lerpAa

lerpAa is a term used in computer graphics to describe a variant of linear interpolation that integrates anti-aliasing considerations into the blend between two values, typically colors or samples. It extends the ordinary lerp by introducing an anti-aliasing factor that modulates the blend based on local geometry or sample coverage, with the aim of reducing jagged edges during scaling, filtering, or sampling operations.

In many formulations, the standard lerp is written as L(a, b, t) = (1 − t) a + t b, where t ranges from 0 to 1. lerpAa modifies the interpolation weight with a coverage or anti-alias factor c in [0, 1]. A common representation is LerpAa(a, b, t, c) = (1 − t)(1 − c) a + t c b, or, equivalently, using an effective weight t_eff = t c + (1 − t)(1 − c). In practice, c may be derived from a local anti-aliasing filter, sample neighborhood, or per-sample coverage. The result is a blended value that preserves smoother transitions at edges or fine details.

Applications of lerpAa occur in shader pipelines, texture sampling, image resampling, and UI rendering where anti-aliasing is desirable during interpolation. The term is not standardized across the field, and implementations vary in how c is computed and applied. Related concepts include standard lerp, alpha-aware interpolation, and anti-aliasing techniques in graphics pipelines.

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