public void AddSegment(RoadTemplate template, MapObject start, MapObject end)
{
var startNode = GetOrCreateNode(start);
var endNode = GetOrCreateNode(end);
var edge = new RoadTopologyEdge(
template,
startNode,
start.RoadType,
endNode,
end.RoadType);
Edges.Add(edge);
startNode.Edges.Add(edge);
endNode.Edges.Add(edge);
}
internal Road(
ContentManager contentManager,
HeightMap heightMap,
RoadTemplate template,
Vector3 startPosition,
Vector3 endPosition)
{
const float heightBias = 1f;
const float createNewVerticesHeightDeltaThreshold = 0.002f;
var distance = Vector3.Distance(startPosition, endPosition);
var direction = Vector3.Normalize(endPosition - startPosition);
var centerToEdgeDirection = Vector3.Cross(Vector3.UnitZ, direction);
var up = Vector3.Cross(direction, centerToEdgeDirection);
var halfWidth = template.RoadWidth / 2;
var textureAtlasSplit = 1 / 3f;
var vertices = new List <RoadVertex>();
// Step along road segment in units of 10. If the delta between
// (a) the straight line from previous point to finish and
// (b) the actual height of the terrain at this point
// is > a threshold, create extra vertices.
// TODO: I don't know if this is the right algorithm.
void AddVertexPair(in Vector3 position, float distanceAlongRoad)
{
var u = distanceAlongRoad / 50;
var p0 = position - centerToEdgeDirection * halfWidth;
p0.Z += heightBias;
vertices.Add(new RoadVertex
{
Position = p0,
Normal = up,
UV = new Vector2(u, 0)
});
var p1 = position + centerToEdgeDirection * halfWidth;
p1.Z += heightBias;
vertices.Add(new RoadVertex
{
Position = p1,
Normal = up,
UV = new Vector2(u, textureAtlasSplit)
});
}
AddVertexPair(startPosition, 0);
var previousPoint = startPosition;
var previousPointDistance = 0;
for (var currentDistance = 10; currentDistance < distance; currentDistance += 10)
{
var position = startPosition + direction * currentDistance;
var actualHeight = heightMap.GetHeight(position.X, position.Y);
var interpolatedHeight = MathUtility.Lerp(previousPoint.Z, endPosition.Z, (currentDistance - previousPointDistance) / distance);
if (Math.Abs(actualHeight - interpolatedHeight) > createNewVerticesHeightDeltaThreshold)
{
AddVertexPair(position, currentDistance);
previousPoint = position;
previousPointDistance = currentDistance;
}
}
// Add last chunk.
AddVertexPair(endPosition, distance);
_boundingBox = BoundingBox.CreateFromPoints(vertices.Select(x => x.Position));
_vertexBuffer = AddDisposable(contentManager.GraphicsDevice.CreateStaticBuffer(
vertices.ToArray(),
BufferUsage.VertexBuffer));
var indices = new List <ushort>();
for (var i = 0; i < vertices.Count - 2; i += 2)
{
indices.Add((ushort)(i + 0));
indices.Add((ushort)(i + 1));
indices.Add((ushort)(i + 2));
indices.Add((ushort)(i + 1));
indices.Add((ushort)(i + 2));
indices.Add((ushort)(i + 3));
}
_numIndices = (uint)indices.Count;
_indexBuffer = AddDisposable(contentManager.GraphicsDevice.CreateStaticBuffer(
indices.ToArray(),
BufferUsage.IndexBuffer));
_material = AddDisposable(new RoadMaterial(
contentManager,
contentManager.EffectLibrary.Road));
var texture = contentManager.Load <Texture>(Path.Combine("Art", "Textures", template.Texture));
_material.SetTexture(texture);
}
internal Road(
ContentManager contentManager,
HeightMap heightMap,
RoadTemplate template,
in Vector3 startPosition,
internal Road(
AssetLoadContext loadContext,
HeightMap heightMap,
RoadTemplate template,
in Vector3 startPosition,