trippy jumping

[thewifitree]

I'm new to using love and made a post on this forum just yesterday for the same project. In my new project I attempted to create jumping, but I don't really understand loves physics. At all. The player teleports 190 pixels up, and slowly falls and it looks very unrealistic. Please help!

Code: Select all

jump = true

function love.keypressed(key)
	--jump
	if key == " " then
		if jump == true then
			jump = false
			player.y = player.y - 190
		else 
			jump = true
		end
	end
end

[Ranguna259]

You say you don't understand love.physics, yet you aren't using the physics module in your code ..?
Are you using [wiki]love.physics[/wiki] ?

[T-Bone]

Well, you're setting the player's y value to decrease by 190 pixels, so that's what you get. If you want to make a more natural motion, try something like this

Code: Select all

function love.load()
    player = {}
    player.x = 10
    player.y = 300 -- or whatever fits your game
    player.dy = 0
end

function love.update(dt)
    player.y = player.y + player.dy*dt
    player.dy = math.max(0, player.dy - 100*dt)
end

function love.keypressed(k)
    if k=="up" then
        player.dy = -100
    end

(Untested code, I hope you get the idea)

[thewifitree]

The code didn't work
Would posting the entire code help?

Code: Select all

require "external"

block = {}
player = {}

local collision = false
jump = true
moveleft = true
moveright = true

--load the images
background_img = love.graphics.newImage("textures/photo.png")
block_img = love.graphics.newImage("textures/block.png")
player_img = love.graphics.newImage("textures/player.png")

function love.load()
	player.x = 0
	player.y = 0
   
	table.insert(block, {x = 0, y = 50})
	table.insert(block, {x = 50, y = 50})
	table.insert(block, {x = 150, y = 200})
	for i=1,3 do
		table.insert(block, {x = 150+i*50, y = 200})
	end
end

function love.draw()
   x, y = love.mouse.getPosition()
   
   --draw the background
   love.graphics.setColor(255, 130, 130, 255)
   love.graphics.draw(background_img, 0, 0)
   
   --draw the blocks
   love.graphics.setColor(255, 255, 255, 255)
   love.graphics.draw(block_img, x, y)
   for i, v in pairs(block) do 
      love.graphics.draw(block_img, block[i].x, block[i].y)
   end
   
   --draw the player
   love.graphics.setColor(255, 130, 130, 255)
   love.graphics.draw(player_img, player.x, player.y)

   
end

function love.update(dt)
	x, y = love.mouse.getPosition()
	if love.mouse.isDown("l") then
		table.insert(block, {x = x, y = y})
	end
   
	hitboxes:update(dt)

   
	--move left
	if moveleft == true then
		if love.keyboard.isDown("left") then
			player.x = player.x - 190*dt
		end
	end
   
	--move right
	if moveright == true then	
		if love.keyboard.isDown("right") then
			player.x = player.x + 190*dt
		end
	end
	
	
end

function love.keypressed(key)
	--jump
	if key == " " then
		if jump == true then
			jump = false
			player.y = player.y - 190
		else 
			jump = true
		end
	end
end

function CheckCollision(x1,y1,w1,h1, x2,y2,w2,h2)
   return x1 < x2+w2 and
      x2 < x1+w1 and
      y1 < y2+h2 and
      y2 < y1+h1
end

Code: Select all

hitboxes = {}

function hitboxes:update(dt)
	
	--Gravity!
	local collision = false --Right there
	for i= 1, #block do
		if collision then break end
	collision = CheckCollision(player.x, player.y, 50, 50, block[i].x, block[i].y, 50, 50)
	end

	if collision == false then
		player.y = player.y + 190*dt
	end
	
end

[lachlaan]

You just need to think of it in physics terms. The gravity you want seems to be either a realistic decceleration upwards followed by acceleration towards the bottom of the screen, or if not, at least a non-instant trip to the peak of the jump.

To do that you need to give the bodies an actual speed variable and modify their position according to their speed each frame (like you've been doing with the "190" everywhere but for the jump). The jump itself should modify the y speed value rather than the position.

Code: Select all

    require "external"

    block = {}
    player = {}

    local collision = false
    jump = true
    moveleft = true
    moveright = true

    --load the images
    background_img = love.graphics.newImage("textures/photo.png")
    block_img = love.graphics.newImage("textures/block.png")
    player_img = love.graphics.newImage("textures/player.png")

    function love.load()
       player.x = 0
       player.y = 0
	   player.xspeed = 0
	   player.yspeed = 0
       
       table.insert(block, {x = 0, y = 50})
       table.insert(block, {x = 50, y = 50})
       table.insert(block, {x = 150, y = 200})
       for i=1,3 do
          table.insert(block, {x = 150+i*50, y = 200})
       end
    end

    function love.draw()
       x, y = love.mouse.getPosition()
       
       --draw the background
       love.graphics.setColor(255, 130, 130, 255)
       love.graphics.draw(background_img, 0, 0)
       
       --draw the blocks
       love.graphics.setColor(255, 255, 255, 255)
       love.graphics.draw(block_img, x, y)
       for i, v in pairs(block) do
          love.graphics.draw(block_img, block[i].x, block[i].y)
       end
       
       --draw the player
       love.graphics.setColor(255, 130, 130, 255)
       love.graphics.draw(player_img, player.x, player.y)

       
    end

    function love.update(dt)
       x, y = love.mouse.getPosition()
       if love.mouse.isDown("l") then
          table.insert(block, {x = x, y = y})
       end
       
       hitboxes:update(dt)

       
       --move left
       if moveleft == true then
          if love.keyboard.isDown("left") then
             player.xspeed = -190
          else
			 player.xspeed = 0
		  end
       end
       
       --move right
       if moveright == true then   
          if love.keyboard.isDown("right") then
             player.xspeed =190
          else
			 player.xspeed = 0
		  end
       end
	   player.x = player.x + player.xspeed * dt
	   player.y = player.y + player.yspeed * dt
       
       
    end

    function love.keypressed(key)
       --jump
       if key == " " then
          if jump == true then
             jump = false
             player.yspeed = player.yspeed - 380
          else
             jump = true
          end
       end
    end

    function CheckCollision(x1,y1,w1,h1, x2,y2,w2,h2)
       return x1 < x2+w2 and
          x2 < x1+w1 and
          y1 < y2+h2 and
          y2 < y1+h1
    end

Code: Select all

    hitboxes = {}

    function hitboxes:update(dt)
       
       --Gravity!
       local collision = false --Right there
       for i= 1, #block do
          if collision then break end
       collision = CheckCollision(player.x, player.y, 50, 50, block[i].x, block[i].y, 50, 50)
       end

       if collision == false then
          player.y = player.y + 190*dt
       end
       
    end

That code should work, but you need to do collision checking for each axis to know which way your guy can't move. For example a lateral collision might stop you falling.

[thewifitree]

I attempted to fix the jumping by taking code from an old project and tweaking it. I did something wrong with the for loop I believe but I can't figure out what. Please help!