[light] Replace powf gamma correction with Python-generated PROGMEM LUTs

Replace runtime powf() calls in light gamma correction with
pre-computed uint16[256] PROGMEM lookup tables generated at
Python codegen time. The gamma value is a compile-time constant,
so the tables can be computed once and shared across all lights
with the same gamma value.

This eliminates powf/ieee754_powf (~2.3KB) from the binary.
Two 512-byte PROGMEM tables (forward + reverse) are shared per
unique gamma value, for a net savings of ~1.3KB flash and zero
RAM impact.

The LUT uses linear interpolation between table entries,
achieving zero PWM errors at both 8-bit and 16-bit resolution
compared to the old powf-based approach.

Breaking change: gamma parameter removed from
LightColorValues::as_*() methods since gamma correction is now
applied externally via LightState::gamma_correct_lut().
gamma_correct() and gamma_uncorrect() in helpers.h are
deprecated (removal in 2026.12.0).

esphome/components/esp32/core.cpp

@@ -47,6 +47,7 @@ void arch_init() {
 void HOT arch_feed_wdt() { esp_task_wdt_reset(); }
 
 uint8_t progmem_read_byte(const uint8_t *addr) { return *addr; }
+uint16_t progmem_read_uint16(const uint16_t *addr) { return *addr; }
 uint32_t arch_get_cpu_cycle_count() { return esp_cpu_get_cycle_count(); }
 uint32_t arch_get_cpu_freq_hz() {
   uint32_t freq = 0;

esphome/components/esp8266/core.cpp

@@ -32,6 +32,9 @@ void HOT arch_feed_wdt() { system_soft_wdt_feed(); }
 uint8_t progmem_read_byte(const uint8_t *addr) {
   return pgm_read_byte(addr);  // NOLINT
 }
+uint16_t progmem_read_uint16(const uint16_t *addr) {
+  return pgm_read_word(addr);  // NOLINT
+}
 uint32_t IRAM_ATTR HOT arch_get_cpu_cycle_count() { return esp_get_cycle_count(); }
 uint32_t arch_get_cpu_freq_hz() { return F_CPU; }
 

esphome/components/host/core.cpp

@@ -53,6 +53,7 @@ void HOT arch_feed_wdt() {
 }
 
 uint8_t progmem_read_byte(const uint8_t *addr) { return *addr; }
+uint16_t progmem_read_uint16(const uint16_t *addr) { return *addr; }
 uint32_t arch_get_cpu_cycle_count() {
   struct timespec spec;
   clock_gettime(CLOCK_MONOTONIC, &spec);

esphome/components/libretiny/core.cpp

@@ -34,6 +34,7 @@ void HOT arch_feed_wdt() { lt_wdt_feed(); }
 uint32_t arch_get_cpu_cycle_count() { return lt_cpu_get_cycle_count(); }
 uint32_t arch_get_cpu_freq_hz() { return lt_cpu_get_freq(); }
 uint8_t progmem_read_byte(const uint8_t *addr) { return *addr; }
+uint16_t progmem_read_uint16(const uint16_t *addr) { return *addr; }
 
 }  // namespace esphome
 

esphome/components/light/__init__.py

@@ -1,3 +1,4 @@
+from dataclasses import dataclass, field
 import enum
 
 import esphome.automation as auto
@@ -37,7 +38,7 @@ from esphome.const import (
     CONF_WEB_SERVER,
     CONF_WHITE,
 )
-from esphome.core import CORE, CoroPriority, coroutine_with_priority
+from esphome.core import CORE, ID, CoroPriority, HexInt, coroutine_with_priority
 from esphome.core.entity_helpers import entity_duplicate_validator, setup_entity
 from esphome.cpp_generator import MockObjClass
 
@@ -66,6 +67,42 @@ from .types import (  # noqa
 CODEOWNERS = ["@esphome/core"]
 IS_PLATFORM_COMPONENT = True
 
+DOMAIN = "light"
+
+
+@dataclass
+class LightData:
+    gamma_tables: dict = field(
+        default_factory=dict
+    )  # gamma_value -> (fwd_arr, rev_arr)
+
+
+def _get_data() -> LightData:
+    if DOMAIN not in CORE.data:
+        CORE.data[DOMAIN] = LightData()
+    return CORE.data[DOMAIN]
+
+
+def _get_or_create_gamma_table(gamma_correct):
+    data = _get_data()
+    if gamma_correct in data.gamma_tables:
+        return data.gamma_tables[gamma_correct]
+
+    if gamma_correct > 0:
+        forward = [
+            HexInt(min(65535, int(round((i / 255.0) ** gamma_correct * 65535))))
+            for i in range(256)
+        ]
+    else:
+        forward = [HexInt(int(round(i / 255.0 * 65535))) for i in range(256)]
+
+    gamma_str = f"{gamma_correct}".replace(".", "_")
+    fwd_id = ID(f"gamma_{gamma_str}_fwd", is_declaration=True, type=cg.uint16)
+    fwd_arr = cg.progmem_array(fwd_id, forward)
+    data.gamma_tables[gamma_correct] = fwd_arr
+    return fwd_arr
+
+
 LightRestoreMode = light_ns.enum("LightRestoreMode")
 RESTORE_MODES = {
     "RESTORE_DEFAULT_OFF": LightRestoreMode.LIGHT_RESTORE_DEFAULT_OFF,
@@ -239,6 +276,8 @@ async def setup_light_core_(light_var, output_var, config):
         cg.add(light_var.set_flash_transition_length(flash_transition_length))
     if (gamma_correct := config.get(CONF_GAMMA_CORRECT)) is not None:
         cg.add(light_var.set_gamma_correct(gamma_correct))
+        fwd_arr = _get_or_create_gamma_table(gamma_correct)
+        cg.add(light_var.set_gamma_table(fwd_arr))
     effects = await cg.build_registry_list(
         EFFECTS_REGISTRY, config.get(CONF_EFFECTS, [])
     )

esphome/components/light/addressable_light.h

@@ -66,7 +66,7 @@ class AddressableLight : public LightOutput, public Component {
         Color(to_uint8_scale(red), to_uint8_scale(green), to_uint8_scale(blue), to_uint8_scale(white)));
   }
   void setup_state(LightState *state) override {
-    this->correction_.calculate_gamma_table(state->get_gamma_correct());
+    this->correction_.set_gamma_table(state->get_gamma_table());
     this->state_parent_ = state;
   }
   void update_state(LightState *state) override;

esphome/components/light/addressable_light_wrapper.h

@@ -74,11 +74,10 @@ class AddressableLightWrapper : public light::AddressableLight {
       return;
     }
 
-    float gamma = this->light_state_->get_gamma_correct();
-    float r = gamma_uncorrect(this->wrapper_state_[0] / 255.0f, gamma);
-    float g = gamma_uncorrect(this->wrapper_state_[1] / 255.0f, gamma);
-    float b = gamma_uncorrect(this->wrapper_state_[2] / 255.0f, gamma);
-    float w = gamma_uncorrect(this->wrapper_state_[3] / 255.0f, gamma);
+    float r = this->light_state_->gamma_uncorrect_lut(this->wrapper_state_[0] / 255.0f);
+    float g = this->light_state_->gamma_uncorrect_lut(this->wrapper_state_[1] / 255.0f);
+    float b = this->light_state_->gamma_uncorrect_lut(this->wrapper_state_[2] / 255.0f);
+    float w = this->light_state_->gamma_uncorrect_lut(this->wrapper_state_[3] / 255.0f);
 
     auto call = this->light_state_->make_call();
 

esphome/components/light/esp_color_correction.cpp

@@ -1,25 +1,25 @@
 #include "esp_color_correction.h"
-#include "light_color_values.h"
-#include "esphome/core/log.h"
 
 namespace esphome::light {
 
-void ESPColorCorrection::calculate_gamma_table(float gamma) {
-  for (uint16_t i = 0; i < 256; i++) {
-    // corrected = val ^ gamma
-    auto corrected = to_uint8_scale(gamma_correct(i / 255.0f, gamma));
-    this->gamma_table_[i] = corrected;
-  }
-  if (gamma == 0.0f) {
-    for (uint16_t i = 0; i < 256; i++)
-      this->gamma_reverse_table_[i] = i;
-    return;
-  }
-  for (uint16_t i = 0; i < 256; i++) {
-    // val = corrected ^ (1/gamma)
-    auto uncorrected = to_uint8_scale(powf(i / 255.0f, 1.0f / gamma));
-    this->gamma_reverse_table_[i] = uncorrected;
-  }
+uint8_t ESPColorCorrection::gamma_correct_(uint8_t value) const {
+  if (this->gamma_table_ == nullptr)
+    return value;
+  return static_cast<uint8_t>((progmem_read_uint16(&this->gamma_table_[value]) + 128) / 257);
+}
+
+uint8_t ESPColorCorrection::gamma_uncorrect_(uint8_t value) const {
+  if (this->gamma_table_ == nullptr)
+    return value;
+  if (value == 0)
+    return 0;
+  uint16_t target = value * 257;  // Scale 0-255 to 0-65535
+  uint8_t lo = gamma_table_reverse_search(this->gamma_table_, target);
+  if (lo >= 255)
+    return 255;
+  uint16_t a = progmem_read_uint16(&this->gamma_table_[lo]);
+  uint16_t b = progmem_read_uint16(&this->gamma_table_[lo + 1]);
+  return (target - a <= b - target) ? lo : lo + 1;
 }
 
 }  // namespace esphome::light

esphome/components/light/esp_color_correction.h

@@ -1,15 +1,29 @@
 #pragma once
 
 #include "esphome/core/color.h"
+#include "esphome/core/hal.h"
 
 namespace esphome::light {
 
+/// Binary search a monotonically increasing uint16[256] PROGMEM table.
+/// Returns the largest index where table[index] <= target.
+inline uint8_t gamma_table_reverse_search(const uint16_t *table, uint16_t target) {
+  uint8_t lo = 0, hi = 255;
+  while (lo < hi) {
+    uint8_t mid = (lo + hi + 1) / 2;
+    if (progmem_read_uint16(&table[mid]) <= target)
+      lo = mid;
+    else
+      hi = mid - 1;
+  }
+  return lo;
+}
+
 class ESPColorCorrection {
  public:
-  ESPColorCorrection() : max_brightness_(255, 255, 255, 255) {}
   void set_max_brightness(const Color &max_brightness) { this->max_brightness_ = max_brightness; }
   void set_local_brightness(uint8_t local_brightness) { this->local_brightness_ = local_brightness; }
-  void calculate_gamma_table(float gamma);
+  void set_gamma_table(const uint16_t *table) { this->gamma_table_ = table; }
   inline Color color_correct(Color color) const ESPHOME_ALWAYS_INLINE {
     // corrected = (uncorrected * max_brightness * local_brightness) ^ gamma
     return Color(this->color_correct_red(color.red), this->color_correct_green(color.green),
@@ -17,19 +31,19 @@ class ESPColorCorrection {
   }
   inline uint8_t color_correct_red(uint8_t red) const ESPHOME_ALWAYS_INLINE {
     uint8_t res = esp_scale8_twice(red, this->max_brightness_.red, this->local_brightness_);
-    return this->gamma_table_[res];
+    return this->gamma_correct_(res);
   }
   inline uint8_t color_correct_green(uint8_t green) const ESPHOME_ALWAYS_INLINE {
     uint8_t res = esp_scale8_twice(green, this->max_brightness_.green, this->local_brightness_);
-    return this->gamma_table_[res];
+    return this->gamma_correct_(res);
   }
   inline uint8_t color_correct_blue(uint8_t blue) const ESPHOME_ALWAYS_INLINE {
     uint8_t res = esp_scale8_twice(blue, this->max_brightness_.blue, this->local_brightness_);
-    return this->gamma_table_[res];
+    return this->gamma_correct_(res);
   }
   inline uint8_t color_correct_white(uint8_t white) const ESPHOME_ALWAYS_INLINE {
     uint8_t res = esp_scale8_twice(white, this->max_brightness_.white, this->local_brightness_);
-    return this->gamma_table_[res];
+    return this->gamma_correct_(res);
   }
   inline Color color_uncorrect(Color color) const ESPHOME_ALWAYS_INLINE {
     // uncorrected = corrected^(1/gamma) / (max_brightness * local_brightness)
@@ -39,36 +53,40 @@ class ESPColorCorrection {
   inline uint8_t color_uncorrect_red(uint8_t red) const ESPHOME_ALWAYS_INLINE {
     if (this->max_brightness_.red == 0 || this->local_brightness_ == 0)
       return 0;
-    uint16_t uncorrected = this->gamma_reverse_table_[red] * 255UL;
+    uint16_t uncorrected = this->gamma_uncorrect_(red) * 255UL;
     uint16_t res = ((uncorrected / this->max_brightness_.red) * 255UL) / this->local_brightness_;
     return (uint8_t) std::min(res, uint16_t(255));
   }
   inline uint8_t color_uncorrect_green(uint8_t green) const ESPHOME_ALWAYS_INLINE {
     if (this->max_brightness_.green == 0 || this->local_brightness_ == 0)
       return 0;
-    uint16_t uncorrected = this->gamma_reverse_table_[green] * 255UL;
+    uint16_t uncorrected = this->gamma_uncorrect_(green) * 255UL;
     uint16_t res = ((uncorrected / this->max_brightness_.green) * 255UL) / this->local_brightness_;
     return (uint8_t) std::min(res, uint16_t(255));
   }
   inline uint8_t color_uncorrect_blue(uint8_t blue) const ESPHOME_ALWAYS_INLINE {
     if (this->max_brightness_.blue == 0 || this->local_brightness_ == 0)
       return 0;
-    uint16_t uncorrected = this->gamma_reverse_table_[blue] * 255UL;
+    uint16_t uncorrected = this->gamma_uncorrect_(blue) * 255UL;
     uint16_t res = ((uncorrected / this->max_brightness_.blue) * 255UL) / this->local_brightness_;
     return (uint8_t) std::min(res, uint16_t(255));
   }
   inline uint8_t color_uncorrect_white(uint8_t white) const ESPHOME_ALWAYS_INLINE {
     if (this->max_brightness_.white == 0 || this->local_brightness_ == 0)
       return 0;
-    uint16_t uncorrected = this->gamma_reverse_table_[white] * 255UL;
+    uint16_t uncorrected = this->gamma_uncorrect_(white) * 255UL;
     uint16_t res = ((uncorrected / this->max_brightness_.white) * 255UL) / this->local_brightness_;
     return (uint8_t) std::min(res, uint16_t(255));
   }
 
  protected:
-  uint8_t gamma_table_[256];
-  uint8_t gamma_reverse_table_[256];
-  Color max_brightness_;
+  /// Forward gamma: read uint16 PROGMEM table, convert to uint8
+  uint8_t gamma_correct_(uint8_t value) const;
+  /// Reverse gamma: binary search the forward PROGMEM table
+  uint8_t gamma_uncorrect_(uint8_t value) const;
+
+  const uint16_t *gamma_table_{nullptr};
+  Color max_brightness_{255, 255, 255, 255};
   uint8_t local_brightness_{255};
 };
 

esphome/components/light/light_call.cpp

@@ -389,9 +389,8 @@ void LightCall::transform_parameters_() {
       const float ww_fraction = (color_temp - min_mireds) / range;
       const float cw_fraction = 1.0f - ww_fraction;
       const float max_cw_ww = std::max(ww_fraction, cw_fraction);
-      const float gamma = this->parent_->get_gamma_correct();
-      this->cold_white_ = gamma_uncorrect(cw_fraction / max_cw_ww, gamma);
-      this->warm_white_ = gamma_uncorrect(ww_fraction / max_cw_ww, gamma);
+      this->cold_white_ = this->parent_->gamma_uncorrect_lut(cw_fraction / max_cw_ww);
+      this->warm_white_ = this->parent_->gamma_uncorrect_lut(ww_fraction / max_cw_ww);
       this->set_flag_(FLAG_HAS_COLD_WHITE);
       this->set_flag_(FLAG_HAS_WARM_WHITE);
     }

esphome/components/light/light_color_values.h

@@ -111,60 +111,54 @@ class LightColorValues {
     }
   }
 
-  // Note that method signature of as_* methods is kept as-is for compatibility reasons, so not all parameters
-  // are always used or necessary. Methods will be deprecated later.
-
   /// Convert these light color values to a binary representation and write them to binary.
   void as_binary(bool *binary) const { *binary = this->state_ == 1.0f; }
 
   /// Convert these light color values to a brightness-only representation and write them to brightness.
-  void as_brightness(float *brightness, float gamma = 0) const {
-    *brightness = gamma_correct(this->state_ * this->brightness_, gamma);
-  }
+  void as_brightness(float *brightness) const { *brightness = this->state_ * this->brightness_; }
 
   /// Convert these light color values to an RGB representation and write them to red, green, blue.
-  void as_rgb(float *red, float *green, float *blue, float gamma = 0, bool color_interlock = false) const {
+  void as_rgb(float *red, float *green, float *blue) const {
     if (this->color_mode_ & ColorCapability::RGB) {
       float brightness = this->state_ * this->brightness_ * this->color_brightness_;
-      *red = gamma_correct(brightness * this->red_, gamma);
-      *green = gamma_correct(brightness * this->green_, gamma);
-      *blue = gamma_correct(brightness * this->blue_, gamma);
+      *red = brightness * this->red_;
+      *green = brightness * this->green_;
+      *blue = brightness * this->blue_;
     } else {
       *red = *green = *blue = 0;
     }
   }
 
   /// Convert these light color values to an RGBW representation and write them to red, green, blue, white.
-  void as_rgbw(float *red, float *green, float *blue, float *white, float gamma = 0,
-               bool color_interlock = false) const {
-    this->as_rgb(red, green, blue, gamma);
+  void as_rgbw(float *red, float *green, float *blue, float *white) const {
+    this->as_rgb(red, green, blue);
     if (this->color_mode_ & ColorCapability::WHITE) {
-      *white = gamma_correct(this->state_ * this->brightness_ * this->white_, gamma);
+      *white = this->state_ * this->brightness_ * this->white_;
     } else {
       *white = 0;
     }
   }
 
   /// Convert these light color values to an RGBWW representation with the given parameters.
-  void as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white, float gamma = 0,
+  void as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white,
                 bool constant_brightness = false) const {
-    this->as_rgb(red, green, blue, gamma);
-    this->as_cwww(cold_white, warm_white, gamma, constant_brightness);
+    this->as_rgb(red, green, blue);
+    this->as_cwww(cold_white, warm_white, constant_brightness);
   }
 
   /// Convert these light color values to an RGB+CT+BR representation with the given parameters.
   void as_rgbct(float color_temperature_cw, float color_temperature_ww, float *red, float *green, float *blue,
-                float *color_temperature, float *white_brightness, float gamma = 0) const {
-    this->as_rgb(red, green, blue, gamma);
-    this->as_ct(color_temperature_cw, color_temperature_ww, color_temperature, white_brightness, gamma);
+                float *color_temperature, float *white_brightness) const {
+    this->as_rgb(red, green, blue);
+    this->as_ct(color_temperature_cw, color_temperature_ww, color_temperature, white_brightness);
   }
 
   /// Convert these light color values to an CWWW representation with the given parameters.
-  void as_cwww(float *cold_white, float *warm_white, float gamma = 0, bool constant_brightness = false) const {
+  void as_cwww(float *cold_white, float *warm_white, bool constant_brightness = false) const {
     if (this->color_mode_ & ColorCapability::COLD_WARM_WHITE) {
-      const float cw_level = gamma_correct(this->cold_white_, gamma);
-      const float ww_level = gamma_correct(this->warm_white_, gamma);
-      const float white_level = gamma_correct(this->state_ * this->brightness_, gamma);
+      const float cw_level = this->cold_white_;
+      const float ww_level = this->warm_white_;
+      const float white_level = this->state_ * this->brightness_;
       if (!constant_brightness) {
         *cold_white = white_level * cw_level;
         *warm_white = white_level * ww_level;
@@ -184,13 +178,13 @@ class LightColorValues {
   }
 
   /// Convert these light color values to a CT+BR representation with the given parameters.
-  void as_ct(float color_temperature_cw, float color_temperature_ww, float *color_temperature, float *white_brightness,
-             float gamma = 0) const {
+  void as_ct(float color_temperature_cw, float color_temperature_ww, float *color_temperature,
+             float *white_brightness) const {
     const float white_level = this->color_mode_ & ColorCapability::RGB ? this->white_ : 1;
     if (this->color_mode_ & ColorCapability::COLOR_TEMPERATURE) {
       *color_temperature =
           (this->color_temperature_ - color_temperature_cw) / (color_temperature_ww - color_temperature_cw);
-      *white_brightness = gamma_correct(this->state_ * this->brightness_ * white_level, gamma);
+      *white_brightness = this->state_ * this->brightness_ * white_level;
     } else {  // Probably won't get here but put this here anyway.
       *white_brightness = 0;
     }

esphome/components/light/light_state.cpp

@@ -1,4 +1,5 @@
 #include "light_state.h"
+#include "esp_color_correction.h"
 #include "esphome/core/defines.h"
 #include "esphome/core/controller_registry.h"
 #include "esphome/core/log.h"
@@ -204,31 +205,86 @@ void LightState::add_effects(const std::initializer_list<LightEffect *> &effects
 
 void LightState::current_values_as_binary(bool *binary) { this->current_values.as_binary(binary); }
 void LightState::current_values_as_brightness(float *brightness) {
-  this->current_values.as_brightness(brightness, this->gamma_correct_);
+  this->current_values.as_brightness(brightness);
+  *brightness = this->gamma_correct_lut(*brightness);
 }
 void LightState::current_values_as_rgb(float *red, float *green, float *blue, bool color_interlock) {
-  this->current_values.as_rgb(red, green, blue, this->gamma_correct_, false);
+  this->current_values.as_rgb(red, green, blue);
+  *red = this->gamma_correct_lut(*red);
+  *green = this->gamma_correct_lut(*green);
+  *blue = this->gamma_correct_lut(*blue);
 }
 void LightState::current_values_as_rgbw(float *red, float *green, float *blue, float *white, bool color_interlock) {
-  this->current_values.as_rgbw(red, green, blue, white, this->gamma_correct_, false);
+  this->current_values.as_rgbw(red, green, blue, white);
+  *red = this->gamma_correct_lut(*red);
+  *green = this->gamma_correct_lut(*green);
+  *blue = this->gamma_correct_lut(*blue);
+  *white = this->gamma_correct_lut(*white);
 }
 void LightState::current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white,
                                          bool constant_brightness) {
-  this->current_values.as_rgbww(red, green, blue, cold_white, warm_white, this->gamma_correct_, constant_brightness);
+  this->current_values.as_rgbww(red, green, blue, cold_white, warm_white, constant_brightness);
+  *red = this->gamma_correct_lut(*red);
+  *green = this->gamma_correct_lut(*green);
+  *blue = this->gamma_correct_lut(*blue);
+  *cold_white = this->gamma_correct_lut(*cold_white);
+  *warm_white = this->gamma_correct_lut(*warm_white);
 }
 void LightState::current_values_as_rgbct(float *red, float *green, float *blue, float *color_temperature,
                                          float *white_brightness) {
   auto traits = this->get_traits();
   this->current_values.as_rgbct(traits.get_min_mireds(), traits.get_max_mireds(), red, green, blue, color_temperature,
-                                white_brightness, this->gamma_correct_);
+                                white_brightness);
+  *red = this->gamma_correct_lut(*red);
+  *green = this->gamma_correct_lut(*green);
+  *blue = this->gamma_correct_lut(*blue);
+  *white_brightness = this->gamma_correct_lut(*white_brightness);
 }
 void LightState::current_values_as_cwww(float *cold_white, float *warm_white, bool constant_brightness) {
-  this->current_values.as_cwww(cold_white, warm_white, this->gamma_correct_, constant_brightness);
+  this->current_values.as_cwww(cold_white, warm_white, constant_brightness);
+  *cold_white = this->gamma_correct_lut(*cold_white);
+  *warm_white = this->gamma_correct_lut(*warm_white);
 }
 void LightState::current_values_as_ct(float *color_temperature, float *white_brightness) {
   auto traits = this->get_traits();
-  this->current_values.as_ct(traits.get_min_mireds(), traits.get_max_mireds(), color_temperature, white_brightness,
-                             this->gamma_correct_);
+  this->current_values.as_ct(traits.get_min_mireds(), traits.get_max_mireds(), color_temperature, white_brightness);
+  *white_brightness = this->gamma_correct_lut(*white_brightness);
+}
+
+float LightState::gamma_correct_lut(float value) const {
+  if (value <= 0.0f)
+    return 0.0f;
+  if (value >= 1.0f)
+    return 1.0f;
+  if (this->gamma_table_ == nullptr)
+    return value;
+  float scaled = value * 255.0f;
+  auto idx = static_cast<uint8_t>(scaled);
+  if (idx >= 255)
+    return progmem_read_uint16(&this->gamma_table_[255]) / 65535.0f;
+  float frac = scaled - idx;
+  float a = progmem_read_uint16(&this->gamma_table_[idx]);
+  float b = progmem_read_uint16(&this->gamma_table_[idx + 1]);
+  return (a + frac * (b - a)) / 65535.0f;
+}
+float LightState::gamma_uncorrect_lut(float value) const {
+  if (value <= 0.0f)
+    return 0.0f;
+  if (value >= 1.0f)
+    return 1.0f;
+  if (this->gamma_table_ == nullptr)
+    return value;
+  uint16_t target = static_cast<uint16_t>(value * 65535.0f);
+  uint8_t lo = gamma_table_reverse_search(this->gamma_table_, target);
+  // Interpolate between lo and lo+1
+  uint16_t a = progmem_read_uint16(&this->gamma_table_[lo]);
+  if (lo >= 255)
+    return 1.0f;
+  uint16_t b = progmem_read_uint16(&this->gamma_table_[lo + 1]);
+  if (b == a)
+    return lo / 255.0f;
+  float frac = static_cast<float>(target - a) / static_cast<float>(b - a);
+  return (lo + frac) / 255.0f;
 }
 
 bool LightState::is_transformer_active() { return this->is_transformer_active_; }

esphome/components/light/light_state.h

@@ -11,6 +11,7 @@
 #include "light_traits.h"
 #include "light_transformer.h"
 
+#include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include <strings.h>
 #include <vector>
@@ -166,6 +167,17 @@ class LightState : public EntityBase, public Component {
   void set_gamma_correct(float gamma_correct);
   float get_gamma_correct() const { return this->gamma_correct_; }
 
+  /// Set pre-computed gamma forward lookup table (256-entry uint16 PROGMEM array)
+  void set_gamma_table(const uint16_t *forward) { this->gamma_table_ = forward; }
+
+  /// Get the forward gamma lookup table
+  const uint16_t *get_gamma_table() const { return this->gamma_table_; }
+
+  /// Apply gamma correction using the pre-computed forward LUT
+  float gamma_correct_lut(float value) const;
+  /// Reverse gamma correction by binary-searching the forward LUT
+  float gamma_uncorrect_lut(float value) const;
+
   /// Set the restore mode of this light
   void set_restore_mode(LightRestoreMode restore_mode);
 
@@ -297,6 +309,8 @@ class LightState : public EntityBase, public Component {
   uint32_t flash_transition_length_{};
   /// Gamma correction factor for the light.
   float gamma_correct_{};
+  const uint16_t *gamma_table_{nullptr};
+
   /// Whether the light value should be written in the next cycle.
   bool next_write_{true};
   // for effects, true if a transformer (transition) is active.

esphome/components/rp2040/core.cpp

@@ -32,6 +32,7 @@ void HOT arch_feed_wdt() { watchdog_update(); }
 uint8_t progmem_read_byte(const uint8_t *addr) {
   return pgm_read_byte(addr);  // NOLINT
 }
+uint16_t progmem_read_uint16(const uint16_t *addr) { return *addr; }
 uint32_t IRAM_ATTR HOT arch_get_cpu_cycle_count() { return ulMainGetRunTimeCounterValue(); }
 uint32_t arch_get_cpu_freq_hz() { return RP2040::f_cpu(); }
 

esphome/core/hal.h

@@ -41,5 +41,6 @@ void arch_feed_wdt();
 uint32_t arch_get_cpu_cycle_count();
 uint32_t arch_get_cpu_freq_hz();
 uint8_t progmem_read_byte(const uint8_t *addr);
+uint16_t progmem_read_uint16(const uint16_t *addr);
 
 }  // namespace esphome

esphome/core/helpers.h

@@ -1350,8 +1350,12 @@ bool base64_decode_int32_vector(const std::string &base64, std::vector<int32_t>
 ///@{
 
 /// Applies gamma correction of \p gamma to \p value.
+// Remove before 2026.12.0
+ESPDEPRECATED("Use LightState::gamma_correct_lut() instead. Removed in 2026.12.0.", "2026.6.0")
 float gamma_correct(float value, float gamma);
 /// Reverts gamma correction of \p gamma to \p value.
+// Remove before 2026.12.0
+ESPDEPRECATED("Use LightState::gamma_uncorrect_lut() instead. Removed in 2026.12.0.", "2026.6.0")
 float gamma_uncorrect(float value, float gamma);
 
 /// Convert \p red, \p green and \p blue (all 0-1) values to \p hue (0-360), \p saturation (0-1) and \p value (0-1).