sleeping with full per-vertex information.
NX_VISUALIZE_SOFTBODY_TEARABLE_VERTICES	0	Visualize tearable soft body vertices.
NX_VISUALIZE_SOFTBODY_TEARING	0	Visualize soft body tearing.
NX_VISUALIZE_SOFTBODY_ATTACHMENT	0	Visualize soft body attachments.
NX_VISUALIZE_SOFTBODY_VALIDBOUNDS	0	Visualize soft body valid bounds.
NX_ADAPTIVE_FORCE	1	Used to enable adaptive forces to accelerate convergence of the solver.
NX_COLL_VETO_JOINTED	1	Controls default filtering for jointed bodies (true = collision disabled).
NX_TRIGGER_TRIGGER_CALLBACK	1	Controls whether two touching triggers generate a callback or not.
NX_SELECT_HW_ALGO	0	Internal parameter, used for debugging and testing. Not to be used.
NX_VISUALIZE_ACTIVE_VERTICES	0	Internal parameter, used for debugging and testing. Not to be used.
NX_CCD_EPSILON	0.01	Distance epsilon for CCD algorithm.
NX_SOLVER_CONVERGENCE_THRESHOLD	0	Used to accelerate the solver.
NX_BBOX_NOISE_LEVEL	0.001	Used to accelerate HW Broad Phase.
NX_IMPLICIT_SWEEP_CACHE_SIZE	5.0	Used to set the sweep cache size.
NX_DEFAULT_SLEEP_ENERGY	0.005	The default sleep energy threshold. Objects with an energy below this threshold are allowed to go to sleep. Note: Only used when the NX_BF_ENERGY_SLEEP_TEST flag is set.
NX_CONSTANT_FLUID_MAX_PACKETS	925	Constant for the maximum number of packets per fluid. Used to compute the fluid packet buffer size in NxFluidPacketData.
NX_CONSTANT_FLUID_MAX_PARTICLES_PER_STEP	4096	Constant for the maximum number of new fluid particles per frame.
NX_VISUALIZE_FORCE_FIELDS	0	Force field visualization.
NX_ASYNCHRONOUS_MESH_CREATION	0	[Experimental] Disables scene locks when creating/releasing meshes.
NX_FORCE_FIELD_CUSTOM_KERNEL_EPSILON	0.001	Epsilon for custom force field kernels.
NX_IMPROVED_SPRING_SOLVER	1	Enable/disable improved spring solver for joints and wheelshapes.
NX_PARAMS_NUM_VALUES		This is not a parameter, it just records the current number of parameters.

 

 

 

 

 

Parameter Ranges

• rigid body transform – 一个坐标向量+一个旋转矩阵
• position vector – 一个坐标向量，可能是本地坐标或者是世界坐标
• rotation matrix – 旋转矩阵
• unit quaternion – 4元数
• direction/extents vector - 偏移量/方向向量。
• force vector - Linear force vector. Forces are added to the momentum of a body; care should be taken to keep the momentum from growing too large.
• torque vector - Torque vector. A torque is added to the angular momentum of a body; care should be taken to keep the angular momentum within a reasonable range.
• velocity vector - Linear velocity vector. Consider the magnitude of the velocity when multiplied by the mass, i.e., a large velocity when applied to a body with a large mass will result in a very large momentum.
• angular velocity vector - Angular velocity vector. Consider the magnitude of the angular velocity when multiplied by the inertia tensor, i.e., the angular momentum.
• momentum vector - Linear momentum vector.
• angular momentum vector - Angular momentum vector.

Utility Functions

2.3以前可以直接调用工具函数，但是之后必须通过调用NxGetUtilLib()创建一个工具库指针，通过该指针进行调用。

Prior 2.3: NxSetFPUPrecision24();

After 2.3 NxUtilLib* gUtiLib = NxGetUtilLib();         gUtiLib-> NxSetFPUPrecision24();