1 files changed, 159 insertions, 0 deletions

diff --git a/apps/plugins/lua/include_lua/math_ex.lua b/apps/plugins/lua/include_lua/math_ex.lua
new file mode 100644
index 0000000000..bd4cc58765
--- /dev/null
+++ b/apps/plugins/lua/include_lua/math_ex.lua
@@ -0,0 +1,159 @@
+--[[ Lua Missing Math functions
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2017 William Wilgus
+ *
+ * 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+]]
+
+--[[ Exposed Functions
+
+    _math.clamp
+    _math.clamp_roll
+    _math.d_sin
+    _math.d_cos
+    _math.d_tan
+    _math.i_sqrt
+
+]]
+
+local _math = {} do
+
+    -- internal constants
+    local _NIL = nil -- _NIL placeholder
+
+   -- clamps value to >= min and <= max
+    local function clamp(iVal, iMin, iMax)
+        if iMin > iMax then
+            local swap = iMin
+            iMin, iMax = iMax, swap
+        end
+
+        if iVal < iMin then
+            return iMin
+        elseif iVal < iMax then
+            return iVal
+        end
+
+        return iMax
+    end
+
+   -- clamps value to >= min and <= max rolls over to opposite
+    local function clamp_roll(iVal, iMin, iMax)
+        if iMin > iMax then
+            local swap = iMin
+            iMin, iMax = iMax, swap
+        end
+
+        if iVal < iMin then
+            iVal = iMax
+        elseif iVal > iMax then
+            iVal = iMin
+        end
+
+        return iVal
+    end
+
+    local function i_sqrt(n)
+        -- Newtons square root approximation
+        if n < 2 then return n end
+        local g = n / 2
+        local l = 1
+
+        for c = 1, 25 do -- if l,g haven't converged after 25 iterations quit
+
+            l = (n / g + g)/ 2
+            g = (n / l + l)/ 2
+
+            if g == l then return g end
+        end
+
+        -- check for period-two cycle between g and l
+        if g - l == 1 then
+            return l
+        elseif l - g == 1 then
+            return g
+        end
+
+        return _NIL
+    end
+
+    local function d_sin(iDeg, bExtraPrecision)
+    --[[  values are returned multiplied by 10000
+          II  |  I       180-90   | 90-0
+         ---(--)---      -------(--)-------
+         III |  IV       180-270 | 270-360
+
+        sine is only positive in quadrants I , II => 0 - 180 degrees
+        sine 180-360 degrees is a reflection of sine 0-180
+        Bhaskara I's sine approximation formula isn't overly accurate
+        but it is close enough for rough image work.
+    ]]
+        local sign, x
+        -- no negative angles -10 degrees = 350 degrees
+        if iDeg < 0 then
+            x = 360 + (iDeg % 360)
+        else --keep rotation in 0-360 range
+            x = iDeg % 360
+        end
+
+        -- reflect II & I onto III & IV
+        if x > 180 then
+            sign = -1
+            x = x % 180
+        else
+            sign = 1
+        end
+
+        local x1 = x * (180 - x)
+
+        if bExtraPrecision then -- ~halves the largest errors
+            if x <= 22 or x >= 158 then
+                return sign * 39818 * x1 / (40497 - x1)
+            elseif (x >= 40 and x <= 56) or (x > 124 and x < 140) then
+                return sign * 40002 * x1 / (40450 - x1)
+            elseif (x > 31 and x < 71) or (x > 109 and x < 150) then
+                return sign * 40009 * x1 / (40470 - x1)
+            end
+        end
+
+        --multiplied by 10000 so no decimal in results (RB LUA is integer only)
+        return sign * 40000 * x1 / (40497 - x1)
+    end
+
+    local function d_cos(iDeg, bExtraPrecision)
+        --cos is just sine shifed by 90 degrees CCW
+        return d_sin(90 - iDeg, bExtraPrecision)
+    end
+
+    local function d_tan(iDeg, bExtraPrecision)
+        --tan = sin0 / cos0
+        return (d_sin(iDeg, bExtraPrecision) * 10000 / d_sin(90 - iDeg, bExtraPrecision))
+    end
+
+    --expose functions to the outside through _math table
+    _math.clamp       = clamp
+    _math.clamp_roll  = clamp_roll
+    _math.i_sqrt      = i_sqrt
+    _math.d_sin       = d_sin
+    _math.d_cos       = d_cos
+    _math.d_tan       = d_tan
+end -- missing math functions
+
+return _math
+