/// <summary>
/// Orientates the Particle to face the camera, but constrains the particle to always be perpendicular to the
/// X-Y plane.
/// </summary>
/// <param name="cParticle">The Particle to update.</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update.</param>
protected void UpdateParticleToBeConstrainedAroundZAxis(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
Vector3 newNormal = CameraPosition - cParticle.Position;
newNormal.Z = 0;
cParticle.Normal = newNormal;
}
//===========================================================
// Vertex Update and Overridden Particle System Functions
//===========================================================
/// <summary>
/// Function to update the Vertex properties according to the Particle properties
/// </summary>
/// <param name="sVertexBuffer">The array containing the Vertices to be drawn</param>
/// <param name="iIndex">The Index in the array where the Particle's Vertex info should be placed</param>
/// <param name="Particle">The Particle to copy the information from</param>
protected virtual void UpdateVertexProperties(ref DefaultQuadParticleVertex[] sVertexBuffer, int iIndex, DPSFParticle Particle)
{
// Cast the Particle to the type it really is
DefaultQuadParticle cParticle = (DefaultQuadParticle)Particle;
// Calculate what half of the Quads Width and Height are
float fHalfWidth = cParticle.Width / 2.0f;
float fHalfHeight = cParticle.Height / 2.0f;
// Calculate the Positions of the Quads corners around the origin
Vector3 sTopLeft = new Vector3(-fHalfWidth, -fHalfHeight, 0);
Vector3 sTopRight = new Vector3(fHalfWidth, -fHalfHeight, 0);
Vector3 sBottomLeft = new Vector3(-fHalfWidth, fHalfHeight, 0);
Vector3 sBottomRight = new Vector3(fHalfWidth, fHalfHeight, 0);
// Rotate the Quad corners around the origin according to its Orientation,
// then calculate their final Positions
sTopLeft = Vector3.Transform(sTopLeft, cParticle.Orientation) + cParticle.Position;
sTopRight = Vector3.Transform(sTopRight, cParticle.Orientation) + cParticle.Position;
sBottomLeft = Vector3.Transform(sBottomLeft, cParticle.Orientation) + cParticle.Position;
sBottomRight = Vector3.Transform(sBottomRight, cParticle.Orientation) + cParticle.Position;
// Copy this Particle's renderable Properties to the Vertex Buffer
// This is a Quad so we must copy all 4 Vertices over
sVertexBuffer[iIndex].Position = sBottomLeft;
sVertexBuffer[iIndex].Color = cParticle.Color;
sVertexBuffer[iIndex + 1].Position = sTopLeft;
sVertexBuffer[iIndex + 1].Color = cParticle.Color;
sVertexBuffer[iIndex + 2].Position = sBottomRight;
sVertexBuffer[iIndex + 2].Color = cParticle.Color;
sVertexBuffer[iIndex + 3].Position = sTopRight;
sVertexBuffer[iIndex + 3].Color = cParticle.Color;
// Fill in the Index Buffer for the newly added Vertices.
// Specify the Vertices in Clockwise order.
// It takes 6 Indices to represent a quad (2 triangles = 6 corners).
// If we're using the HiDef profile, fill in the regular Index Buffer.
if (this.GraphicsDevice.GraphicsProfile == GraphicsProfile.HiDef)
{
IndexBuffer[IndexBufferIndex++] = iIndex + 1;
IndexBuffer[IndexBufferIndex++] = iIndex + 2;
IndexBuffer[IndexBufferIndex++] = iIndex;
IndexBuffer[IndexBufferIndex++] = iIndex + 1;
IndexBuffer[IndexBufferIndex++] = iIndex + 3;
IndexBuffer[IndexBufferIndex++] = iIndex + 2;
}
// Else we're using the Reach profile, so fill the Reach Index Buffer instead.
else
{
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex + 1);
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex + 2);
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex);
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex + 1);
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex + 3);
IndexBufferReach[IndexBufferIndex++] = (short)(iIndex + 2);
}
}
/// <summary>
/// Update a Particle's Rotational Velocity according to its Rotational Acceleration
/// </summary>
/// <param name="cParticle">The Particle to update</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update</param>
protected void UpdateParticleRotationalVelocityUsingRotationalAcceleration(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
// If Rotational Acceleration is being used
if (cParticle.RotationalAcceleration != Vector3.Zero)
{
// Update the Particle's Rotational Velocity according to its Rotational Acceleration
cParticle.RotationalVelocity += cParticle.RotationalAcceleration * fElapsedTimeInSeconds;
}
}
//===========================================================
// Initialization Function
//===========================================================
/// <summary>
/// Function to Initialize a Default Particle with default settings
/// </summary>
/// <param name="Particle">The Particle to be Initialized</param>
public override void InitializeParticleUsingInitialProperties(DPSFParticle Particle)
{
// Cast the Particle to the type it really is
DefaultQuadParticle cParticle = (DefaultQuadParticle)Particle;
// Initialize the Particle according to the values specified in the Initial Settings
base.InitializeParticleUsingInitialProperties(cParticle, mcInitialProperties);
// If the Rotation should be interpolated between the Min and Max Rotation
if (mcInitialProperties.InterpolateBetweenMinAndMaxRotation)
{
// Calculate the Particle's initial Rotational values
Vector3 sRotation = Vector3.Lerp(mcInitialProperties.RotationMin, mcInitialProperties.RotationMax, RandomNumber.NextFloat());
cParticle.Orientation = Quaternion.CreateFromYawPitchRoll(sRotation.Y, sRotation.X, sRotation.Z);
}
// Else the Rotation XYZ values should each be calculated individually
else
{
// Calculate the Particle's initial Rotational values
Vector3 sRotation = DPSFHelper.RandomVectorBetweenTwoVectors(mcInitialProperties.RotationMin, mcInitialProperties.RotationMax);
cParticle.Orientation = Quaternion.CreateFromYawPitchRoll(sRotation.Y, sRotation.X, sRotation.Z);
}
// If the Rotational Velocity should be interpolated between the Min and Max Rotational Velocities
if (mcInitialProperties.InterpolateBetweenMinAndMaxRotationalVelocity)
{
cParticle.RotationalVelocity = Vector3.Lerp(mcInitialProperties.RotationalVelocityMin, mcInitialProperties.RotationalVelocityMax, RandomNumber.NextFloat());
}
// Else the Rotational Velocity XYZ values should each be calculated individually
else
{
cParticle.RotationalVelocity = DPSFHelper.RandomVectorBetweenTwoVectors(mcInitialProperties.RotationalVelocityMin, mcInitialProperties.RotationalVelocityMax);
}
// If the Rotational Acceleration should be interpolated between the Min and Max Rotational Acceleration
if (mcInitialProperties.InterpolateBetweenMinAndMaxRotationalAcceleration)
{
cParticle.RotationalAcceleration = Vector3.Lerp(mcInitialProperties.RotationalAccelerationMin, mcInitialProperties.RotationalAccelerationMax, RandomNumber.NextFloat());
}
// Else the Rotational Acceleration XYZ values should each be calculated individually
else
{
cParticle.RotationalAcceleration = DPSFHelper.RandomVectorBetweenTwoVectors(mcInitialProperties.RotationalAccelerationMin, mcInitialProperties.RotationalAccelerationMax);
}
// Calculate the Particle's Width and Height values
cParticle.StartWidth = DPSFHelper.RandomNumberBetween(mcInitialProperties.StartSizeMin > 0 ? mcInitialProperties.StartSizeMin : mcInitialProperties.StartWidthMin, mcInitialProperties.StartSizeMax > 0 ? mcInitialProperties.StartSizeMax : mcInitialProperties.StartWidthMax);
cParticle.EndWidth = DPSFHelper.RandomNumberBetween(mcInitialProperties.EndSizeMin > 0 ? mcInitialProperties.EndSizeMin : mcInitialProperties.EndWidthMin, mcInitialProperties.EndSizeMax > 0 ? mcInitialProperties.EndSizeMax : mcInitialProperties.EndWidthMax);
cParticle.StartHeight = DPSFHelper.RandomNumberBetween(mcInitialProperties.StartSizeMin > 0 ? mcInitialProperties.StartSizeMin : mcInitialProperties.StartHeightMin, mcInitialProperties.StartSizeMax > 0 ? mcInitialProperties.StartSizeMax : mcInitialProperties.StartHeightMax);
cParticle.EndHeight = DPSFHelper.RandomNumberBetween(mcInitialProperties.EndSizeMin > 0 ? mcInitialProperties.EndSizeMin : mcInitialProperties.EndHeightMin, mcInitialProperties.EndSizeMax > 0 ? mcInitialProperties.EndSizeMax : mcInitialProperties.EndHeightMax);
cParticle.Width = cParticle.StartWidth;
cParticle.Height = cParticle.StartHeight;
}
//===========================================================
// Particle Update Functions
//===========================================================
/// <summary>
/// Update a Particle's Rotation according to its Rotational Velocity
/// </summary>
/// <param name="cParticle">The Particle to update</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update</param>
protected void UpdateParticleRotationUsingRotationalVelocity(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
// Update the Particle's Rotation according to its Rotational Velocity
// If Rotational Velocity is being used
if (cParticle.RotationalVelocity != Vector3.Zero)
{
// Quaternion Rotation Formula: NewOrientation = OldNormalizedOrientation * Rotation(v*t) * 0.5,
// where v is the angular(rotational) velocity vector, and t is the amount of time elapsed.
// The 0.5 is used to scale the rotation so that Pi = 180 degree rotation
cParticle.Orientation.Normalize();
Quaternion sRotation = new Quaternion(cParticle.RotationalVelocity * (fElapsedTimeInSeconds * 0.5f), 0);
cParticle.Orientation += cParticle.Orientation * sRotation;
}
}
//===========================================================
// Particle System Update Functions
//===========================================================
/// <summary>
/// Sorts the particles to draw particles furthest from the camera first, in order to achieve proper depth perspective.
///
/// <para>NOTE: This operation is very expensive and should only be used when you are
/// drawing particles with both opaque and semi-transparent portions, and not using additive blending.</para>
/// <para>Merge Sort is the sorting algorithm used, as it tends to be best for linked lists.
/// TODO - WHILE MERGE SORT SHOULD BE USED, DUE TO TIME CONSTRAINTS A (PROBABLY) SLOWER METHOD (QUICK-SORT)
/// IS BEING USED INSTEAD. THIS FUNCTION NEEDS TO BE UPDATED TO USE MERGE SORT STILL.
/// THE LINKED LIST MERGE SORT ALGORITHM CAN BE FOUND AT http://www.chiark.greenend.org.uk/~sgtatham/algorithms/listsort.html</para>
/// </summary>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update</param>
protected void UpdateParticleSystemToSortParticlesByDistanceFromCamera(float fElapsedTimeInSeconds)
{
// Store the Number of Active Particles to sort
int iNumberOfActiveParticles = ActiveParticles.Count;
// If there is nothing to sort
if (iNumberOfActiveParticles <= 1)
{
// Exit without sorting
return;
}
// Create a List to put the Active Particles in to be sorted
List <Particle> cActiveParticleList = new List <Particle>(iNumberOfActiveParticles);
// Add all of the Particles to the List
LinkedListNode <Particle> cNode = ActiveParticles.First;
while (cNode != null)
{
// Copy this Particle into the Array
cActiveParticleList.Add(cNode.Value);
// Move to the next Active Particle
cNode = cNode.Next;
}
// Now that the List is full, sort it
cActiveParticleList.Sort(delegate(Particle Particle1, Particle Particle2)
{
DefaultQuadParticle cParticle1 = (DefaultQuadParticle)(DPSFParticle)Particle1;
DefaultQuadParticle cParticle2 = (DefaultQuadParticle)(DPSFParticle)Particle2;
return(cParticle1.DistanceFromCameraSquared.CompareTo(cParticle2.DistanceFromCameraSquared));
});
// Now that the List is sorted, add the Particles into the Active Particles Linked List in sorted order
ActiveParticles.Clear();
for (int iIndex = 0; iIndex < iNumberOfActiveParticles; iIndex++)
{
// Add this Particle to the Active Particles Linked List.
// List is sorted from smallest to largest, but we want
// our Linked List sorted from largest to smallest, since
// the Particles at the end of the Linked List are drawn last.
ActiveParticles.AddFirst(cActiveParticleList[iIndex]);
}
}
/// <summary>
/// Deep copy all of the Particle properties
/// </summary>
/// <param name="ParticleToCopy">The Particle to Copy the properties from</param>
public override void CopyFrom(DPSFParticle ParticleToCopy)
{
// Cast the Particle to the type it really is
DefaultQuadParticle cParticleToCopy = (DefaultQuadParticle)ParticleToCopy;
base.CopyFrom(cParticleToCopy);
this.Orientation = cParticleToCopy.Orientation;
this.RotationalVelocity = cParticleToCopy.RotationalVelocity;
this.RotationalAcceleration = cParticleToCopy.RotationalAcceleration;
this.Width = cParticleToCopy.Width;
this.Height = cParticleToCopy.Height;
this.StartHeight = cParticleToCopy.StartHeight;
this.StartWidth = cParticleToCopy.StartWidth;
this.EndHeight = cParticleToCopy.EndHeight;
this.EndWidth = cParticleToCopy.EndWidth;
this.DistanceFromCameraSquared = cParticleToCopy.DistanceFromCameraSquared;
}
/// <summary>
/// Updates the Particle's DistanceFromCameraSquared property to reflect how far this Particle is from the Camera.
/// </summary>
/// <param name="cParticle">The Particle to update.</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update.</param>
protected void UpdateParticleDistanceFromCameraSquared(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
cParticle.DistanceFromCameraSquared = Vector3.DistanceSquared(this.CameraPosition, cParticle.Position);
}
/// <summary>
/// Turns the Particle into a Billboard Particle (i.e. The Particle always faces the Camera).
/// <para>NOTE: This Update function should be called after all other Update functions to ensure that
/// the Particle is orientated correctly.</para>
/// <para>NOTE: Update the Particle System's Camera Position every frame to ensure that this works correctly.</para>
/// <para>NOTE: Only Roll Rotations (i.e. around the Z axis) will be visible when this is used.</para>
/// </summary>
/// <param name="cParticle">The Particle to update.</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update.</param>
protected void UpdateParticleToFaceTheCamera(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
// Make the Particle face the Camera
cParticle.Normal = CameraPosition - cParticle.Position;
}
/// <summary>
/// Linearly interpolate the Particle's Width and Height between the Start and End values according
/// to the Particle's Normalized Lifetime
/// </summary>
/// <param name="cParticle">The Particle to update</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update</param>
protected void UpdateParticleWidthAndHeightUsingLerp(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
// Calculate the Particle's new Width and Height
cParticle.Width = MathHelper.Lerp(cParticle.StartWidth, cParticle.EndWidth, cParticle.NormalizedElapsedTime);
cParticle.Height = MathHelper.Lerp(cParticle.StartHeight, cParticle.EndHeight, cParticle.NormalizedElapsedTime);
}
/// <summary>
/// Update a Particle's Rotation and Rotational Velocity according to its Rotational Acceleration
/// </summary>
/// <param name="cParticle">The Particle to update</param>
/// <param name="fElapsedTimeInSeconds">How long it has been since the last update</param>
protected void UpdateParticleRotationAndRotationalVelocityUsingRotationalAcceleration(DefaultQuadParticle cParticle, float fElapsedTimeInSeconds)
{
// Update the Particle's Rotational Velocity and Rotation according to its Rotational Acceleration
UpdateParticleRotationalVelocityUsingRotationalAcceleration(cParticle, fElapsedTimeInSeconds);
UpdateParticleRotationUsingRotationalVelocity(cParticle, fElapsedTimeInSeconds);
}
//===========================================================
// Vertex Update and Overridden Particle System Functions
//===========================================================
/// <summary>
/// Function to update the Vertex properties according to the Particle properties
/// </summary>
/// <param name="sVertexBuffer">The array containing the Vertices to be drawn</param>
/// <param name="iIndex">The Index in the array where the Particle's Vertex info should be placed</param>
/// <param name="Particle">The Particle to copy the information from</param>
protected virtual void UpdateVertexProperties(ref DefaultQuadParticleVertex[] sVertexBuffer, int iIndex, DPSFParticle Particle)
{
// Cast the Particle to the type it really is
DefaultQuadParticle cParticle = (DefaultQuadParticle)Particle;
// Calculate what half of the Quads Width and Height are
float fHalfWidth = cParticle.Width / 2.0f;
float fHalfHeight = cParticle.Height / 2.0f;
// Calculate the Positions of the Quads corners around the origin
Vector3 sTopLeft = new Vector3(-fHalfWidth, -fHalfHeight, 0);
Vector3 sTopRight = new Vector3(fHalfWidth, -fHalfHeight, 0);
Vector3 sBottomLeft = new Vector3(-fHalfWidth, fHalfHeight, 0);
Vector3 sBottomRight = new Vector3(fHalfWidth, fHalfHeight, 0);
// Rotate the Quad corners around the origin according to its Orientation,
// then calculate their final Positions
sTopLeft = Vector3.Transform(sTopLeft, cParticle.Orientation) + cParticle.Position;
sTopRight = Vector3.Transform(sTopRight, cParticle.Orientation) + cParticle.Position;
sBottomLeft = Vector3.Transform(sBottomLeft, cParticle.Orientation) + cParticle.Position;
sBottomRight = Vector3.Transform(sBottomRight, cParticle.Orientation) + cParticle.Position;
// Effect expects a premultiplied color, so get the actual color to use.
Color premultipliedColor = cParticle.ColorAsPremultiplied;
// Copy this Particle's renderable Properties to the Vertex Buffer
// This is a Quad so we must copy all 4 Vertices over
sVertexBuffer[iIndex].Position = sBottomLeft;
sVertexBuffer[iIndex].Color = premultipliedColor;
sVertexBuffer[iIndex + 1].Position = sTopLeft;
sVertexBuffer[iIndex + 1].Color = premultipliedColor;
sVertexBuffer[iIndex + 2].Position = sBottomRight;
sVertexBuffer[iIndex + 2].Color = premultipliedColor;
sVertexBuffer[iIndex + 3].Position = sTopRight;
sVertexBuffer[iIndex + 3].Color = premultipliedColor;
// Fill in the Index Buffer for the newly added Vertices.
// Specify the Vertices in Clockwise order.
// It takes 6 Indices to represent a quad (2 triangles = 6 corners).
// If we should be using the 32-bit Integer Index Buffer, fill it.
if (this.IsUsingIntegerIndexBuffer)
{
IndexBuffer[IndexBufferIndex++] = iIndex + 1;
IndexBuffer[IndexBufferIndex++] = iIndex + 2;
IndexBuffer[IndexBufferIndex++] = iIndex;
IndexBuffer[IndexBufferIndex++] = iIndex + 1;
IndexBuffer[IndexBufferIndex++] = iIndex + 3;
IndexBuffer[IndexBufferIndex++] = iIndex + 2;
}
// Else we should be using the 16-bit Short Index Buffer.
else
{
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex + 1);
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex + 2);
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex);
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex + 1);
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex + 3);
IndexBufferShort[IndexBufferIndex++] = (short)(iIndex + 2);
}
}
