/// <summary>
/// Precomputes the transform to bring triangles from their native local space to the local space of the convex.
/// </summary>
/// <param name="convexInverseWorldTransform">Inverse of the world transform of the convex shape.</param>
/// <param name="fromMeshLocalToConvexLocal">Transform to apply to native local triangles to bring them into the local space of the convex.</param>
protected override void PrecomputeTriangleTransform(ref AffineTransform convexInverseWorldTransform, out AffineTransform fromMeshLocalToConvexLocal)
{
//StaticMeshes only have transformable mesh data.
var data = ((TransformableMeshData)mesh.Mesh.Data);
AffineTransform.Multiply(ref data.worldTransform, ref convexInverseWorldTransform, out fromMeshLocalToConvexLocal);
}
//Transform the convex into the space of something else.
/// <summary>
/// Gets the bounding box of the convex shape transformed first into world space, and then into the local space of another affine transform.
/// </summary>
/// <param name="shapeTransform">Transform to use to put the shape into world space.</param>
/// <param name="spaceTransform">Used as the frame of reference to compute the bounding box.
/// In effect, the shape is transformed by the inverse of the space transform to compute its bounding box in local space.</param>
/// <param name="boundingBox">Bounding box in the local space.</param>
public void GetLocalBoundingBox(ref RigidTransform shapeTransform, ref AffineTransform spaceTransform, out BoundingBox boundingBox)
{
#if !WINDOWS
boundingBox = new BoundingBox();
#endif
//TODO: This method peforms quite a few sqrts because the collision margin can get scaled, and so cannot be applied as a final step.
//There should be a better way to do this. At the very least, it should be possible to avoid the 6 square roots involved currently.
//If this shows a a bottleneck, it might be best to virtualize this function and implement a per-shape variant.
//Also... It might be better just to have the internal function be a GetBoundingBox that takes an AffineTransform, and an outer function
//does the local space fiddling.
//Move forward into convex's space, backwards into the new space's local space.
AffineTransform transform;
AffineTransform.Invert(ref spaceTransform, out transform);
AffineTransform.Multiply(ref shapeTransform, ref transform, out transform);
//Sample the local directions from the orientation matrix, implicitly transposed.
Vector3 right;
var direction = new Vector3(transform.LinearTransform.M11, transform.LinearTransform.M21, transform.LinearTransform.M31);
GetLocalExtremePoint(direction, out right);
Vector3 left;
direction = new Vector3(-transform.LinearTransform.M11, -transform.LinearTransform.M21, -transform.LinearTransform.M31);
GetLocalExtremePoint(direction, out left);
Vector3 up;
direction = new Vector3(transform.LinearTransform.M12, transform.LinearTransform.M22, transform.LinearTransform.M32);
GetLocalExtremePoint(direction, out up);
Vector3 down;
direction = new Vector3(-transform.LinearTransform.M12, -transform.LinearTransform.M22, -transform.LinearTransform.M32);
GetLocalExtremePoint(direction, out down);
Vector3 backward;
direction = new Vector3(transform.LinearTransform.M13, transform.LinearTransform.M23, transform.LinearTransform.M33);
GetLocalExtremePoint(direction, out backward);
Vector3 forward;
direction = new Vector3(-transform.LinearTransform.M13, -transform.LinearTransform.M23, -transform.LinearTransform.M33);
GetLocalExtremePoint(direction, out forward);
//Rather than transforming each axis independently (and doing three times as many operations as required), just get the 6 required values directly.
Vector3 positive, negative;
TransformLocalExtremePoints(ref right, ref up, ref backward, ref transform.LinearTransform, out positive);
TransformLocalExtremePoints(ref left, ref down, ref forward, ref transform.LinearTransform, out negative);
//The positive and negative vectors represent the X, Y and Z coordinates of the extreme points in world space along the world space axes.
boundingBox.Max.X = transform.Translation.X + positive.X;
boundingBox.Max.Y = transform.Translation.Y + positive.Y;
boundingBox.Max.Z = transform.Translation.Z + positive.Z;
boundingBox.Min.X = transform.Translation.X + negative.X;
boundingBox.Min.Y = transform.Translation.Y + negative.Y;
boundingBox.Min.Z = transform.Translation.Z + negative.Z;
}
/// <summary>
/// Precomputes the transform to bring triangles from their native local space to the local space of the convex.
/// </summary>
/// <param name="convexInverseWorldTransform">Inverse of the world transform of the convex shape.</param>
/// <param name="fromMeshLocalToConvexLocal">Transform to apply to native local triangles to bring them into the local space of the convex.</param>
protected override void PrecomputeTriangleTransform(ref AffineTransform convexInverseWorldTransform, out AffineTransform fromMeshLocalToConvexLocal)
{
//MobileMeshes only have TransformableMeshData sources.
var data = ((TransformableMeshData)mesh.Shape.TriangleMesh.Data);
//The mobile mesh has a shape-based transform followed by the rigid body transform.
AffineTransform mobileMeshWorldTransform;
AffineTransform.CreateFromRigidTransform(ref mesh.worldTransform, out mobileMeshWorldTransform);
AffineTransform combinedMobileMeshWorldTransform;
AffineTransform.Multiply(ref data.worldTransform, ref mobileMeshWorldTransform, out combinedMobileMeshWorldTransform);
AffineTransform.Multiply(ref combinedMobileMeshWorldTransform, ref convexInverseWorldTransform, out fromMeshLocalToConvexLocal);
}
/// <summary>
/// Gets the bounding box of the mesh transformed first into world space, and then into the local space of another affine transform.
/// </summary>
/// <param name="shapeTransform">Transform to use to put the shape into world space.</param>
/// <param name="spaceTransform">Used as the frame of reference to compute the bounding box.
/// In effect, the shape is transformed by the inverse of the space transform to compute its bounding box in local space.</param>
/// <param name="boundingBox">Bounding box in the local space.</param>
public void GetLocalBoundingBox(ref RigidTransform shapeTransform, ref AffineTransform spaceTransform, out BoundingBox boundingBox)
{
#if !WINDOWS
boundingBox = new BoundingBox();
#endif
//TODO: This method peforms quite a few sqrts because the collision margin can get scaled, and so cannot be applied as a final step.
//There should be a better way to do this.
//Additionally, this bounding box is not consistent in all cases with the post-add version. Adding the collision margin at the end can
//slightly overestimate the size of a margin expanded shape at the corners, which is fine (and actually important for the box-box special case).
//Move forward into convex's space, backwards into the new space's local space.
AffineTransform transform;
AffineTransform.Invert(ref spaceTransform, out transform);
AffineTransform.Multiply(ref shapeTransform, ref transform, out transform);
GetBoundingBox(ref transform.LinearTransform, out boundingBox);
boundingBox.Max.X += transform.Translation.X;
boundingBox.Max.Y += transform.Translation.Y;
boundingBox.Max.Z += transform.Translation.Z;
boundingBox.Min.X += transform.Translation.X;
boundingBox.Min.Y += transform.Translation.Y;
boundingBox.Min.Z += transform.Translation.Z;
}
/// <summary>
/// Precomputes the transform to bring triangles from their native local space to the local space of the convex.
/// </summary>
/// <param name="convexInverseWorldTransform">Inverse of the world transform of the convex shape.</param>
/// <param name="fromMeshLocalToConvexLocal">Transform to apply to native local triangles to bring them into the local space of the convex.</param>
protected override void PrecomputeTriangleTransform(ref AffineTransform convexInverseWorldTransform, out AffineTransform fromMeshLocalToConvexLocal)
{
//InstancedMeshShapes don't have a shape-level transform. The instance transform is all there is.
AffineTransform.Multiply(ref mesh.worldTransform, ref convexInverseWorldTransform, out fromMeshLocalToConvexLocal);
}
/// <summary>
/// Precomputes the transform to bring triangles from their native local space to the local space of the convex.
/// </summary>
/// <param name="convexInverseWorldTransform">Inverse of the world transform of the convex shape.</param>
/// <param name="fromMeshLocalToConvexLocal">Transform to apply to native local triangles to bring them into the local space of the convex.</param>
protected override void PrecomputeTriangleTransform(ref AffineTransform convexInverseWorldTransform, out AffineTransform fromMeshLocalToConvexLocal)
{
AffineTransform.Multiply(ref terrain.worldTransform, ref convexInverseWorldTransform, out fromMeshLocalToConvexLocal);
}