axmol/thirdparty/box2d-optimized/include/box2d/b2_particle_system.h

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51 KiB
C++

/*
* Copyright (c) 2013 Google, Inc.
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_PARTICLE_SYSTEM_H
#define B2_PARTICLE_SYSTEM_H
#include "b2_slab_allocator.h"
#include "b2_growable_buffer.h"
#include "b2_particle.h"
#include "b2_time_step.h"
#ifdef LIQUIDFUN_UNIT_TESTS
#include <gtest/gtest.h>
#endif // LIQUIDFUN_UNIT_TESTS
#if LIQUIDFUN_EXTERNAL_LANGUAGE_API
#include <cstring>
#endif // LIQUIDFUN_EXTERNAL_LANGUAGE_API
class b2World;
class b2Body;
class b2Shape;
class b2ParticleGroup;
class b2BlockAllocator;
class b2StackAllocator;
class b2QueryCallback;
class b2RayCastCallback;
class b2Fixture;
class b2ContactFilter;
class b2ContactListener;
class b2ParticlePairSet;
class FixtureParticleSet;
struct b2ParticleGroupDef;
struct b2Vec2;
struct b2AABB;
struct FindContactInput;
struct FindContactCheck;
struct b2ParticleContact
{
private:
typedef int32 b2ParticleIndex;
/// Indices of the respective particles making contact.
b2ParticleIndex indexA, indexB;
/// Weight of the contact. A value between 0.0f and 1.0f.
/// 0.0f ==> particles are just barely touching
/// 1.0f ==> particles are perfectly on top of each other
float32 weight;
/// The normalized direction from A to B.
b2Vec2 normal;
/// The logical sum of the particle behaviors that have been set.
/// See the b2ParticleFlag enum.
uint32 flags;
public:
void SetIndices(int32 a, int32 b);
void SetWeight(float32 w) { weight = w; }
void SetNormal(const b2Vec2& n) { normal = n; }
void SetFlags(uint32 f) { flags = f; }
int32 GetIndexA() const { return indexA; }
int32 GetIndexB() const { return indexB; }
float32 GetWeight() const { return weight; }
const b2Vec2& GetNormal() const { return normal; }
uint32 GetFlags() const { return flags; }
bool operator==(const b2ParticleContact& rhs) const;
bool operator!=(const b2ParticleContact& rhs) const { return !operator==(rhs); }
bool ApproximatelyEqual(const b2ParticleContact& rhs) const;
};
struct b2ParticleBodyContact
{
/// Index of the particle making contact.
int32 index;
/// The body making contact.
b2Body* body;
/// The specific fixture making contact
b2Fixture* fixture;
/// Weight of the contact. A value between 0.0f and 1.0f.
float32 weight;
/// The normalized direction from the particle to the body.
b2Vec2 normal;
/// The effective mass used in calculating force.
float32 mass;
};
/// Connection between two particles
struct b2ParticlePair
{
/// Indices of the respective particles making pair.
int32 indexA, indexB;
/// The logical sum of the particle flags. See the b2ParticleFlag enum.
uint32 flags;
/// The strength of cohesion among the particles.
float32 strength;
/// The initial distance of the particles.
float32 distance;
};
/// Connection between three particles
struct b2ParticleTriad
{
/// Indices of the respective particles making triad.
int32 indexA, indexB, indexC;
/// The logical sum of the particle flags. See the b2ParticleFlag enum.
uint32 flags;
/// The strength of cohesion among the particles.
float32 strength;
/// Values used for calculation.
b2Vec2 pa, pb, pc;
float32 ka, kb, kc, s;
};
struct b2ParticleSystemDef
{
b2ParticleSystemDef()
{
strictContactCheck = false;
density = 1.0f;
gravityScale = 1.0f;
radius = 1.0f;
maxCount = 0;
// Initialize physical coefficients to the maximum values that
// maintain numerical stability.
pressureStrength = 0.05f;
dampingStrength = 1.0f;
elasticStrength = 0.25f;
springStrength = 0.25f;
viscousStrength = 0.25f;
surfaceTensionPressureStrength = 0.2f;
surfaceTensionNormalStrength = 0.2f;
repulsiveStrength = 1.0f;
powderStrength = 0.5f;
ejectionStrength = 0.5f;
staticPressureStrength = 0.2f;
staticPressureRelaxation = 0.2f;
staticPressureIterations = 8;
colorMixingStrength = 0.5f;
destroyByAge = true;
lifetimeGranularity = 1.0f / 60.0f;
}
/// Enable strict Particle/Body contact check.
/// See SetStrictContactCheck for details.
bool strictContactCheck;
/// Set the particle density.
/// See SetDensity for details.
float32 density;
/// Change the particle gravity scale. Adjusts the effect of the global
/// gravity vector on particles. Default value is 1.0f.
float32 gravityScale;
/// Particles behave as circles with this radius. In Box2D units.
float32 radius;
/// Set the maximum number of particles.
/// By default, there is no maximum. The particle buffers can continue to
/// grow while b2World's block allocator still has memory.
/// See SetMaxParticleCount for details.
int32 maxCount;
/// Increases pressure in response to compression
/// Smaller values allow more compression
float32 pressureStrength;
/// Reduces velocity along the collision normal
/// Smaller value reduces less
float32 dampingStrength;
/// Restores shape of elastic particle groups
/// Larger values increase elastic particle velocity
float32 elasticStrength;
/// Restores length of spring particle groups
/// Larger values increase spring particle velocity
float32 springStrength;
/// Reduces relative velocity of viscous particles
/// Larger values slow down viscous particles more
float32 viscousStrength;
/// Produces pressure on tensile particles
/// 0~0.2. Larger values increase the amount of surface tension.
float32 surfaceTensionPressureStrength;
/// Smoothes outline of tensile particles
/// 0~0.2. Larger values result in rounder, smoother, water-drop-like
/// clusters of particles.
float32 surfaceTensionNormalStrength;
/// Produces additional pressure on repulsive particles
/// Larger values repulse more
/// Negative values mean attraction. The range where particles behave
/// stably is about -0.2 to 2.0.
float32 repulsiveStrength;
/// Produces repulsion between powder particles
/// Larger values repulse more
float32 powderStrength;
/// Pushes particles out of solid particle group
/// Larger values repulse more
float32 ejectionStrength;
/// Produces static pressure
/// Larger values increase the pressure on neighboring partilces
/// For a description of static pressure, see
/// http://en.wikipedia.org/wiki/Static_pressure#Static_pressure_in_fluid_dynamics
float32 staticPressureStrength;
/// Reduces instability in static pressure calculation
/// Larger values make stabilize static pressure with fewer iterations
float32 staticPressureRelaxation;
/// Computes static pressure more precisely
/// See SetStaticPressureIterations for details
int32 staticPressureIterations;
/// Determines how fast colors are mixed
/// 1.0f ==> mixed immediately
/// 0.5f ==> mixed half way each simulation step (see b2World::Step())
float32 colorMixingStrength;
/// Whether to destroy particles by age when no more particles can be
/// created. See #b2ParticleSystem::SetDestructionByAge() for
/// more information.
bool destroyByAge;
/// Granularity of particle lifetimes in seconds. By default this is
/// set to (1.0f / 60.0f) seconds. b2ParticleSystem uses a 32-bit signed
/// value to track particle lifetimes so the maximum lifetime of a
/// particle is (2^32 - 1) / (1.0f / lifetimeGranularity) seconds.
/// With the value set to 1/60 the maximum lifetime or age of a particle is
/// 2.27 years.
float32 lifetimeGranularity;
};
class b2ParticleSystem
{
public:
/// Create a particle whose properties have been defined.
/// No reference to the definition is retained.
/// A simulation step must occur before it's possible to interact with a
/// newly created particle. For example, DestroyParticleInShape() will
/// not destroy a particle until b2World::Step() has been called.
/// @warning This function is locked during callbacks.
/// @return the index of the particle.
int32 CreateParticle(const b2ParticleDef& def);
/// Retrieve a handle to the particle at the specified index.
/// Please see #b2ParticleHandle for why you might want a handle.
const b2ParticleHandle* GetParticleHandleFromIndex(const int32 index);
/// Destroy a particle.
/// The particle is removed after the next simulation step (see
/// b2World::Step()).
void DestroyParticle(int32 index)
{
DestroyParticle(index, false);
}
/// Destroy a particle.
/// The particle is removed after the next step.
/// @param Index of the particle to destroy.
/// @param Whether to call the destruction listener just before the
/// particle is destroyed.
void DestroyParticle(int32 index, bool callDestructionListener);
/// Destroy the Nth oldest particle in the system.
/// The particle is removed after the next b2World::Step().
/// @param Index of the Nth oldest particle to destroy, 0 will destroy the
/// oldest particle in the system, 1 will destroy the next oldest
/// particle etc.
/// @param Whether to call the destruction listener just before the
/// particle is destroyed.
void DestroyOldestParticle(const int32 index,
const bool callDestructionListener);
/// Destroy particles inside a shape without enabling the destruction
/// callback for destroyed particles.
/// This function is locked during callbacks.
/// For more information see
/// DestroyParticleInShape(const b2Shape&, const b2Transform&,bool).
/// @param Shape which encloses particles that should be destroyed.
/// @param Transform applied to the shape.
/// @warning This function is locked during callbacks.
/// @return Number of particles destroyed.
int32 DestroyParticlesInShape(const b2Shape& shape, const b2Transform& xf)
{
return DestroyParticlesInShape(shape, xf, false);
}
/// Destroy particles inside a shape.
/// This function is locked during callbacks.
/// In addition, this function immediately destroys particles in the shape
/// in constrast to DestroyParticle() which defers the destruction until
/// the next simulation step.
/// @param Shape which encloses particles that should be destroyed.
/// @param Transform applied to the shape.
/// @param Whether to call the world b2DestructionListener for each
/// particle destroyed.
/// @warning This function is locked during callbacks.
/// @return Number of particles destroyed.
int32 DestroyParticlesInShape(const b2Shape& shape, const b2Transform& xf,
bool callDestructionListener);
/// Create a particle group whose properties have been defined. No
/// reference to the definition is retained.
/// @warning This function is locked during callbacks.
b2ParticleGroup* CreateParticleGroup(const b2ParticleGroupDef& def);
/// Join two particle groups.
/// @param the first group. Expands to encompass the second group.
/// @param the second group. It is destroyed.
/// @warning This function is locked during callbacks.
void JoinParticleGroups(b2ParticleGroup* groupA, b2ParticleGroup* groupB);
/// Split particle group into multiple disconnected groups.
/// @param the group to be split.
/// @warning This function is locked during callbacks.
void SplitParticleGroup(b2ParticleGroup* group);
/// Get the world particle group list. With the returned group, use
/// b2ParticleGroup::GetNext to get the next group in the world list.
/// A NULL group indicates the end of the list.
/// @return the head of the world particle group list.
b2ParticleGroup* GetParticleGroupList();
const b2ParticleGroup* GetParticleGroupList() const;
/// Get the number of particle groups.
int32 GetParticleGroupCount() const;
/// Get the number of particles.
int32 GetParticleCount() const;
/// Get the maximum number of particles.
int32 GetMaxParticleCount() const;
/// Set the maximum number of particles.
/// A value of 0 means there is no maximum. The particle buffers can
/// continue to grow while b2World's block allocator still has memory.
/// Note: If you try to CreateParticle() with more than this count,
/// b2_invalidParticleIndex is returned unless
/// SetDestructionByAge() is used to enable the destruction of the
/// oldest particles in the system.
void SetMaxParticleCount(int32 count);
/// Get all existing particle flags.
uint32 GetAllParticleFlags() const;
/// Get all existing particle group flags.
uint32 GetAllGroupFlags() const;
/// Pause or unpause the particle system. When paused, b2World::Step()
/// skips over this particle system. All b2ParticleSystem function calls
/// still work.
/// @param paused is true to pause, false to un-pause.
void SetPaused(bool paused);
/// @return true if the particle system is being updated in
/// b2World::Step().
/// Initially, true, then, the last value passed into SetPaused().
bool GetPaused() const;
/// Change the particle density.
/// Particle density affects the mass of the particles, which in turn
/// affects how the particles interact with b2Bodies. Note that the density
/// does not affect how the particles interact with each other.
void SetDensity(float32 density);
/// Get the particle density.
float32 GetDensity() const;
/// Change the particle gravity scale. Adjusts the effect of the global
/// gravity vector on particles.
void SetGravityScale(float32 gravityScale);
/// Get the particle gravity scale.
float32 GetGravityScale() const;
/// Damping is used to reduce the velocity of particles. The damping
/// parameter can be larger than 1.0f but the damping effect becomes
/// sensitive to the time step when the damping parameter is large.
void SetDamping(float32 damping);
/// Get damping for particles
float32 GetDamping() const;
/// Change the number of iterations when calculating the static pressure of
/// particles. By default, 8 iterations. You can reduce the number of
/// iterations down to 1 in some situations, but this may cause
/// instabilities when many particles come together. If you see particles
/// popping away from each other like popcorn, you may have to increase the
/// number of iterations.
/// For a description of static pressure, see
/// http://en.wikipedia.org/wiki/Static_pressure#Static_pressure_in_fluid_dynamics
void SetStaticPressureIterations(int32 iterations);
/// Get the number of iterations for static pressure of particles.
int32 GetStaticPressureIterations() const;
/// Change the particle radius.
/// You should set this only once, on world start.
/// If you change the radius during execution, existing particles may
/// explode, shrink, or behave unexpectedly.
void SetRadius(float32 radius);
/// Get the particle radius.
float32 GetRadius() const;
/// Get the position of each particle
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle positions array.
b2Vec2* GetPositionBuffer();
const b2Vec2* GetPositionBuffer() const;
/// Get the velocity of each particle
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle velocities array.
b2Vec2* GetVelocityBuffer();
const b2Vec2* GetVelocityBuffer() const;
/// Get the color of each particle
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle colors array.
b2ParticleColor* GetColorBuffer();
const b2ParticleColor* GetColorBuffer() const;
/// Get the particle-group of each particle.
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle group array.
b2ParticleGroup* const* GetGroupBuffer();
const b2ParticleGroup* const* GetGroupBuffer() const;
/// Get the weight of each particle
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle positions array.
float32* GetWeightBuffer();
const float32* GetWeightBuffer() const;
/// Get the user-specified data of each particle.
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle user-data array.
void** GetUserDataBuffer();
void* const* GetUserDataBuffer() const;
/// Get the flags for each particle. See the b2ParticleFlag enum.
/// Array is length GetParticleCount()
/// @return the pointer to the head of the particle-flags array.
const uint32* GetFlagsBuffer() const;
/// Set flags for a particle. See the b2ParticleFlag enum.
void SetParticleFlags(int32 index, uint32 flags);
/// Get flags for a particle. See the b2ParticleFlag enum.
uint32 GetParticleFlags(const int32 index);
/// Set an external buffer for particle data.
/// Normally, the b2World's block allocator is used for particle data.
/// However, sometimes you may have an OpenGL or Java buffer for particle
/// data. To avoid data duplication, you may supply this external buffer.
///
/// Note that, when b2World's block allocator is used, the particle data
/// buffers can grow as required. However, when external buffers are used,
/// the maximum number of particles is clamped to the size of the smallest
/// external buffer.
///
/// @param buffer is a pointer to a block of memory.
/// @param size is the number of values in the block.
void SetFlagsBuffer(uint32* buffer, int32 capacity);
void SetPositionBuffer(b2Vec2* buffer, int32 capacity);
void SetVelocityBuffer(b2Vec2* buffer, int32 capacity);
void SetColorBuffer(b2ParticleColor* buffer, int32 capacity);
void SetUserDataBuffer(void** buffer, int32 capacity);
/// Get contacts between particles
/// Contact data can be used for many reasons, for example to trigger
/// rendering or audio effects.
const b2ParticleContact* GetContacts() const;
int32 GetContactCount() const;
/// Get contacts between particles and bodies
/// Contact data can be used for many reasons, for example to trigger
/// rendering or audio effects.
const b2ParticleBodyContact* GetBodyContacts() const;
int32 GetBodyContactCount() const;
/// Get array of particle pairs. The particles in a pair:
/// (1) are contacting,
/// (2) are in the same particle group,
/// (3) are part of a rigid particle group, or are spring, elastic,
/// or wall particles.
/// (4) have at least one particle that is a spring or barrier
/// particle (i.e. one of the types in k_pairFlags),
/// (5) have at least one particle that returns true for
/// ConnectionFilter::IsNecessary,
/// (6) are not zombie particles.
/// Essentially, this is an array of spring or barrier particles that
/// are interacting. The array is sorted by b2ParticlePair's indexA,
/// and then indexB. There are no duplicate entries.
const b2ParticlePair* GetPairs() const;
int32 GetPairCount() const;
/// Get array of particle triads. The particles in a triad:
/// (1) are in the same particle group,
/// (2) are in a Voronoi triangle together,
/// (3) are within b2_maxTriadDistance particle diameters of each
/// other,
/// (4) return true for ConnectionFilter::ShouldCreateTriad
/// (5) have at least one particle of type elastic (i.e. one of the
/// types in k_triadFlags),
/// (6) are part of a rigid particle group, or are spring, elastic,
/// or wall particles.
/// (7) are not zombie particles.
/// Essentially, this is an array of elastic particles that are
/// interacting. The array is sorted by b2ParticleTriad's indexA,
/// then indexB, then indexC. There are no duplicate entries.
const b2ParticleTriad* GetTriads() const;
int32 GetTriadCount() const;
/// Set an optional threshold for the maximum number of
/// consecutive particle iterations that a particle may contact
/// multiple bodies before it is considered a candidate for being
/// "stuck". Setting to zero or less disables.
void SetStuckThreshold(int32 iterations);
/// Get potentially stuck particles from the last step; the user must
/// decide if they are stuck or not, and if so, delete or move them
const int32* GetStuckCandidates() const;
/// Get the number of stuck particle candidates from the last step.
int32 GetStuckCandidateCount() const;
/// Compute the kinetic energy that can be lost by damping force
float32 ComputeCollisionEnergy() const;
/// Set strict Particle/Body contact check.
/// This is an option that will help ensure correct behavior if there are
/// corners in the world model where Particle/Body contact is ambiguous.
/// This option scales at n*log(n) of the number of Particle/Body contacts,
/// so it is best to only enable if it is necessary for your geometry.
/// Enable if you see strange particle behavior around b2Body
/// intersections.
void SetStrictContactCheck(bool enabled);
/// Get the status of the strict contact check.
bool GetStrictContactCheck() const;
/// Set the lifetime (in seconds) of a particle relative to the current
/// time. A lifetime of less than or equal to 0.0f results in the particle
/// living forever until it's manually destroyed by the application.
void SetParticleLifetime(const int32 index, const float32 lifetime);
/// Get the lifetime (in seconds) of a particle relative to the current
/// time. A value > 0.0f is returned if the particle is scheduled to be
/// destroyed in the future, values <= 0.0f indicate the particle has an
/// infinite lifetime.
float32 GetParticleLifetime(const int32 index);
/// Enable / disable destruction of particles in CreateParticle() when
/// no more particles can be created due to a prior call to
/// SetMaxParticleCount(). When this is enabled, the oldest particle is
/// destroyed in CreateParticle() favoring the destruction of particles
/// with a finite lifetime over particles with infinite lifetimes.
/// This feature is enabled by default when particle lifetimes are
/// tracked. Explicitly enabling this feature using this function enables
/// particle lifetime tracking.
void SetDestructionByAge(const bool enable);
/// Get whether the oldest particle will be destroyed in CreateParticle()
/// when the maximum number of particles are present in the system.
bool GetDestructionByAge() const;
/// Get the array of particle expiration times indexed by particle index.
/// GetParticleCount() items are in the returned array.
const int32* GetExpirationTimeBuffer();
/// Convert a expiration time value in returned by
/// GetExpirationTimeBuffer() to a time in seconds relative to the
/// current simulation time.
float32 ExpirationTimeToLifetime(const int32 expirationTime) const;
/// Get the array of particle indices ordered by reverse lifetime.
/// The oldest particle indexes are at the end of the array with the
/// newest at the start. Particles with infinite lifetimes
/// (i.e expiration times less than or equal to 0) are placed at the start
/// of the array.
/// ExpirationTimeToLifetime(GetExpirationTimeBuffer()[index])
/// is equivalent to GetParticleLifetime(index).
/// GetParticleCount() items are in the returned array.
const int32* GetIndexByExpirationTimeBuffer();
/// Apply an impulse to one particle. This immediately modifies the
/// velocity. Similar to b2Body::ApplyLinearImpulse.
/// @param index the particle that will be modified.
/// @param impulse the world impulse vector, usually in N-seconds or
/// kg-m/s.
void ParticleApplyLinearImpulse(int32 index, const b2Vec2& impulse);
/// Apply an impulse to all particles between 'firstIndex' and 'lastIndex'.
/// This immediately modifies the velocity. Note that the impulse is
/// applied to the total mass of all particles. So, calling
/// ParticleApplyLinearImpulse(0, impulse) and
/// ParticleApplyLinearImpulse(1, impulse) will impart twice as much
/// velocity as calling just ApplyLinearImpulse(0, 1, impulse).
/// @param firstIndex the first particle to be modified.
/// @param lastIndex the last particle to be modified.
/// @param impulse the world impulse vector, usually in N-seconds or
/// kg-m/s.
void ApplyLinearImpulse(int32 firstIndex, int32 lastIndex,
const b2Vec2& impulse);
/// Apply a force to the center of a particle.
/// @param index the particle that will be modified.
/// @param force the world force vector, usually in Newtons (N).
void ParticleApplyForce(int32 index, const b2Vec2& force);
/// Distribute a force across several particles. The particles must not be
/// wall particles. Note that the force is distributed across all the
/// particles, so calling this function for indices 0..N is not the same as
/// calling ParticleApplyForce(i, force) for i in 0..N.
/// @param firstIndex the first particle to be modified.
/// @param lastIndex the last particle to be modified.
/// @param force the world force vector, usually in Newtons (N).
void ApplyForce(int32 firstIndex, int32 lastIndex, const b2Vec2& force);
/// Get the next particle-system in the world's particle-system list.
b2ParticleSystem* GetNext();
const b2ParticleSystem* GetNext() const;
/// Query the particle system for all particles that potentially overlap
/// the provided AABB. b2QueryCallback::ShouldQueryParticleSystem is
/// ignored.
/// @param callback a user implemented callback class.
/// @param aabb the query box.
void QueryAABB(b2QueryCallback* callback, const b2AABB& aabb) const;
/// Query the particle system for all particles that potentially overlap
/// the provided shape's AABB. Calls QueryAABB internally.
/// b2QueryCallback::ShouldQueryParticleSystem is ignored.
/// @param callback a user implemented callback class.
/// @param shape the query shape
/// @param xf the transform of the AABB
void QueryShapeAABB(b2QueryCallback* callback, const b2Shape& shape,
const b2Transform& xf) const;
/// Ray-cast the particle system for all particles in the path of the ray.
/// Your callback controls whether you get the closest point, any point, or
/// n-points. The ray-cast ignores particles that contain the starting
/// point. b2RayCastCallback::ShouldQueryParticleSystem is ignored.
/// @param callback a user implemented callback class.
/// @param point1 the ray starting point
/// @param point2 the ray ending point
void RayCast(b2RayCastCallback* callback, const b2Vec2& point1,
const b2Vec2& point2) const;
/// Compute the axis-aligned bounding box for all particles contained
/// within this particle system.
/// @param aabb Returns the axis-aligned bounding box of the system.
void ComputeAABB(b2AABB* const aabb) const;
#if LIQUIDFUN_EXTERNAL_LANGUAGE_API
public:
enum b2ExceptionType
{
b2_bufferTooSmall,
b2_particleIndexOutOfBounds,
b2_numErrors,
b2_noExceptions,
};
/// Set the velocity of particle at index with direct floats.
void SetParticleVelocity(int32 index, float32 vx, float32 vy);
/// Get the x-coordinate of particle at index.
float GetParticlePositionX(int32 index) const;
/// Get the y-coordinate of particle at index.
float GetParticlePositionY(int32 index) const;
/// Copy position buffer into a specified buffer, starting from startIndex.
int CopyPositionBuffer(int startIndex, int numParticles, void* outBuf,
int size) const;
/// Copy color buffer into a specified buffer, starting from startIndex.
int CopyColorBuffer(int startIndex, int numParticles, void* outBuf,
int size) const;
/// Copy color buffer into a specified buffer, starting from startIndex.
int CopyWeightBuffer(int startIndex, int numParticles, void* outBuf,
int size) const;
private:
/// Helper function for buffer copies.
int CopyBuffer(int startIndex, int numParticles, void* inBufWithOffset,
void* outBuf, int outBufSize, int copySize) const;
/// Check if buffer copy is valid for the Get*Buffer functions that have
/// a user-supplied output buffer.
b2ExceptionType IsBufCopyValid(int startIndex, int numParticles,
int copySize, int bufSize) const;
#endif // LIQUIDFUN_EXTERNAL_LANGUAGE_API
private:
friend class b2World;
friend class b2ParticleGroup;
friend class b2ParticleBodyContactRemovePredicate;
friend class b2FixtureParticleQueryCallback;
#ifdef LIQUIDFUN_UNIT_TESTS
FRIEND_TEST(FunctionTests, GetParticleMass);
FRIEND_TEST(FunctionTests, AreProxyBuffersTheSame);
#endif // LIQUIDFUN_UNIT_TESTS
template <typename T>
struct UserOverridableBuffer
{
UserOverridableBuffer()
{
data = NULL;
userSuppliedCapacity = 0;
}
T* data;
int32 userSuppliedCapacity;
};
/// Used for detecting particle contacts
struct Proxy
{
int32 index;
uint32 tag;
friend inline bool operator<(const Proxy &a, const Proxy &b)
{
return a.tag < b.tag;
}
friend inline bool operator<(uint32 a, const Proxy &b)
{
return a < b.tag;
}
friend inline bool operator<(const Proxy &a, uint32 b)
{
return a.tag < b;
}
};
/// Class for filtering pairs or triads.
class ConnectionFilter
{
public:
virtual ~ConnectionFilter() {}
/// Is the particle necessary for connection?
/// A pair or a triad should contain at least one 'necessary' particle.
virtual bool IsNecessary(int32 index) const
{
B2_NOT_USED(index);
return true;
}
/// An additional condition for creating a pair.
virtual bool ShouldCreatePair(int32 a, int32 b) const
{
B2_NOT_USED(a);
B2_NOT_USED(b);
return true;
}
/// An additional condition for creating a triad.
virtual bool ShouldCreateTriad(int32 a, int32 b, int32 c) const
{
B2_NOT_USED(a);
B2_NOT_USED(b);
B2_NOT_USED(c);
return true;
}
};
/// InsideBoundsEnumerator enumerates all particles inside the given bounds.
class InsideBoundsEnumerator
{
public:
/// Construct an enumerator with bounds of tags and a range of proxies.
InsideBoundsEnumerator(
uint32 lower, uint32 upper,
const Proxy* first, const Proxy* last);
/// Get index of the next particle. Returns b2_invalidParticleIndex if
/// there are no more particles.
int32 GetNext();
private:
/// The lower and upper bound of x component in the tag.
uint32 m_xLower, m_xUpper;
/// The lower and upper bound of y component in the tag.
uint32 m_yLower, m_yUpper;
/// The range of proxies.
const Proxy* m_first;
const Proxy* m_last;
};
/// Node of linked lists of connected particles
struct ParticleListNode
{
/// The head of the list.
ParticleListNode* list;
/// The next node in the list.
ParticleListNode* next;
/// Number of entries in the list. Valid only for the node at the head
/// of the list.
int32 count;
/// Particle index.
int32 index;
};
/// All particle types that require creating pairs
static const int32 k_pairFlags =
b2_springParticle |
b2_barrierParticle;
/// All particle types that require creating triads
static const int32 k_triadFlags =
b2_elasticParticle;
/// All particle types that do not produce dynamic pressure
static const int32 k_noPressureFlags =
b2_powderParticle |
b2_tensileParticle;
/// All particle types that apply extra damping force with bodies
static const int32 k_extraDampingFlags =
b2_staticPressureParticle;
b2ParticleSystem(const b2ParticleSystemDef* def, b2World* world);
~b2ParticleSystem();
template <typename T> void FreeBuffer(T** b, int capacity);
template <typename T> void FreeUserOverridableBuffer(
UserOverridableBuffer<T>* b);
template <typename T> T* ReallocateBuffer(T* buffer, int32 oldCapacity,
int32 newCapacity);
template <typename T> T* ReallocateBuffer(
T* buffer, int32 userSuppliedCapacity, int32 oldCapacity,
int32 newCapacity, bool deferred);
template <typename T> T* ReallocateBuffer(
UserOverridableBuffer<T>* buffer, int32 oldCapacity, int32 newCapacity,
bool deferred);
template <typename T> T* RequestBuffer(T* buffer);
/// Reallocate the handle / index map and schedule the allocation of a new
/// pool for handle allocation.
void ReallocateHandleBuffers(int32 newCapacity);
void ReallocateInternalAllocatedBuffers(int32 capacity);
int32 CreateParticleForGroup(
const b2ParticleGroupDef& groupDef,
const b2Transform& xf, const b2Vec2& position);
void CreateParticlesStrokeShapeForGroup(
const b2Shape* shape,
const b2ParticleGroupDef& groupDef, const b2Transform& xf);
void CreateParticlesFillShapeForGroup(
const b2Shape* shape,
const b2ParticleGroupDef& groupDef, const b2Transform& xf);
void CreateParticlesWithShapeForGroup(
const b2Shape* shape,
const b2ParticleGroupDef& groupDef, const b2Transform& xf);
void CreateParticlesWithShapesForGroup(
const b2Shape* const* shapes, int32 shapeCount,
const b2ParticleGroupDef& groupDef, const b2Transform& xf);
int32 CloneParticle(int32 index, b2ParticleGroup* group);
void DestroyParticleGroup(b2ParticleGroup* group);
void UpdatePairsAndTriads(
int32 firstIndex, int32 lastIndex, const ConnectionFilter& filter);
void UpdatePairsAndTriadsWithReactiveParticles();
static bool ComparePairIndices(const b2ParticlePair& a, const b2ParticlePair& b);
static bool MatchPairIndices(const b2ParticlePair& a, const b2ParticlePair& b);
static bool CompareTriadIndices(const b2ParticleTriad& a, const b2ParticleTriad& b);
static bool MatchTriadIndices(const b2ParticleTriad& a, const b2ParticleTriad& b);
static void InitializeParticleLists(
const b2ParticleGroup* group, ParticleListNode* nodeBuffer);
void MergeParticleListsInContact(
const b2ParticleGroup* group, ParticleListNode* nodeBuffer) const;
static void MergeParticleLists(
ParticleListNode* listA, ParticleListNode* listB);
static ParticleListNode* FindLongestParticleList(
const b2ParticleGroup* group, ParticleListNode* nodeBuffer);
void MergeZombieParticleListNodes(
const b2ParticleGroup* group, ParticleListNode* nodeBuffer,
ParticleListNode* survivingList) const;
static void MergeParticleListAndNode(
ParticleListNode* list, ParticleListNode* node);
void CreateParticleGroupsFromParticleList(
const b2ParticleGroup* group, ParticleListNode* nodeBuffer,
const ParticleListNode* survivingList);
void UpdatePairsAndTriadsWithParticleList(
const b2ParticleGroup* group, const ParticleListNode* nodeBuffer);
void ComputeDepth();
InsideBoundsEnumerator GetInsideBoundsEnumerator(const b2AABB& aabb) const;
void UpdateAllParticleFlags();
void UpdateAllGroupFlags();
void AddContact(int32 a, int32 b,
b2GrowableBuffer<b2ParticleContact>& contacts) const;
void FindContacts(
b2GrowableBuffer<b2ParticleContact>& contacts) const;
static bool ProxyBufferHasIndex(
int32 index, const Proxy* const a, int count);
static int NumProxiesWithSameTag(
const Proxy* const a, const Proxy* const b, int count);
static bool AreProxyBuffersTheSame(const b2GrowableBuffer<Proxy>& a,
const b2GrowableBuffer<Proxy>& b);
void UpdateProxies(b2GrowableBuffer<Proxy>& proxies) const;
void SortProxies(b2GrowableBuffer<Proxy>& proxies) const;
void FilterContacts(b2GrowableBuffer<b2ParticleContact>& contacts);
void NotifyContactListenerPreContact(
b2ParticlePairSet* particlePairs) const;
void NotifyContactListenerPostContact(b2ParticlePairSet& particlePairs);
void UpdateContacts(bool exceptZombie);
void NotifyBodyContactListenerPreContact(
FixtureParticleSet* fixtureSet) const;
void NotifyBodyContactListenerPostContact(FixtureParticleSet& fixtureSet);
void UpdateBodyContacts();
void Solve(const b2TimeStep& step);
void SolveCollision(const b2TimeStep& step);
void LimitVelocity(const b2TimeStep& step);
void SolveGravity(const b2TimeStep& step);
void SolveBarrier(const b2TimeStep& step);
void SolveStaticPressure(const b2TimeStep& step);
void ComputeWeight();
void SolvePressure(const b2TimeStep& step);
void SolveDamping(const b2TimeStep& step);
void SolveRigidDamping();
void SolveExtraDamping();
void SolveWall();
void SolveRigid(const b2TimeStep& step);
void SolveElastic(const b2TimeStep& step);
void SolveSpring(const b2TimeStep& step);
void SolveTensile(const b2TimeStep& step);
void SolveViscous();
void SolveRepulsive(const b2TimeStep& step);
void SolvePowder(const b2TimeStep& step);
void SolveSolid(const b2TimeStep& step);
void SolveForce(const b2TimeStep& step);
void SolveColorMixing();
void SolveZombie();
/// Destroy all particles which have outlived their lifetimes set by
/// SetParticleLifetime().
void SolveLifetimes(const b2TimeStep& step);
void RotateBuffer(int32 start, int32 mid, int32 end);
float32 GetCriticalVelocity(const b2TimeStep& step) const;
float32 GetCriticalVelocitySquared(const b2TimeStep& step) const;
float32 GetCriticalPressure(const b2TimeStep& step) const;
float32 GetParticleStride() const;
float32 GetParticleMass() const;
float32 GetParticleInvMass() const;
// Get the world's contact filter if any particles with the
// b2_contactFilterParticle flag are present in the system.
b2ContactFilter* GetFixtureContactFilter() const;
// Get the world's contact filter if any particles with the
// b2_particleContactFilterParticle flag are present in the system.
b2ContactFilter* GetParticleContactFilter() const;
// Get the world's contact listener if any particles with the
// b2_fixtureContactListenerParticle flag are present in the system.
b2ContactListener* GetFixtureContactListener() const;
// Get the world's contact listener if any particles with the
// b2_particleContactListenerParticle flag are present in the system.
b2ContactListener* GetParticleContactListener() const;
template <typename T> void SetUserOverridableBuffer(
UserOverridableBuffer<T>* buffer, T* newBufferData, int32 newCapacity);
void SetGroupFlags(b2ParticleGroup* group, uint32 flags);
void RemoveSpuriousBodyContacts();
static bool BodyContactCompare(const b2ParticleBodyContact& lhs,
const b2ParticleBodyContact& rhs);
void DetectStuckParticle(int32 particle);
/// Determine whether a particle index is valid.
bool ValidateParticleIndex(const int32 index) const;
/// Get the time elapsed in b2ParticleSystemDef::lifetimeGranularity.
int32 GetQuantizedTimeElapsed() const;
/// Convert a lifetime in seconds to an expiration time.
int64 LifetimeToExpirationTime(const float32 lifetime) const;
bool ForceCanBeApplied(uint32 flags) const;
void PrepareForceBuffer();
bool IsRigidGroup(b2ParticleGroup *group) const;
b2Vec2 GetLinearVelocity(
b2ParticleGroup *group, int32 particleIndex,
const b2Vec2 &point) const;
void InitDampingParameter(
float32* invMass, float32* invInertia, float32* tangentDistance,
float32 mass, float32 inertia, const b2Vec2& center,
const b2Vec2& point, const b2Vec2& normal) const;
void InitDampingParameterWithRigidGroupOrParticle(
float32* invMass, float32* invInertia, float32* tangentDistance,
bool isRigidGroup, b2ParticleGroup* group, int32 particleIndex,
const b2Vec2& point, const b2Vec2& normal) const;
float32 ComputeDampingImpulse(
float32 invMassA, float32 invInertiaA, float32 tangentDistanceA,
float32 invMassB, float32 invInertiaB, float32 tangentDistanceB,
float32 normalVelocity) const;
void ApplyDamping(
float32 invMass, float32 invInertia, float32 tangentDistance,
bool isRigidGroup, b2ParticleGroup* group, int32 particleIndex,
float32 impulse, const b2Vec2& normal);
bool m_paused;
int32 m_timestamp;
int32 m_allParticleFlags;
bool m_needsUpdateAllParticleFlags;
int32 m_allGroupFlags;
bool m_needsUpdateAllGroupFlags;
bool m_hasForce;
int32 m_iterationIndex;
float32 m_inverseDensity;
float32 m_particleDiameter;
float32 m_inverseDiameter;
float32 m_squaredDiameter;
int32 m_count;
int32 m_internalAllocatedCapacity;
/// Allocator for b2ParticleHandle instances.
b2SlabAllocator<b2ParticleHandle> m_handleAllocator;
/// Maps particle indicies to handles.
UserOverridableBuffer<b2ParticleHandle*> m_handleIndexBuffer;
UserOverridableBuffer<uint32> m_flagsBuffer;
UserOverridableBuffer<b2Vec2> m_positionBuffer;
UserOverridableBuffer<b2Vec2> m_velocityBuffer;
b2Vec2* m_forceBuffer;
/// m_weightBuffer is populated in ComputeWeight and used in
/// ComputeDepth(), SolveStaticPressure() and SolvePressure().
float32* m_weightBuffer;
/// When any particles have the flag b2_staticPressureParticle,
/// m_staticPressureBuffer is first allocated and used in
/// SolveStaticPressure() and SolvePressure(). It will be reallocated on
/// subsequent CreateParticle() calls.
float32* m_staticPressureBuffer;
/// m_accumulationBuffer is used in many functions as a temporary buffer
/// for scalar values.
float32* m_accumulationBuffer;
/// When any particles have the flag b2_tensileParticle,
/// m_accumulation2Buffer is first allocated and used in SolveTensile()
/// as a temporary buffer for vector values. It will be reallocated on
/// subsequent CreateParticle() calls.
b2Vec2* m_accumulation2Buffer;
/// When any particle groups have the flag b2_solidParticleGroup,
/// m_depthBuffer is first allocated and populated in ComputeDepth() and
/// used in SolveSolid(). It will be reallocated on subsequent
/// CreateParticle() calls.
float32* m_depthBuffer;
UserOverridableBuffer<b2ParticleColor> m_colorBuffer;
b2ParticleGroup** m_groupBuffer;
UserOverridableBuffer<void*> m_userDataBuffer;
/// Stuck particle detection parameters and record keeping
int32 m_stuckThreshold;
UserOverridableBuffer<int32> m_lastBodyContactStepBuffer;
UserOverridableBuffer<int32> m_bodyContactCountBuffer;
UserOverridableBuffer<int32> m_consecutiveContactStepsBuffer;
b2GrowableBuffer<int32> m_stuckParticleBuffer;
b2GrowableBuffer<Proxy> m_proxyBuffer;
b2GrowableBuffer<b2ParticleContact> m_contactBuffer;
b2GrowableBuffer<b2ParticleBodyContact> m_bodyContactBuffer;
b2GrowableBuffer<b2ParticlePair> m_pairBuffer;
b2GrowableBuffer<b2ParticleTriad> m_triadBuffer;
/// Time each particle should be destroyed relative to the last time
/// m_timeElapsed was initialized. Each unit of time corresponds to
/// b2ParticleSystemDef::lifetimeGranularity seconds.
UserOverridableBuffer<int32> m_expirationTimeBuffer;
/// List of particle indices sorted by expiration time.
UserOverridableBuffer<int32> m_indexByExpirationTimeBuffer;
/// Time elapsed in 32:32 fixed point. Each non-fractional unit of time
/// corresponds to b2ParticleSystemDef::lifetimeGranularity seconds.
int64 m_timeElapsed;
/// Whether the expiration time buffer has been modified and needs to be
/// resorted.
bool m_expirationTimeBufferRequiresSorting;
int32 m_groupCount;
b2ParticleGroup* m_groupList;
b2ParticleSystemDef m_def;
b2World* m_world;
b2ParticleSystem* m_prev;
b2ParticleSystem* m_next;
};
inline void b2ParticleContact::SetIndices(int32 a, int32 b)
{
b2Assert(a <= b2_maxParticleIndex && b <= b2_maxParticleIndex);
indexA = (b2ParticleIndex)a;
indexB = (b2ParticleIndex)b;
}
inline bool b2ParticleContact::operator==(
const b2ParticleContact& rhs) const
{
return indexA == rhs.indexA
&& indexB == rhs.indexB
&& flags == rhs.flags
&& weight == rhs.weight
&& normal == rhs.normal;
}
// The reciprocal sqrt function differs between SIMD and non-SIMD, but they
// should create approximately equal results.
inline bool b2ParticleContact::ApproximatelyEqual(
const b2ParticleContact& rhs) const
{
static const float MAX_WEIGHT_DIFF = 0.01f; // Weight 0 ~ 1, so about 1%
static const float MAX_NORMAL_DIFF = 0.01f; // Normal length = 1, so 1%
return indexA == rhs.indexA
&& indexB == rhs.indexB
&& flags == rhs.flags
&& b2Abs(weight - rhs.weight) < MAX_WEIGHT_DIFF
&& (normal - rhs.normal).Length() < MAX_NORMAL_DIFF;
}
inline b2ParticleGroup* b2ParticleSystem::GetParticleGroupList()
{
return m_groupList;
}
inline const b2ParticleGroup* b2ParticleSystem::GetParticleGroupList() const
{
return m_groupList;
}
inline int32 b2ParticleSystem::GetParticleGroupCount() const
{
return m_groupCount;
}
inline int32 b2ParticleSystem::GetParticleCount() const
{
return m_count;
}
inline void b2ParticleSystem::SetPaused(bool paused)
{
m_paused = paused;
}
inline bool b2ParticleSystem::GetPaused() const
{
return m_paused;
}
inline const b2ParticleContact* b2ParticleSystem::GetContacts() const
{
return m_contactBuffer.Data();
}
inline int32 b2ParticleSystem::GetContactCount() const
{
return m_contactBuffer.GetCount();
}
inline const b2ParticleBodyContact* b2ParticleSystem::GetBodyContacts() const
{
return m_bodyContactBuffer.Data();
}
inline int32 b2ParticleSystem::GetBodyContactCount() const
{
return m_bodyContactBuffer.GetCount();
}
inline const b2ParticlePair* b2ParticleSystem::GetPairs() const
{
return m_pairBuffer.Data();
}
inline int32 b2ParticleSystem::GetPairCount() const
{
return m_pairBuffer.GetCount();
}
inline const b2ParticleTriad* b2ParticleSystem::GetTriads() const
{
return m_triadBuffer.Data();
}
inline int32 b2ParticleSystem::GetTriadCount() const
{
return m_triadBuffer.GetCount();
}
inline b2ParticleSystem* b2ParticleSystem::GetNext()
{
return m_next;
}
inline const b2ParticleSystem* b2ParticleSystem::GetNext() const
{
return m_next;
}
inline const int32* b2ParticleSystem::GetStuckCandidates() const
{
return m_stuckParticleBuffer.Data();
}
inline int32 b2ParticleSystem::GetStuckCandidateCount() const
{
return m_stuckParticleBuffer.GetCount();
}
inline void b2ParticleSystem::SetStrictContactCheck(bool enabled)
{
m_def.strictContactCheck = enabled;
}
inline bool b2ParticleSystem::GetStrictContactCheck() const
{
return m_def.strictContactCheck;
}
inline void b2ParticleSystem::SetRadius(float32 radius)
{
m_particleDiameter = 2 * radius;
m_squaredDiameter = m_particleDiameter * m_particleDiameter;
m_inverseDiameter = 1 / m_particleDiameter;
}
inline void b2ParticleSystem::SetDensity(float32 density)
{
m_def.density = density;
m_inverseDensity = 1 / m_def.density;
}
inline float32 b2ParticleSystem::GetDensity() const
{
return m_def.density;
}
inline void b2ParticleSystem::SetGravityScale(float32 gravityScale)
{
m_def.gravityScale = gravityScale;
}
inline float32 b2ParticleSystem::GetGravityScale() const
{
return m_def.gravityScale;
}
inline void b2ParticleSystem::SetDamping(float32 damping)
{
m_def.dampingStrength = damping;
}
inline float32 b2ParticleSystem::GetDamping() const
{
return m_def.dampingStrength;
}
inline void b2ParticleSystem::SetStaticPressureIterations(int32 iterations)
{
m_def.staticPressureIterations = iterations;
}
inline int32 b2ParticleSystem::GetStaticPressureIterations() const
{
return m_def.staticPressureIterations;
}
inline float32 b2ParticleSystem::GetRadius() const
{
return m_particleDiameter / 2;
}
inline float32 b2ParticleSystem::GetCriticalVelocity(const b2TimeStep& step) const
{
return m_particleDiameter * step.inv_dt;
}
inline float32 b2ParticleSystem::GetCriticalVelocitySquared(
const b2TimeStep& step) const
{
float32 velocity = GetCriticalVelocity(step);
return velocity * velocity;
}
inline float32 b2ParticleSystem::GetCriticalPressure(const b2TimeStep& step) const
{
return m_def.density * GetCriticalVelocitySquared(step);
}
inline float32 b2ParticleSystem::GetParticleStride() const
{
return b2_particleStride * m_particleDiameter;
}
inline float32 b2ParticleSystem::GetParticleMass() const
{
float32 stride = GetParticleStride();
return m_def.density * stride * stride;
}
inline float32 b2ParticleSystem::GetParticleInvMass() const
{
// mass = density * stride^2, so we take the inverse of this.
float32 inverseStride = m_inverseDiameter * (1.0f / b2_particleStride);
return m_inverseDensity * inverseStride * inverseStride;
}
inline b2Vec2* b2ParticleSystem::GetPositionBuffer()
{
return m_positionBuffer.data;
}
inline b2Vec2* b2ParticleSystem::GetVelocityBuffer()
{
return m_velocityBuffer.data;
}
inline float32* b2ParticleSystem::GetWeightBuffer()
{
return m_weightBuffer;
}
inline int32 b2ParticleSystem::GetMaxParticleCount() const
{
return m_def.maxCount;
}
inline void b2ParticleSystem::SetMaxParticleCount(int32 count)
{
b2Assert(m_count <= count || count == 0);
m_def.maxCount = count;
}
inline uint32 b2ParticleSystem::GetAllParticleFlags() const
{
return m_allParticleFlags;
}
inline uint32 b2ParticleSystem::GetAllGroupFlags() const
{
return m_allGroupFlags;
}
inline const uint32* b2ParticleSystem::GetFlagsBuffer() const
{
return m_flagsBuffer.data;
}
inline const b2Vec2* b2ParticleSystem::GetPositionBuffer() const
{
return m_positionBuffer.data;
}
inline const b2Vec2* b2ParticleSystem::GetVelocityBuffer() const
{
return m_velocityBuffer.data;
}
inline const b2ParticleColor* b2ParticleSystem::GetColorBuffer() const
{
return ((b2ParticleSystem*) this)->GetColorBuffer();
}
inline const b2ParticleGroup* const* b2ParticleSystem::GetGroupBuffer() const
{
return m_groupBuffer;
}
inline const float32* b2ParticleSystem::GetWeightBuffer() const
{
return m_weightBuffer;
}
inline void* const* b2ParticleSystem::GetUserDataBuffer() const
{
return ((b2ParticleSystem*) this)->GetUserDataBuffer();
}
inline b2ParticleGroup* const* b2ParticleSystem::GetGroupBuffer()
{
return m_groupBuffer;
}
inline uint32 b2ParticleSystem::GetParticleFlags(int32 index)
{
return GetFlagsBuffer()[index];
}
inline bool b2ParticleSystem::ValidateParticleIndex(const int32 index) const
{
return index >= 0 && index < GetParticleCount() &&
index != b2_invalidParticleIndex;
}
inline bool b2ParticleSystem::GetDestructionByAge() const
{
return m_def.destroyByAge;
}
inline void b2ParticleSystem::ParticleApplyLinearImpulse(int32 index,
const b2Vec2& impulse)
{
ApplyLinearImpulse(index, index + 1, impulse);
}
// Note: These functions must go in the header so the unit tests will compile
// them. b2ParticleSystem.cpp does not compile with this #define.
#if LIQUIDFUN_EXTERNAL_LANGUAGE_API
inline void b2ParticleSystem::SetParticleVelocity(int32 index,
float32 vx,
float32 vy)
{
b2Vec2& v = GetVelocityBuffer()[index];
v.x = vx;
v.y = vy;
}
inline float b2ParticleSystem::GetParticlePositionX(int32 index) const
{
return GetPositionBuffer()[index].x;
}
inline float b2ParticleSystem::GetParticlePositionY(int32 index) const
{
return GetPositionBuffer()[index].y;
}
inline int b2ParticleSystem::CopyPositionBuffer(int startIndex,
int numParticles,
void* outBuf,
int size) const
{
int copySize = numParticles * sizeof(b2Vec2);
void* inBufWithOffset = (void*) (GetPositionBuffer() + startIndex);
return CopyBuffer(startIndex, numParticles, inBufWithOffset, outBuf, size,
copySize);
}
inline int b2ParticleSystem::CopyColorBuffer(int startIndex,
int numParticles,
void* outBuf,
int size) const
{
int copySize = numParticles * sizeof(b2ParticleColor);
void* inBufWithOffset = (void*) (GetColorBuffer() + startIndex);
return CopyBuffer(startIndex, numParticles, inBufWithOffset, outBuf, size,
copySize);
}
inline int b2ParticleSystem::CopyWeightBuffer(int startIndex,
int numParticles,
void* outBuf,
int size) const
{
int copySize = numParticles * sizeof(float32);
void* inBufWithOffset = (void*) (GetWeightBuffer() + startIndex);
return CopyBuffer(startIndex, numParticles, inBufWithOffset, outBuf, size,
copySize);
}
inline int b2ParticleSystem::CopyBuffer(int startIndex, int numParticles,
void* inBufWithOffset, void* outBuf,
int outBufSize, int copySize) const
{
b2ExceptionType exception = IsBufCopyValid(startIndex, numParticles,
copySize, outBufSize);
if (exception != b2_noExceptions)
{
return exception;
}
memcpy(outBuf, inBufWithOffset, copySize);
return b2_noExceptions;
}
#endif // LIQUIDFUN_EXTERNAL_LANGUAGE_API
#endif