平滑移動，可修改移動速度

function love.load()
    player = {
        grid_x = 256,
        grid_y = 256,
        act_x = 200,
        act_y = 200,
speed = 8    }
end


function love.update(dt)
    --player.act_y = player.act_y - (player.act_y - player.grid_y)*dt
    --player.act_x = player.act_x - (player.act_x - player.grid_x)*dt
player.act_y = player.act_y - (player.act_y - player.grid_y)*dt*player.speed
    player.act_x = player.act_x - (player.act_x - player.grid_x)*dt*player.speed
end


function love.draw()
    love.graphics.rectangle("fill", player.act_x, player.act_y, 32, 32)
end


function love.keypressed(key)
    if key == "up" then
        player.grid_y = player.grid_y - 32
    elseif key == "down" then
        player.grid_y = player.grid_y + 32
    elseif key == "left" then
        player.grid_x = player.grid_x - 32
    elseif key == "right" then
        player.grid_x = player.grid_x + 32
    end
end