Worked on heading stuff.

mineleader.lua

@@ -134,6 +134,13 @@ local function attemptMove(movef)
 	return true
 end
 
+local function locatePosition()
+	local x, y, z = gps.locate()
+	if x == nil then return false end
+	position = vector.new(x, y, z)
+	return true
+end
+
 local function attemptMoveUp()
 	if attemptMove(turtle.up) then
 		relativePos.y = relativePos.y + 1
@@ -155,8 +162,12 @@ end
 local function attemptMoveForward()
 	if attemptMove(turtle.forward) then
 		relativePos = relativePos + relHeading
-		if (position ~= nil and heading ~= nil) then
+		if (position ~= nil) then
+			if ( heading ~= nil and heading:length() ~= 0) then
 				position = position + heading
+			else
+				locatePosition()
+			end
 		end
 		return true
 	end
@@ -166,8 +177,12 @@ end
 local function attemptMoveBackward()
 	if attemptMove(turtle.back) then
 		relativePos = relativePos - relHeading
-		if (position ~= nil and heading ~= nil) then
+		if (position ~= nil) then
+			if (heading ~= nil and heading:length() ~= 0) then
 				position = position - heading
+			else
+				locatePosition()
+			end
 		end
 		return true
 	end
@@ -180,7 +195,7 @@ local function attemptMoveLeft()
 		relHeading = -relRightAxis
 		relRightAxis = previousHeading
 		
-		if heading ~= nil then
+		if heading ~= nil and heading:length() ~= 0 then
 			local previousHeading = heading
 			heading = -rightAxis
 			rightAxis = previousHeading
@@ -196,7 +211,7 @@ local function attemptMoveRight()
 		relHeading = relRightAxis
 		relRightAxis = -previousHeading
 		
-		if heading ~= nil then
+		if heading ~= nil and heading:length() ~= 0 then
 			local previousHeading = heading
 			heading = rightAxis
 			rightAxis = -previousHeading
@@ -231,20 +246,21 @@ local function attemptStartTask(name, f, ...)
 	taskArgs = arg
 end
 
--- actions
 
-local function locatePosition()
+-- Actions
-	sendLog(POSITION, "Using GPS to determine position.")
+
-	local x, y, z = gps.locate()
+local function determinePosition()
-	if x == nil then sendLog(POSITION, "could not locate.") end
+	if not locatePosition() then
-	position = vector.new(x, y, z)
+		sendLog(FAILED, "Unable to obtain GPS based position.")
+		return
+	end
 	sendLog(POSITION, "Position obtained: " .. tostring(position))
 end
 
 local function determineHeading()
 	sendLog(HEADING, "Calculating heading.")
-	if position == nil then
+	if position == nil && locatePosition() then
-		sendLog(FAILED, "No current position")
+		sendLog(FAILED, "Unable to get current position.")
 		return
 	end
 	local oldPos = vector.new(position.x, position.y, position.z)
@@ -252,28 +268,34 @@ local function determineHeading()
 		sendLog(FAILED, "Could not move to get delta.")
 		return
 	end
-	if position == nil then 
-		sendLog(FAILED, "Could not locate.")
-		return
-	end
 	local fDelta = position - oldPos
 	
+	if not attemptMoveBackward() then
+		sendLog(FAILED, "Could not return to original position after first axis.")
+		return
+	end
 
 	if not attemptMoveRight() then
 		sendLog(FAILED, "Unable to rotate right.")
 		return
 	end
-	local oldPos = vector.new(position.x, position.y, position.z)
+	
 	if not attemptMoveForward() then
 		sendLog(FAILED, "Unable to move forward after rotation.")
 		return
 	end
+	local rDelta = position - oldPos
+	if not attemptMoveBackward() then
+		sendLog(FAILED, "Could not return to original position after second  axis.")
+		return
+	end
 	if not attemptMoveLeft() then
 		sendLog(FAILED, "Unable to rotate left.")
 		return
 	end
+
 	heading = fDelta
-	rightAxis = position - oldPos
+	rightAxis = rDelta
 	sendLog(HEADING, "Heading obtained. \nForward: " .. textutils.serialiseJSON(heading) .. "\nRight direction: " .. textutils.serialiseJSON(rightAxis))
 end
 
@@ -389,7 +411,7 @@ local function listen()
 								"\nfuel: " .. tostring(status["fuel"]) .. 
 								"\ncurrent task: " .. status["task"], status)
 			elseif data["request"] == POSITION then
-				locatePosition()
+				determinePosition()
 			elseif data["request"] == HEADING then
 				determineHeading()
 			elseif data["request"] == QUARRY then