protected void SpawnCircle(Particle p, float emitPosX, float emitPosY, float i = -1f)
{
//set the initial rotation/direction of the particle based on starting
//particle angle and rotation of emitter
if (minStartRotation == maxStartRotation)
{
p.Rotation = minStartRotation + rotation;
}
else
{
p.Rotation = Mathf.Random() * (maxStartRotation - minStartRotation) +
minStartRotation + rotation;
}
//place the particle at a random radius in the circle
helperPoint.X = Mathf.Random() * spawnCircle.radius;
helperPoint.Y = 0;
//rotate the point to a random angle in the circle
helperPoint = ParticleUtils.RotatePoint(Mathf.Random() * 360, helperPoint);
//offset by the circle's center
helperPoint.X += spawnCircle.x;
helperPoint.Y += spawnCircle.y;
//rotate the point by the emitter's rotation
if (rotation != 0)
{
ParticleUtils.RotatePoint(rotation, helperPoint);
}
//set the position, offset by the emitter's position
p.X = emitPosX + helperPoint.X;
p.Y = emitPosY + helperPoint.Y;
}
/// <summary>
/// Sets the rotation of the emitter to a new value.
/// </summary>
/// <param name="newRot">The new rotation, in degrees.</param>
public void Rotate(float newRot)
{
if (rotation == newRot)
{
return;
}
//caclulate the difference in rotation for rotating spawnPos
var diff = newRot - rotation;
rotation = newRot;
//rotate spawnPos
spawnPos = ParticleUtils.RotatePoint(diff, spawnPos);
//mark the position as having changed
posChanged = true;
}
/// <summary>
/// Initializes the particle for use, based on the properties that have to
/// have been set already on the particle.
/// </summary>
public void Init()
{
//reset the age
age = 0f;
//set up the velocity based on the start speed and rotation
velocity.X = speedList.current.value * speedMultiplier;
velocity.Y = 0;
velocity = ParticleUtils.RotatePoint(Rotation, velocity);
if (noRotation)
{
Rotation = 0;
}
else
{
//convert rotation to Radians from Degrees
Rotation *= ParticleUtils.DEG_TO_RADS;
}
//convert rotation speed to Radians from Degrees
rotationSpeed *= ParticleUtils.DEG_TO_RADS;
rotationAcceleration *= ParticleUtils.DEG_TO_RADS;
//set alpha to inital alpha
Alpha = alphaList.current.value;
//set scale to initial scale
Scale = new Vector2(scaleList.current.value, scaleList.current.value);
//figure out what we need to interpolate
doAlpha = (alphaList.current.next != null);
doSpeed = (speedList.current.next != null);
doScale = (scaleList.current.next != null);
doColor = (colorList.current.next != null);
doAcceleration = acceleration.X != 0 || acceleration.Y != 0;
//_doNormalMovement can be cancelled by subclasses
doNormalMovement = doSpeed || speedList.current.value != 0 || doAcceleration;
//save our lerp helper
oneOverLife = 1 / maxLife;
//set the inital color
var color = colorList.current.value;
Tint = new Color(color.R, color.G, color.B);
//ensure visibility
Visible = true;
}
protected void SpawnRect(Particle p, float emitPosX, float emitPosY, float i = -1f)
{
//set the initial rotation/direction of the particle based on starting
//particle angle and rotation of emitter
if (minStartRotation == maxStartRotation)
{
p.Rotation = minStartRotation + rotation;
}
else
{
p.Rotation = Mathf.Random() * (maxStartRotation - minStartRotation) + minStartRotation + rotation;
}
//place the particle at a random point in the rectangle
helperPoint.X = Mathf.Random() * spawnRect.Width + spawnRect.X;
helperPoint.Y = Mathf.Random() * spawnRect.Height + spawnRect.Y;
if (rotation != 0)
{
helperPoint = ParticleUtils.RotatePoint(rotation, helperPoint);
}
p.X = emitPosX + helperPoint.X;
p.Y = emitPosY + helperPoint.Y;
}