source: GTP/trunk/App/Games/Jungle_Rumble/src/physic/physics/include/NxMaterialDesc.h @ 1378

#ifndef NX_PHYSICS_NXMATERIALDESC
#define NX_PHYSICS_NXMATERIALDESC
/*----------------------------------------------------------------------------*\
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|                                               Public Interface to NovodeX Technology
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|                                                            www.novodex.com
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\*----------------------------------------------------------------------------*/
/** \addtogroup physics
  @{
*/

#include "Nxp.h"
#include "NxSpringDesc.h"

/**
\brief Flags which control the behavior of a material.

@see NxMaterial NxMaterialDesc
*/
enum NxMaterialFlag
        {
        /**
        \brief Flag to enable anisotropic friction computation. 

        For a pair of actors, anisotropic friction is used only if at least one of the two actors' materials are anisotropic.
        The anisotropic friction parameters for the pair are taken from the material which is more anisotropic (i.e. the difference
        between its two dynamic friction coefficients is greater).

        The anisotropy direction of the chosen material is transformed to world space:

        dirOfAnisotropyWS = shape2world * dirOfAnisotropy

        Next, the directions of anisotropy in one or more contact planes (i.e. orthogonal to the contact normal) have to be determined. 
        The two directions are:

        uAxis = (dirOfAnisotropyWS ^ contactNormal).normalize()
        vAxis = contactNormal ^ uAxis

        This way [uAxis, contactNormal, vAxis] forms a basis.

        It may happen, however, that (dirOfAnisotropyWS | contactNormal).magnitude() == 1 
        and then (dirOfAnisotropyWS ^ contactNormal) has zero length. This happens when 
        the contactNormal is coincident to the direction of anisotropy. In this case we perform isotropic friction. 

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yex
        \li PS3  : Yes
        \li XB360: Yes

        @see NxMaterialDesc.dirOfAnisotropy
        */
        NX_MF_ANISOTROPIC = 1 << 0,

        /**
        \brief If a material with this flag set is involved in the contact, the contact constraints generated behave like a unilateral spring.

        The user must assign the spring member to point to a NxSpringDesc object.
        Do not use this together with ::NxWheelShape, that already includes the suspension component automatically.

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NxWheelShape NxMaterialDesc.spring
        */
        NX_MF_SPRING_CONTACT = 1 << 2,

        /**
        If this flag is set, friction computations are always skipped between shapes with this material and any other shape.
        It may be a good idea to use this when all friction is to be performed using the tire friction model (see ::NxWheelShape).

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NxWheelShape
        */
        NX_MF_DISABLE_FRICTION = 1 << 4,

        /**
        If this flag is set, strong static friction computations are skipped.  These can cause problems for very fast sliding objects that 
        still need precise steering behavior, such as raycast vehicles.  It may make sense to reenable this when the car has come to rest to prevent it from
        creeping down inclines.
        This setting only matters if the NX_MF_DISABLE_FRICTION bit is 0.

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NxWheelShape
        */
        NX_MF_DISABLE_STRONG_FRICTION = 1 << 5,

        /**
        This flag is only used when NX_MF_SPRING_CONTACT is also specified.  In this case the spring contact's direction will be determined by the
        associated capsule shape's axis, rather than the contact normal.

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NX_MF_SPRING_CONTACT NxWheelShape
        */
        NX_MF_WHEEL_AXIS_CONTACT_NORMAL = 1 << 6, 

        //Note: Bits 16-31 are reserved for internal use!
        };

/**
Flag that determines the combine mode. When two actors come in contact with eachother, they each have
materials with various coefficients, but we only need a single set of coefficients for the pair.

Physics doesn't have any inherent combinations because the coefficients are determined empirically on a case by case
basis. However, simulating this with a pairwise lookup table is often impractical.

For this reason the following combine behaviors are available:

NX_CM_AVERAGE = 2,
NX_CM_MIN = 0,
NX_CM_MULTIPLY = 1,
NX_CM_MAX = 3,

The effective combine mode for the pair is max(material0.combineMode, material1.combineMode).

<b>Platform:</b>
\li PC SW: Yes
\li PPU  : No
\li PS3  : Yes
\li XB360: Yes

@see NxMaterial NxMaterialDesc NxMaterialDesc.frictionCombineMode NxMaterialDesc.restitutionCombineMode
*/
enum NxCombineMode
        {
        NX_CM_AVERAGE = 0,              //!< Average: (a + b)/2. 
        NX_CM_MIN = 1,                  //!< Minimum: min(a,b)
        NX_CM_MULTIPLY = 2,             //!< Mutiply: a*b
        NX_CM_MAX = 3,                  //!< Maximum: max(a,b)
        NX_CM_N_VALUES = 4,     //this a sentinel to denote the number of possible values. We assert that the variable's value is smaller than this.
        NX_CM_PAD_32 = 0xffffffff 
        };


/**
\brief Descriptor of #NxMaterial.

@see NxMaterial NxScene.createMaterial()
*/
class NxMaterialDesc
        {
        public:
        /**
        coefficient of dynamic friction -- should be in [0, 1] and also be less or equal to staticFriction.
        if flags & NX_MF_ANISOTROPIC is set, then this value is used for the primary direction of anisotropy (U axis)

        <b>Range:</b> [0,1]<br>
        <b>Default:</b> 0.0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags frictionCombineMode
        */
        NxReal  dynamicFriction;
        
        /**
        coefficient of static friction -- should be in [0, +inf]
        if flags & NX_MF_ANISOTROPIC is set, then this value is used for the primary direction of anisotropy (U axis)

        <b>Range:</b> [0,inf]<br>
        <b>Default:</b> 0.0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags frictionCombineMode
        */
        NxReal  staticFriction;

        /**
        coefficient of restitution --  0 makes the object bounce as little as possible, higher values up to 1.0 result in more bounce.

        <b>Range:</b> [0,1]<br>
        <b>Default:</b> 0.0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags restitutionCombineMode
        */
        NxReal  restitution;

        /**
        anisotropic dynamic friction coefficient for along the secondary (V) axis of anisotropy. 
        This is only used if flags & NX_MF_ANISOTROPIC is set.

        <b>Range:</b> [0,1]<br>
        <b>Default:</b> 0.0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags dynamicFriction
        */
        NxReal dynamicFrictionV;

        /**
        anisotropic static  friction coefficient for along the secondary (V) axis of anisotropy. 
        This is only used if flags & NX_MF_ANISOTROPIC is set.

        <b>Range:</b> [0,inf]<br>
        <b>Default:</b> 0.0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags staticFriction
        */
        NxReal staticFrictionV;
        
        /**
        shape space direction (unit vector) of anisotropy.
        This is only used if flags & NX_MF_ANISOTROPIC is set.

        <b>Range:</b> direction vector<br>
        <b>Default:</b> 1.0f,0.0f,0.0f

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see flags staticFrictionV dynamicFrictionV
        */
        NxVec3 dirOfAnisotropy;

        /**
        Flags, a combination of the bits defined by the enum ::NxMaterialFlag . 

        <b>Default:</b> 0

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Partial
        \li PS3  : Yes
        \li XB360: Yes

        @see NxMaterialFlag
        */
        NxU32 flags;

        /**
        Friction combine mode. See the enum ::NxCombineMode .

        <b>Default:</b> NX_CM_AVERAGE

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NxCombineMode staticFriction dynamicFriction
        */
        NxCombineMode frictionCombineMode;

        /**
        Restitution combine mode. See the enum ::NxCombineMode .

        <b>Default:</b> NX_CM_AVERAGE

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see NxCombineMode restitution
        */
        NxCombineMode restitutionCombineMode;

        /**
        additional spring data for special materials with flag NX_MF_SPRING_CONTACT.
        The object pointed to will be copied by the SDK at material creation time.

        Note: This replaces programData and programDataSize used in prior versions.

        <b>Range:</b> See #NxSpringDesc<br>
        <b>Default:</b> NULL

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : No
        \li PS3  : Yes
        \li XB360: Yes

        @see flags NxSpringDesc
        */
        NxSpringDesc * spring;

        /**
        \brief constructor sets to default.
        */
        NX_INLINE NxMaterialDesc();     
        /**
        \brief (re)sets the structure to the default.   
        */
        NX_INLINE void setToDefault();
        /**
        \brief Returns true if the descriptor is valid.

        \return true if the current settings are valid
        */
        NX_INLINE bool isValid() const;
        };

NX_INLINE NxMaterialDesc::NxMaterialDesc()
        {
        setToDefault();
        }

NX_INLINE       void NxMaterialDesc::setToDefault()
        {
        dynamicFriction = 0.0f;
        staticFriction  = 0.0f;
        restitution             = 0.0f;


        dynamicFrictionV= 0.0f;
        staticFrictionV = 0.0f;

        dirOfAnisotropy.set(1,0,0);
        flags = 0;
        frictionCombineMode = NX_CM_AVERAGE;
        restitutionCombineMode = NX_CM_AVERAGE;
        spring = 0;
        }

NX_INLINE       bool NxMaterialDesc::isValid()  const
        {
        if(dynamicFriction < 0.0f || dynamicFriction > 1.0f) 
                return false;
        if(staticFriction < 0.0f) 
                return false;
        if(restitution < 0.0f || restitution > 1.0f) 
                return false;


        if (flags & NX_MF_ANISOTROPIC)
                {
                NxReal ad = dirOfAnisotropy.magnitudeSquared();
                if (ad < 0.98f || ad > 1.03f)
                        return false;
                if(dynamicFrictionV < 0.0f || dynamicFrictionV > 1.0f) 
                        return false;
                if(staticFrictionV < 0.0f) 
                        return false;
                }
        /*
        if (flags & NX_MF_MOVING_SURFACE)
                {
                NxReal md = dirOfMotion.magnitudeSquared();
                if (md < 0.98f || md > 1.03f)
                        return false;
                }
        */
        if (frictionCombineMode >= NX_CM_N_VALUES)
                return false;
        if (restitutionCombineMode >= NX_CM_N_VALUES)
                return false;

        return true;
        }

/** @} */
#endif


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