// Modify the terrain height values to add the road to the terrain.
private void ClampTerrainToRoad()
{
// We have to manipulate the height and normal texture of each tile which contains the road.
foreach (var tile in _terrainObject.TerrainNode.Terrain.Tiles)
{
// Get the current height texture of the tile and extract the heights into a float array.
var heightTexture = tile.HeightTexture;
float[] heights = TerrainHelper.GetTextureLevelSingle(heightTexture, 0);
// Create a temporary height field.
var heightField = new HeightField(
tile.OriginX,
tile.OriginZ,
tile.WidthX,
tile.WidthZ,
heights,
heightTexture.Width,
heightTexture.Height);
// Change the height values of the height field.
TerrainRoadLayer.ClampTerrainToRoad(heightField, _roadPath, 8, 30, 10, 0.1f);
// Rebuild the height texture.
TerrainHelper.CreateHeightTexture(
GraphicsService.GraphicsDevice,
heights,
heightTexture.Width,
heightTexture.Height,
false,
ref heightTexture);
// Rebuild the normal texture.
var normalTexture = tile.NormalTexture;
TerrainHelper.CreateNormalTexture(
GraphicsService.GraphicsDevice,
heights,
heightTexture.Width,
heightTexture.Height,
tile.CellSize,
false,
ref normalTexture);
// Get rigid body that represents this tile.
var rigidBody = Simulation.RigidBodies.First(body => body.UserData == tile);
// Update the height values of the collision detection height field.
((HeightField)rigidBody.Shape).SetSamples(heights, heightTexture.Width, heightTexture.Height);
}
}
private void CreateRoad()
{
//RandomHelper.Random = new Random(1234567);
// Set isClosed to true join the start and the end of the road.
bool isClosed = false;
// Create a new TerrainRoadLayer which paints a road onto the terrain.
// The road itself is defined by a mesh which is set later.
_roadLayer = new TerrainRoadLayer(GraphicsService)
{
DiffuseColor = new Vector3(0.5f),
SpecularColor = new Vector3(1),
DiffuseTexture = ContentManager.Load <Texture2D>("Terrain/Road-Asphalt-Diffuse"),
NormalTexture = ContentManager.Load <Texture2D>("Terrain/Road-Asphalt-Normal"),
SpecularTexture = ContentManager.Load <Texture2D>("Terrain/Road-Asphalt-Specular"),
HeightTexture = ContentManager.Load <Texture2D>("Terrain/Road-Asphalt-Height"),
// The size of the tileable detail textures in world space units.
TileSize = 5,
// The border blend range controls how the border of the road fades out.
// We fade out 5% of the texture on each side of the road.
BorderBlendRange = new Vector4(0.05f, 0.05f, 0.05f, 0.05f),
};
// Create 3D spline path with some semi-random control points.
_roadPath = new Path3F
{
PreLoop = isClosed ? CurveLoopType.Cycle : CurveLoopType.Linear,
PostLoop = isClosed ? CurveLoopType.Cycle : CurveLoopType.Linear,
SmoothEnds = isClosed,
};
// The position of the next path key.
Vector3 position = new Vector3(
RandomHelper.Random.NextFloat(-20, 20),
0,
RandomHelper.Random.NextFloat(-20, 20));
// The direction to the next path key.
Vector3 direction = Quaternion.CreateRotationY(RandomHelper.Random.NextFloat(0, 10)).Rotate(Vector3.Forward);
// Add path keys.
for (int j = 0; j < 10; j++)
{
// Instead of a normal PathKey3F, we use a TerrainRoadPathKey which allows to control
// the road with and the side falloff.
var key = new TerrainRoadPathKey
{
Interpolation = SplineInterpolation.CatmullRom,
Parameter = j,
Point = position,
// The width of the road at the path key.
Width = RandomHelper.Random.NextFloat(6, 10),
// The side falloff (which is used in ClampTerrainToRoad to blend the height values with
// the road).
SideFalloff = RandomHelper.Random.NextFloat(20, 40),
};
_roadPath.Add(key);
// Get next random position and direction.
position += direction * RandomHelper.Random.NextFloat(20, 40);
position.Y += RandomHelper.Random.NextFloat(-2, 2);
direction = Quaternion.CreateRotationY(RandomHelper.Random.NextFloat(-1, 1))
.Rotate(direction);
}
if (isClosed)
{
// To create a closed path the first and the last key should be identical.
_roadPath[_roadPath.Count - 1].Point = _roadPath[0].Point;
((TerrainRoadPathKey)_roadPath[_roadPath.Count - 1]).Width = ((TerrainRoadPathKey)_roadPath[0]).Width;
((TerrainRoadPathKey)_roadPath[_roadPath.Count - 1]).SideFalloff =
((TerrainRoadPathKey)_roadPath[0]).SideFalloff;
// Since the path is closed we do not have to fade out the start and the end of the road.
_roadLayer.BorderBlendRange *= new Vector4(1, 0, 1, 0);
}
// Convert the path to a mesh.
Submesh roadSubmesh;
Aabb roadAabb;
float roadLength;
TerrainRoadLayer.CreateMesh(
GraphicsService.GraphicsDevice,
_roadPath,
4,
10,
0.1f,
out roadSubmesh,
out roadAabb,
out roadLength);
// Set the mesh in the road layer.
_roadLayer.SetMesh(roadSubmesh, roadAabb, roadLength, true);
if (isClosed)
{
// When the path is closed, the end texture and the start texture coordinates should
// match. This is the case if (roadLength / tileSize) is an integer.
var numberOfTiles = (int)(roadLength / _roadLayer.TileSize);
_roadLayer.TileSize = roadLength / numberOfTiles;
}
// The road layer is added to the layers of a tile. We have to add the road to each terrain
// tile which it overlaps.
foreach (var tile in _terrainObject.TerrainNode.Terrain.Tiles)
{
if (GeometryHelper.HaveContact(tile.Aabb, _roadLayer.Aabb.Value))
{
tile.Layers.Add(_roadLayer);
}
}
}
