/// <summary>
/// Constructor
/// </summary>
/// <param name="game">Game</param>
/// <param name="name">Name</param>
/// <param name="description">Particle system description</param>
/// <param name="emitter">Particle emitter</param>
public ParticleSystemCpu(Game game, string name, ParticleSystemDescription description, ParticleEmitter emitter)
{
this.Game = game;
this.Name = name;
this.parameters = new ParticleSystemParams(description) * emitter.Scale;
var imgContent = new ImageContent()
{
Streams = ContentManager.FindContent(description.ContentPath, description.TextureName),
};
this.Texture = game.ResourceManager.CreateResource(imgContent);
this.TextureCount = (uint)imgContent.Count;
this.Emitter = emitter;
this.Emitter.UpdateBounds(this.parameters);
this.MaxConcurrentParticles = this.Emitter.GetMaximumConcurrentParticles(description.MaxDuration);
this.particles = new VertexCpuParticle[this.MaxConcurrentParticles];
this.buffer = new EngineBuffer <VertexCpuParticle>(game.Graphics, description.Name, this.particles, true);
buffer.AddInputLayout(game.Graphics.CreateInputLayout(DrawerPool.EffectDefaultCPUParticles.RotationDraw.GetSignature(), VertexCpuParticle.Input(BufferSlot)));
buffer.AddInputLayout(game.Graphics.CreateInputLayout(DrawerPool.EffectDefaultCPUParticles.NonRotationDraw.GetSignature(), VertexCpuParticle.Input(BufferSlot)));
this.TimeToEnd = this.Emitter.Duration + this.parameters.MaxDuration;
}
/// <summary>
/// Calculates the initial velocity for a particle
/// </summary>
/// <param name="parameters">Particle system parameters</param>
/// <param name="hVelVariance">Horizontal velocity variance</param>
/// <param name="vVelVariance">Vertical velocity variance</param>
/// <param name="hAngleVariance">Horizontal angle variance</param>
/// <returns>Returns the initial velocity vector with magnitude</returns>
public Vector3 CalcInitialVelocity(ParticleSystemParams parameters, float hVelVariance, float vVelVariance, float hAngleVariance)
{
Vector3 velocity = this.Velocity * parameters.EmitterVelocitySensitivity;
float horizontalVelocity = MathUtil.Lerp(
parameters.HorizontalVelocity.X,
parameters.HorizontalVelocity.Y,
hVelVariance);
float horizontalAngle = hAngleVariance * MathUtil.TwoPi;
velocity.X += horizontalVelocity * (float)Math.Cos(horizontalAngle);
velocity.Z += horizontalVelocity * (float)Math.Sin(horizontalAngle);
velocity.Y += MathUtil.Lerp(
parameters.VerticalVelocity.X,
parameters.VerticalVelocity.Y,
vVelVariance);
return(velocity);
}
/// <summary>
/// Samples a bounding box for the current emitter at the specified time
/// </summary>
/// <param name="emitter">Emitter</param>
/// <param name="systemParams">Particle system parameters</param>
/// <param name="time">Time</param>
/// <returns>Returns the sampled bounding box</returns>
private static BoundingBox SampleBBox(ParticleEmitter emitter, ParticleSystemParams systemParams, float time)
{
//Initial position
Vector3 initialPos = Vector3.Zero;
Vector3 velocity = emitter.Velocity * systemParams.EmitterVelocitySensitivity;
float horizontalVelocity = Math.Max(systemParams.HorizontalVelocity.X, systemParams.HorizontalVelocity.Y);
//Max v velocity
Vector3 vVelocity = velocity;
vVelocity.Y *= Math.Max(systemParams.VerticalVelocity.X, systemParams.VerticalVelocity.Y);
//Max h velocity
Vector3 hVelocity1 = velocity;
hVelocity1.X *= horizontalVelocity * (float)Math.Cos(0);
hVelocity1.Z *= horizontalVelocity * (float)Math.Sin(0);
Vector3 hVelocity2 = velocity;
hVelocity2.X *= horizontalVelocity * (float)Math.Cos(1);
hVelocity2.Z *= horizontalVelocity * (float)Math.Sin(1);
//Final positions
Vector3 finalPosV = ComputeParticlePosition(
initialPos,
vVelocity,
systemParams.EndVelocity,
systemParams.MaxDuration * time,
time,
systemParams.Gravity);
Vector3 finalPosH1 = ComputeParticlePosition(
initialPos,
hVelocity1,
systemParams.EndVelocity,
systemParams.MaxDuration * time,
time,
systemParams.Gravity);
Vector3 finalPosH2 = ComputeParticlePosition(
initialPos,
hVelocity2,
systemParams.EndVelocity,
systemParams.MaxDuration * time,
time,
systemParams.Gravity);
float startSize = systemParams.MaxStartSize * 0.5f;
BoundingSphere initial = new BoundingSphere(initialPos + new Vector3(0, startSize, 0), startSize * 0.5f);
float endSize = systemParams.MaxEndSize * 0.5f;
BoundingSphere finalV = new BoundingSphere(finalPosV + new Vector3(0, endSize, 0), endSize * 0.5f);
BoundingSphere finalH1 = new BoundingSphere(finalPosH1 + new Vector3(0, endSize, 0), endSize * 0.5f);
BoundingSphere finalH2 = new BoundingSphere(finalPosH2 + new Vector3(0, endSize, 0), endSize * 0.5f);
var bbox = BoundingBox.FromSphere(initial);
bbox = BoundingBox.Merge(bbox, BoundingBox.FromSphere(finalV));
bbox = BoundingBox.Merge(bbox, BoundingBox.FromSphere(finalH1));
bbox = BoundingBox.Merge(bbox, BoundingBox.FromSphere(finalH2));
return(bbox);
}
