Struct PowerTables 

pub struct PowerTables {
    pub factr: [[u32; 2]; 256],
    pub logint: [f64; 256],
}

Tables that voxlap precomputes once in initvoxlap and reuses across every meltsphere / setsphere call.

Both tables are indexed by an integer z ∈ [0, SETSPHMAXRAD):

• factr[z] is voxlap’s prime-decomposition cache. If z is prime, factr[z][0] == 0. If z is composite, factr[z][0] * factr[z][1] == z and factr[z][0] is the smallest prime divisor of z. factr[2][0] is forced to 0.
• logint[z] = ln(z) (natural log) for z >= 1; logint[0] is unused.

Used by PowerTables::build_tempfloatbuf to compute i^curpow cheaply: prime indices go through exp(ln(i) * curpow), composite indices fold into a multiplication of two already-computed entries (avoiding pow per index).

Fields

factr: [[u32; 2]; 256]

logint: [f64; 256]

Implementations

impl PowerTables

pub fn new() -> Self

Mirror of voxlap’s initvoxlap factr-/logint-init block (voxlap5.c:12224-12236). Sieves the prime decomposition and fills logint[i] = ln(i).

pub fn build_tempfloatbuf(&self, hitrad: i32, curpow: f32) -> [f32; 256]

Build a per-call tempfloatbuf such that tempfloatbuf[i] ≈ i.powf(curpow) for i ∈ [0, hitrad]. hitrad + 1 is filled with the IEEE-754 max-finite-float sentinel (0x7f7fffff) so the int-bit-pattern comparisons in meltsphere terminate cleanly at the table edge.

Port of voxlap5.c:10240-10252. hitrad is clamped to SETSPHMAXRAD - 2.

Trait Implementations

impl Clone for PowerTables

fn clone(&self) -> PowerTables

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PowerTables

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

Formats the value using the given formatter.

impl Default for PowerTables

fn default() -> Self

Returns the “default value” for a type.