//! Utilities for world generation.

use base::ChunkPosition;

/// Deterministically a seed for the given chunk. This allows

/// different seeds to be used for different chunk.

pub fn shuffle_seed_for_chunk(seed: u64, chunk: ChunkPosition) -> u64 {

seed.wrapping_mul((chunk.x as u64).wrapping_add(1))

.wrapping_add((chunk.z as u64).wrapping_add(1))

}

/// Deterministically shuffles a seed for the given chunk and chunk column.

pub fn shuffle_seed_for_column(seed: u64, chunk: ChunkPosition, col_x: usize, col_z: usize) -> u64 {

shuffle_seed_for_chunk(seed, chunk)

.wrapping_add(2)

.wrapping_mul(((col_x as u64) << 4) + 4)

.wrapping_mul(col_z as u64 + 4)

}