[editor] Toggleable rotation mechanic and improve threshold (#542)

* [editor] Toggle rotation mechanic and improve threshold

Make the "Enable rotation patches" work as a toggle between the current rotation behaviour and the old 1.5.9 rotation.
editor_gui field might need a renaming.

* added threshold variable

Author: chris1384

[editor]/editor_main/client/rotation.lua

@@ -1,15 +1,16 @@
 local rotationFixes = {}
 local elementQuat = {}
+local fromQuatThreshold = 0.499999999
 
 function loadRotationFixXML()
 	local xmlRoot = xmlLoadFile("client/rotation_fix.xml")
 	if not xmlRoot then
 		outputDebugString("Cannot load rotation_fix.xml")
 		return false
 	end
-	
+
 	rotationFixes = {}
-	
+
 	local models = xmlNodeGetChildren(xmlRoot)
 	for k,model in ipairs(models) do
 		local id = tonumber(xmlNodeGetAttribute(model, "id"))
@@ -24,9 +25,9 @@ function loadRotationFixXML()
 			outputDebugString("Incorrect entry in rotation_fix.xml")
 		end
 	end
-	
+
 	xmlUnloadFile(xmlRoot)
-	
+
 	return true
 end
 
@@ -43,7 +44,7 @@ function applyIncrementalRotation(element, axis, angle, world_space)
 	local offset_quat -- Normalized
 	local arad = math.rad(angle)
 	local sina = math.sin(arad / 2)
-	
+
 	if axis == "yaw" then
 		offset_quat = {
 			sina, 0, 0
@@ -60,7 +61,10 @@ function applyIncrementalRotation(element, axis, angle, world_space)
 		return false
 	end
 	offset_quat[4] = math.cos(arad / 2)
-	
+
+	-- Get rotation patch userdata
+	local enableRotPatch = exports["editor_gui"]:sx_getOptionData("enableRotPatch")
+
 	-- Get current rotation
 	local cur_quat
 	if elementQuat[element] then
@@ -71,7 +75,7 @@ function applyIncrementalRotation(element, axis, angle, world_space)
 		if euler_rot[1] == 0 and euler_rot[2] == 0 and euler_rot[3] == 0 then
 			-- Is there a fix and are rotation patches enabled
 			local id = getElementModel(element)
-			if rotationFixes[id] and exports["editor_gui"]:sx_getOptionData("enableRotPatch") then
+			if rotationFixes[id] and enableRotPatch then
 				-- Rotate from the fix
 				cur_quat = {unpack(rotationFixes[id])}
 			else
@@ -83,20 +87,27 @@ function applyIncrementalRotation(element, axis, angle, world_space)
 			cur_quat = getQuatFromEuler(euler_rot)
 		end
 	end
-	
-	-- Rotate by the offset quaternion
-	-- Right or left multiplication for world or local space
-	if world_space then
-		cur_quat = quatMul(cur_quat, offset_quat)
+
+	-- Check if rotation patch is enabled
+	if enableRotPatch then
+		-- Rotate by the offset quaternion
+		-- Right or left multiplication for world or local space
+		cur_quat = world_space == true and quatMul(cur_quat, offset_quat) or quatMul(offset_quat, cur_quat)
 	else
-		cur_quat = quatMul(offset_quat, cur_quat)
+		-- Do the old rotation behaviour
+		if world_space then
+			cur_quat = axis == "yaw" and quatMul(cur_quat, offset_quat) or quatMul(offset_quat, cur_quat)
+		else
+			cur_quat = quatMul(offset_quat, cur_quat)
+		end
 	end
+
 	elementQuat[element] = cur_quat
-	
+
 	-- Convert to euler and apply
 	local cur_euler = getEulerFromQuat(cur_quat)
 	setElementRotation(element, cur_euler[1], cur_euler[2], cur_euler[3], "ZYX")
-	
+
 	return unpack(cur_euler)
 end
 
@@ -128,16 +139,16 @@ end
 
 function getEulerFromQuat(quat)
     local q0, q1, q2, q3 = quat[1], quat[2], quat[3], quat[4]
-    local treshold = q0 * q2 - q3 * q1
-	
-    if treshold > 0.499 then
+    local threshold = q0 * q2 - q3 * q1
+
+    if threshold > fromQuatThreshold then
         return {math.deg(2 * math.atan2(q1, q0)), 90, 0}
-    elseif treshold < -0.499 then
-        return {math.deg(-2 * math.atan2(q1, q0)), -90, 0}
+    elseif threshold < -fromQuatThreshold then
+        return {math.deg(2 * math.atan2(q1, q0)), -90, 0}
     else
         return {
             math.deg(math.atan2(2 * (q0 * q1 + q2 * q3), 1 - 2 * (q1^2 + q2^2))),
-            math.deg(math.asin(2 * treshold)),
+            math.deg(math.asin(2 * threshold)),
             math.deg(math.atan2(2 * (q0 * q3 + q1 * q2), 1 - 2 * (q2^2 + q3^2)))
         }
     end