LÖVE

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io.stdout:setvbuf('no')


local testPoly
local renderPolys
local testShape

local inside = false


function createPickablePolygon(points)
    local poly = { }
    local lastX = points[#points-1]
    local lastY = points[#points]
    for index = 1, #points-1, 2 do
        local px = points[index]
        local py = points[index+1]

        if py ~= lastY then
            local index = #poly
            poly[index+1] = px
            poly[index+2] = py
            poly[index+3] = (lastX - px) / (lastY - py)
        end
        lastX = px
        lastY = py
    end
    return poly
end


function isPointInPolygon(x, y, poly)
    local lastPX = poly[#poly-2]
    local lastPY = poly[#poly-1]
    local inside = false
    for index = 1, #poly, 3 do
        local px = poly[index]
        local py = poly[index+1]
        local deltaX_div_deltaY = poly[index+2]
        if ((py > y) ~= (lastPY > y)) and (x < (y - py) * deltaX_div_deltaY + px) then
            inside = not inside
        end
        lastPX = px
        lastPY = py
    end
    return inside
end


function love.load()
    local points = {}
    local TOTAL_POINTS = 8
    local angleStep = math.pi * 2.0 / TOTAL_POINTS
    for x = 0, TOTAL_POINTS - 1 do
        local index = x * 2 + 1
        points[index]     = math.cos(x * angleStep) * 100.0 + 200.0
        points[index + 1] = math.sin(x * angleStep) * 100.0 + 200.0
    end
    testPoly = createPickablePolygon(points)
    renderPolys = love.math.triangulate(unpack(points))
    testShape = love.physics.newPolygonShape(unpack(points))

    -- Set to false to disable the benchmark.
    local DO_BENCHMARK = true

    if DO_BENCHMARK then
        -- Sleep a bit to try to get the purest results.
        love.timer.sleep(2.0)
        local luaDelta = math.huge
        local b2Delta = math.huge
        for r = 1, 10 do
            local start = love.timer.getTime()
            for i = 1, 10000 do
                inside = isPointInPolygon(210, 210, testPoly)
            end
            local tempDelta = love.timer.getTime() - start
            if tempDelta < luaDelta then luaDelta = tempDelta end
        end
        -- Get a local reference so it's slightly faster.
        local testPoint = testShape.testPoint
        for r = 1, 10 do
            local start = love.timer.getTime()
            for i = 1, 10000 do
                inside = testPoint(testShape, 0, 0, 0, 210, 210)
            end
            local tempDelta = love.timer.getTime() - start
            if tempDelta < b2Delta then b2Delta = tempDelta end
        end
        error(string.format('Delta seconds (smaller is better):\nLua: %.8f\nBox2D: %.8f',
                            luaDelta, b2Delta))
    end
end


function love.mousemoved(x, y)
    -- Lua-based method.
    --inside = isPointInPolygon(x, y, testPoly)
    -- Box2D-based method.
    inside = testShape:testPoint(0, 0, 0, x, y)
end


function love.draw()
    love.graphics.print('Hover the polygon with the mouse cursor. Press Esc to quit.', 10, 10)
    if inside then
        love.graphics.setColor(0.4, 0.65, 1.0)
    else
        love.graphics.setColor(0.2, 0.2, 0.6)
    end
    for index = 1, #renderPolys do
        love.graphics.polygon('fill', renderPolys[index])
    end
    love.graphics.setColor(1.0, 1.0, 1.0)
end


function love.keypressed(key)
    if key == 'escape' then love.event.quit() end
end

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        if py ~= lastY then