From 6cbfa854f186a4a0889525e3f2869d8e2f47cb71 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <cfr34k-git@tkolb.de>
Date: Mon, 25 Nov 2019 22:02:00 +0100
Subject: [PATCH] Fader: flip logical addressing in specific sub-strips
MIME-Version: 1.0
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This is useful if „displays“ are build using zig-zag interconnection of
the single strips
---
 include/Fader.h |  8 +++-----
 src/Fader.cpp   | 12 +++++++++++-
 src/main.cpp    |  7 ++++---
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/include/Fader.h b/include/Fader.h
index 4a42222..9a496dd 100644
--- a/include/Fader.h
+++ b/include/Fader.h
@@ -28,7 +28,7 @@ class Fader
         };
 
 
-        Fader(std::size_t nstrips, std::size_t nmodules_per_strip, uint8_t fadestep = 1);
+        Fader(std::size_t nstrips, std::size_t nmodules_per_strip, uint8_t fadestep = 1, uint32_t flip_strips_mask = 0x00);
 
         void set_color(uint32_t strip, uint32_t module, const Color &color);
         void fade_color(uint32_t strip, uint32_t module, const Color &color);
@@ -63,14 +63,12 @@ class Fader
          */
         bool update_fade(int16_t *cur, const int16_t *target);
 
-        inline uint32_t make_module_idx(uint32_t strip, uint32_t module)
-        {
-            return strip * m_modulesPerStrip + module;
-        }
+        inline uint32_t make_module_idx(uint32_t strip, uint32_t module);
 
         std::size_t m_strips;
         std::size_t m_modulesPerStrip;
         uint8_t m_fadestep;
+        uint32_t m_flipStripsMask;
         bool m_somethingChanged;
 
         std::vector<Color> m_curColor;
diff --git a/src/Fader.cpp b/src/Fader.cpp
index a9db117..ffcd9bf 100644
--- a/src/Fader.cpp
+++ b/src/Fader.cpp
@@ -1,9 +1,10 @@
 #include "Fader.h"
 
-Fader::Fader(std::size_t nstrips, std::size_t nmodules_per_strip, uint8_t fadestep)
+Fader::Fader(std::size_t nstrips, std::size_t nmodules_per_strip, uint8_t fadestep, uint32_t flip_strips_mask)
 	: m_strips(nstrips),
 	  m_modulesPerStrip(nmodules_per_strip),
 	  m_fadestep(fadestep),
+	  m_flipStripsMask(flip_strips_mask),
 	  m_curColor(nstrips * nmodules_per_strip),
 	  m_targetColor(nstrips * nmodules_per_strip)
 {}
@@ -107,3 +108,12 @@ void Fader::update(void)
 		m_somethingChanged =  update_fade(&(m_curColor[i].w), &(m_targetColor[i].w)) || m_somethingChanged;
 	}
 }
+
+uint32_t Fader::make_module_idx(uint32_t strip, uint32_t module)
+{
+	bool flip = m_flipStripsMask & (1 << strip);
+	if(flip) {
+		module = m_modulesPerStrip - module - 1;
+	}
+	return strip * m_modulesPerStrip + module;
+}
diff --git a/src/main.cpp b/src/main.cpp
index 7e74986..efe0889 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,8 +14,9 @@
 #include <esp32_digital_led_funcs.h>
 
 const uint32_t FRAME_INTERVAL_US = 16666;
-const uint32_t NUM_STRIPS = 2;
-const uint32_t NUM_LEDS = 69;
+const uint32_t NUM_STRIPS = 8;
+const uint32_t NUM_LEDS = 16;
+const uint32_t FLIP_STRIPS_MASK = 0x000000AA;
 
 std::array<strand_t, 1> STRANDS { // Avoid using any of the strapping pins on the ESP32, anything >=32, 16, 17... not much left.
   strand_t {.rmtChannel = 0, .gpioNum = 4, .ledType = LED_SK6812W_V1, .brightLimit = 32, .numPixels = NUM_LEDS * NUM_STRIPS},
@@ -28,7 +29,7 @@ size_t frame;
 
 WiFiMulti wiFiMulti;
 
-Fader ledFader(NUM_STRIPS, NUM_LEDS);
+Fader ledFader(NUM_STRIPS, NUM_LEDS, 1, FLIP_STRIPS_MASK);
 UDPProto udpProto(&ledFader);
 
 bool initLEDs()