local width = 7
local height = 7
local distance = 5

function getHeadsetMatrix()
    local fx, fy, fz, fangle, fax, fay, faz = lovr.headset.getPose("head")
    return lovr.math.newMat4(lovr.math.vec3(fx, fy, fz), lovr.math.vec3(1, 1, 1), lovr.math.quat(fangle, fax, fay, faz))
end

function drawGrid(pass, matrix)

	for i=-0.5,0.5,0.05 do
		local startVect = matrix*lovr.math.newVec3(width*-1, height*i, -distance)
		local endVect = matrix*lovr.math.newVec3(width*1, height*i, -distance)
		pass:line(startVect, endVect)
	end

	for i=-0.5,0.5,0.05 do
		local startVect = matrix*lovr.math.newVec3(width*i, height*-1, -distance)
		local endVect = matrix*lovr.math.newVec3(width*i, height*1, -distance)
		pass:line(startVect, endVect)
	end
end

function lovr.draw(pass)
	if headMatrix == nil then
		headMatrix = getHeadsetMatrix()
	end

	if headMatrix ~= nil then

		pass:setColor(0, 1, 0)
		drawGrid(pass, headMatrix)

		local center = headMatrix * lovr.math.newVec3(0.0, 0.0, -distance)
	pass:circle(center, 0.05, 0, 0, 0, 1, 'fill')
	end
end