public void generateEFieldLines()
{
if (charges.Count == 0)
{
eFieldLineVerts = null;
return;
}
int numLinesPerCharge = 25;
List <VertexPositionColor> tempVerts = new List <VertexPositionColor>();
Random random = new Random();
int lineSegmentsPerLine = 65535 / (charges.Count * numLinesPerCharge);
float minLon = 0;
float maxLon = (float)Math.PI;
float minLat = (float)-Math.PI;
float maxLat = (float)Math.PI;
int numLoops = (int)Math.Sqrt(numLinesPerCharge);
for (int i = 0; i < charges.Count; i++)
{
// Non-random line starting algorithm
PointCharge charge = charges[i];
for (int lonIndex = 0; lonIndex < numLoops; lonIndex++)
{
float lon = MathHelper.Lerp(minLon, maxLon, (float)lonIndex / (float)numLoops);
for (int latIndex = 0; latIndex < numLoops; latIndex++)
{
float lat = MathHelper.Lerp(minLat, maxLat, (float)latIndex / (float)numLoops);
Vector3 startOffset = 2 * charge.radius * Vector3.Transform(Vector3.UnitX, Matrix.CreateRotationY(lon) * Matrix.CreateRotationX(lat));
Vector3 startPos = charge.center + startOffset;
VertexPositionColor[] line = calculateVerticesForEFieldLineFromStartPosition(startPos, charge.charge < 0, lineSegmentsPerLine);
tempVerts.AddRange(line);
}
}
// Random line starting algorithm
/*PointCharge charge = charges[i];
* for (int n = 0; n < numLinesPerCharge; n++)
* {
* float lon = (float)(random.NextDouble() * Math.PI);
* float lat = (float)(random.NextDouble() * MathHelper.TwoPi - Math.PI);
*
* Vector3 startOffset = 2 * charge.radius * Vector3.Transform(Vector3.UnitX, Matrix.CreateRotationY(lon) * Matrix.CreateRotationX(lat));
* Vector3 startPos = charge.center + startOffset;
*
* VertexPositionColor[] line = calculateVerticesForEFieldLineFromStartPosition(startPos, charge.charge < 0, lineSegmentsPerLine);
* tempVerts.AddRange(line);
* }*/
}
eFieldLineVerts = tempVerts.ToArray();
}
public PointCharge GetChargeWithID(int id)
{
for (int i = 0; i < charges.Count; i++)
{
PointCharge c = charges[i];
if (c.id == id)
{
return(c);
}
}
return(null);
}
public void AddCharge(PointCharge charge)
{
idCounter++;
charges.Add(charge);
float minX = float.MaxValue;
float minY = float.MaxValue;
float minZ = float.MaxValue;
float maxX = float.MinValue;
float maxY = float.MinValue;
float maxZ = float.MinValue;
for (int i = 0; i < charges.Count; i++)
{
PointCharge c = charges[i];
if (c.center.X < minX)
{
minX = c.center.X;
}
if (c.center.Y < minY)
{
minY = c.center.Y;
}
if (c.center.Z < minZ)
{
minZ = c.center.Z;
}
if (c.center.X > maxX)
{
maxX = c.center.X;
}
if (c.center.Y > maxY)
{
maxY = c.center.Y;
}
if (c.center.Z > maxZ)
{
maxZ = c.center.Z;
}
}
minX -= 5;
minY -= 5;
minZ -= 5;
maxX += 5;
maxY += 5;
maxZ += 5;
this.SetBounds(minX, minY, minZ, maxX, maxY, maxZ);
}
protected override void LoadContent()
{
device = this.GraphicsDevice;
cam = new Camera(new Vector3(-5, 5, 5), -MathHelper.PiOver4, -MathHelper.PiOver4, 0.001f, 0.1f, device);
// Setup axes grid
grid = new Grid(device, 0.1f);
// Test charge
testCharge = new PointCharge(device, 1.0f, -1.0f);
}
public void DeleteChargeWithID(int id)
{
for (int i = 0; i < charges.Count; i++)
{
PointCharge c = charges[i];
if (c.id == id)
{
charges.RemoveAt(i);
generateArrows();
generateEFieldLines();
return;
}
}
}
public static void ModifyChargeID(int id, string property, float value)
{
PointCharge oldC = sim.GetField().GetChargeWithID(id);
if (oldC == null)
{
console.Log("Charge with ID " + id + " not defined");
return;
}
float x = oldC.center.X;
float y = oldC.center.Y;
float z = oldC.center.Z;
float charge = oldC.charge * 1000000;
if (property == "x")
{
x = value;
}
else if (property == "y")
{
y = value;
}
else if (property == "z")
{
z = value;
}
else if (property == "charge")
{
charge = value;
}
else
{
console.Log("Invalid property \"" + value + "\"");
return;
}
PointCharge c = new PointCharge(sim.GraphicsDevice, new Vector3(x, y, z), charge, id);
sim.GetField().DeleteChargeWithID(id);
sim.GetField().AddCharge(c);
if (shouldAutogen)
{
sim.GetField().generateArrows();
sim.GetField().generateEFieldLines();
}
}
public override Vector3 r(float x, float y, float z)
{
Vector3 pos = new Vector3(x, y, z);
Vector3 sum = Vector3.Zero;
for (int i = 0; i < charges.Count; i++)
{
PointCharge charge = charges[i];
float distance = Vector3.Distance(pos, charge.center);
float magnitude = -k * charge.charge / (distance * distance);
Vector3 vec = charge.center - pos;
vec.Normalize();
vec *= magnitude;
sum += vec;
}
return(sum);
}
public void AddCharge(Vector3 pos, float chargeInMicroCoulombs)
{
PointCharge pointCharge = new PointCharge(this.device, pos, chargeInMicroCoulombs, idCounter);
AddCharge(pointCharge);
}