From 3a916b4ef29b3ae5db11e2086878089b05f80537 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Thu, 14 Mar 2019 03:19:22 -0500
Subject: [PATCH] Create bresenham.h

---
 Marlin/src/libs/bresenham.h | 132 ++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 Marlin/src/libs/bresenham.h

diff --git a/Marlin/src/libs/bresenham.h b/Marlin/src/libs/bresenham.h
new file mode 100644
index 0000000000..139c3ba801
--- /dev/null
+++ b/Marlin/src/libs/bresenham.h
@@ -0,0 +1,132 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include "../core/serial.h"
+
+/**
+ * bresenham_t.h - Bresenham algorithm template
+ *
+ * An array of values / counters that tick together
+ */
+
+#define FORCE_INLINE  __attribute__((always_inline)) inline
+#define _O3           __attribute__((optimize("O3")))
+
+template <uint8_t uid, uint8_t size>
+struct BresenhamCfg { static constexpr uint8_t UID = uid, SIZE = size; };
+
+template<typename T, typename Cfg>
+class Bresenham {
+private:
+
+  static constexpr T signtest = -1;
+  static_assert(signtest < 0, "Bresenham type must be signed!");
+
+public:
+
+  static T divisor, value[Cfg::SIZE], dir[Cfg::SIZE], dividend[Cfg::SIZE], counter[Cfg::SIZE];
+
+  // Default: Instantiate all items with the identical parameters
+  Bresenham(const T &inDivisor=1, const int8_t &inDir=1, const T &inDividend=1, const T &inValue=0) {
+    for (uint8_t i = 0; i < Cfg::SIZE; i++) init(i, inDivisor, inDir, inDividend, inValue);
+  }
+
+  // Instantiate all items with the same divisor
+  Bresenham(const T &inDivisor, const int8_t (&inDir)[Cfg::SIZE], const T (&inDividend)[Cfg::SIZE], const T (&inValue)[Cfg::SIZE]={0}) {
+    init(inDivisor, inDir, inDividend, inValue);
+  }
+
+  // Instantiate all items with the same divisor and direction
+  Bresenham(const T &inDivisor, const int8_t &inDir, const T (&inDividend)[Cfg::SIZE], const T (&inValue)[Cfg::SIZE]={0}) {
+    init(inDivisor, inDir, inDividend, inValue);
+  }
+
+  // Init all items with the same parameters
+  FORCE_INLINE static void init(const uint8_t index, const T &inDivisor=1, const int8_t &inDir=1, const T &inDividend=1, const T &inValue=0) {
+    divisor         = inDivisor;
+    dir[index]      = inDir;
+    dividend[index] = inDividend;
+    value[index]    = inValue;
+    prime(index);
+  }
+
+  // Init all items with the same divisor
+  FORCE_INLINE static void init(const T &inDivisor, const int8_t (&inDir)[Cfg::SIZE], const T (&inDividend)[Cfg::SIZE], const T (&inValue)[Cfg::SIZE]={0}) {
+    divisor = inDivisor;
+    for (uint8_t i = 0; i < Cfg::SIZE; i++) {
+      dir[i]      = inDir[i];
+      dividend[i] = inDividend[i];
+      value[i]    = inValue[i];
+    }
+    prime();
+  }
+
+  // Init all items with the same divisor and direction
+  FORCE_INLINE static void init(const T &inDivisor, const int8_t &inDir, const T (&inDividend)[Cfg::SIZE], const T (&inValue)[Cfg::SIZE]={0}) {
+    divisor = inDivisor;
+    for (uint8_t i = 0; i < Cfg::SIZE; i++) {
+      dir[i]      = inDir;
+      dividend[i] = inDividend[i];
+      value[i]    = inValue[i];
+    }
+    prime();
+  }
+
+  // Reinit item with new dir, dividend, value keeping the same divisor
+  FORCE_INLINE static void reinit(const uint8_t index, const int8_t &inDir=1, const T &inDividend=1, const T &inValue=0) {
+    dir[index]      = inDir;
+    dividend[index] = inDividend;
+    value[index]    = inValue;
+    prime();
+  }
+
+  FORCE_INLINE static void prime(const uint8_t index) { counter[index] = -(divisor / 2); }
+  FORCE_INLINE static void prime() { for (uint8_t i = 0; i < Cfg::SIZE; i++) prime(i); }
+
+  FORCE_INLINE static void back(const uint8_t index) { counter[index] -= divisor; }
+
+  FORCE_INLINE static bool tick1(const uint8_t index) {
+    counter[index] += dividend[index];
+    return counter[index] > 0;
+  }
+
+  FORCE_INLINE static void tick(const uint8_t index) {
+    if (tick1(index)) { value[index] += dir[index]; back(index); }
+  }
+
+  FORCE_INLINE static void tick1() _O3 { for (uint8_t i = 0; i < Cfg::SIZE; i++) (void)tick1(i); }
+
+  FORCE_INLINE static void tick() _O3 { for (uint8_t i = 0; i < Cfg::SIZE; i++) (void)tick(i); }
+
+  static void report(const uint8_t index) {
+    if (index < Cfg::SIZE) {
+      SERIAL_ECHOPAIR("bresenham ", int(index), " : (", dividend[index], "/", divisor, ") ");
+      if (counter[index] >= 0) SERIAL_CHAR(' ');
+      if (labs(counter[index]) < 100) { SERIAL_CHAR(' '); if (labs(counter[index]) < 10) SERIAL_CHAR(' '); }
+      SERIAL_ECHO(counter[index]);
+      SERIAL_ECHOLNPAIR(" ... ", value[index]);
+    }
+  }
+
+  static void report() { for (uint8_t i = 0; i < Cfg::SIZE; i++) report(i); }
+};