public static FastList <Vector3> GetPoints(SplineMeshComponent component, FastCollection <TransformComponent> children)
{
// Setup the points
var points = new FastList <Vector3>();
foreach (var child in children)
{
points.Add(child.WorldMatrix.TranslationVector);
}
var output = new FastList <Vector3>();
GetPoints(points, component.SegmentLength, output);
return(output);
}
public static void CreateSplineMesh(SplineMeshComponent component, FastList <VertexPositionNormalTangentColorTexture> vertices, FastList <int> indices)
{
var children = component.Entity.Transform.Children;
if (children.Count < 2 || component.Width <= 0.0f)
{
return;
}
var points = SplineEvaluator.GetPoints(component, children);
var indexCount = 0;
var vertexCount = 0;
vertices.Clear();
indices.Clear();
// Align points to terrain if needed
var terrain = component.Terrain;
if (terrain != null)
{
for (var i = 0; i < points.Count; i++)
{
SetHeight(terrain, component.HeightOffset, ref points.Items[i]);
}
}
// Generate spline mesh
float totalDistance = 0.0f;
var halfWidth = component.Width * 0.5f;
for (var i = 0; i < points.Count; i++)
{
// Calculate forward direction
var forward = Vector3.Zero;
if (i < points.Count - 1)
{
forward += points[i + 1] - points[i];
}
if (i > 0)
{
forward += points[i] - points[i - 1];
}
forward.Normalize();
var right = Vector3.Cross(forward, Vector3.UnitY);
var left = -right;
var p0 = points[i] + left * halfWidth;
var p1 = points[i];
var p2 = points[i] + right * halfWidth;
// Align to terrain if needed
if (terrain != null)
{
SetHeight(terrain, component.HeightOffset, ref p0);
SetHeight(terrain, component.HeightOffset, ref p1);
SetHeight(terrain, component.HeightOffset, ref p2);
}
// Calculate UV coordinates
float uvY = 0.0f;
if (i > 0)
{
var distance = (points[i] - points[i - 1]).Length();
totalDistance += distance;
uvY = totalDistance / component.SegmentUVLength;
}
// Calculate color
var color = Color.White;
// Alpha fades out at edges
if (i == 0 || i == points.Count - 1)
{
color.A = 0;
}
// Store forward direction in RGB
var forwardBiasedAndScaled = ((forward + 1.0f) / 2.0f) * 255.0f;
color.R = (byte)forwardBiasedAndScaled.X;
color.G = (byte)forwardBiasedAndScaled.Y;
color.B = (byte)forwardBiasedAndScaled.Z;
vertices.Add(new VertexPositionNormalTangentColorTexture(p0, Vector3.UnitY, Vector3.UnitZ, color, new Vector2(0.0f, uvY)));
vertices.Add(new VertexPositionNormalTangentColorTexture(p1, Vector3.UnitY, Vector3.UnitZ, color, new Vector2(0.5f, uvY)));
vertices.Add(new VertexPositionNormalTangentColorTexture(p2, Vector3.UnitY, Vector3.UnitZ, color, new Vector2(1.0f, uvY)));
if (i < points.Count - 1)
{
indices.Add(vertexCount + 0);
indices.Add(vertexCount + 3);
indices.Add(vertexCount + 1);
indices.Add(vertexCount + 1);
indices.Add(vertexCount + 3);
indices.Add(vertexCount + 4);
indices.Add(vertexCount + 1);
indices.Add(vertexCount + 4);
indices.Add(vertexCount + 2);
indices.Add(vertexCount + 2);
indices.Add(vertexCount + 4);
indices.Add(vertexCount + 5);
}
vertexCount += 3;
indexCount += 12;
}
}