From 38c759f87fc7de47d9dee60088f2dbc60e0a55fb Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tomas=20Wenstr=C3=B6m?= <tomas.wenstrom@gmail.com>
Date: Mon, 5 Jun 2017 22:04:03 +0200
Subject: [PATCH] Added gamma correction

---
 config.properties                     |  2 ++
 src/kaka/cakelight/CakeLight.java     |  1 +
 src/kaka/cakelight/Color.java         | 14 +++++++++++---
 src/kaka/cakelight/Configuration.java |  2 ++
 src/kaka/cakelight/LedFrame.java      | 13 +++++++------
 5 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/config.properties b/config.properties
index 4fec08b..7e04ee2 100644
--- a/config.properties
+++ b/config.properties
@@ -14,3 +14,5 @@ video.crop.bottom=18
 
 leds.cols=32
 leds.rows=17
+
+gamma=1.5
diff --git a/src/kaka/cakelight/CakeLight.java b/src/kaka/cakelight/CakeLight.java
index 5401c0f..c51a534 100644
--- a/src/kaka/cakelight/CakeLight.java
+++ b/src/kaka/cakelight/CakeLight.java
@@ -8,6 +8,7 @@ public class CakeLight {
     public CakeLight(Configuration config, LedController ledController) {
         this.config = config;
         this.ledController = ledController;
+        Color.calculateGammaCorrection(config.gamma);
     }
 
     public void setMode(Mode mode) {
diff --git a/src/kaka/cakelight/Color.java b/src/kaka/cakelight/Color.java
index 1e92da9..0756209 100644
--- a/src/kaka/cakelight/Color.java
+++ b/src/kaka/cakelight/Color.java
@@ -1,6 +1,14 @@
 package kaka.cakelight;
 
 public class Color {
+    private static int[] gammaCorrection = new int[256];
+
+    public static void calculateGammaCorrection(double gamma) {
+        for (int i = 0, max = 255; i <= max; i++) {
+            gammaCorrection[i] = (int)(Math.pow((double)i / max, gamma) * max);
+        }
+    }
+
     private int r, g, b;
 
     public static Color rgb(double r, double g, double b) {
@@ -35,15 +43,15 @@ public class Color {
     }
 
     public int r() {
-        return r;
+        return gammaCorrection[r];
     }
 
     public int g() {
-        return g;
+        return gammaCorrection[g];
     }
 
     public int b() {
-        return b;
+        return gammaCorrection[b];
     }
 
     public Color interpolate(Color other, double value) {
diff --git a/src/kaka/cakelight/Configuration.java b/src/kaka/cakelight/Configuration.java
index 2932c01..86ade8e 100644
--- a/src/kaka/cakelight/Configuration.java
+++ b/src/kaka/cakelight/Configuration.java
@@ -12,10 +12,12 @@ public class Configuration {
     private List<Map.Entry<String, String>> settings = new ArrayList<>();
     public VideoConfiguration video;
     public LedConfiguration leds;
+    public double gamma;
 
     private Configuration(Properties prop) {
         video = new VideoConfiguration(prop);
         leds = new LedConfiguration(prop);
+        gamma = Double.parseDouble(get(prop,"gamma", "1"));
     }
 
     public static Configuration from(String propertiesFile) {
diff --git a/src/kaka/cakelight/LedFrame.java b/src/kaka/cakelight/LedFrame.java
index 9d95b0c..ab4ef5c 100644
--- a/src/kaka/cakelight/LedFrame.java
+++ b/src/kaka/cakelight/LedFrame.java
@@ -13,15 +13,16 @@ public class LedFrame {
     }
 
     public void fillColor(int r, int g, int b) {
-        for (int i = 0; i < bytes.length; i += 3) {
-            bytes[i + roff] = (byte)r;
-            bytes[i + goff] = (byte)g;
-            bytes[i + boff] = (byte)b;
-        }
+        fillColor(Color.rgb(r, g, b));
     }
 
     public void fillColor(Color color) {
-        fillColor(color.r(), color.g(), color.b());
+        byte r = (byte)color.r(), g = (byte)color.g(), b = (byte)color.b(); // Gamma corrected values
+        for (int i = 0; i < bytes.length; i += 3) {
+            bytes[i + roff] = r;
+            bytes[i + goff] = g;
+            bytes[i + boff] = b;
+        }
     }
 
     public void setLedColor(int led, Color color) {
-- 
2.11.0