/// <summary>
/// Update given particle over passed time interval, in seconds.
/// </summary>
/// <param name="particle">Particle to integrate.</param>
/// <param name="dt">Amount to advance time, in seconds.</param>
public void IntegrateParticle(ref T2DParticle particle, float dt)
{
// Increase particle age.
particle.Age += dt;
// Calculate Particle unit-age.
float unitAge = particle.Age / particle.Lifetime;
// **********************************************************************************************************************
// Scale Speed.
// **********************************************************************************************************************
float renderSpeed = particle._speed * _emitterData.SpeedLife[unitAge];
// **********************************************************************************************************************
// Scale Fixed-Force.
// **********************************************************************************************************************
float renderFixedForce = particle._fixedForce * _emitterData.FixedForceLife[unitAge];
// **********************************************************************************************************************
// Scale Random-Motion.
// **********************************************************************************************************************
float renderRandomMotion = particle._randomMotion * _emitterData.RandomMotionLife[unitAge];
// **********************************************************************************************************************
// Calculate New Velocity...
// **********************************************************************************************************************
// Is random motion non-zero?
if (Epsilon.FloatIsNotZero(renderRandomMotion))
{
// Yes, so fetch half random motion.
float randomMotion = renderRandomMotion * 0.5f;
// Add integrated random motion into velocity.
particle._velocity.X += TorqueUtil.GetFastRandomFloat(-randomMotion, randomMotion) * dt;
particle._velocity.Y += TorqueUtil.GetFastRandomFloat(-randomMotion, randomMotion) * dt;
}
Vector2 outVel;
// Add integrated fixed force into velocity.
//particle._velocity += _emitterData.FixedForceDirection * renderFixedForce * dt;
Vector2 dir = _emitterData.FixedForceDirection;
Vector2.Multiply(ref dir, renderFixedForce * dt, out outVel);
Vector2.Add(ref outVel, ref particle._velocity, out particle._velocity);
// Adjust particle position.
//particle._position += particle._velocity * renderSpeed * dt;
Vector2.Multiply(ref particle._velocity, renderSpeed * dt, out outVel);
Vector2.Add(ref outVel, ref particle._position, out particle._position);
// **********************************************************************************************************************
// Aligning to motion.
// **********************************************************************************************************************
// Are we aligning to motion?
if (_emitterData.ParticleOrientation == T2DParticleEmitterData.ParticleOrientationMode.Aligned)
{
// Yes, so calculate last movement direction.
float movementAngle = T2DVectorUtil.AngleFromVector(particle._velocity);
// Set new Orientation Angle.
particle._rotationAngle = movementAngle + _emitterData.OrientationAngleOffset;
}
else
{
// Calculate render spin.
float renderSpin = particle._spin * _emitterData.SpinLife[unitAge];
// Have we got some spin?
if (Epsilon.FloatIsNotZero(renderSpin))
{
// Yes, so add integrated spin into orientation.
particle._rotationAngle += renderSpin * dt;
// Keep within bounds.
particle._rotationAngle %= 360.0f;
}
}
// **********************************************************************************************************************
// Update emitter clip boundary
// **********************************************************************************************************************
//Vector2 renderSize = particle._size * _maxParticleSize;
Vector2 renderSize;
Vector2.Multiply(ref particle._size, ref _maxParticleSize, out renderSize);
Vector2 center = particle._position;
// compute upper bound for maximum extent from center
float radius = renderSize.X + renderSize.Y;
radius += Math.Abs(_emitterData.ParticlePivotPoint.X) * _maxParticleSize.X;
radius += Math.Abs(_emitterData.ParticlePivotPoint.Y) * _maxParticleSize.Y;
if (center.X - radius < _particleExtentTopLeft.X)
_particleExtentTopLeft.X = center.X - radius;
if (center.X + radius > _particleExtentBottomRight.X)
_particleExtentBottomRight.X = center.X + radius;
if (center.Y - radius < _particleExtentTopLeft.Y)
_particleExtentTopLeft.Y = center.Y - radius;
if (center.Y + radius > _particleExtentBottomRight.Y)
_particleExtentBottomRight.Y = center.Y + radius;
}
/// <summary>
/// Initialize given particle.
/// </summary>
/// <param name="particle">Particle to initialize.</param>
public void InitializeParticle(ref T2DParticle particle)
{
// Fetch Effect Age.
float effectAge = _parentEffect.Age;
// Fetch Effect Position.
Vector2 effectPosition = _parentEffect.Position;
// Fetch Parent Effect Effect-Data.
T2DParticleEffectData parentEffectData = _parentEffect.CurrentEffectData;
// **********************************************************************************************************************
// Calculate Particle Position...
// **********************************************************************************************************************
// Single Particle?
if (_emitterData.SingleParticle)
{
// Yes, so are we using effect position?
if (_emitterData.AttachPositionToEmitter)
{
// Yes, so set position.
particle.Position = Vector2.Zero;
}
else
{
// No, so use effect position.
particle.Position = effectPosition;
}
}
else
{
// No, so select emitter type.
switch (_emitterData.EmitterArea)
{
// Point.
case T2DParticleEmitterData.EmitterAreaType.Point:
{
// Set Particle position.
particle.Position = Vector2.Zero;
} break;
// LineX.
case T2DParticleEmitterData.EmitterAreaType.LineX:
{
// Calculate Area Size X.
float areaSizeX = 0.5f * TorqueUtil.GetFastRandomFloat(0.0f, _parentEffect.Size.X);
// Calculate Sign.
if ((TorqueUtil.GetFastRandomInt() & 1) == 0)
{
areaSizeX = -areaSizeX;
}
// Choose particle location.
particle.PositionX = areaSizeX;
particle.PositionY = 0.0f;
} break;
// LineY.
case T2DParticleEmitterData.EmitterAreaType.LineY:
{
// Calculate Area Size Y.
float areaSizeY = 0.5f * TorqueUtil.GetFastRandomFloat(0.0f, _parentEffect.Size.Y);
// Calculate Sign.
if ((TorqueUtil.GetFastRandomInt() & 1) == 0)
{
areaSizeY = -areaSizeY;
}
// Choose particle location.
particle.PositionX = 0.0f;
particle.PositionY = 0.0f + areaSizeY;
} break;
// Rectangle.
case T2DParticleEmitterData.EmitterAreaType.Rectangle:
{
// Calculate Min/Max Area Size X.
float minAreaSizeX = 0.0f;
float maxAreaSizeX = 0.5f * _parentEffect.Size.X;
// Inline Clamp.
if (maxAreaSizeX < minAreaSizeX)
{
maxAreaSizeX = minAreaSizeX;
}
// Choose Random Area.
float areaSizeX = TorqueUtil.GetFastRandomFloat(maxAreaSizeX);
// Assume Fixed Area Aspect.
float minAreaSizeY;
float maxAreaSizeY;
float areaSizeY;
if (_emitterData.FixedAreaAspect)
{
// Yes, so calculate Min/Max Area Size Y (using X).
minAreaSizeY = minAreaSizeX;
maxAreaSizeY = maxAreaSizeX;
}
else
{
// No, so calculate Area Size Y.
minAreaSizeY = 0.0f;
maxAreaSizeY = 0.5f * _parentEffect.Size.Y;
}
// Inline Clamp.
if (maxAreaSizeY < minAreaSizeY)
{
maxAreaSizeY = minAreaSizeY;
}
// Choose Random Area.
areaSizeY = TorqueUtil.GetFastRandomFloat(maxAreaSizeY);
// Inner Region X?
if (areaSizeX < minAreaSizeX && areaSizeY < minAreaSizeY)
{
// Yes, so randomize within outer region.
areaSizeX = minAreaSizeX + (areaSizeX % Math.Abs(maxAreaSizeX - minAreaSizeX + Epsilon.Value));
}
// Inner Region Y?
if (areaSizeY < minAreaSizeY && areaSizeX < minAreaSizeX)
{
// Yes, so randomize within outer region.
areaSizeY = minAreaSizeY + (areaSizeY % Math.Abs(maxAreaSizeY - minAreaSizeY + Epsilon.Value));
}
// Calculate Sign.
int areaFlip = TorqueUtil.GetFastRandomInt();
if ((areaFlip & 1) == 0)
{
areaSizeX = -areaSizeX;
}
// Calculate Sign.
if ((areaFlip & 2) == 0)
{
areaSizeY = -areaSizeY;
}
// Choose particle location.
particle.PositionX = areaSizeX;
particle.PositionY = areaSizeY;
} break;
}
// Attach position to emitter?
if (!_emitterData.AttachPositionToEmitter)
{
// No, so attach rotation to emitter?
if (!_emitterData.AttachRotationToEmitter)
{
// No, so we need to fully transform in non-scaled effect world-space.
particle.Position = Vector2.Transform(particle.Position, _parentEffect.EffectRotationTranslationMatrix);
}
else
{
// Yes, so we need to transform in non-scaled, non-rotated effect world-space.
particle.Position = Vector2.Transform(particle.Position, _parentEffect.EffectTranslationMatrix);
}
}
}
// **********************************************************************************************************************
// Calculate Particle Lifetime.
// **********************************************************************************************************************
// Reset Age.
particle.Age = 0.0f;
// Calculate Lifetime.
particle.Lifetime = T2DKeyGraph.CalcGraphBVE(_emitterData.ParticleLifeBase, _emitterData.ParticleLifeVariation, parentEffectData.ParticleLifeScale, effectAge);
if (particle.Lifetime < Epsilon.Value)
particle.Lifetime = Epsilon.Value;
// **********************************************************************************************************************
// Calculate Particle Size.
// **********************************************************************************************************************
// Calculate SizeX.
particle.SizeX = T2DKeyGraph.CalcGraphBVE(_emitterData.SizeXBase, _emitterData.SizeXVariation, parentEffectData.SizeXScale, effectAge);
particle.SizeY = _emitterData.FixedParticleAspect ? particle.SizeX : T2DKeyGraph.CalcGraphBVE(_emitterData.SizeYBase, _emitterData.SizeYVariation, parentEffectData.SizeYScale, effectAge);
Assert.Fatal(particle.SizeX > 0.0f && particle.SizeY > 0.0f, "Zero or negative size particles not recommended.");
// **********************************************************************************************************************
// Calculate Speed, Fixed-Force, Random Motion
// **********************************************************************************************************************
if (_emitterData.SingleParticle)
{
particle.Speed = 0.0f;
particle.FixedForce = 0.0f;
particle.RandomMotion = 0.0f;
}
else
{
particle.Speed = T2DKeyGraph.CalcGraphBVE(_emitterData.SpeedBase, _emitterData.SpeedVariation, parentEffectData.SpeedScale, effectAge);
particle.FixedForce = T2DKeyGraph.CalcGraphBVE(_emitterData.FixedForceBase, _emitterData.FixedForceVariation, parentEffectData.FixedForceScale, effectAge);
particle.RandomMotion = T2DKeyGraph.CalcGraphBVE(_emitterData.RandomMotionBase, _emitterData.RandomMotionVariation, parentEffectData.RandomMotionScale, effectAge);
}
// **********************************************************************************************************************
// Calculate Spin.
// **********************************************************************************************************************
particle.Spin = T2DKeyGraph.CalcGraphBVE(_emitterData.SpinBase, _emitterData.SpinVariation, parentEffectData.SpinScale, effectAge);
// **********************************************************************************************************************
// Calculate Emission Angle.
// **********************************************************************************************************************
float emissionForce = 0.0f;
float emissionAngle = 0.0f;
float emissionArc = 0.0f;
// Ignore if we're using Single Particle.
if (!_emitterData.SingleParticle)
{
// Are we using effect emission?
if (_emitterData.UseEffectEmission)
{
// Yes, so calculate emission from effect.
emissionForce = -T2DKeyGraph.CalcGraphBV(parentEffectData.EmissionForceBase, parentEffectData.EmissionForceVariation, effectAge);
emissionAngle = T2DKeyGraph.CalcGraphBV(parentEffectData.EmissionAngleBase, parentEffectData.EmissionAngleVariation, effectAge);
// NOTE:- We're only interested in half the emission arc!
emissionArc = T2DKeyGraph.CalcGraphBV(parentEffectData.EmissionArcBase, parentEffectData.EmissionArcVariation, effectAge) * 0.5f;
}
else
{
// No, so calculate emission from emitter.
emissionForce = T2DKeyGraph.CalcGraphBV(_emitterData.EmissionForceBase, _emitterData.EmissionForceVariation, effectAge);
// No, so calculate standard emission angle.
emissionAngle = T2DKeyGraph.CalcGraphBV(_emitterData.EmissionAngleBase, _emitterData.EmissionAngleVariation, effectAge);
// Calculate Emission Arc.
// NOTE:- We're only interested in half the emission arc!
emissionArc = T2DKeyGraph.CalcGraphBV(_emitterData.EmissionArcBase, _emitterData.EmissionArcVariation, effectAge) * 0.5f;
}
// Is the emission rotation linked?
if (_emitterData.LinkEmissionRotation)
{
// Yes, so add effect rotation onto emission angle.
emissionAngle += _parentEffect.Rotation;
}
// Calculate final emission angle by choosing random arc.
emissionAngle = TorqueUtil.GetFastRandomFloat(emissionAngle - emissionArc, emissionAngle + emissionArc) % 360.0f;
float emissionAngleRad = MathHelper.ToRadians(emissionAngle);
particle.VelocityX = emissionForce * (float)Math.Sin(emissionAngleRad);
particle.VelocityY = emissionForce * (float)-Math.Cos(emissionAngleRad);
}
// **********************************************************************************************************************
// Calculate Orientation Angle.
// **********************************************************************************************************************
switch (_emitterData.ParticleOrientation)
{
// Aligned.
case T2DParticleEmitterData.ParticleOrientationMode.Aligned:
{
// Use the emission angle plus offset.
particle.RotationAngle = (emissionAngle + _emitterData.OrientationAngleOffset) % 360.0f;
} break;
// Fixed.
case T2DParticleEmitterData.ParticleOrientationMode.Fixed:
{
// Use fixed angle.
particle.RotationAngle = _emitterData.OrientationAngleOffset % 360.0f;
} break;
// Random.
case T2DParticleEmitterData.ParticleOrientationMode.Random:
{
float halfRandomArc = _emitterData.OrientationRandomArc * 0.5f;
// Use the emission angle plus offset.
particle.RotationAngle = TorqueUtil.GetFastRandomFloat(_emitterData.OrientationAngleOffset - halfRandomArc, _emitterData.OrientationAngleOffset + halfRandomArc) % 360.0f;
} break;
}
}