///<summary>
/// Gets a world space triangle in the terrain at the given indices (as if it were a mesh).
///</summary>
///<param name="indices">Indices of the triangle.</param>
///<param name="transform">Transform to apply to the triangle vertices.</param>
///<param name="a">First vertex of the triangle.</param>
///<param name="b">Second vertex of the triangle.</param>
///<param name="c">Third vertex of the triangle.</param>
public void GetTriangle(ref TriangleMeshConvexContactManifold.TriangleIndices indices, ref AffineTransform transform, out Vector3 a, out Vector3 b, out Vector3 c)
{
//Reverse the encoded index:
//index = i + width * j
int width = heights.GetLength(0);
int columnA = indices.A / width;
int rowA = indices.A - columnA * width;
int columnB = indices.B / width;
int rowB = indices.B - columnB * width;
int columnC = indices.C / width;
int rowC = indices.C - columnC * width;
GetPosition(rowA, columnA, ref transform, out a);
GetPosition(rowB, columnB, ref transform, out b);
GetPosition(rowC, columnC, ref transform, out c);
}
///<summary>
/// Gets overlapped triangles with the terrain shape with a bounding box in the local space of the shape.
///</summary>
///<param name="localSpaceBoundingBox">Bounding box in the local space of the terrain shape.</param>
///<param name="overlappedTriangles">Triangles whose bounding boxes overlap the input bounding box.</param>
public bool GetOverlaps(BoundingBox localSpaceBoundingBox, RawList <TriangleMeshConvexContactManifold.TriangleIndices> overlappedTriangles)
{
int width = heights.GetLength(0);
int minX = Math.Max((int)localSpaceBoundingBox.Min.X, 0);
int minY = Math.Max((int)localSpaceBoundingBox.Min.Z, 0);
int maxX = Math.Min((int)localSpaceBoundingBox.Max.X, width - 2);
int maxY = Math.Min((int)localSpaceBoundingBox.Max.Z, heights.GetLength(1) - 2);
for (int i = minX; i <= maxX; i++)
{
for (int j = minY; j <= maxY; j++)
{
//Before adding a triangle to the list, make sure the object isn't too high or low from the quad.
float highest, lowest;
float y1 = heights[i, j];
float y2 = heights[i + 1, j];
float y3 = heights[i, j + 1];
float y4 = heights[i + 1, j + 1];
highest = y1;
lowest = y1;
if (y2 > highest)
{
highest = y2;
}
else if (y2 < lowest)
{
lowest = y2;
}
if (y3 > highest)
{
highest = y3;
}
else if (y3 < lowest)
{
lowest = y3;
}
if (y4 > highest)
{
highest = y4;
}
else if (y4 < lowest)
{
lowest = y4;
}
if (localSpaceBoundingBox.Max.Y < lowest ||
localSpaceBoundingBox.Min.Y > highest)
{
continue;
}
//Now the local bounding box is very likely intersecting those of the triangles.
//Add the triangles to the list.
var indices = new TriangleMeshConvexContactManifold.TriangleIndices();
//v3 v4
//v1 v2
if (quadTriangleOrganization == QuadTriangleOrganization.BottomLeftUpperRight)
{
//v1 v2 v3
indices.A = i + j * width;
indices.B = i + 1 + j * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
//v2 v4 v3
indices.A = i + 1 + j * width;
indices.B = i + 1 + (j + 1) * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
}
else //Bottom right, Upper left
{
//v1 v2 v4
indices.A = i + j * width;
indices.B = i + 1 + j * width;
indices.C = i + 1 + (j + 1) * width;
overlappedTriangles.Add(indices);
//v1 v4 v3
indices.A = i + j * width;
indices.B = i + 1 + (j + 1) * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
}
}
}
return(overlappedTriangles.count > 0);
}
///<summary>
/// Gets overlapped triangles with the terrain shape with a bounding box in the local space of the shape.
///</summary>
///<param name="localSpaceBoundingBox">Bounding box in the local space of the terrain shape.</param>
///<param name="overlappedTriangles">Triangles whose bounding boxes overlap the input bounding box.</param>
public bool GetOverlaps(BoundingBox localSpaceBoundingBox, RawList<TriangleMeshConvexContactManifold.TriangleIndices> overlappedTriangles)
{
int width = heights.GetLength(0);
int minX = Math.Max((int)localSpaceBoundingBox.Min.X, 0);
int minY = Math.Max((int)localSpaceBoundingBox.Min.Z, 0);
int maxX = Math.Min((int)localSpaceBoundingBox.Max.X, width - 2);
int maxY = Math.Min((int)localSpaceBoundingBox.Max.Z, heights.GetLength(1) - 2);
for (int i = minX; i <= maxX; i++)
{
for (int j = minY; j <= maxY; j++)
{
//Before adding a triangle to the list, make sure the object isn't too high or low from the quad.
float highest, lowest;
float y1 = heights[i, j];
float y2 = heights[i + 1, j];
float y3 = heights[i, j + 1];
float y4 = heights[i + 1, j + 1];
highest = y1;
lowest = y1;
if (y2 > highest)
highest = y2;
else if (y2 < lowest)
lowest = y2;
if (y3 > highest)
highest = y3;
else if (y3 < lowest)
lowest = y3;
if (y4 > highest)
highest = y4;
else if (y4 < lowest)
lowest = y4;
if (localSpaceBoundingBox.Max.Y < lowest ||
localSpaceBoundingBox.Min.Y > highest)
continue;
//Now the local bounding box is very likely intersecting those of the triangles.
//Add the triangles to the list.
var indices = new TriangleMeshConvexContactManifold.TriangleIndices();
//v3 v4
//v1 v2
if (quadTriangleOrganization == QuadTriangleOrganization.BottomLeftUpperRight)
{
//v1 v2 v3
indices.A = i + j * width;
indices.B = i + 1 + j * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
//v2 v4 v3
indices.A = i + 1 + j * width;
indices.B = i + 1 + (j + 1) * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
}
else //Bottom right, Upper left
{
//v1 v2 v4
indices.A = i + j * width;
indices.B = i + 1 + j * width;
indices.C = i + 1 + (j + 1) * width;
overlappedTriangles.Add(indices);
//v1 v4 v3
indices.A = i + j * width;
indices.B = i + 1 + (j + 1) * width;
indices.C = i + (j + 1) * width;
overlappedTriangles.Add(indices);
}
}
}
return overlappedTriangles.Count > 0;
}
