Struct LpVec3 

pub struct LpVec3 {
    pub x: f64,
    pub y: f64,
    pub z: f64,
}

Three doubles compressed into a shared-scale, low-precision vector.

LpVec3 normally occupies six bytes. The coordinates are divided by their rounded-up maximum absolute value, quantized into three unsigned 15-bit values, and packed with a shared scale factor:

X: 15 bits | Y: 15 bits | Z: 15 bits | continuation: 1 bit | scale: 2 bits

The first two packed bytes are written in little-endian order, while the remaining four bytes are written in big-endian order. If the scale factor is greater than three, its upper bits follow as a VarInt. A vector whose greatest absolute coordinate is below 1 / 32766, or which contains NaN, is encoded as the single byte 0x00 and decodes as zero.

This format is used by the Java Edition Spawn Entity and Set Entity Velocity packets.

Examples

use mcproto_types::{TypeCodec, basic::LpVec3};

let value = LpVec3::new(10.0, 0.2, -5.0);
let mut encoded = Vec::new();
value.encode(&mut encoded)?;
assert_eq!(encoded, [0xf6, 0xff, 0x40, 0x01, 0x05, 0x1f, 0x02]);

let mut input = encoded.as_slice();
let decoded = LpVec3::decode(&mut input)?;
assert!((decoded.x - value.x).abs() < 0.001);
assert!((decoded.y - value.y).abs() < 0.001);
assert!((decoded.z - value.z).abs() < 0.001);
assert!(input.is_empty());

Fields

x: f64

The x coordinate.

y: f64

The y coordinate.

z: f64

The z coordinate.

Implementations

impl LpVec3

pub const MAX_QUANTIZED_VALUE: f64 = 32766.0

Greatest quantized coordinate value stored in a 15-bit field.

pub const ZERO_THRESHOLD: f64

Coordinates below this absolute maximum use the one-byte zero form.

pub const MAX_SCALE_FACTOR: u64

Greatest shared scale factor representable by two low bits and a 32-bit VarInt continuation.

pub const fn new(x: f64, y: f64, z: f64) -> Self

Creates a low-precision vector from its coordinates.

Trait Implementations

impl Clone for LpVec3

fn clone(&self) -> LpVec3

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for LpVec3

impl Debug for LpVec3

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for LpVec3

fn default() -> LpVec3

Returns the “default value” for a type.

impl PartialEq for LpVec3

fn eq(&self, other: &LpVec3) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for LpVec3

impl TypeCodec for LpVec3

fn encode(&self, writer: &mut impl Write) -> Result<(), CodecError>

Encodes this value to the writer.

fn decode(reader: &mut impl Read) -> Result<Self, CodecError>

Decodes this value from the reader.