package org.jbox2d.particle;
import java.lang.reflect.Array;
import java.util.Arrays;
import org.jbox2d.callbacks.ParticleDestructionListener;
import org.jbox2d.callbacks.ParticleQueryCallback;
import org.jbox2d.callbacks.ParticleRaycastCallback;
import org.jbox2d.callbacks.QueryCallback;
import org.jbox2d.collision.AABB;
import org.jbox2d.collision.RayCastInput;
import org.jbox2d.collision.RayCastOutput;
import org.jbox2d.collision.shapes.Shape;
import org.jbox2d.common.BufferUtils;
import org.jbox2d.common.MathUtils;
import org.jbox2d.common.Rot;
import org.jbox2d.common.Settings;
import org.jbox2d.common.Transform;
import org.jbox2d.common.Vec2;
import org.jbox2d.dynamics.Body;
import org.jbox2d.dynamics.Fixture;
import org.jbox2d.dynamics.TimeStep;
import org.jbox2d.dynamics.World;
import org.jbox2d.particle.VoronoiDiagram.VoronoiDiagramCallback;
public class ParticleSystem {
/** All particle types that require creating pairs */
private static final int k_pairFlags = ParticleType.b2_springParticle;
/** All particle types that require creating triads */
private static final int k_triadFlags = ParticleType.b2_elasticParticle;
/** All particle types that require computing depth */
private static final int k_noPressureFlags = ParticleType.b2_powderParticle;
static final int xTruncBits = 12;
static final int yTruncBits = 12;
static final int tagBits = 8 * 4 - 1 /* sizeof(int) */;
static final long yOffset = 1 << (yTruncBits - 1);
static final int yShift = tagBits - yTruncBits;
static final int xShift = tagBits - yTruncBits - xTruncBits;
static final long xScale = 1 << xShift;
static final long xOffset = xScale * (1 << (xTruncBits - 1));
static final int xMask = (1 << xTruncBits) - 1;
static final int yMask = (1 << yTruncBits) - 1;
static long computeTag(float x, float y) {
return (((long) (y + yOffset)) << yShift) + (((long) (xScale * x)) + xOffset);
}
static long computeRelativeTag(long tag, int x, int y) {
return tag + (y << yShift) + (x << xShift);
}
static int limitCapacity(int capacity, int maxCount) {
return maxCount != 0 && capacity > maxCount ? maxCount : capacity;
}
int m_timestamp;
int m_allParticleFlags;
int m_allGroupFlags;
float m_density;
float m_inverseDensity;
float m_gravityScale;
float m_particleDiameter;
float m_inverseDiameter;
float m_squaredDiameter;
int m_count;
int m_internalAllocatedCapacity;
int m_maxCount;
ParticleBufferInt m_flagsBuffer;
ParticleBuffer<Vec2> m_positionBuffer;
ParticleBuffer<Vec2> m_velocityBuffer;
float[] m_accumulationBuffer; // temporary values
Vec2[] m_accumulation2Buffer; // temporary vector values
float[] m_depthBuffer; // distance from the surface
public ParticleBuffer<ParticleColor> m_colorBuffer;
ParticleGroup[] m_groupBuffer;
ParticleBuffer<Object> m_userDataBuffer;
int m_proxyCount;
int m_proxyCapacity;
Proxy[] m_proxyBuffer;
public int m_contactCount;
int m_contactCapacity;
public ParticleContact[] m_contactBuffer;
public int m_bodyContactCount;
int m_bodyContactCapacity;
public ParticleBodyContact[] m_bodyContactBuffer;
int m_pairCount;
int m_pairCapacity;
Pair[] m_pairBuffer;
int m_triadCount;
int m_triadCapacity;
Triad[] m_triadBuffer;
int m_groupCount;
ParticleGroup m_groupList;
float m_pressureStrength;
float m_dampingStrength;
float m_elasticStrength;
float m_springStrength;
float m_viscousStrength;
float m_surfaceTensionStrengthA;
float m_surfaceTensionStrengthB;
float m_powderStrength;
float m_ejectionStrength;
float m_colorMixingStrength;
World m_world;
public ParticleSystem(World world) {
m_world = world;
m_timestamp = 0;
m_allParticleFlags = 0;
m_allGroupFlags = 0;
m_density = 1;
m_inverseDensity = 1;
m_gravityScale = 1;
m_particleDiameter = 1;
m_inverseDiameter = 1;
m_squaredDiameter = 1;
m_count = 0;
m_internalAllocatedCapacity = 0;
m_maxCount = 0;
m_proxyCount = 0;
m_proxyCapacity = 0;
m_contactCount = 0;
m_contactCapacity = 0;
m_bodyContactCount = 0;
m_bodyContactCapacity = 0;
m_pairCount = 0;
m_pairCapacity = 0;
m_triadCount = 0;
m_triadCapacity = 0;
m_groupCount = 0;
m_pressureStrength = 0.05f;
m_dampingStrength = 1.0f;
m_elasticStrength = 0.25f;
m_springStrength = 0.25f;
m_viscousStrength = 0.25f;
m_surfaceTensionStrengthA = 0.1f;
m_surfaceTensionStrengthB = 0.2f;
m_powderStrength = 0.5f;
m_ejectionStrength = 0.5f;
m_colorMixingStrength = 0.5f;
m_flagsBuffer = new ParticleBufferInt();
m_positionBuffer = new ParticleBuffer<Vec2>(Vec2.class);
m_velocityBuffer = new ParticleBuffer<Vec2>(Vec2.class);
m_colorBuffer = new ParticleBuffer<ParticleColor>(ParticleColor.class);
m_userDataBuffer = new ParticleBuffer<Object>(Object.class);
}
// public void assertNotSamePosition() {
// for (int i = 0; i < m_count; i++) {
// Vec2 vi = m_positionBuffer.data[i];
// for (int j = i + 1; j < m_count; j++) {
// Vec2 vj = m_positionBuffer.data[j];
// assert(vi.x != vj.x || vi.y != vj.y);
// }
// }
// }
public int createParticle(ParticleDef def) {
if (m_count >= m_internalAllocatedCapacity) {
int capacity = m_count != 0 ? 2 * m_count : Settings.minParticleBufferCapacity;
capacity = limitCapacity(capacity, m_maxCount);
capacity = limitCapacity(capacity, m_flagsBuffer.userSuppliedCapacity);
capacity = limitCapacity(capacity, m_positionBuffer.userSuppliedCapacity);
capacity = limitCapacity(capacity, m_velocityBuffer.userSuppliedCapacity);
capacity = limitCapacity(capacity, m_colorBuffer.userSuppliedCapacity);
capacity = limitCapacity(capacity, m_userDataBuffer.userSuppliedCapacity);
if (m_internalAllocatedCapacity < capacity) {
m_flagsBuffer.data =
reallocateBuffer(m_flagsBuffer, m_internalAllocatedCapacity, capacity, false);
m_positionBuffer.data =
reallocateBuffer(m_positionBuffer, m_internalAllocatedCapacity, capacity, false);
m_velocityBuffer.data =
reallocateBuffer(m_velocityBuffer, m_internalAllocatedCapacity, capacity, false);
m_accumulationBuffer =
BufferUtils.reallocateBuffer(m_accumulationBuffer, 0, m_internalAllocatedCapacity,
capacity, false);
m_accumulation2Buffer =
BufferUtils.reallocateBuffer(Vec2.class, m_accumulation2Buffer, 0,
m_internalAllocatedCapacity, capacity, true);
m_depthBuffer =
BufferUtils.reallocateBuffer(m_depthBuffer, 0, m_internalAllocatedCapacity, capacity,
true);
m_colorBuffer.data =
reallocateBuffer(m_colorBuffer, m_internalAllocatedCapacity, capacity, true);
m_groupBuffer =
BufferUtils.reallocateBuffer(ParticleGroup.class, m_groupBuffer, 0,
m_internalAllocatedCapacity, capacity, false);
m_userDataBuffer.data =
reallocateBuffer(m_userDataBuffer, m_internalAllocatedCapacity, capacity, true);
m_internalAllocatedCapacity = capacity;
}
}
if (m_count >= m_internalAllocatedCapacity) {
return Settings.invalidParticleIndex;
}
int index = m_count++;
m_flagsBuffer.data[index] = def.flags;
m_positionBuffer.data[index].set(def.position);
// assertNotSamePosition();
m_velocityBuffer.data[index].set(def.velocity);
m_groupBuffer[index] = null;
if (m_depthBuffer != null) {
m_depthBuffer[index] = 0;
}
if (m_colorBuffer.data != null || def.color != null) {
m_colorBuffer.data = requestParticleBuffer(m_colorBuffer.dataClass, m_colorBuffer.data);
m_colorBuffer.data[index].set(def.color);
}
if (m_userDataBuffer.data != null || def.userData != null) {
m_userDataBuffer.data =
requestParticleBuffer(m_userDataBuffer.dataClass, m_userDataBuffer.data);
m_userDataBuffer.data[index] = def.userData;
}
if (m_proxyCount >= m_proxyCapacity) {
int oldCapacity = m_proxyCapacity;
int newCapacity = m_proxyCount != 0 ? 2 * m_proxyCount : Settings.minParticleBufferCapacity;
m_proxyBuffer =
BufferUtils.reallocateBuffer(Proxy.class, m_proxyBuffer, oldCapacity, newCapacity);
m_proxyCapacity = newCapacity;
}
m_proxyBuffer[m_proxyCount++].index = index;
return index;
}
public void destroyParticle(int index, boolean callDestructionListener) {
int flags = ParticleType.b2_zombieParticle;
if (callDestructionListener) {
flags |= ParticleType.b2_destructionListener;
}
m_flagsBuffer.data[index] |= flags;
}
private final AABB temp = new AABB();
private final DestroyParticlesInShapeCallback dpcallback = new DestroyParticlesInShapeCallback();
public int destroyParticlesInShape(Shape shape, Transform xf, boolean callDestructionListener) {
dpcallback.init(this, shape, xf, callDestructionListener);
shape.computeAABB(temp, xf, 0);
m_world.queryAABB(dpcallback, temp);
return dpcallback.destroyed;
}
public void destroyParticlesInGroup(ParticleGroup group, boolean callDestructionListener) {
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
destroyParticle(i, callDestructionListener);
}
}
private final AABB temp2 = new AABB();
private final Vec2 tempVec = new Vec2();
private final Transform tempTransform = new Transform();
private final Transform tempTransform2 = new Transform();
private CreateParticleGroupCallback createParticleGroupCallback =
new CreateParticleGroupCallback();
private final ParticleDef tempParticleDef = new ParticleDef();
public ParticleGroup createParticleGroup(ParticleGroupDef groupDef) {
float stride = getParticleStride();
final Transform identity = tempTransform;
identity.setIdentity();
Transform transform = tempTransform2;
transform.setIdentity();
int firstIndex = m_count;
if (groupDef.shape != null) {
final ParticleDef particleDef = tempParticleDef;
particleDef.flags = groupDef.flags;
particleDef.color = groupDef.color;
particleDef.userData = groupDef.userData;
Shape shape = groupDef.shape;
transform.set(groupDef.position, groupDef.angle);
AABB aabb = temp;
int childCount = shape.getChildCount();
for (int childIndex = 0; childIndex < childCount; childIndex++) {
if (childIndex == 0) {
shape.computeAABB(aabb, identity, childIndex);
} else {
AABB childAABB = temp2;
shape.computeAABB(childAABB, identity, childIndex);
aabb.combine(childAABB);
}
}
final float upperBoundY = aabb.upperBound.y;
final float upperBoundX = aabb.upperBound.x;
for (float y = MathUtils.floor(aabb.lowerBound.y / stride) * stride; y < upperBoundY; y +=
stride) {
for (float x = MathUtils.floor(aabb.lowerBound.x / stride) * stride; x < upperBoundX; x +=
stride) {
Vec2 p = tempVec;
p.x = x;
p.y = y;
if (shape.testPoint(identity, p)) {
Transform.mulToOut(transform, p, p);
particleDef.position.x = p.x;
particleDef.position.y = p.y;
p.subLocal(groupDef.position);
Vec2.crossToOutUnsafe(groupDef.angularVelocity, p, particleDef.velocity);
particleDef.velocity.addLocal(groupDef.linearVelocity);
createParticle(particleDef);
}
}
}
}
int lastIndex = m_count;
ParticleGroup group = new ParticleGroup();
group.m_system = this;
group.m_firstIndex = firstIndex;
group.m_lastIndex = lastIndex;
group.m_groupFlags = groupDef.groupFlags;
group.m_strength = groupDef.strength;
group.m_userData = groupDef.userData;
group.m_transform.set(transform);
group.m_destroyAutomatically = groupDef.destroyAutomatically;
group.m_prev = null;
group.m_next = m_groupList;
if (m_groupList != null) {
m_groupList.m_prev = group;
}
m_groupList = group;
++m_groupCount;
for (int i = firstIndex; i < lastIndex; i++) {
m_groupBuffer[i] = group;
}
updateContacts(true);
if ((groupDef.flags & k_pairFlags) != 0) {
for (int k = 0; k < m_contactCount; k++) {
ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if (a > b) {
int temp = a;
a = b;
b = temp;
}
if (firstIndex <= a && b < lastIndex) {
if (m_pairCount >= m_pairCapacity) {
int oldCapacity = m_pairCapacity;
int newCapacity =
m_pairCount != 0 ? 2 * m_pairCount : Settings.minParticleBufferCapacity;
m_pairBuffer =
BufferUtils.reallocateBuffer(Pair.class, m_pairBuffer, oldCapacity, newCapacity);
m_pairCapacity = newCapacity;
}
Pair pair = m_pairBuffer[m_pairCount];
pair.indexA = a;
pair.indexB = b;
pair.flags = contact.flags;
pair.strength = groupDef.strength;
pair.distance = MathUtils.distance(m_positionBuffer.data[a], m_positionBuffer.data[b]);
m_pairCount++;
}
}
}
if ((groupDef.flags & k_triadFlags) != 0) {
VoronoiDiagram diagram = new VoronoiDiagram(lastIndex - firstIndex);
for (int i = firstIndex; i < lastIndex; i++) {
diagram.addGenerator(m_positionBuffer.data[i], i);
}
diagram.generate(stride / 2);
createParticleGroupCallback.system = this;
createParticleGroupCallback.def = groupDef;
createParticleGroupCallback.firstIndex = firstIndex;
diagram.getNodes(createParticleGroupCallback);
}
if ((groupDef.groupFlags & ParticleGroupType.b2_solidParticleGroup) != 0) {
computeDepthForGroup(group);
}
return group;
}
public void joinParticleGroups(ParticleGroup groupA, ParticleGroup groupB) {
assert (groupA != groupB);
RotateBuffer(groupB.m_firstIndex, groupB.m_lastIndex, m_count);
assert (groupB.m_lastIndex == m_count);
RotateBuffer(groupA.m_firstIndex, groupA.m_lastIndex, groupB.m_firstIndex);
assert (groupA.m_lastIndex == groupB.m_firstIndex);
int particleFlags = 0;
for (int i = groupA.m_firstIndex; i < groupB.m_lastIndex; i++) {
particleFlags |= m_flagsBuffer.data[i];
}
updateContacts(true);
if ((particleFlags & k_pairFlags) != 0) {
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if (a > b) {
int temp = a;
a = b;
b = temp;
}
if (groupA.m_firstIndex <= a && a < groupA.m_lastIndex && groupB.m_firstIndex <= b
&& b < groupB.m_lastIndex) {
if (m_pairCount >= m_pairCapacity) {
int oldCapacity = m_pairCapacity;
int newCapacity =
m_pairCount != 0 ? 2 * m_pairCount : Settings.minParticleBufferCapacity;
m_pairBuffer =
BufferUtils.reallocateBuffer(Pair.class, m_pairBuffer, oldCapacity, newCapacity);
m_pairCapacity = newCapacity;
}
Pair pair = m_pairBuffer[m_pairCount];
pair.indexA = a;
pair.indexB = b;
pair.flags = contact.flags;
pair.strength = MathUtils.min(groupA.m_strength, groupB.m_strength);
pair.distance = MathUtils.distance(m_positionBuffer.data[a], m_positionBuffer.data[b]);
m_pairCount++;
}
}
}
if ((particleFlags & k_triadFlags) != 0) {
VoronoiDiagram diagram = new VoronoiDiagram(groupB.m_lastIndex - groupA.m_firstIndex);
for (int i = groupA.m_firstIndex; i < groupB.m_lastIndex; i++) {
if ((m_flagsBuffer.data[i] & ParticleType.b2_zombieParticle) == 0) {
diagram.addGenerator(m_positionBuffer.data[i], i);
}
}
diagram.generate(getParticleStride() / 2);
JoinParticleGroupsCallback callback = new JoinParticleGroupsCallback();
callback.system = this;
callback.groupA = groupA;
callback.groupB = groupB;
diagram.getNodes(callback);
}
for (int i = groupB.m_firstIndex; i < groupB.m_lastIndex; i++) {
m_groupBuffer[i] = groupA;
}
int groupFlags = groupA.m_groupFlags | groupB.m_groupFlags;
groupA.m_groupFlags = groupFlags;
groupA.m_lastIndex = groupB.m_lastIndex;
groupB.m_firstIndex = groupB.m_lastIndex;
destroyParticleGroup(groupB);
if ((groupFlags & ParticleGroupType.b2_solidParticleGroup) != 0) {
computeDepthForGroup(groupA);
}
}
// Only called from solveZombie() or joinParticleGroups().
void destroyParticleGroup(ParticleGroup group) {
assert (m_groupCount > 0);
assert (group != null);
if (m_world.getParticleDestructionListener() != null) {
m_world.getParticleDestructionListener().sayGoodbye(group);
}
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
m_groupBuffer[i] = null;
}
if (group.m_prev != null) {
group.m_prev.m_next = group.m_next;
}
if (group.m_next != null) {
group.m_next.m_prev = group.m_prev;
}
if (group == m_groupList) {
m_groupList = group.m_next;
}
--m_groupCount;
}
public void computeDepthForGroup(ParticleGroup group) {
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
m_accumulationBuffer[i] = 0;
}
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if (a >= group.m_firstIndex && a < group.m_lastIndex && b >= group.m_firstIndex
&& b < group.m_lastIndex) {
float w = contact.weight;
m_accumulationBuffer[a] += w;
m_accumulationBuffer[b] += w;
}
}
m_depthBuffer = requestParticleBuffer(m_depthBuffer);
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
float w = m_accumulationBuffer[i];
m_depthBuffer[i] = w < 0.8f ? 0 : Float.MAX_VALUE;
}
int interationCount = group.getParticleCount();
for (int t = 0; t < interationCount; t++) {
boolean updated = false;
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if (a >= group.m_firstIndex && a < group.m_lastIndex && b >= group.m_firstIndex
&& b < group.m_lastIndex) {
float r = 1 - contact.weight;
float ap0 = m_depthBuffer[a];
float bp0 = m_depthBuffer[b];
float ap1 = bp0 + r;
float bp1 = ap0 + r;
if (ap0 > ap1) {
m_depthBuffer[a] = ap1;
updated = true;
}
if (bp0 > bp1) {
m_depthBuffer[b] = bp1;
updated = true;
}
}
}
if (!updated) {
break;
}
}
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
float p = m_depthBuffer[i];
if (p < Float.MAX_VALUE) {
m_depthBuffer[i] *= m_particleDiameter;
} else {
m_depthBuffer[i] = 0;
}
}
}
public void addContact(int a, int b) {
assert(a != b);
Vec2 pa = m_positionBuffer.data[a];
Vec2 pb = m_positionBuffer.data[b];
float dx = pb.x - pa.x;
float dy = pb.y - pa.y;
float d2 = dx * dx + dy * dy;
// assert(d2 != 0);
if (d2 < m_squaredDiameter) {
if (m_contactCount >= m_contactCapacity) {
int oldCapacity = m_contactCapacity;
int newCapacity =
m_contactCount != 0 ? 2 * m_contactCount : Settings.minParticleBufferCapacity;
m_contactBuffer =
BufferUtils.reallocateBuffer(ParticleContact.class, m_contactBuffer, oldCapacity,
newCapacity);
m_contactCapacity = newCapacity;
}
float invD = d2 != 0 ? MathUtils.sqrt(1 / d2) : Float.MAX_VALUE;
ParticleContact contact = m_contactBuffer[m_contactCount];
contact.indexA = a;
contact.indexB = b;
contact.flags = m_flagsBuffer.data[a] | m_flagsBuffer.data[b];
contact.weight = 1 - d2 * invD * m_inverseDiameter;
contact.normal.x = invD * dx;
contact.normal.y = invD * dy;
m_contactCount++;
}
}
public void updateContacts(boolean exceptZombie) {
for (int p = 0; p < m_proxyCount; p++) {
Proxy proxy = m_proxyBuffer[p];
int i = proxy.index;
Vec2 pos = m_positionBuffer.data[i];
proxy.tag = computeTag(m_inverseDiameter * pos.x, m_inverseDiameter * pos.y);
}
Arrays.sort(m_proxyBuffer, 0, m_proxyCount);
m_contactCount = 0;
int c_index = 0;
for (int i = 0; i < m_proxyCount; i++) {
Proxy a = m_proxyBuffer[i];
long rightTag = computeRelativeTag(a.tag, 1, 0);
for (int j = i + 1; j < m_proxyCount; j++) {
Proxy b = m_proxyBuffer[j];
if (rightTag < b.tag) {
break;
}
addContact(a.index, b.index);
}
long bottomLeftTag = computeRelativeTag(a.tag, -1, 1);
for (; c_index < m_proxyCount; c_index++) {
Proxy c = m_proxyBuffer[c_index];
if (bottomLeftTag <= c.tag) {
break;
}
}
long bottomRightTag = computeRelativeTag(a.tag, 1, 1);
for (int b_index = c_index; b_index < m_proxyCount; b_index++) {
Proxy b = m_proxyBuffer[b_index];
if (bottomRightTag < b.tag) {
break;
}
addContact(a.index, b.index);
}
}
if (exceptZombie) {
int j = m_contactCount;
for (int i = 0; i < j; i++) {
if ((m_contactBuffer[i].flags & ParticleType.b2_zombieParticle) != 0) {
--j;
ParticleContact temp = m_contactBuffer[j];
m_contactBuffer[j] = m_contactBuffer[i];
m_contactBuffer[i] = temp;
--i;
}
}
m_contactCount = j;
}
}
private final UpdateBodyContactsCallback ubccallback = new UpdateBodyContactsCallback();
public void updateBodyContacts() {
final AABB aabb = temp;
aabb.lowerBound.x = Float.MAX_VALUE;
aabb.lowerBound.y = Float.MAX_VALUE;
aabb.upperBound.x = -Float.MAX_VALUE;
aabb.upperBound.y = -Float.MAX_VALUE;
for (int i = 0; i < m_count; i++) {
Vec2 p = m_positionBuffer.data[i];
Vec2.minToOut(aabb.lowerBound, p, aabb.lowerBound);
Vec2.maxToOut(aabb.upperBound, p, aabb.upperBound);
}
aabb.lowerBound.x -= m_particleDiameter;
aabb.lowerBound.y -= m_particleDiameter;
aabb.upperBound.x += m_particleDiameter;
aabb.upperBound.y += m_particleDiameter;
m_bodyContactCount = 0;
ubccallback.system = this;
m_world.queryAABB(ubccallback, aabb);
}
private SolveCollisionCallback sccallback = new SolveCollisionCallback();
public void solveCollision(TimeStep step) {
final AABB aabb = temp;
final Vec2 lowerBound = aabb.lowerBound;
final Vec2 upperBound = aabb.upperBound;
lowerBound.x = Float.MAX_VALUE;
lowerBound.y = Float.MAX_VALUE;
upperBound.x = -Float.MAX_VALUE;
upperBound.y = -Float.MAX_VALUE;
for (int i = 0; i < m_count; i++) {
final Vec2 v = m_velocityBuffer.data[i];
final Vec2 p1 = m_positionBuffer.data[i];
final float p1x = p1.x;
final float p1y = p1.y;
final float p2x = p1x + step.dt * v.x;
final float p2y = p1y + step.dt * v.y;
final float bx = p1x < p2x ? p1x : p2x;
final float by = p1y < p2y ? p1y : p2y;
lowerBound.x = lowerBound.x < bx ? lowerBound.x : bx;
lowerBound.y = lowerBound.y < by ? lowerBound.y : by;
final float b1x = p1x > p2x ? p1x : p2x;
final float b1y = p1y > p2y ? p1y : p2y;
upperBound.x = upperBound.x > b1x ? upperBound.x : b1x;
upperBound.y = upperBound.y > b1y ? upperBound.y : b1y;
}
sccallback.step = step;
sccallback.system = this;
m_world.queryAABB(sccallback, aabb);
}
public void solve(TimeStep step) {
++m_timestamp;
if (m_count == 0) {
return;
}
m_allParticleFlags = 0;
for (int i = 0; i < m_count; i++) {
m_allParticleFlags |= m_flagsBuffer.data[i];
}
if ((m_allParticleFlags & ParticleType.b2_zombieParticle) != 0) {
solveZombie();
}
if (m_count == 0) {
return;
}
m_allGroupFlags = 0;
for (ParticleGroup group = m_groupList; group != null; group = group.getNext()) {
m_allGroupFlags |= group.m_groupFlags;
}
final float gravityx = step.dt * m_gravityScale * m_world.getGravity().x;
final float gravityy = step.dt * m_gravityScale * m_world.getGravity().y;
float criticalVelocytySquared = getCriticalVelocitySquared(step);
for (int i = 0; i < m_count; i++) {
Vec2 v = m_velocityBuffer.data[i];
v.x += gravityx;
v.y += gravityy;
float v2 = v.x * v.x + v.y * v.y;
if (v2 > criticalVelocytySquared) {
float a = v2 == 0 ? Float.MAX_VALUE : MathUtils.sqrt(criticalVelocytySquared / v2);
v.x *= a;
v.y *= a;
}
}
solveCollision(step);
if ((m_allGroupFlags & ParticleGroupType.b2_rigidParticleGroup) != 0) {
solveRigid(step);
}
if ((m_allParticleFlags & ParticleType.b2_wallParticle) != 0) {
solveWall(step);
}
for (int i = 0; i < m_count; i++) {
Vec2 pos = m_positionBuffer.data[i];
Vec2 vel = m_velocityBuffer.data[i];
pos.x += step.dt * vel.x;
pos.y += step.dt * vel.y;
}
updateBodyContacts();
updateContacts(false);
if ((m_allParticleFlags & ParticleType.b2_viscousParticle) != 0) {
solveViscous(step);
}
if ((m_allParticleFlags & ParticleType.b2_powderParticle) != 0) {
solvePowder(step);
}
if ((m_allParticleFlags & ParticleType.b2_tensileParticle) != 0) {
solveTensile(step);
}
if ((m_allParticleFlags & ParticleType.b2_elasticParticle) != 0) {
solveElastic(step);
}
if ((m_allParticleFlags & ParticleType.b2_springParticle) != 0) {
solveSpring(step);
}
if ((m_allGroupFlags & ParticleGroupType.b2_solidParticleGroup) != 0) {
solveSolid(step);
}
if ((m_allParticleFlags & ParticleType.b2_colorMixingParticle) != 0) {
solveColorMixing(step);
}
solvePressure(step);
solveDamping(step);
}
void solvePressure(TimeStep step) {
// calculates the sum of contact-weights for each particle
// that means dimensionless density
for (int i = 0; i < m_count; i++) {
m_accumulationBuffer[i] = 0;
}
for (int k = 0; k < m_bodyContactCount; k++) {
ParticleBodyContact contact = m_bodyContactBuffer[k];
int a = contact.index;
float w = contact.weight;
m_accumulationBuffer[a] += w;
}
for (int k = 0; k < m_contactCount; k++) {
ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
m_accumulationBuffer[a] += w;
m_accumulationBuffer[b] += w;
}
// ignores powder particles
if ((m_allParticleFlags & k_noPressureFlags) != 0) {
for (int i = 0; i < m_count; i++) {
if ((m_flagsBuffer.data[i] & k_noPressureFlags) != 0) {
m_accumulationBuffer[i] = 0;
}
}
}
// calculates pressure as a linear function of density
float pressurePerWeight = m_pressureStrength * getCriticalPressure(step);
for (int i = 0; i < m_count; i++) {
float w = m_accumulationBuffer[i];
float h =
pressurePerWeight
* MathUtils.max(0.0f, MathUtils.min(w, Settings.maxParticleWeight)
- Settings.minParticleWeight);
m_accumulationBuffer[i] = h;
}
// applies pressure between each particles in contact
float velocityPerPressure = step.dt / (m_density * m_particleDiameter);
for (int k = 0; k < m_bodyContactCount; k++) {
ParticleBodyContact contact = m_bodyContactBuffer[k];
int a = contact.index;
Body b = contact.body;
float w = contact.weight;
float m = contact.mass;
Vec2 n = contact.normal;
Vec2 p = m_positionBuffer.data[a];
float h = m_accumulationBuffer[a] + pressurePerWeight * w;
final Vec2 f = tempVec;
final float coef = velocityPerPressure * w * m * h;
f.x = coef * n.x;
f.y = coef * n.y;
final Vec2 velData = m_velocityBuffer.data[a];
final float particleInvMass = getParticleInvMass();
velData.x -= particleInvMass * f.x;
velData.y -= particleInvMass * f.y;
b.applyLinearImpulse(f, p, true);
}
for (int k = 0; k < m_contactCount; k++) {
ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
Vec2 n = contact.normal;
float h = m_accumulationBuffer[a] + m_accumulationBuffer[b];
final float fx = velocityPerPressure * w * h * n.x;
final float fy = velocityPerPressure * w * h * n.y;
final Vec2 velDataA = m_velocityBuffer.data[a];
final Vec2 velDataB = m_velocityBuffer.data[b];
velDataA.x -= fx;
velDataA.y -= fy;
velDataB.x += fx;
velDataB.y += fy;
}
}
void solveDamping(TimeStep step) {
// reduces normal velocity of each contact
float damping = m_dampingStrength;
for (int k = 0; k < m_bodyContactCount; k++) {
final ParticleBodyContact contact = m_bodyContactBuffer[k];
int a = contact.index;
Body b = contact.body;
float w = contact.weight;
float m = contact.mass;
Vec2 n = contact.normal;
Vec2 p = m_positionBuffer.data[a];
final float tempX = p.x - b.m_sweep.c.x;
final float tempY = p.y - b.m_sweep.c.y;
final Vec2 velA = m_velocityBuffer.data[a];
// getLinearVelocityFromWorldPointToOut, with -= velA
float vx = -b.m_angularVelocity * tempY + b.m_linearVelocity.x - velA.x;
float vy = b.m_angularVelocity * tempX + b.m_linearVelocity.y - velA.y;
// done
float vn = vx * n.x + vy * n.y;
if (vn < 0) {
final Vec2 f = tempVec;
f.x = damping * w * m * vn * n.x;
f.y = damping * w * m * vn * n.y;
final float invMass = getParticleInvMass();
velA.x += invMass * f.x;
velA.y += invMass * f.y;
f.x = -f.x;
f.y = -f.y;
b.applyLinearImpulse(f, p, true);
}
}
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
Vec2 n = contact.normal;
final Vec2 velA = m_velocityBuffer.data[a];
final Vec2 velB = m_velocityBuffer.data[b];
final float vx = velB.x - velA.x;
final float vy = velB.y - velA.y;
float vn = vx * n.x + vy * n.y;
if (vn < 0) {
float fx = damping * w * vn * n.x;
float fy = damping * w * vn * n.y;
velA.x += fx;
velA.y += fy;
velB.x -= fx;
velB.y -= fy;
}
}
}
public void solveWall(TimeStep step) {
for (int i = 0; i < m_count; i++) {
if ((m_flagsBuffer.data[i] & ParticleType.b2_wallParticle) != 0) {
final Vec2 r = m_velocityBuffer.data[i];
r.x = 0.0f;
r.y = 0.0f;
}
}
}
private final Vec2 tempVec2 = new Vec2();
private final Rot tempRot = new Rot();
private final Transform tempXf = new Transform();
private final Transform tempXf2 = new Transform();
void solveRigid(final TimeStep step) {
for (ParticleGroup group = m_groupList; group != null; group = group.getNext()) {
if ((group.m_groupFlags & ParticleGroupType.b2_rigidParticleGroup) != 0) {
group.updateStatistics();
Vec2 temp = tempVec;
Vec2 cross = tempVec2;
Rot rotation = tempRot;
rotation.set(step.dt * group.m_angularVelocity);
Rot.mulToOutUnsafe(rotation, group.m_center, cross);
temp.set(group.m_linearVelocity).mulLocal(step.dt).addLocal(group.m_center).subLocal(cross);
tempXf.p.set(temp);
tempXf.q.set(rotation);
Transform.mulToOut(tempXf, group.m_transform, group.m_transform);
final Transform velocityTransform = tempXf2;
velocityTransform.p.x = step.inv_dt * tempXf.p.x;
velocityTransform.p.y = step.inv_dt * tempXf.p.y;
velocityTransform.q.s = step.inv_dt * tempXf.q.s;
velocityTransform.q.c = step.inv_dt * (tempXf.q.c - 1);
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
Transform.mulToOutUnsafe(velocityTransform, m_positionBuffer.data[i],
m_velocityBuffer.data[i]);
}
}
}
}
void solveElastic(final TimeStep step) {
float elasticStrength = step.inv_dt * m_elasticStrength;
for (int k = 0; k < m_triadCount; k++) {
final Triad triad = m_triadBuffer[k];
if ((triad.flags & ParticleType.b2_elasticParticle) != 0) {
int a = triad.indexA;
int b = triad.indexB;
int c = triad.indexC;
final Vec2 oa = triad.pa;
final Vec2 ob = triad.pb;
final Vec2 oc = triad.pc;
final Vec2 pa = m_positionBuffer.data[a];
final Vec2 pb = m_positionBuffer.data[b];
final Vec2 pc = m_positionBuffer.data[c];
final float px = 1f / 3 * (pa.x + pb.x + pc.x);
final float py = 1f / 3 * (pa.y + pb.y + pc.y);
float rs = Vec2.cross(oa, pa) + Vec2.cross(ob, pb) + Vec2.cross(oc, pc);
float rc = Vec2.dot(oa, pa) + Vec2.dot(ob, pb) + Vec2.dot(oc, pc);
float r2 = rs * rs + rc * rc;
float invR = r2 == 0 ? Float.MAX_VALUE : MathUtils.sqrt(1f / r2);
rs *= invR;
rc *= invR;
final float strength = elasticStrength * triad.strength;
final float roax = rc * oa.x - rs * oa.y;
final float roay = rs * oa.x + rc * oa.y;
final float robx = rc * ob.x - rs * ob.y;
final float roby = rs * ob.x + rc * ob.y;
final float rocx = rc * oc.x - rs * oc.y;
final float rocy = rs * oc.x + rc * oc.y;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
final Vec2 vc = m_velocityBuffer.data[c];
va.x += strength * (roax - (pa.x - px));
va.y += strength * (roay - (pa.y - py));
vb.x += strength * (robx - (pb.x - px));
vb.y += strength * (roby - (pb.y - py));
vc.x += strength * (rocx - (pc.x - px));
vc.y += strength * (rocy - (pc.y - py));
}
}
}
void solveSpring(final TimeStep step) {
float springStrength = step.inv_dt * m_springStrength;
for (int k = 0; k < m_pairCount; k++) {
final Pair pair = m_pairBuffer[k];
if ((pair.flags & ParticleType.b2_springParticle) != 0) {
int a = pair.indexA;
int b = pair.indexB;
final Vec2 pa = m_positionBuffer.data[a];
final Vec2 pb = m_positionBuffer.data[b];
final float dx = pb.x - pa.x;
final float dy = pb.y - pa.y;
float r0 = pair.distance;
float r1 = MathUtils.sqrt(dx * dx + dy * dy);
if (r1 == 0) r1 = Float.MAX_VALUE;
float strength = springStrength * pair.strength;
final float fx = strength * (r0 - r1) / r1 * dx;
final float fy = strength * (r0 - r1) / r1 * dy;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
va.x -= fx;
va.y -= fy;
vb.x += fx;
vb.y += fy;
}
}
}
void solveTensile(final TimeStep step) {
m_accumulation2Buffer = requestParticleBuffer(Vec2.class, m_accumulation2Buffer);
for (int i = 0; i < m_count; i++) {
m_accumulationBuffer[i] = 0;
m_accumulation2Buffer[i].setZero();
}
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
if ((contact.flags & ParticleType.b2_tensileParticle) != 0) {
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
Vec2 n = contact.normal;
m_accumulationBuffer[a] += w;
m_accumulationBuffer[b] += w;
final Vec2 a2A = m_accumulation2Buffer[a];
final Vec2 a2B = m_accumulation2Buffer[b];
final float inter = (1 - w) * w;
a2A.x -= inter * n.x;
a2A.y -= inter * n.y;
a2B.x += inter * n.x;
a2B.y += inter * n.y;
}
}
float strengthA = m_surfaceTensionStrengthA * getCriticalVelocity(step);
float strengthB = m_surfaceTensionStrengthB * getCriticalVelocity(step);
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
if ((contact.flags & ParticleType.b2_tensileParticle) != 0) {
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
Vec2 n = contact.normal;
final Vec2 a2A = m_accumulation2Buffer[a];
final Vec2 a2B = m_accumulation2Buffer[b];
float h = m_accumulationBuffer[a] + m_accumulationBuffer[b];
final float sx = a2B.x - a2A.x;
final float sy = a2B.y - a2A.y;
float fn = (strengthA * (h - 2) + strengthB * (sx * n.x + sy * n.y)) * w;
final float fx = fn * n.x;
final float fy = fn * n.y;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
va.x -= fx;
va.y -= fy;
vb.x += fx;
vb.y += fy;
}
}
}
void solveViscous(final TimeStep step) {
float viscousStrength = m_viscousStrength;
for (int k = 0; k < m_bodyContactCount; k++) {
final ParticleBodyContact contact = m_bodyContactBuffer[k];
int a = contact.index;
if ((m_flagsBuffer.data[a] & ParticleType.b2_viscousParticle) != 0) {
Body b = contact.body;
float w = contact.weight;
float m = contact.mass;
Vec2 p = m_positionBuffer.data[a];
final Vec2 va = m_velocityBuffer.data[a];
final float tempX = p.x - b.m_sweep.c.x;
final float tempY = p.y - b.m_sweep.c.y;
final float vx = -b.m_angularVelocity * tempY + b.m_linearVelocity.x - va.x;
final float vy = b.m_angularVelocity * tempX + b.m_linearVelocity.y - va.y;
final Vec2 f = tempVec;
final float pInvMass = getParticleInvMass();
f.x = viscousStrength * m * w * vx;
f.y = viscousStrength * m * w * vy;
va.x += pInvMass * f.x;
va.y += pInvMass * f.y;
f.x = -f.x;
f.y = -f.y;
b.applyLinearImpulse(f, p, true);
}
}
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
if ((contact.flags & ParticleType.b2_viscousParticle) != 0) {
int a = contact.indexA;
int b = contact.indexB;
float w = contact.weight;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
final float vx = vb.x - va.x;
final float vy = vb.y - va.y;
final float fx = viscousStrength * w * vx;
final float fy = viscousStrength * w * vy;
va.x += fx;
va.y += fy;
vb.x -= fx;
vb.y -= fy;
}
}
}
void solvePowder(final TimeStep step) {
float powderStrength = m_powderStrength * getCriticalVelocity(step);
float minWeight = 1.0f - Settings.particleStride;
for (int k = 0; k < m_bodyContactCount; k++) {
final ParticleBodyContact contact = m_bodyContactBuffer[k];
int a = contact.index;
if ((m_flagsBuffer.data[a] & ParticleType.b2_powderParticle) != 0) {
float w = contact.weight;
if (w > minWeight) {
Body b = contact.body;
float m = contact.mass;
Vec2 p = m_positionBuffer.data[a];
Vec2 n = contact.normal;
final Vec2 f = tempVec;
final Vec2 va = m_velocityBuffer.data[a];
final float inter = powderStrength * m * (w - minWeight);
final float pInvMass = getParticleInvMass();
f.x = inter * n.x;
f.y = inter * n.y;
va.x -= pInvMass * f.x;
va.y -= pInvMass * f.y;
b.applyLinearImpulse(f, p, true);
}
}
}
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
if ((contact.flags & ParticleType.b2_powderParticle) != 0) {
float w = contact.weight;
if (w > minWeight) {
int a = contact.indexA;
int b = contact.indexB;
Vec2 n = contact.normal;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
final float inter = powderStrength * (w - minWeight);
final float fx = inter * n.x;
final float fy = inter * n.y;
va.x -= fx;
va.y -= fy;
vb.x += fx;
vb.y += fy;
}
}
}
}
void solveSolid(final TimeStep step) {
// applies extra repulsive force from solid particle groups
m_depthBuffer = requestParticleBuffer(m_depthBuffer);
float ejectionStrength = step.inv_dt * m_ejectionStrength;
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if (m_groupBuffer[a] != m_groupBuffer[b]) {
float w = contact.weight;
Vec2 n = contact.normal;
float h = m_depthBuffer[a] + m_depthBuffer[b];
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
final float inter = ejectionStrength * h * w;
final float fx = inter * n.x;
final float fy = inter * n.y;
va.x -= fx;
va.y -= fy;
vb.x += fx;
vb.y += fy;
}
}
}
void solveColorMixing(final TimeStep step) {
// mixes color between contacting particles
m_colorBuffer.data = requestParticleBuffer(ParticleColor.class, m_colorBuffer.data);
int colorMixing256 = (int) (256 * m_colorMixingStrength);
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
if ((m_flagsBuffer.data[a] & m_flagsBuffer.data[b] & ParticleType.b2_colorMixingParticle) != 0) {
ParticleColor colorA = m_colorBuffer.data[a];
ParticleColor colorB = m_colorBuffer.data[b];
int dr = (colorMixing256 * (colorB.r - colorA.r)) >> 8;
int dg = (colorMixing256 * (colorB.g - colorA.g)) >> 8;
int db = (colorMixing256 * (colorB.b - colorA.b)) >> 8;
int da = (colorMixing256 * (colorB.a - colorA.a)) >> 8;
colorA.r += dr;
colorA.g += dg;
colorA.b += db;
colorA.a += da;
colorB.r -= dr;
colorB.g -= dg;
colorB.b -= db;
colorB.a -= da;
}
}
}
void solveZombie() {
// removes particles with zombie flag
int newCount = 0;
int[] newIndices = new int[m_count];
for (int i = 0; i < m_count; i++) {
int flags = m_flagsBuffer.data[i];
if ((flags & ParticleType.b2_zombieParticle) != 0) {
ParticleDestructionListener destructionListener = m_world.getParticleDestructionListener();
if ((flags & ParticleType.b2_destructionListener) != 0 && destructionListener != null) {
destructionListener.sayGoodbye(i);
}
newIndices[i] = Settings.invalidParticleIndex;
} else {
newIndices[i] = newCount;
if (i != newCount) {
m_flagsBuffer.data[newCount] = m_flagsBuffer.data[i];
m_positionBuffer.data[newCount].set(m_positionBuffer.data[i]);
m_velocityBuffer.data[newCount].set(m_velocityBuffer.data[i]);
m_groupBuffer[newCount] = m_groupBuffer[i];
if (m_depthBuffer != null) {
m_depthBuffer[newCount] = m_depthBuffer[i];
}
if (m_colorBuffer.data != null) {
m_colorBuffer.data[newCount].set(m_colorBuffer.data[i]);
}
if (m_userDataBuffer.data != null) {
m_userDataBuffer.data[newCount] = m_userDataBuffer.data[i];
}
}
newCount++;
}
}
// update proxies
for (int k = 0; k < m_proxyCount; k++) {
Proxy proxy = m_proxyBuffer[k];
proxy.index = newIndices[proxy.index];
}
// Proxy lastProxy = std.remove_if(
// m_proxyBuffer, m_proxyBuffer + m_proxyCount,
// Test.IsProxyInvalid);
// m_proxyCount = (int) (lastProxy - m_proxyBuffer);
int j = m_proxyCount;
for (int i = 0; i < j; i++) {
if (Test.IsProxyInvalid(m_proxyBuffer[i])) {
--j;
Proxy temp = m_proxyBuffer[j];
m_proxyBuffer[j] = m_proxyBuffer[i];
m_proxyBuffer[i] = temp;
--i;
}
}
m_proxyCount = j;
// update contacts
for (int k = 0; k < m_contactCount; k++) {
ParticleContact contact = m_contactBuffer[k];
contact.indexA = newIndices[contact.indexA];
contact.indexB = newIndices[contact.indexB];
}
// ParticleContact lastContact = std.remove_if(
// m_contactBuffer, m_contactBuffer + m_contactCount,
// Test.IsContactInvalid);
// m_contactCount = (int) (lastContact - m_contactBuffer);
j = m_contactCount;
for (int i = 0; i < j; i++) {
if (Test.IsContactInvalid(m_contactBuffer[i])) {
--j;
ParticleContact temp = m_contactBuffer[j];
m_contactBuffer[j] = m_contactBuffer[i];
m_contactBuffer[i] = temp;
--i;
}
}
m_contactCount = j;
// update particle-body contacts
for (int k = 0; k < m_bodyContactCount; k++) {
ParticleBodyContact contact = m_bodyContactBuffer[k];
contact.index = newIndices[contact.index];
}
// ParticleBodyContact lastBodyContact = std.remove_if(
// m_bodyContactBuffer, m_bodyContactBuffer + m_bodyContactCount,
// Test.IsBodyContactInvalid);
// m_bodyContactCount = (int) (lastBodyContact - m_bodyContactBuffer);
j = m_bodyContactCount;
for (int i = 0; i < j; i++) {
if (Test.IsBodyContactInvalid(m_bodyContactBuffer[i])) {
--j;
ParticleBodyContact temp = m_bodyContactBuffer[j];
m_bodyContactBuffer[j] = m_bodyContactBuffer[i];
m_bodyContactBuffer[i] = temp;
--i;
}
}
m_bodyContactCount = j;
// update pairs
for (int k = 0; k < m_pairCount; k++) {
Pair pair = m_pairBuffer[k];
pair.indexA = newIndices[pair.indexA];
pair.indexB = newIndices[pair.indexB];
}
// Pair lastPair = std.remove_if(m_pairBuffer, m_pairBuffer + m_pairCount, Test.IsPairInvalid);
// m_pairCount = (int) (lastPair - m_pairBuffer);
j = m_pairCount;
for (int i = 0; i < j; i++) {
if (Test.IsPairInvalid(m_pairBuffer[i])) {
--j;
Pair temp = m_pairBuffer[j];
m_pairBuffer[j] = m_pairBuffer[i];
m_pairBuffer[i] = temp;
--i;
}
}
m_pairCount = j;
// update triads
for (int k = 0; k < m_triadCount; k++) {
Triad triad = m_triadBuffer[k];
triad.indexA = newIndices[triad.indexA];
triad.indexB = newIndices[triad.indexB];
triad.indexC = newIndices[triad.indexC];
}
// Triad lastTriad =
// std.remove_if(m_triadBuffer, m_triadBuffer + m_triadCount, Test.isTriadInvalid);
// m_triadCount = (int) (lastTriad - m_triadBuffer);
j = m_triadCount;
for (int i = 0; i < j; i++) {
if (Test.IsTriadInvalid(m_triadBuffer[i])) {
--j;
Triad temp = m_triadBuffer[j];
m_triadBuffer[j] = m_triadBuffer[i];
m_triadBuffer[i] = temp;
--i;
}
}
m_triadCount = j;
// update groups
for (ParticleGroup group = m_groupList; group != null; group = group.getNext()) {
int firstIndex = newCount;
int lastIndex = 0;
boolean modified = false;
for (int i = group.m_firstIndex; i < group.m_lastIndex; i++) {
j = newIndices[i];
if (j >= 0) {
firstIndex = MathUtils.min(firstIndex, j);
lastIndex = MathUtils.max(lastIndex, j + 1);
} else {
modified = true;
}
}
if (firstIndex < lastIndex) {
group.m_firstIndex = firstIndex;
group.m_lastIndex = lastIndex;
if (modified) {
if ((group.m_groupFlags & ParticleGroupType.b2_rigidParticleGroup) != 0) {
group.m_toBeSplit = true;
}
}
} else {
group.m_firstIndex = 0;
group.m_lastIndex = 0;
if (group.m_destroyAutomatically) {
group.m_toBeDestroyed = true;
}
}
}
// update particle count
m_count = newCount;
// m_world.m_stackAllocator.Free(newIndices);
// destroy bodies with no particles
for (ParticleGroup group = m_groupList; group != null;) {
ParticleGroup next = group.getNext();
if (group.m_toBeDestroyed) {
destroyParticleGroup(group);
} else if (group.m_toBeSplit) {
// TODO: split the group
}
group = next;
}
}
private static class NewIndices {
int start, mid, end;
final int getIndex(final int i) {
if (i < start) {
return i;
} else if (i < mid) {
return i + end - mid;
} else if (i < end) {
return i + start - mid;
} else {
return i;
}
}
}
private final NewIndices newIndices = new NewIndices();
void RotateBuffer(int start, int mid, int end) {
// move the particles assigned to the given group toward the end of array
if (start == mid || mid == end) {
return;
}
newIndices.start = start;
newIndices.mid = mid;
newIndices.end = end;
BufferUtils.rotate(m_flagsBuffer.data, start, mid, end);
BufferUtils.rotate(m_positionBuffer.data, start, mid, end);
BufferUtils.rotate(m_velocityBuffer.data, start, mid, end);
BufferUtils.rotate(m_groupBuffer, start, mid, end);
if (m_depthBuffer != null) {
BufferUtils.rotate(m_depthBuffer, start, mid, end);
}
if (m_colorBuffer.data != null) {
BufferUtils.rotate(m_colorBuffer.data, start, mid, end);
}
if (m_userDataBuffer.data != null) {
BufferUtils.rotate(m_userDataBuffer.data, start, mid, end);
}
// update proxies
for (int k = 0; k < m_proxyCount; k++) {
Proxy proxy = m_proxyBuffer[k];
proxy.index = newIndices.getIndex(proxy.index);
}
// update contacts
for (int k = 0; k < m_contactCount; k++) {
ParticleContact contact = m_contactBuffer[k];
contact.indexA = newIndices.getIndex(contact.indexA);
contact.indexB = newIndices.getIndex(contact.indexB);
}
// update particle-body contacts
for (int k = 0; k < m_bodyContactCount; k++) {
ParticleBodyContact contact = m_bodyContactBuffer[k];
contact.index = newIndices.getIndex(contact.index);
}
// update pairs
for (int k = 0; k < m_pairCount; k++) {
Pair pair = m_pairBuffer[k];
pair.indexA = newIndices.getIndex(pair.indexA);
pair.indexB = newIndices.getIndex(pair.indexB);
}
// update triads
for (int k = 0; k < m_triadCount; k++) {
Triad triad = m_triadBuffer[k];
triad.indexA = newIndices.getIndex(triad.indexA);
triad.indexB = newIndices.getIndex(triad.indexB);
triad.indexC = newIndices.getIndex(triad.indexC);
}
// update groups
for (ParticleGroup group = m_groupList; group != null; group = group.getNext()) {
group.m_firstIndex = newIndices.getIndex(group.m_firstIndex);
group.m_lastIndex = newIndices.getIndex(group.m_lastIndex - 1) + 1;
}
}
public void setParticleRadius(float radius) {
m_particleDiameter = 2 * radius;
m_squaredDiameter = m_particleDiameter * m_particleDiameter;
m_inverseDiameter = 1 / m_particleDiameter;
}
public void setParticleDensity(float density) {
m_density = density;
m_inverseDensity = 1 / m_density;
}
public float getParticleDensity() {
return m_density;
}
public void setParticleGravityScale(float gravityScale) {
m_gravityScale = gravityScale;
}
public float getParticleGravityScale() {
return m_gravityScale;
}
public void setParticleDamping(float damping) {
m_dampingStrength = damping;
}
public float getParticleDamping() {
return m_dampingStrength;
}
public float getParticleRadius() {
return m_particleDiameter / 2;
}
float getCriticalVelocity(final TimeStep step) {
return m_particleDiameter * step.inv_dt;
}
float getCriticalVelocitySquared(final TimeStep step) {
float velocity = getCriticalVelocity(step);
return velocity * velocity;
}
float getCriticalPressure(final TimeStep step) {
return m_density * getCriticalVelocitySquared(step);
}
float getParticleStride() {
return Settings.particleStride * m_particleDiameter;
}
float getParticleMass() {
float stride = getParticleStride();
return m_density * stride * stride;
}
float getParticleInvMass() {
return 1.777777f * m_inverseDensity * m_inverseDiameter * m_inverseDiameter;
}
public int[] getParticleFlagsBuffer() {
return m_flagsBuffer.data;
}
public Vec2[] getParticlePositionBuffer() {
return m_positionBuffer.data;
}
public Vec2[] getParticleVelocityBuffer() {
return m_velocityBuffer.data;
}
public ParticleColor[] getParticleColorBuffer() {
m_colorBuffer.data = requestParticleBuffer(ParticleColor.class, m_colorBuffer.data);
return m_colorBuffer.data;
}
public Object[] getParticleUserDataBuffer() {
m_userDataBuffer.data = requestParticleBuffer(Object.class, m_userDataBuffer.data);
return m_userDataBuffer.data;
}
public int getParticleMaxCount() {
return m_maxCount;
}
public void setParticleMaxCount(int count) {
assert (m_count <= count);
m_maxCount = count;
}
void setParticleBuffer(ParticleBufferInt buffer, int[] newData, int newCapacity) {
assert ((newData != null && newCapacity != 0) || (newData == null && newCapacity == 0));
if (buffer.userSuppliedCapacity != 0) {
// m_world.m_blockAllocator.Free(buffer.data, sizeof(T) * m_internalAllocatedCapacity);
}
buffer.data = newData;
buffer.userSuppliedCapacity = newCapacity;
}
<T> void setParticleBuffer(ParticleBuffer<T> buffer, T[] newData, int newCapacity) {
assert ((newData != null && newCapacity != 0) || (newData == null && newCapacity == 0));
if (buffer.userSuppliedCapacity != 0) {
// m_world.m_blockAllocator.Free(buffer.data, sizeof(T) * m_internalAllocatedCapacity);
}
buffer.data = newData;
buffer.userSuppliedCapacity = newCapacity;
}
public void setParticleFlagsBuffer(int[] buffer, int capacity) {
setParticleBuffer(m_flagsBuffer, buffer, capacity);
}
public void setParticlePositionBuffer(Vec2[] buffer, int capacity) {
setParticleBuffer(m_positionBuffer, buffer, capacity);
}
public void setParticleVelocityBuffer(Vec2[] buffer, int capacity) {
setParticleBuffer(m_velocityBuffer, buffer, capacity);
}
public void setParticleColorBuffer(ParticleColor[] buffer, int capacity) {
setParticleBuffer(m_colorBuffer, buffer, capacity);
}
public ParticleGroup[] getParticleGroupBuffer() {
return m_groupBuffer;
}
public int getParticleGroupCount() {
return m_groupCount;
}
public ParticleGroup[] getParticleGroupList() {
return m_groupBuffer;
}
public int getParticleCount() {
return m_count;
}
public void setParticleUserDataBuffer(Object[] buffer, int capacity) {
setParticleBuffer(m_userDataBuffer, buffer, capacity);
}
private static final int lowerBound(Proxy[] ray, int length, long tag) {
int left = 0;
int step, curr;
while (length > 0) {
step = length / 2;
curr = left + step;
if (ray[curr].tag < tag) {
left = curr + 1;
length -= step + 1;
} else {
length = step;
}
}
return left;
}
private static final int upperBound(Proxy[] ray, int length, long tag) {
int left = 0;
int step, curr;
while (length > 0) {
step = length / 2;
curr = left + step;
if (ray[curr].tag <= tag) {
left = curr + 1;
length -= step + 1;
} else {
length = step;
}
}
return left;
}
public void queryAABB(ParticleQueryCallback callback, final AABB aabb) {
if (m_proxyCount == 0) {
return;
}
final float lowerBoundX = aabb.lowerBound.x;
final float lowerBoundY = aabb.lowerBound.y;
final float upperBoundX = aabb.upperBound.x;
final float upperBoundY = aabb.upperBound.y;
int firstProxy =
lowerBound(m_proxyBuffer, m_proxyCount,
computeTag(m_inverseDiameter * lowerBoundX, m_inverseDiameter * lowerBoundY));
int lastProxy =
upperBound(m_proxyBuffer, m_proxyCount,
computeTag(m_inverseDiameter * upperBoundX, m_inverseDiameter * upperBoundY));
for (int proxy = firstProxy; proxy < lastProxy; ++proxy) {
int i = m_proxyBuffer[proxy].index;
final Vec2 p = m_positionBuffer.data[i];
if (lowerBoundX < p.x && p.x < upperBoundX && lowerBoundY < p.y && p.y < upperBoundY) {
if (!callback.reportParticle(i)) {
break;
}
}
}
}
/**
* @param callback
* @param point1
* @param point2
*/
public void raycast(ParticleRaycastCallback callback, final Vec2 point1, final Vec2 point2) {
if (m_proxyCount == 0) {
return;
}
int firstProxy =
lowerBound(
m_proxyBuffer,
m_proxyCount,
computeTag(m_inverseDiameter * MathUtils.min(point1.x, point2.x) - 1, m_inverseDiameter
* MathUtils.min(point1.y, point2.y) - 1));
int lastProxy =
upperBound(
m_proxyBuffer,
m_proxyCount,
computeTag(m_inverseDiameter * MathUtils.max(point1.x, point2.x) + 1, m_inverseDiameter
* MathUtils.max(point1.y, point2.y) + 1));
float fraction = 1;
// solving the following equation:
// ((1-t)*point1+t*point2-position)^2=diameter^2
// where t is a potential fraction
final float vx = point2.x - point1.x;
final float vy = point2.y - point1.y;
float v2 = vx * vx + vy * vy;
if (v2 == 0) v2 = Float.MAX_VALUE;
for (int proxy = firstProxy; proxy < lastProxy; ++proxy) {
int i = m_proxyBuffer[proxy].index;
final Vec2 posI = m_positionBuffer.data[i];
final float px = point1.x - posI.x;
final float py = point1.y - posI.y;
float pv = px * vx + py * vy;
float p2 = px * px + py * py;
float determinant = pv * pv - v2 * (p2 - m_squaredDiameter);
if (determinant >= 0) {
float sqrtDeterminant = MathUtils.sqrt(determinant);
// find a solution between 0 and fraction
float t = (-pv - sqrtDeterminant) / v2;
if (t > fraction) {
continue;
}
if (t < 0) {
t = (-pv + sqrtDeterminant) / v2;
if (t < 0 || t > fraction) {
continue;
}
}
final Vec2 n = tempVec;
tempVec.x = px + t * vx;
tempVec.y = py + t * vy;
n.normalize();
final Vec2 point = tempVec2;
point.x = point1.x + t * vx;
point.y = point1.y + t * vy;
float f = callback.reportParticle(i, point, n, t);
fraction = MathUtils.min(fraction, f);
if (fraction <= 0) {
break;
}
}
}
}
public float computeParticleCollisionEnergy() {
float sum_v2 = 0;
for (int k = 0; k < m_contactCount; k++) {
final ParticleContact contact = m_contactBuffer[k];
int a = contact.indexA;
int b = contact.indexB;
Vec2 n = contact.normal;
final Vec2 va = m_velocityBuffer.data[a];
final Vec2 vb = m_velocityBuffer.data[b];
final float vx = vb.x - va.x;
final float vy = vb.y - va.y;
float vn = vx * n.x + vy * n.y;
if (vn < 0) {
sum_v2 += vn * vn;
}
}
return 0.5f * getParticleMass() * sum_v2;
}
// reallocate a buffer
static <T> T[] reallocateBuffer(ParticleBuffer<T> buffer, int oldCapacity, int newCapacity,
boolean deferred) {
assert (newCapacity > oldCapacity);
return BufferUtils.reallocateBuffer(buffer.dataClass, buffer.data, buffer.userSuppliedCapacity,
oldCapacity, newCapacity, deferred);
}
static int[] reallocateBuffer(ParticleBufferInt buffer, int oldCapacity, int newCapacity,
boolean deferred) {
assert (newCapacity > oldCapacity);
return BufferUtils.reallocateBuffer(buffer.data, buffer.userSuppliedCapacity, oldCapacity,
newCapacity, deferred);
}
@SuppressWarnings("unchecked")
<T> T[] requestParticleBuffer(Class<T> klass, T[] buffer) {
if (buffer == null) {
buffer = (T[]) Array.newInstance(klass, m_internalAllocatedCapacity);
for (int i = 0; i < m_internalAllocatedCapacity; i++) {
try {
buffer[i] = klass.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
return buffer;
}
float[] requestParticleBuffer(float[] buffer) {
if (buffer == null) {
buffer = new float[m_internalAllocatedCapacity];
}
return buffer;
}
public static class ParticleBuffer<T> {
public T[] data;
final Class<T> dataClass;
int userSuppliedCapacity;
public ParticleBuffer(Class<T> dataClass) {
this.dataClass = dataClass;
}
}
static class ParticleBufferInt {
int[] data;
int userSuppliedCapacity;
}
/** Used for detecting particle contacts */
public static class Proxy implements Comparable<Proxy> {
int index;
long tag;
@Override
public int compareTo(Proxy o) {
return (tag - o.tag) < 0 ? -1 : (o.tag == tag ? 0 : 1);
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
Proxy other = (Proxy) obj;
if (tag != other.tag) return false;
return true;
}
}
/** Connection between two particles */
public static class Pair {
int indexA, indexB;
int flags;
float strength;
float distance;
}
/** Connection between three particles */
public static class Triad {
int indexA, indexB, indexC;
int flags;
float strength;
final Vec2 pa = new Vec2(), pb = new Vec2(), pc = new Vec2();
float ka, kb, kc, s;
}
// Callback used with VoronoiDiagram.
static class CreateParticleGroupCallback implements VoronoiDiagramCallback {
public void callback(int a, int b, int c) {
final Vec2 pa = system.m_positionBuffer.data[a];
final Vec2 pb = system.m_positionBuffer.data[b];
final Vec2 pc = system.m_positionBuffer.data[c];
final float dabx = pa.x - pb.x;
final float daby = pa.y - pb.y;
final float dbcx = pb.x - pc.x;
final float dbcy = pb.y - pc.y;
final float dcax = pc.x - pa.x;
final float dcay = pc.y - pa.y;
float maxDistanceSquared = Settings.maxTriadDistanceSquared * system.m_squaredDiameter;
if (dabx * dabx + daby * daby < maxDistanceSquared
&& dbcx * dbcx + dbcy * dbcy < maxDistanceSquared
&& dcax * dcax + dcay * dcay < maxDistanceSquared) {
if (system.m_triadCount >= system.m_triadCapacity) {
int oldCapacity = system.m_triadCapacity;
int newCapacity =
system.m_triadCount != 0
? 2 * system.m_triadCount
: Settings.minParticleBufferCapacity;
system.m_triadBuffer =
BufferUtils.reallocateBuffer(Triad.class, system.m_triadBuffer, oldCapacity,
newCapacity);
system.m_triadCapacity = newCapacity;
}
Triad triad = system.m_triadBuffer[system.m_triadCount];
triad.indexA = a;
triad.indexB = b;
triad.indexC = c;
triad.flags =
system.m_flagsBuffer.data[a] | system.m_flagsBuffer.data[b]
| system.m_flagsBuffer.data[c];
triad.strength = def.strength;
final float midPointx = (float) 1 / 3 * (pa.x + pb.x + pc.x);
final float midPointy = (float) 1 / 3 * (pa.y + pb.y + pc.y);
triad.pa.x = pa.x - midPointx;
triad.pa.y = pa.y - midPointy;
triad.pb.x = pb.x - midPointx;
triad.pb.y = pb.y - midPointy;
triad.pc.x = pc.x - midPointx;
triad.pc.y = pc.y - midPointy;
triad.ka = -(dcax * dabx + dcay * daby);
triad.kb = -(dabx * dbcx + daby * dbcy);
triad.kc = -(dbcx * dcax + dbcy * dcay);
triad.s = Vec2.cross(pa, pb) + Vec2.cross(pb, pc) + Vec2.cross(pc, pa);
system.m_triadCount++;
}
}
ParticleSystem system;
ParticleGroupDef def; // pointer
int firstIndex;
}
// Callback used with VoronoiDiagram.
static class JoinParticleGroupsCallback implements VoronoiDiagramCallback {
public void callback(int a, int b, int c) {
// Create a triad if it will contain particles from both groups.
int countA =
((a < groupB.m_firstIndex) ? 1 : 0) + ((b < groupB.m_firstIndex) ? 1 : 0)
+ ((c < groupB.m_firstIndex) ? 1 : 0);
if (countA > 0 && countA < 3) {
int af = system.m_flagsBuffer.data[a];
int bf = system.m_flagsBuffer.data[b];
int cf = system.m_flagsBuffer.data[c];
if ((af & bf & cf & k_triadFlags) != 0) {
final Vec2 pa = system.m_positionBuffer.data[a];
final Vec2 pb = system.m_positionBuffer.data[b];
final Vec2 pc = system.m_positionBuffer.data[c];
final float dabx = pa.x - pb.x;
final float daby = pa.y - pb.y;
final float dbcx = pb.x - pc.x;
final float dbcy = pb.y - pc.y;
final float dcax = pc.x - pa.x;
final float dcay = pc.y - pa.y;
float maxDistanceSquared = Settings.maxTriadDistanceSquared * system.m_squaredDiameter;
if (dabx * dabx + daby * daby < maxDistanceSquared
&& dbcx * dbcx + dbcy * dbcy < maxDistanceSquared
&& dcax * dcax + dcay * dcay < maxDistanceSquared) {
if (system.m_triadCount >= system.m_triadCapacity) {
int oldCapacity = system.m_triadCapacity;
int newCapacity =
system.m_triadCount != 0
? 2 * system.m_triadCount
: Settings.minParticleBufferCapacity;
system.m_triadBuffer =
BufferUtils.reallocateBuffer(Triad.class, system.m_triadBuffer, oldCapacity,
newCapacity);
system.m_triadCapacity = newCapacity;
}
Triad triad = system.m_triadBuffer[system.m_triadCount];
triad.indexA = a;
triad.indexB = b;
triad.indexC = c;
triad.flags = af | bf | cf;
triad.strength = MathUtils.min(groupA.m_strength, groupB.m_strength);
final float midPointx = (float) 1 / 3 * (pa.x + pb.x + pc.x);
final float midPointy = (float) 1 / 3 * (pa.y + pb.y + pc.y);
triad.pa.x = pa.x - midPointx;
triad.pa.y = pa.y - midPointy;
triad.pb.x = pb.x - midPointx;
triad.pb.y = pb.y - midPointy;
triad.pc.x = pc.x - midPointx;
triad.pc.y = pc.y - midPointy;
triad.ka = -(dcax * dabx + dcay * daby);
triad.kb = -(dabx * dbcx + daby * dbcy);
triad.kc = -(dbcx * dcax + dbcy * dcay);
triad.s = Vec2.cross(pa, pb) + Vec2.cross(pb, pc) + Vec2.cross(pc, pa);
system.m_triadCount++;
}
}
}
}
ParticleSystem system;
ParticleGroup groupA;
ParticleGroup groupB;
};
static class DestroyParticlesInShapeCallback implements ParticleQueryCallback {
ParticleSystem system;
Shape shape;
Transform xf;
boolean callDestructionListener;
int destroyed;
public DestroyParticlesInShapeCallback() {
// TODO Auto-generated constructor stub
}
public void init(ParticleSystem system, Shape shape, Transform xf,
boolean callDestructionListener) {
this.system = system;
this.shape = shape;
this.xf = xf;
this.destroyed = 0;
this.callDestructionListener = callDestructionListener;
}
@Override
public boolean reportParticle(int index) {
assert (index >= 0 && index < system.m_count);
if (shape.testPoint(xf, system.m_positionBuffer.data[index])) {
system.destroyParticle(index, callDestructionListener);
destroyed++;
}
return true;
}
}
static class UpdateBodyContactsCallback implements QueryCallback {
ParticleSystem system;
private final Vec2 tempVec = new Vec2();
@Override
public boolean reportFixture(Fixture fixture) {
if (fixture.isSensor()) {
return true;
}
final Shape shape = fixture.getShape();
Body b = fixture.getBody();
Vec2 bp = b.getWorldCenter();
float bm = b.getMass();
float bI = b.getInertia() - bm * b.getLocalCenter().lengthSquared();
float invBm = bm > 0 ? 1 / bm : 0;
float invBI = bI > 0 ? 1 / bI : 0;
int childCount = shape.getChildCount();
for (int childIndex = 0; childIndex < childCount; childIndex++) {
AABB aabb = fixture.getAABB(childIndex);
final float aabblowerBoundx = aabb.lowerBound.x - system.m_particleDiameter;
final float aabblowerBoundy = aabb.lowerBound.y - system.m_particleDiameter;
final float aabbupperBoundx = aabb.upperBound.x + system.m_particleDiameter;
final float aabbupperBoundy = aabb.upperBound.y + system.m_particleDiameter;
int firstProxy =
lowerBound(
system.m_proxyBuffer,
system.m_proxyCount,
computeTag(system.m_inverseDiameter * aabblowerBoundx, system.m_inverseDiameter
* aabblowerBoundy));
int lastProxy =
upperBound(
system.m_proxyBuffer,
system.m_proxyCount,
computeTag(system.m_inverseDiameter * aabbupperBoundx, system.m_inverseDiameter
* aabbupperBoundy));
for (int proxy = firstProxy; proxy != lastProxy; ++proxy) {
int a = system.m_proxyBuffer[proxy].index;
Vec2 ap = system.m_positionBuffer.data[a];
if (aabblowerBoundx <= ap.x && ap.x <= aabbupperBoundx && aabblowerBoundy <= ap.y
&& ap.y <= aabbupperBoundy) {
float d;
final Vec2 n = tempVec;
d = fixture.computeDistance(ap, childIndex, n);
if (d < system.m_particleDiameter) {
float invAm =
(system.m_flagsBuffer.data[a] & ParticleType.b2_wallParticle) != 0 ? 0 : system
.getParticleInvMass();
final float rpx = ap.x - bp.x;
final float rpy = ap.y - bp.y;
float rpn = rpx * n.y - rpy * n.x;
if (system.m_bodyContactCount >= system.m_bodyContactCapacity) {
int oldCapacity = system.m_bodyContactCapacity;
int newCapacity =
system.m_bodyContactCount != 0
? 2 * system.m_bodyContactCount
: Settings.minParticleBufferCapacity;
system.m_bodyContactBuffer =
BufferUtils.reallocateBuffer(ParticleBodyContact.class,
system.m_bodyContactBuffer, oldCapacity, newCapacity);
system.m_bodyContactCapacity = newCapacity;
}
ParticleBodyContact contact = system.m_bodyContactBuffer[system.m_bodyContactCount];
contact.index = a;
contact.body = b;
contact.weight = 1 - d * system.m_inverseDiameter;
contact.normal.x = -n.x;
contact.normal.y = -n.y;
contact.mass = 1 / (invAm + invBm + invBI * rpn * rpn);
system.m_bodyContactCount++;
}
}
}
}
return true;
}
}
static class SolveCollisionCallback implements QueryCallback {
ParticleSystem system;
TimeStep step;
private final RayCastInput input = new RayCastInput();
private final RayCastOutput output = new RayCastOutput();
private final Vec2 tempVec = new Vec2();
private final Vec2 tempVec2 = new Vec2();
@Override
public boolean reportFixture(Fixture fixture) {
if (fixture.isSensor()) {
return true;
}
final Shape shape = fixture.getShape();
Body body = fixture.getBody();
int childCount = shape.getChildCount();
for (int childIndex = 0; childIndex < childCount; childIndex++) {
AABB aabb = fixture.getAABB(childIndex);
final float aabblowerBoundx = aabb.lowerBound.x - system.m_particleDiameter;
final float aabblowerBoundy = aabb.lowerBound.y - system.m_particleDiameter;
final float aabbupperBoundx = aabb.upperBound.x + system.m_particleDiameter;
final float aabbupperBoundy = aabb.upperBound.y + system.m_particleDiameter;
int firstProxy =
lowerBound(
system.m_proxyBuffer,
system.m_proxyCount,
computeTag(system.m_inverseDiameter * aabblowerBoundx, system.m_inverseDiameter
* aabblowerBoundy));
int lastProxy =
upperBound(
system.m_proxyBuffer,
system.m_proxyCount,
computeTag(system.m_inverseDiameter * aabbupperBoundx, system.m_inverseDiameter
* aabbupperBoundy));
for (int proxy = firstProxy; proxy != lastProxy; ++proxy) {
int a = system.m_proxyBuffer[proxy].index;
Vec2 ap = system.m_positionBuffer.data[a];
if (aabblowerBoundx <= ap.x && ap.x <= aabbupperBoundx && aabblowerBoundy <= ap.y
&& ap.y <= aabbupperBoundy) {
Vec2 av = system.m_velocityBuffer.data[a];
final Vec2 temp = tempVec;
Transform.mulTransToOutUnsafe(body.m_xf0, ap, temp);
Transform.mulToOutUnsafe(body.m_xf, temp, input.p1);
input.p2.x = ap.x + step.dt * av.x;
input.p2.y = ap.y + step.dt * av.y;
input.maxFraction = 1;
if (fixture.raycast(output, input, childIndex)) {
final Vec2 p = tempVec;
p.x =
(1 - output.fraction) * input.p1.x + output.fraction * input.p2.x
+ Settings.linearSlop * output.normal.x;
p.y =
(1 - output.fraction) * input.p1.y + output.fraction * input.p2.y
+ Settings.linearSlop * output.normal.y;
final float vx = step.inv_dt * (p.x - ap.x);
final float vy = step.inv_dt * (p.y - ap.y);
av.x = vx;
av.y = vy;
final float particleMass = system.getParticleMass();
final float ax = particleMass * (av.x - vx);
final float ay = particleMass * (av.y - vy);
Vec2 b = output.normal;
final float fdn = ax * b.x + ay * b.y;
final Vec2 f = tempVec2;
f.x = fdn * b.x;
f.y = fdn * b.y;
body.applyLinearImpulse(f, p, true);
}
}
}
}
return true;
}
}
static class Test {
static boolean IsProxyInvalid(final Proxy proxy) {
return proxy.index < 0;
}
static boolean IsContactInvalid(final ParticleContact contact) {
return contact.indexA < 0 || contact.indexB < 0;
}
static boolean IsBodyContactInvalid(final ParticleBodyContact contact) {
return contact.index < 0;
}
static boolean IsPairInvalid(final Pair pair) {
return pair.indexA < 0 || pair.indexB < 0;
}
static boolean IsTriadInvalid(final Triad triad) {
return triad.indexA < 0 || triad.indexB < 0 || triad.indexC < 0;
}
};
}