From 964cf5eedf3c23d77374ac0b0f1d7f617a069f0a Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@gadgetoid.com>
Date: Mon, 11 Mar 2024 21:14:42 +0000
Subject: [PATCH] G/S/C Unicorn: Fix get_brightness to use correct max value.

Add a comment noting that 256 is the correct maximum brightness.
---
 libraries/cosmic_unicorn/cosmic_unicorn.cpp     | 5 ++++-
 libraries/galactic_unicorn/galactic_unicorn.cpp | 5 ++++-
 libraries/stellar_unicorn/stellar_unicorn.cpp   | 5 ++++-
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/libraries/cosmic_unicorn/cosmic_unicorn.cpp b/libraries/cosmic_unicorn/cosmic_unicorn.cpp
index b7d16ab7..0dfec9c4 100644
--- a/libraries/cosmic_unicorn/cosmic_unicorn.cpp
+++ b/libraries/cosmic_unicorn/cosmic_unicorn.cpp
@@ -494,11 +494,14 @@ namespace pimoroni {
   void CosmicUnicorn::set_brightness(float value) {
     value = value < 0.0f ? 0.0f : value;
     value = value > 1.0f ? 1.0f : value;
+    // Max brightness is - in fact - 256 since it's applied with:
+    // result = (channel * brightness) >> 8
+    // eg: (255 * 256) >> 8 == 255
     this->brightness = floor(value * 256.0f);
   }
 
   float CosmicUnicorn::get_brightness() {
-    return this->brightness / 255.0f;
+    return this->brightness / 256.0f;
   }
 
   void CosmicUnicorn::adjust_brightness(float delta) {
diff --git a/libraries/galactic_unicorn/galactic_unicorn.cpp b/libraries/galactic_unicorn/galactic_unicorn.cpp
index 44defb02..9bfc8465 100644
--- a/libraries/galactic_unicorn/galactic_unicorn.cpp
+++ b/libraries/galactic_unicorn/galactic_unicorn.cpp
@@ -488,11 +488,14 @@ namespace pimoroni {
   void GalacticUnicorn::set_brightness(float value) {
     value = value < 0.0f ? 0.0f : value;
     value = value > 1.0f ? 1.0f : value;
+    // Max brightness is - in fact - 256 since it's applied with:
+    // result = (channel * brightness) >> 8
+    // eg: (255 * 256) >> 8 == 255
     this->brightness = floor(value * 256.0f);
   }
 
   float GalacticUnicorn::get_brightness() {
-    return this->brightness / 255.0f;
+    return this->brightness / 256.0f;
   }
 
   void GalacticUnicorn::adjust_brightness(float delta) {
diff --git a/libraries/stellar_unicorn/stellar_unicorn.cpp b/libraries/stellar_unicorn/stellar_unicorn.cpp
index f71de50b..95e93229 100644
--- a/libraries/stellar_unicorn/stellar_unicorn.cpp
+++ b/libraries/stellar_unicorn/stellar_unicorn.cpp
@@ -485,11 +485,14 @@ namespace pimoroni {
   void StellarUnicorn::set_brightness(float value) {
     value = value < 0.0f ? 0.0f : value;
     value = value > 1.0f ? 1.0f : value;
+    // Max brightness is - in fact - 256 since it's applied with:
+    // result = (channel * brightness) >> 8
+    // eg: (255 * 256) >> 8 == 255
     this->brightness = floor(value * 256.0f);
   }
 
   float StellarUnicorn::get_brightness() {
-    return this->brightness / 255.0f;
+    return this->brightness / 256.0f;
   }
 
   void StellarUnicorn::adjust_brightness(float delta) {