lessons_love2d/physics/player.lua

function love.update(dt)
    world:update(dt) -- start the world
    love.graphics.print(player.body:getY(), canw/2, canv/2)
    love.graphics.print(platform.body:getY(), canw/3, canv/2)

    if love.keyboard.isDown("right") then
        plritate()
        if player.body:getX() < (love.graphics.getWidth() - player.img:getWidth()) then
	player.body:setLinearVelocity(player.speed,0+player.body:getY()/3 )
    end
	
    elseif love.keyboard.isDown("left") then
        plrotate()
	if player.x > 0 then 
	player.body:setLinearVelocity(-player.speed,0+player.body:getY()/3 )
     end
end

    if love.keyboard.isDown("space") then
       if player.body:getY() + 200 > platform.body:getY() then
          player.body:setLinearVelocity(0,player.jump)
       end
    end

    if love.keyboard.isDown("down") then
       player.body:setPosition(650/2, 650/2)
       -- reset velocity to 0
       player.body:setLinearVelocity(0, 0) 
    end
end

function plrotate()
	 player.img = love.graphics.newImage('images/tux1.png')
end

function plritate()
	 player.img = love.graphics.newImage('images/tux.png')
end