Enum AlphaComparison 

pub enum AlphaComparison {
    Output,
    Transformed,
    Dithered {
        scale_word: u32,
    },
    Unwritten,
}

What a discard compares against a constant word (an alpha reference), proved from the program’s data flow (iridia::output_uses::discard_compares).

Variants

Output

The output alpha itself (including unchanged branch arms).

Transformed

A scalar that reaches output alpha through arithmetic. Cutting the output is an approximation.

Dithered

A pre-transform alpha plus (dither.a - 0.5) * scale. scale_word is a word offset in the reference’s own buffer. A hard cutoff on output alpha approximates the program’s stochastic, pre-transform test.

Fields

scale_word: u32

Word offset of the dither scale in the reference’s own buffer.

Unwritten

The discard compares a value made of texture samples and constants that reaches no target’s alpha (a G-buffer program writes none: t1.w * t0.w + scale * (noise - 0.5) < reference). The test is the program’s own expression, read exactly from its graph (iridia::output_uses::alpha_tests); a cutoff on any output alpha is not it, and a consumer that cuts evaluates that expression, or does not cut.

Trait Implementations

impl Clone for AlphaComparison

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for AlphaComparison

impl Debug for AlphaComparison

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

Formats the value using the given formatter.

impl Eq for AlphaComparison

impl PartialEq for AlphaComparison

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for AlphaComparison

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for AlphaComparison