/// <summary>
/// Adds thurst in the given direction.
/// </summary>
/// <param name="dir">The direction.</param>
public void Thrust(Vector2 dir)
{
// Rotate the direction.
var rotatedForce = new Vector2(
dir.X * MathCore.Cos(Body.Rotation) + -dir.Y * MathCore.Sin(Body.Rotation),
dir.Y * MathCore.Cos(Body.Rotation) + dir.X * MathCore.Sin(Body.Rotation));
// Add the thrust as acceleration.
var velocity = Body.LinearVelocity;
if (velocity != Vector2.Zero)
{
var currentSpeed = velocity.Length();
var velocityDir = Vector2.Normalize(velocity);
var forceDir = Vector2.Normalize(rotatedForce);
float dotProduct;
Vector2.Dot(ref velocityDir, ref forceDir, out dotProduct);
var damping = 1.0f - (1.0f / _maxSpeed * currentSpeed) * dotProduct;
_force += rotatedForce * damping;
}
else
{
_force += rotatedForce;
}
}
private void GenerateTunnels(Vector2 start, float maxLength = 2000.0f, float turnStrength = 0.2f)
{
//1234
//12345
//498764867
//582764
var random = new FastRandom(498764867);
const float step = 2.0f;
var terrainHeight = _terrain.TerrainSize.Y / 2.0f;
var maxSize = new Vector2(30.0f);
var currentPosition = start;
var currentDirection = Vector2.UnitX;
var length = 0.0f;
while (length < maxLength)
{
var currentSize = maxSize + new Vector2(Math.Max(0.0f, length + 200.0f - maxLength)) * 1.0f;
var brushSize = new Vector2(random.NextFloat() * currentSize.X, random.NextFloat() * currentSize.Y);
var brush = new CircleBrush(
(brushSize.X + brushSize.Y) / 4.0f,
currentPosition + new Vector2(random.NextRangedFloat(), random.NextRangedFloat()));
_terrain.SetQuads(brush, false, true);
// Add rotation.
var rotationDir = random.NextRangedFloat();
// Prevent going outside terrain or going back.
if (currentPosition.Y > terrainHeight - 200.0f ||
(currentDirection.X < 0.0f && currentDirection.Y > 0.0f))
{
rotationDir = (rotationDir - 1.0f) * 0.1f;
}
else if (currentPosition.Y < -(terrainHeight + 200.0f) ||
(currentDirection.X < 0.0f && currentDirection.Y < 0.0f))
{
rotationDir = (rotationDir + 1.0f) * 0.1f;
}
// Apply rotation.
var rotation = rotationDir * turnStrength;
currentDirection = new Vector2(
currentDirection.X * MathCore.Cos(rotation) + -currentDirection.Y * MathCore.Sin(rotation),
currentDirection.Y * MathCore.Cos(rotation) + currentDirection.X * MathCore.Sin(rotation));
currentPosition += currentDirection * step;
length += step;
}
_terrain.Refresh();
}
