private bool IsInViewingFrustum(GameClient gameClient, EntityOffset offset, ChunkPos chunkPos)
{
/* Check if the bounding sphere of the chunk is in the viewing frustum. */
var df = (double)GeometryConstants.ChunkSize;
// Determine the chunk center relative to the viewer.
double dx = (chunkPos.X + 0.5) * df - offset.X;
double dy = (chunkPos.Y + 0.5) * df - offset.Y;
double dz = (chunkPos.Z + 0.5) * df - offset.Z;
double t0, t1;
// Perform mouselook rotation
double ha = gameClient.PositionData.Placement.Orientation.Horizontal;
double hc = Math.Cos(ha), hs = Math.Sin(ha);
t0 = dx * hc - dz * hs; t1 = dz * hc + dx * hs; dx = t0; dz = t1;
double va = -gameClient.PositionData.Placement.Orientation.Vertical;
double vc = Math.Cos(va), vs = Math.Sin(va);
t0 = dz * vc - dy * vs; t1 = dy * vc + dz * vs; dz = t0; dy = t1;
// Check if the chunk is behind the viewer.
if (dz > ChunkRadius && dz > ChunkRadius) return false;
/* TODO: We can discard even more chunks by taking the left, right, top and bottom planes into account. */
return true;
}
public static void MoveEntity(PhysicsValues physicsValues, World world, PositionData positionData, GameDuration elapsedDuration, EntityOffset offset)
{
offset.Y -= 0.5 * elapsedDuration.Seconds * physicsValues.Gravity;
if (MoveY(physicsValues, world, positionData, offset.Y * elapsedDuration.Seconds))
{
positionData.IsFalling = false;
}
else
{
if (!positionData.IsFalling)
{
/* Re-evaluate the fall from the apparent position. */
positionData.InternalPos = positionData.Placement.Pos;
MoveY(physicsValues, world, positionData, offset.Y * elapsedDuration.Seconds);
positionData.IsFalling = true;
}
}
if (positionData.IsFalling)
{
offset.Y -= 0.5 * elapsedDuration.Seconds * physicsValues.Gravity;
}
else
{
if (Math.Abs(offset.Y) > Math.Sqrt(2 * physicsValues.Gravity * physicsValues.TerminalHeight))
{
Respawn(positionData);
}
offset.Y = 0;
}
if (offset.X != 0 || offset.Z != 0)
{
long savedY = positionData.InternalPos.Y;
if (!positionData.IsFalling && world[(BlockPos)positionData.InternalPos - BlockOffset.UnitY] != 0)
{
// Temporarily move the character up a block so that it can climb up stairs.
MoveY(physicsValues, world, positionData, 1);
}
EntityPos positionBeforeMovement = positionData.InternalPos;
double moveX = offset.X * elapsedDuration.Seconds;
double moveZ = offset.Z * elapsedDuration.Seconds;
if (offset.X > offset.Z)
{
MoveX(physicsValues, world, positionData, moveX);
MoveZ(physicsValues, world, positionData, moveZ);
}
else
{
MoveZ(physicsValues, world, positionData, moveZ);
MoveX(physicsValues, world, positionData, moveX);
}
var moveDelta = positionData.InternalPos - positionBeforeMovement;
moveX -= moveDelta.X;
moveZ -= moveDelta.Z;
if (!positionData.IsFalling)
{
// Attempt to move the character back down to the ground in case we didn't climb a stair.
MoveY(physicsValues, world, positionData, (savedY - positionData.InternalPos.Y) / (double)(1L << 32));
savedY = positionData.InternalPos.Y;
// Attempt to move the caracter down an additional block so that it can walk down stairs.
if (!MoveY(physicsValues, world, positionData, -((1L << 32) + 1) / (double)(1L << 32)))
{
positionData.InternalPos.Y = savedY;
positionData.IsFalling = true;
}
}
// Attempt to continue movement at this new (lower) Y position.
if (offset.X > offset.Z)
{
if (MoveX(physicsValues, world, positionData, moveX)) offset.X = 0;
if (MoveZ(physicsValues, world, positionData, moveZ)) offset.Z = 0;
}
else
{
if (MoveZ(physicsValues, world, positionData, moveZ)) offset.Z = 0;
if (MoveX(physicsValues, world, positionData, moveX)) offset.X = 0;
}
}
positionData.Velocity = offset;
SetPositionFromCollisionPosition(physicsValues, world, positionData);
}
private static void SetPositionFromCollisionPosition(PhysicsValues physicsValues, World world, PositionData positionData)
{
if (positionData.IsFalling)
{
positionData.Placement.Pos = positionData.InternalPos;
return;
}
var entityPos = positionData.InternalPos;
var blockPos = (BlockPos)entityPos;
/*
* When standing on an edge, the entities bottom center might be hanging in the air.
* Find the true floor position by iterating downward and looking for the floor.
*/
if (world[blockPos] == 0 && world[blockPos - BlockOffset.UnitY] == 0)
{
blockPos -= BlockOffset.UnitY;
entityPos -= EntityOffset.UnitY;
if (world[blockPos - new BlockOffset(0, 2, 0)] == 0)
{
blockPos -= BlockOffset.UnitY;
entityPos -= EntityOffset.UnitY;
}
}
var entityOffset = entityPos - blockPos;
double yOffset = 0;
/*
* Take the integral of all floor heights in a 2 by 2 area around the center.
* Since the height is piecewise constant, this is a weighted sum of the heights around the entity position.
*/
yOffset += (1 - entityOffset.X) * FindHeight(world, blockPos - BlockOffset.UnitX);
yOffset += entityOffset.X * FindHeight(world, blockPos + BlockOffset.UnitX);
yOffset += (1 - entityOffset.Z) * FindHeight(world, blockPos - BlockOffset.UnitZ);
yOffset += entityOffset.Z * FindHeight(world, blockPos + BlockOffset.UnitZ);
yOffset += (1 - entityOffset.X) * (1 - entityOffset.Z) * FindHeight(world, blockPos + new BlockOffset(-1, 0, -1));
yOffset += (1 - entityOffset.X) * entityOffset.Z * FindHeight(world, blockPos + new BlockOffset(-1, 0, 1));
yOffset += entityOffset.X * (1 - entityOffset.Z) * FindHeight(world, blockPos + new BlockOffset(1, 0, -1));
yOffset += entityOffset.X * entityOffset.Z * FindHeight(world, blockPos + new BlockOffset(1, 0, 1));
// Normalize.
yOffset *= 0.25;
entityPos += new EntityOffset(0, yOffset, 0);
positionData.Placement.Pos = entityPos;
}
public RayCastResult CastRay(EntityPos entityPos, EntityOffset direction, double max)
{
long x = entityPos.X, y = entityPos.Y, z = entityPos.Z;
double dx = direction.X, dy = direction.Y, dz = direction.Z;
int sdx = (int)Math.Sign(dx);
int sdy = (int)Math.Sign(dy);
int sdz = (int)Math.Sign(dz);
if (sdx == 0 && sdy == 0 && sdz == 0)
{
return null;
}
const long edgeLength = 1L << 32;
const double oneOverEdge = 1.0 / edgeLength;
var blockPos = (BlockPos)entityPos;
if (this[blockPos] != 0)
{
return new RayCastResult { EntityPos = entityPos, BlockPos = blockPos };
}
while (max > 0 && IsNumber(max))
{
/* Check which edge of the current block is hit first */
long edgeX;
if (sdx > 0)
{
edgeX = (x + edgeLength) & _upperMask;
}
else
{
edgeX = (x - 1) & _upperMask;
}
double tx = (edgeX - x) * oneOverEdge / dx;
long edgeY;
if (sdy > 0)
{
edgeY = (y + edgeLength) & _upperMask;
}
else
{
edgeY = (y - 1) & _upperMask;
}
double ty = (edgeY - y) * oneOverEdge / dy;
long edgeZ;
if (sdz > 0)
{
edgeZ = (z + edgeLength) & _upperMask;
}
else
{
edgeZ = (z - 1) & _upperMask;
}
double tz = (edgeZ - z) * oneOverEdge / dz;
if (Math.Abs(edgeX - x) > edgeLength || Math.Abs(edgeY - y) > edgeLength
|| Math.Abs(edgeZ - z) > edgeLength)
{
// Shouldn't happen.
throw new Exception();
}
if (IsNumber(tx) && (tx <= ty || !IsNumber(ty)) && (tx <= tz || !IsNumber(tz)))
{
x = edgeX;
y += (long)(tx * dy * edgeLength);
z += (long)(tx * dz * edgeLength);
max -= tx;
blockPos.X += sdx;
if (max >= 0 && this[blockPos] != 0)
{
return new RayCastResult { EntityPos = new EntityPos(x, y, z), BlockPos = blockPos, Normal = new BlockOffset(-sdx, 0, 0) };
}
}
else if (IsNumber(ty) && (ty <= tz || !IsNumber(tz)))
{
x += (long)(ty * dx * edgeLength);
y = edgeY;
z += (long)(ty * dz * edgeLength);
max -= ty;
blockPos.Y += sdy;
if (max >= 0 && this[blockPos] != 0)
{
return new RayCastResult { EntityPos = new EntityPos(x, y, z), BlockPos = blockPos, Normal = new BlockOffset(0, -sdy, 0) };
}
}
else if (IsNumber(tz))
{
x += (long)(tz * dx * edgeLength);
y += (long)(tz * dy * edgeLength);
z = edgeZ;
max -= tz;
blockPos.Z += sdz;
if (max >= 0 && this[blockPos] != 0)
{
return new RayCastResult { EntityPos = new EntityPos(x, y, z), BlockPos = blockPos, Normal = new BlockOffset(0, 0, -sdz) };
}
}
else
{
// Shouldn't happen.
throw new Exception();
}
}
return null;
}
