private static Rect3D GetChildrenBoundsRecursive(ModelVisual3D visual, Matrix3D tx)
{
Rect3D bounds = Rect3D.Empty;
Matrix3D currentTransform = MatrixUtils.Multiply(MatrixUtils.Value(visual.Transform), tx);
if (visual.Content != null)
{
bounds = ModelBounder.CalculateBounds(visual.Content, currentTransform);
}
foreach (Visual3D v in visual.Children)
{
if (v is ModelVisual3D)
{
bounds.Union(GetChildrenBoundsRecursive((ModelVisual3D)v, currentTransform));
}
}
return(bounds);
}
private void AdjustCamera(Camera camera, Model3DGroup scene)
{
ProjectionCamera pc = camera as ProjectionCamera;
if (pc == null)
{
// Can't adjust MatrixCamera
return;
}
if (double.IsNaN(pc.NearPlaneDistance) ||
double.IsNaN(pc.FarPlaneDistance) ||
double.IsPositiveInfinity(pc.NearPlaneDistance) ||
double.IsNegativeInfinity(pc.FarPlaneDistance) ||
pc.NearPlaneDistance > pc.FarPlaneDistance)
{
// Don't render, and don't use NaN.
pc.NearPlaneDistance = double.MaxValue;
pc.FarPlaneDistance = double.MaxValue;
return;
}
bool adjustNearPlane = double.IsNegativeInfinity(pc.NearPlaneDistance);
bool adjustFarPlane = double.IsPositiveInfinity(pc.FarPlaneDistance);
if (!adjustNearPlane && !adjustFarPlane)
{
// Camera is fine. Leave it alone.
return;
}
Matrix3D view = MatrixUtils.ViewMatrix(this.camera);
Rect3D sceneBounds = ModelBounder.CalculateBounds(scene, view);
if (sceneBounds.IsEmpty)
{
// It doesn't really matter what these are since there's nothing in the scene.
// But I do like to avoid infinity...
pc.NearPlaneDistance = double.MaxValue;
pc.FarPlaneDistance = double.MaxValue;
}
else
{
// sceneBounds is aligned to the axes defined by the camera's view matrix,
// but it's facing the wrong way!
//
// +-----------+
// |sceneBounds|
// o---|-----------|---> look direction (-z axis)
// | |
// +-----------+
// ^ ^
// Z+sizeZ Z
//
// o is the camera position (also origin; z == 0)
// This works regardless of the camera's position relative to the sceneBounds
double np = pc.NearPlaneDistance;
double fp = pc.FarPlaneDistance;
double zBufferEpsilon = Math.Pow(2, -10); // Add a little padding to the scene bounds
double sceneNearClip = -(sceneBounds.Z + sceneBounds.SizeZ + zBufferEpsilon);
double sceneFarClip = -(sceneBounds.Z - zBufferEpsilon);
// Shrink the user specified clipping planes to the tightest fit around
// the scene without modifying what is visible.
// Do not expand user's clipping plane values (unless we need a little more zBuffer tolerance)!
if (adjustFarPlane)
{
pc.FarPlaneDistance = sceneFarClip;
}
if (adjustNearPlane)
{
pc.NearPlaneDistance = sceneNearClip;
}
if (pc.NearPlaneDistance > pc.FarPlaneDistance)
{
// Don't render.
pc.NearPlaneDistance = double.MaxValue;
pc.FarPlaneDistance = double.MaxValue;
return;
}
if (pc is PerspectiveCamera && pc.NearPlaneDistance <= 0)
{
// We don't currently handle this case correctly. Just don't crash.
pc.NearPlaneDistance = 0.125;
}
AdjustCameraTolerance(pc, adjustNearPlane, adjustFarPlane);
}
}