public static void ComputePerspectiveFrustumCorners(
ref Vector3 viewPosition,
ref Vector3 viewDirection,
ref Vector3 globalUpDirection,
float fov,
float nearDistance,
float farDistance,
float aspectRatio,
out FrustumCorners corners)
{
float nearHeight = (float)(2 * Math.Tan(fov / 2.0) * nearDistance);
float nearWidth = nearHeight * aspectRatio;
float farHeight = (float)(2 * Math.Tan(fov / 2.0) * farDistance);
float farWidth = farHeight * aspectRatio;
Vector3 right = Vector3.Normalize(Vector3.Cross(viewDirection, globalUpDirection));
Vector3 up = Vector3.Normalize(Vector3.Cross(right, viewDirection));
Vector3 nearCenter = viewPosition + viewDirection * nearDistance;
Vector3 farCenter = viewPosition + viewDirection * farDistance;
corners.NearTopLeft = nearCenter - ((nearWidth / 2f) * right) + ((nearHeight / 2) * up);
corners.NearTopRight = nearCenter + ((nearWidth / 2f) * right) + ((nearHeight / 2) * up);
corners.NearBottomLeft = nearCenter - ((nearWidth / 2f) * right) - ((nearHeight / 2) * up);
corners.NearBottomRight = nearCenter + ((nearWidth / 2f) * right) - ((nearHeight / 2) * up);
corners.FarTopLeft = farCenter - ((farWidth / 2f) * right) + ((farHeight / 2) * up);
corners.FarTopRight = farCenter + ((farWidth / 2f) * right) + ((farHeight / 2) * up);
corners.FarBottomLeft = farCenter - ((farWidth / 2f) * right) - ((farHeight / 2) * up);
corners.FarBottomRight = farCenter + ((farWidth / 2f) * right) - ((farHeight / 2) * up);
}
public unsafe ContainmentType Contains(ref BoundingFrustum other)
{
int pointsContained = 0;
FrustumCorners corners = other.GetCorners();
Vector3 * cornersPtr = (Vector3 *)&corners;
for (int i = 0; i < 8; i++)
{
if (Contains(&cornersPtr[i]) != ContainmentType.Disjoint)
{
pointsContained++;
}
}
if (pointsContained == 8)
{
return(ContainmentType.Contains);
}
else if (pointsContained == 0)
{
return(ContainmentType.Disjoint);
}
else
{
return(ContainmentType.Intersects);
}
}
public void GetCorners(out FrustumCorners corners)
{
PlaneIntersection(ref _planes.Near, ref _planes.Top, ref _planes.Left, out corners.NearTopLeft);
PlaneIntersection(ref _planes.Near, ref _planes.Top, ref _planes.Right, out corners.NearTopRight);
PlaneIntersection(ref _planes.Near, ref _planes.Bottom, ref _planes.Left, out corners.NearBottomLeft);
PlaneIntersection(ref _planes.Near, ref _planes.Bottom, ref _planes.Right, out corners.NearBottomRight);
PlaneIntersection(ref _planes.Far, ref _planes.Top, ref _planes.Left, out corners.FarTopLeft);
PlaneIntersection(ref _planes.Far, ref _planes.Top, ref _planes.Right, out corners.FarTopRight);
PlaneIntersection(ref _planes.Far, ref _planes.Bottom, ref _planes.Left, out corners.FarBottomLeft);
PlaneIntersection(ref _planes.Far, ref _planes.Bottom, ref _planes.Right, out corners.FarBottomRight);
}
public static unsafe void ComputeOrthographicBoundsForPerpectiveFrustum(
ref FrustumCorners corners,
ref Vector3 lightDir,
float cameraFarDistance,
out Matrix4x4 lightView,
out OrthographicBounds bounds)
{
float nearClipOffset = 40.0f;
Vector3 centroid =
(corners.NearTopLeft + corners.NearTopRight + corners.NearBottomLeft + corners.NearBottomRight
+ corners.FarTopLeft + corners.FarTopRight + corners.FarBottomLeft + corners.FarBottomRight)
/ 8f;
Vector3 lightOrigin = centroid - (lightDir * (cameraFarDistance + nearClipOffset));
lightView = Matrix4x4.CreateLookAt(lightOrigin, centroid, Vector3.UnitY);
float * lightSpaceCornerFloats = stackalloc float[3 * 8];
Vector3 *lightSpaceCorners = (Vector3 *)lightSpaceCornerFloats;
// Light-view-space
lightSpaceCorners[0] = Vector3.Transform(corners.NearTopLeft, lightView);
lightSpaceCorners[1] = Vector3.Transform(corners.NearTopRight, lightView);
lightSpaceCorners[2] = Vector3.Transform(corners.NearBottomLeft, lightView);
lightSpaceCorners[3] = Vector3.Transform(corners.NearBottomRight, lightView);
lightSpaceCorners[4] = Vector3.Transform(corners.FarTopLeft, lightView);
lightSpaceCorners[5] = Vector3.Transform(corners.FarTopRight, lightView);
lightSpaceCorners[6] = Vector3.Transform(corners.FarBottomLeft, lightView);
lightSpaceCorners[7] = Vector3.Transform(corners.FarBottomRight, lightView);
bounds.MinX = lightSpaceCorners[0].X;
bounds.MaxX = lightSpaceCorners[0].X;
bounds.MinY = lightSpaceCorners[0].Y;
bounds.MaxY = lightSpaceCorners[0].Y;
bounds.MinZ = lightSpaceCorners[0].Z;
bounds.MaxZ = lightSpaceCorners[0].Z;
for (int i = 1; i < 8; i++)
{
if (lightSpaceCorners[i].X < bounds.MinX)
{
bounds.MinX = lightSpaceCorners[i].X;
}
if (lightSpaceCorners[i].X > bounds.MaxX)
{
bounds.MaxX = lightSpaceCorners[i].X;
}
if (lightSpaceCorners[i].Y < bounds.MinY)
{
bounds.MinY = lightSpaceCorners[i].Y;
}
if (lightSpaceCorners[i].Y > bounds.MaxY)
{
bounds.MaxY = lightSpaceCorners[i].Y;
}
if (lightSpaceCorners[i].Z < bounds.MinZ)
{
bounds.MinZ = lightSpaceCorners[i].Z;
}
if (lightSpaceCorners[i].Z > bounds.MaxZ)
{
bounds.MaxZ = lightSpaceCorners[i].Z;
}
}
}
