public BlockID this[Vector3I pos]
{
get { return(this[pos.X, pos.Y, pos.Z]); }
set { this[pos.X, pos.Y, pos.Z] = value; }
}
/// <summary>
/// Gets the cells which intersect with the specified <see cref="Ray"/>.
/// </summary>
/// <param name="ray">The cell-relative <see cref="Ray"/>.</param>
/// <param name="maxDepth">The maximum search depth, which equals the maximum number of
/// returned points.</param>
/// <returns>An enumerable list of points, starting with the cell closest to the starting
/// point of the ray.</returns>
/// <remarks>
/// <para>The position and direction of the <paramref name="ray"/> must be in the cell
/// coordinate system.</para>
/// <para>The first cell which is returned refers to the cell in which the ray starts.</para>
/// </remarks>
public IEnumerable <Vector3I> GetCellsOnRay(Ray ray, int maxDepth)
{
// Implementation is based on:
// "A Fast Voxel Traversal Algorithm for Ray Tracing"
// John Amanatides, Andrew Woo
// http://www.cse.yorku.ca/~amana/research/grid.pdf
// http://www.devmaster.net/articles/raytracing_series/A%20faster%20voxel%20traversal%20algorithm%20for%20ray%20tracing.pdf
// NOTES:
// * This code assumes that the ray's position and direction are in 'cell coordinates', which means
// that one unit equals one cell in all directions.
// * When the ray doesn't start within the voxel grid, calculate the first position at which the
// ray could enter the grid. If it never enters the grid, there is nothing more to do here.
// * Also, it is important to test when the ray exits the voxel grid when the grid isn't infinite.
// * The Point3D structure is a simple structure having three integer fields (X, Y and Z).
if (float.IsNaN(ray.Position.X) || float.IsNaN(ray.Position.Y) || float.IsNaN(ray.Position.Z))
{
yield break;
}
int x = FastFloor(ray.Position.X);
int y = FastFloor(ray.Position.Y);
int z = FastFloor(ray.Position.Z);
// Determine which way we go.
int stepX = Math.Sign(ray.Direction.X);
int stepY = Math.Sign(ray.Direction.Y);
int stepZ = Math.Sign(ray.Direction.Z);
// Calculate cell boundaries. When the step (i.e. direction sign) is positive,
// the next boundary is AFTER our current position, meaning that we have to add 1.
// Otherwise, it is BEFORE our current position, in which case we add nothing.
//Point3D cellBoundary = new Point3D(
Vector3I cellBoundary = new Vector3I(
x + (stepX > 0 ? 1 : 0),
y + (stepY > 0 ? 1 : 0),
z + (stepZ > 0 ? 1 : 0));
// NOTE: For the following calculations, the result will be Single.PositiveInfinity
// when ray.Direction.X, Y or Z equals zero, which is OK. However, when the left-hand
// value of the division also equals zero, the result is Single.NaN, which is not OK.
// Determine how far we can travel along the ray before we hit a voxel boundary.
Vector3 tMax = new Vector3(
(cellBoundary.X - ray.Position.X) / ray.Direction.X, // Boundary is a plane on the YZ axis.
(cellBoundary.Y - ray.Position.Y) / ray.Direction.Y, // Boundary is a plane on the XZ axis.
(cellBoundary.Z - ray.Position.Z) / ray.Direction.Z); // Boundary is a plane on the XY axis.
if (Single.IsNaN(tMax.X))
{
tMax.X = Single.PositiveInfinity;
}
if (Single.IsNaN(tMax.Y))
{
tMax.Y = Single.PositiveInfinity;
}
if (Single.IsNaN(tMax.Z))
{
tMax.Z = Single.PositiveInfinity;
}
// Determine how far we must travel along the ray before we have crossed a gridcell.
Vector3 tDelta = new Vector3(
stepX / ray.Direction.X, // Crossing the width of a cell.
stepY / ray.Direction.Y, // Crossing the height of a cell.
stepZ / ray.Direction.Z); // Crossing the depth of a cell.
if (Single.IsNaN(tDelta.X))
{
tDelta.X = Single.PositiveInfinity;
}
if (Single.IsNaN(tDelta.Y))
{
tDelta.Y = Single.PositiveInfinity;
}
if (Single.IsNaN(tDelta.Z))
{
tDelta.Z = Single.PositiveInfinity;
}
// For each step, determine which distance to the next voxel boundary is lowest (i.e.
// which voxel boundary is nearest) and walk that way.
for (int i = 0; i < maxDepth; i++)
{
// Return it.
yield return(new Vector3(x, y, z).ToBlockCoords());
// Do the next step.
if (tMax.X < tMax.Y && tMax.X < tMax.Z)
{
// tMax.X is the lowest, an YZ cell boundary plane is nearest.
x += stepX;
tMax.X += tDelta.X;
}
else if (tMax.Y < tMax.Z)
{
// tMax.Y is the lowest, an XZ cell boundary plane is nearest.
y += stepY;
tMax.Y += tDelta.Y;
}
else
{
// tMax.Z is the lowest, an XY cell boundary plane is nearest.
z += stepZ;
tMax.Z += tDelta.Z;
}
}
}
public bool InBounds(Vector3I pos)
{
return(InBounds(pos.X, pos.Y, pos.Z));
}
public void Draw2D(object sender, Draw2DEventArgs e)
{
frameCounter++;
e.SpriteBatch.Begin();
if (!Client.Paused)
{
// Crosshair
e.SpriteBatch.Draw(Client.CrosshairTexture,
Client.WindowCenter, // Center of screen
null, // Source rectangle
Color.White, // Color
0f, // Rotation
new Vector2(Client.CrosshairTexture.Width, Client.CrosshairTexture.Height) / 2, // Image center
1f, // Scale
SpriteEffects.None,
0f // Depth
);
e.SpriteBatch.Draw(Client.EmptyTexture, Client.WindowCenter, Color.Red);
string fps = string.Format("FPS: {0}", frameRate);
e.SpriteBatch.DrawString(Client.Font, fps, Vector2.Zero, Color.White);
MouseState m = Mouse.GetState();
int mouseX = m.X;
int mouseY = m.Y;
Vector3 nearsource = new Vector3((float)mouseX, (float)mouseY, 0f);
Vector3 farsource = new Vector3((float)mouseX, (float)mouseY, 1f);
Vector3 nearPoint = Client.Viewport.Unproject(nearsource,
Client.MainPlayer.Camera.ProjectionMatrix,
Client.MainPlayer.Camera.ViewMatrix,
Matrix.Identity);
Vector3 farPoint = Client.Viewport.Unproject(farsource,
Client.MainPlayer.Camera.ProjectionMatrix,
Client.MainPlayer.Camera.ViewMatrix,
Matrix.Identity);
Vector3 direction = farPoint - nearPoint;
direction.Normalize();
//Matrix rotationMatrix = Matrix.CreateRotationX(Client.MainPlayer.Camera.Rotation.X) *
// Matrix.CreateRotationY(Client.MainPlayer.Camera.Rotation.Y);
//distance = Vector3.Transform(distance, rotationMatrix);
Ray r = new Ray(nearPoint.Center(), direction);
foreach (Vector3I coord in GetCellsOnRay(r, 15))
{
BlockID id = Client.MainWorld[coord];
Vector3 renderPos = coord.ToRenderCoords();
Vector3 min = new Vector3(renderPos.X - 1f, renderPos.Y - 1f, renderPos.Z - 1f);
Vector3 max = new Vector3(renderPos.X + 1f, renderPos.Y + 1f, renderPos.Z + 1f);
float i = Vector3.Distance(Client.MainPlayer.Camera.Position, renderPos);
if (i < 2)
{
continue;
}
if (id != BlockID.None && id != BlockID.Air)
{
e.SpriteBatch.DrawString(Client.Font, "Looking: " + id + " - " + i, new Vector2(0, 80), Color.White);
BoundingBoxRenderer.Render(new BoundingBox(min, max),
Client.Device,
Client.MainPlayer.Camera.ViewMatrix,
Client.MainPlayer.Camera.ProjectionMatrix,
Color.Red);
Selected = coord;
break;
}
else
{
BoundingBoxRenderer.Render(new BoundingBox(min, max),
Client.Device,
Client.MainPlayer.Camera.ViewMatrix,
Client.MainPlayer.Camera.ProjectionMatrix,
Color.White);
}
}
if (Mouse.GetState().LeftButton == ButtonState.Pressed &&
Client.MainWorld[Selected] != BlockID.None &&
Client.MainWorld[Selected] != BlockID.Air)
{
Client.MainWorld[Selected] = BlockID.Air;
}
}
else
{
AnchoredText t = new AnchoredText(Client.Font, "PAUSED: " + Client.Version, Client.WindowCenter, TextAnchor.MiddleCenter);
t.Draw(e.SpriteBatch);
}
e.SpriteBatch.End();
}
