From 8db3f67be4c2331c4719b96ab1db953e6b2faf18 Mon Sep 17 00:00:00 2001 From: "J. Nick Koston" Date: Mon, 23 Feb 2026 17:22:21 -0600 Subject: [PATCH] [light] Replace std::lerp with lightweight fast_lerp in LightColorValues::lerp std::lerp includes NaN/infinity edge-case handling per C++20 spec, which generates ~200 bytes of overhead per call. With 10 fields interpolated, this bloated the symbol to 2,038 bytes. Since all light color values are pre-clamped finite floats, a simple a + t * (b - a) is sufficient. Reduces LightColorValues::lerp from 2,038 B to 286 B (86% reduction). --- .../components/light/light_color_values.cpp | 28 ++++++++++--------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/esphome/components/light/light_color_values.cpp b/esphome/components/light/light_color_values.cpp index 2f22bb3c688..391179acfc0 100644 --- a/esphome/components/light/light_color_values.cpp +++ b/esphome/components/light/light_color_values.cpp @@ -1,27 +1,29 @@ #include "light_color_values.h" -#include - namespace esphome::light { +// Lightweight lerp without std::lerp's NaN/infinity handling overhead. +// Safe here because all color values are pre-clamped finite floats. +static inline float fast_lerp(float a, float b, float t) { return a + t * (b - a); } + LightColorValues LightColorValues::lerp(const LightColorValues &start, const LightColorValues &end, float completion) { // Directly interpolate the raw values to avoid getter/setter overhead. // This is safe because: // - All LightColorValues have their values clamped when set via the setters - // - std::lerp guarantees output is in the same range as inputs + // - fast_lerp output stays in range when inputs are in range and 0 <= completion <= 1 // - Therefore the output doesn't need clamping, so we can skip the setters LightColorValues v; v.color_mode_ = end.color_mode_; - v.state_ = std::lerp(start.state_, end.state_, completion); - v.brightness_ = std::lerp(start.brightness_, end.brightness_, completion); - v.color_brightness_ = std::lerp(start.color_brightness_, end.color_brightness_, completion); - v.red_ = std::lerp(start.red_, end.red_, completion); - v.green_ = std::lerp(start.green_, end.green_, completion); - v.blue_ = std::lerp(start.blue_, end.blue_, completion); - v.white_ = std::lerp(start.white_, end.white_, completion); - v.color_temperature_ = std::lerp(start.color_temperature_, end.color_temperature_, completion); - v.cold_white_ = std::lerp(start.cold_white_, end.cold_white_, completion); - v.warm_white_ = std::lerp(start.warm_white_, end.warm_white_, completion); + v.state_ = fast_lerp(start.state_, end.state_, completion); + v.brightness_ = fast_lerp(start.brightness_, end.brightness_, completion); + v.color_brightness_ = fast_lerp(start.color_brightness_, end.color_brightness_, completion); + v.red_ = fast_lerp(start.red_, end.red_, completion); + v.green_ = fast_lerp(start.green_, end.green_, completion); + v.blue_ = fast_lerp(start.blue_, end.blue_, completion); + v.white_ = fast_lerp(start.white_, end.white_, completion); + v.color_temperature_ = fast_lerp(start.color_temperature_, end.color_temperature_, completion); + v.cold_white_ = fast_lerp(start.cold_white_, end.cold_white_, completion); + v.warm_white_ = fast_lerp(start.warm_white_, end.warm_white_, completion); return v; }