Added support for APA102 LED strips

[kaka/cakelight.git] / src / kaka / cakelight / LedFrame.java

diff --git a/src/kaka/cakelight/LedFrame.java b/src/kaka/cakelight/LedFrame.java
index ab4ef5c..a0e1404 100644 (file)
--- a/src/kaka/cakelight/LedFrame.java
+++ b/src/kaka/cakelight/LedFrame.java
@@ -1,14 +1,45 @@
 package kaka.cakelight;
 
+import java.util.Arrays;
+
 public class LedFrame {
     private Configuration config;
     private byte[] bytes;
-    private int roff = 0, goff = 2, boff = 1; // Color values are stored as RBG, which is what the LED list takes.
+    private int stride;
+    private int roff, goff, boff; // RGB offsets
 
     public static LedFrame from(Configuration config) {
         LedFrame frame = new LedFrame();
         frame.config = config;
-        frame.bytes = new byte[config.leds.getCount() * 3];
+        switch (config.leds.type) {
+            /*
+             * The WS2801 strip takes its input as a plain list of 24-bit colors in RBG order (at least mine did).
+             */
+            case WS2801:
+                frame.stride = 3;
+                frame.roff = 0;
+                frame.goff = 2;
+                frame.boff = 1;
+                frame.bytes = new byte[config.leds.getCount() * frame.stride];
+                break;
+
+            /*
+             * The APA102 strip takes its input as:
+             * <ol>
+             * <li>a start frame of 4 bytes (all zeroes)</li>
+             * <li>a frame of 4 bytes for each LED (111 (3 bits) + global illumination (5 bits) + BGR)</li>
+             * <li>an (optional) end frame of 4 bytes (all ones)</li>
+             * </ol>
+             */
+            case APA102:
+                frame.stride = 4;
+                frame.roff = 3 + 4;
+                frame.goff = 2 + 4;
+                frame.boff = 1 + 4;
+                frame.bytes = new byte[4 + config.leds.getCount() * frame.stride + 4];
+                Arrays.fill(frame.bytes, 4, frame.bytes.length - 1, (byte)0xff); // Initiate the first byte of each LED + the end frame with ones
+                break;
+        }
         return frame;
     }
 
@@ -18,7 +49,7 @@ public class LedFrame {
 
     public void fillColor(Color color) {
         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) {
+        for (int i = 0; i < bytes.length; i += stride) {
             bytes[i + roff] = r;
             bytes[i + goff] = g;
             bytes[i + boff] = b;
@@ -26,14 +57,14 @@ public class LedFrame {
     }
 
     public void setLedColor(int led, Color color) {
-        int offset = led * 3;
+        int offset = led * stride;
         bytes[offset + roff] = (byte)color.r();
         bytes[offset + goff] = (byte)color.g();
         bytes[offset + boff] = (byte)color.b();
     }
 
     public Color getLedColor(int led) {
-        int offset = led * 3;
+        int offset = led * stride;
         return Color.rgb(
                 bytes[offset + roff] & 0xff,
                 bytes[offset + goff] & 0xff,