trying 2 set up walking animation with sprite sheets and tables. will this work?

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yougetagoldstar
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trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by yougetagoldstar » Sat Feb 11, 2017 8:27 am

My first time making a table, and it looks like I don't yet know exactly what you can and cannot put in tables. I heard that you can put tables inside of tables... i think?

Trying to come up with a clean way to organize sprite sheets and quads to animate the player. I managed to make the walking_down animation work but all the lines of code are just thrown in my main.lua file. b4 I attempt to add the other directions / standing directions i want to ask if there's a way to keep code neat and tidy.
I'm also trying to avoid libraries made by other people, just in case using too many causes problems and I have no idea what's going on.

Here's my code, so sorry if this is disgusting.

-- test table
char_anims = {player = playerImage = love.graphics.newImage("walking sprite sheet.png"), -- sprite sheet
{walking_down = { -- trying to put a table of quads from my sprite sheet in this table. This possible?
walking_down[1] = love.graphics.newQuad(0, 0, 29, 57, player:getDimensions()), -- quads
walking_down[2] = love.graphics.newQuad(29, 0, 29, 57, player:getDimensions()),
walking_down[3] = love.graphics.newQuad(58, 0, 29, 57, player:getDimensions()),
walking_down[4] = love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())
}

Tried using the code tags, but they didn't use line breaks for some reason.

Will this table above just not work? If not why?
Last edited by yougetagoldstar on Sun Feb 12, 2017 7:10 pm, edited 1 time in total.

Santos
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Posts: 383
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Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by Santos » Sat Feb 11, 2017 10:10 am

Hi yougetagoldstar,

The code won't run as is because there are syntax errors in it, which LOVE will let you know when you try to run it (tip: run stuff you're not sure of, error messages are useful!).

You might be wanting something like this:

Code: Select all

-- test table 
char_anims = {
	playerImage = love.graphics.newImage("walking sprite sheet.png"), -- sprite sheet
	walking_down = { -- This is indeed a table inside of a table!
		love.graphics.newQuad(0, 0, 29, 57, player:getDimensions()), -- quads
		love.graphics.newQuad(29, 0, 29, 57, player:getDimensions()),
		love.graphics.newQuad(58, 0, 29, 57, player:getDimensions()),
		love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())
	}
}
Note that this:

Code: Select all

walking_down = { -- This is indeed a table inside of a table!
	love.graphics.newQuad(0, 0, 29, 57, player:getDimensions()), -- quads
	love.graphics.newQuad(29, 0, 29, 57, player:getDimensions()),
	love.graphics.newQuad(58, 0, 29, 57, player:getDimensions()),
	love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())
}
is the same as this (i.e. the numbers are automatic if you leave them out):

Code: Select all

walking_down = { -- This is indeed a table inside of a table!
	[1] = love.graphics.newQuad(0, 0, 29, 57, player:getDimensions()), -- quads
	[2] = love.graphics.newQuad(29, 0, 29, 57, player:getDimensions()),
	[3] = love.graphics.newQuad(58, 0, 29, 57, player:getDimensions()),
	[4] = love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())
}
You say that you made the animation work. Am I right in thinking you're trying to improve it because you're not happy with the solution you came up with? If you want, you could show us what you've come up with so far, and what you think is wrong with it, and we could help think of solutions.

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yougetagoldstar
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Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by yougetagoldstar » Sat Feb 11, 2017 7:28 pm

Thanks for laying this out, i'll be taking a good look at it. Yeah I got the walking animations to work (but not changing the standing idle animation after you move yet), and yeah after looking at the code I immediately thought "there has to be a cleaner way to do this". I'm used to using classes in python. And I heard that lua's thing was tables.

here's my starter code. all this is just for the player, and it's already so many lines. just felt like taking a stab at organizing sooner than later.

Code: Select all

walkingFramesRight = {}
walkingFramesLeft = {}
walkingFramesUp = {}
walkingFramesDown = {}
activeFrame = 0
currentFrame = 2
elapsedTime = 0
player_x = 333
player_y = 250
playerSpeed = 200
isWalking = false
directionRight = false -- still figuring out where to use these
directionLeft = false -- still figuring out where to use these
directionUp = false -- still figuring out where to use these
directionDown = false -- still figuring out where to use these



function love.load()
    bg_image = love.graphics.newImage("my background.png")
    player = love.graphics.newImage("player walking test.png")
    walkingFramesDown[1] = love.graphics.newQuad(0, 0, 29, 57, player:getDimensions())
    walkingFramesDown[2] = love.graphics.newQuad(29, 0, 29, 57, player:getDimensions())
    walkingFramesDown[3] = love.graphics.newQuad(58, 0, 29, 57, player:getDimensions())
    walkingFramesDown[4] = love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())

    walkingFramesUp[1] = love.graphics.newQuad(0, 171, 29, 57, player:getDimensions())
    walkingFramesUp[2] = love.graphics.newQuad(29, 171, 29, 57, player:getDimensions())
    walkingFramesUp[3] = love.graphics.newQuad(58, 171, 29, 57, player:getDimensions())
    walkingFramesUp[4] = love.graphics.newQuad(87, 171, 29, 57, player:getDimensions())

    walkingFramesRight[1] = love.graphics.newQuad(0, 114, 29, 57, player:getDimensions())
    walkingFramesRight[2] = love.graphics.newQuad(29, 114, 29, 57, player:getDimensions())
    walkingFramesRight[3] = love.graphics.newQuad(58, 114, 29, 57, player:getDimensions())
    walkingFramesRight[4] = love.graphics.newQuad(87, 114, 29, 57, player:getDimensions())

    walkingFramesLeft[1] = love.graphics.newQuad(0, 57, 29, 57, player:getDimensions())
    walkingFramesLeft[2] = love.graphics.newQuad(29, 57, 29, 57, player:getDimensions())
    walkingFramesLeft[3] = love.graphics.newQuad(58, 57, 29, 57, player:getDimensions())
    walkingFramesLeft[4] = love.graphics.newQuad(87, 57, 29, 57, player:getDimensions())

    activeFrame = walkingFramesDown[currentFrame]
end

function love.update(dt)
    elapsedTime = elapsedTime + dt
    if love.keyboard.isDown("down") then
        isWalking = true -- I just have this in case I need to use it later
        player_y = player_y + playerSpeed * dt
        if (elapsedTime > 0.1) then
            if (currentFrame < 4) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesDown[currentFrame]
            elapsedTime = 0
        end

    end

    -- if love.keyreleased("down") then
    --     directionDown = true
    -- end

    if love.keyboard.isDown("up") then
        isWalking = true
        player_y = player_y - playerSpeed * dt
        if (elapsedTime > 0.1) then
            if (currentFrame < 4) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesUp[currentFrame]
            elapsedTime = 0
        end

    end
    if love.keyboard.isDown("right") then
        isWalking = true
        player_x = player_x + playerSpeed * dt
        if (elapsedTime > 0.1) then
            if (currentFrame < 4) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesRight[currentFrame]
            elapsedTime = 0
        end

    end
    if love.keyboard.isDown("left") then
        isWalking = true
        player_x = player_x - playerSpeed * dt
        if (elapsedTime > 0.1) then
            if (currentFrame < 4) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesLeft[currentFrame]
            elapsedTime = 0
        end

    end
end

function love.draw()
    love.graphics.draw(bg_image, 0, 0)
    love.graphics.draw(player,activeFrame, player_x, player_y)
    if directionDown then
        love.graphics.print("down = true", 100, 100)
    end
end
Oh, do people ask these types of questions in the support section of the forums?

Santos
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Posts: 383
Joined: Sat Oct 22, 2011 7:37 am

Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by Santos » Sun Feb 12, 2017 11:15 am

The "cleanliness" of code is an interesting thing... I think it's important to think of what kinds of things make code "clean", and what the actual practical benefits are. (I used to think that splitting programs up into lots of different files and having classes for everything and having lots of different functions meant having "clean code", but I don't think I was thinking about what it fundamentally meant for code to be "clean" and what the practical benefits were, I was just doing stuff because "everyone" said it was good.)

Looking at the code you have, here are some "cleanliness" ideas. These are just what I believe at the moment, I'm not a good programmer and I am no authority on this stuff.

Number 1: Consistency

What benefit it has: When things are consistent, they're easier to remember because they're like all of the other things. (Plus there's some kind of aesthetic feeling of cleanliness with it.)

One place I thought that consistency could make this code "cleaner" is where some names are use underscores (specifically player_x, player_y and bg_image) and some use camelCase.

So, the first thing I did was made everything camelCase.

Number 2: Non-duplication

What benefit it has: When code or a value exists in only one place, it can be changed in one place instead of many, which can be quicker to do and maybe more reliable because there aren't places to change that you could miss. It also makes the code smaller, which can make it easier to navigate, and, perhaps the main reason, easier to think about.

Looking at the code, I can see two places where the code is very similar: creating the quads, and moving the player.

Looking at this code:

Code: Select all

walkingFramesDown[1] = love.graphics.newQuad(0, 0, 29, 57, player:getDimensions())
walkingFramesDown[2] = love.graphics.newQuad(29, 0, 29, 57, player:getDimensions())
walkingFramesDown[3] = love.graphics.newQuad(58, 0, 29, 57, player:getDimensions())
walkingFramesDown[4] = love.graphics.newQuad(87, 0, 29, 57, player:getDimensions())

walkingFramesUp[1] = love.graphics.newQuad(0, 171, 29, 57, player:getDimensions())
walkingFramesUp[2] = love.graphics.newQuad(29, 171, 29, 57, player:getDimensions())
walkingFramesUp[3] = love.graphics.newQuad(58, 171, 29, 57, player:getDimensions())
walkingFramesUp[4] = love.graphics.newQuad(87, 171, 29, 57, player:getDimensions())

walkingFramesRight[1] = love.graphics.newQuad(0, 114, 29, 57, player:getDimensions())
walkingFramesRight[2] = love.graphics.newQuad(29, 114, 29, 57, player:getDimensions())
walkingFramesRight[3] = love.graphics.newQuad(58, 114, 29, 57, player:getDimensions())
walkingFramesRight[4] = love.graphics.newQuad(87, 114, 29, 57, player:getDimensions())

walkingFramesLeft[1] = love.graphics.newQuad(0, 57, 29, 57, player:getDimensions())
walkingFramesLeft[2] = love.graphics.newQuad(29, 57, 29, 57, player:getDimensions())
walkingFramesLeft[3] = love.graphics.newQuad(58, 57, 29, 57, player:getDimensions())
walkingFramesLeft[4] = love.graphics.newQuad(87, 57, 29, 57, player:getDimensions())

it can be seen that the differences between the lines are the table to store the quad, the table index, and the X and Y position for the quad.

What changes to make to reduce the duplication will depend on things like how you think the code will change over time, and I'm not very good at this stuff, but here's just some ideas.

My first thought was "just create a function which takes the things which change between the lines".

Code: Select all

local function newFrame(frameTable, frameIndex, x, y)
  frameTable[frameIndex] = love.graphics.newQuad(0, 0, x, y, player:getDimensions())
end

newFrame(walkingFramesDown, 1, 0, 0)
newFrame(walkingFramesDown, 2, 29, 0)
newFrame(walkingFramesDown, 3, 58, 0)
newFrame(walkingFramesDown, 4, 87, 0)   

newFrame(walkingFramesUp, 1, 0, 171)
newFrame(walkingFramesUp, 2, 29, 171)
newFrame(walkingFramesUp, 3, 58, 171)
newFrame(walkingFramesUp, 4, 87, 171)

newFrame(walkingFramesRight, 1, 0, 114)
newFrame(walkingFramesRight, 2, 29, 114)
newFrame(walkingFramesRight, 3, 58, 114)
newFrame(walkingFramesRight, 4, 87, 114)

newFrame(walkingFramesLeft, 1, 0, 57)
newFrame(walkingFramesLeft, 2, 29, 57)
newFrame(walkingFramesLeft, 3, 58, 57)
newFrame(walkingFramesLeft, 4, 87, 57)

These lines are still pretty similar though, with the 1 to 4 sequence, so I guess the only difference between the sections is the table and the Y offset.

Code: Select all

local function newFrames(frameTable, y)
  for frameIndex = 1, 4 do
    frameTable[frameIndex] = love.graphics.newQuad((frameIndex - 1) * 29, y, 29, 57, player:getDimensions())
  end
end

newFrames(walkingFramesDown, 0)
newFrames(walkingFramesUp, 171)
newFrames(walkingFramesRight, 114)
newFrames(walkingFramesLeft, 57)

So that went from 19 lines to 10. Maybe this isn't suitable for your game though, or maybe you'd prefer doing things a different way, and I'm not saying that what I did was "good", but the basic idea is that you can remove duplication and it can have benefits.

With the player movement code:

Code: Select all

if love.keyboard.isDown("down") then
    isWalking = true -- I just have this in case I need to use it later
    playerY = playerY + playerSpeed * dt
    if (elapsedTime > 0.1) then
        if (currentFrame < 4) then
            currentFrame = currentFrame + 1
        else
            currentFrame = 1
        end
        activeFrame = walkingFramesDown[currentFrame]
        elapsedTime = 0
    end

end

if love.keyboard.isDown("up") then
    isWalking = true
    playerY = playerY - playerSpeed * dt
    if (elapsedTime > 0.1) then
        if (currentFrame < 4) then
            currentFrame = currentFrame + 1
        else
            currentFrame = 1
        end
        activeFrame = walkingFramesUp[currentFrame]
        elapsedTime = 0
    end

end
if love.keyboard.isDown("right") then
    isWalking = true
    playerX = playerX + playerSpeed * dt
    if (elapsedTime > 0.1) then
        if (currentFrame < 4) then
            currentFrame = currentFrame + 1
        else
            currentFrame = 1
        end
        activeFrame = walkingFramesRight[currentFrame]
        elapsedTime = 0
    end

end
if love.keyboard.isDown("left") then
    isWalking = true
    playerX = playerX - playerSpeed * dt
    if (elapsedTime > 0.1) then
        if (currentFrame < 4) then
            currentFrame = currentFrame + 1
        else
            currentFrame = 1
        end
        activeFrame = walkingFramesLeft[currentFrame]
        elapsedTime = 0
    end

end

I can see that the only difference between these parts is the key which is down and the direction the player is moving (which is based on the key).

So, maybe you could do something like this (except you'd probably want a better name than "movePlayer" because that sounds like it moves the player, but whatever).

Code: Select all

local function movePlayer(key)
    if love.keyboard.isDown(key) then
        isWalking = true
        
        if key == "down" then
            playerY = playerY + playerSpeed * dt
        elseif key == "up" then
            playerY = playerY - playerSpeed * dt
        elseif key == "right" then
            playerX = playerX + playerSpeed * dt
        elseif key == "left" then
            playerX = playerX - playerSpeed * dt
        end
        
        if (elapsedTime > 0.1) then
            if (currentFrame < 4) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesUp[currentFrame]
            elapsedTime = 0
        end
    end
end

movePlayer("down")
movePlayer("up")
movePlayer("right")
movePlayer("left")
57 lines to 30, I think. See how it's kind of easier to see what's going when stuff isn't repeated, because there's less to read?

I just noticed the number of frames per animation (4) is repeated as well, so you can make that into a variable.

Code: Select all

walkingFrameCount = 4

local function newFrames(frameTable, y)
	for frameIndex = 1, 4 do

	-- etc.


local movePlayer(key)
	-- etc.
    
    if (currentFrame < walkingFrameCount) then


Number 3: Keeping variables/functions close to where they are used

What benefit it has: If you're reading the code which uses the variable/function, it's nearby to read if you need to. And if read a variable/function somewhere where it's not used, you might be unsure of where it actually is used. I dunno.

For example, the player speed is only used when moving the player, so you can make it near the code which uses it.

Code: Select all

local function movePlayer(key)
    if love.keyboard.isDown(key) then
        isWalking = true
        
        local playerSpeed = 200

        if key == "down" then
            playerY = playerY + playerSpeed * dt
        elseif key == "up" then
            playerY = playerY - playerSpeed * dt
        elseif key == "right" then
            playerX = playerX + playerSpeed * dt
        elseif key == "left" then
            playerX = playerX - playerSpeed * dt
        end
        
        if (elapsedTime > 0.1) then
            if (currentFrame < walkingFrameCount) then
                currentFrame = currentFrame + 1
            else
                currentFrame = 1
            end
            activeFrame = walkingFramesUp[currentFrame]
            elapsedTime = 0
        end
    end
end

Number 4: Not doing stuff because you think you might need it in the future but you're not really sure

What benefit it has: It's hard to know what you'll actually need in the future, so you might spend time doing things you don't actually need.

For example, the variables like isWalking and directionRight can be saved until you have a reason to use them.



Most importantly though, none of this stuff really matters. I remember briefly looking at the source code for Mari0 and thinking to myself "this doesn't look particularly clean", but it doesn't matter, it could have the cleanest code in the world or the uncleanest code in the world, but it got made and it's one of the best games made with LOVE.

And yeah generally people do use the support section for these types of questions, you might get more responses there. :ultraglee:

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MadByte
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Location: Germany

Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by MadByte » Sun Feb 12, 2017 11:32 am

Awesome amount of effort in your answers Santos, just wanted to say that. *thumbs up*

Santos
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Posts: 383
Joined: Sat Oct 22, 2011 7:37 am

Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by Santos » Sun Feb 12, 2017 12:46 pm

Thanks MadByte, really nice of you to say. :nyu:

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yougetagoldstar
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Re: trying 2 set up walking animation with sprite sheets and tables. will this work?

Post by yougetagoldstar » Sun Feb 12, 2017 9:22 pm

wow, thanks a lot for this response santos. I'm definitely gonna be using this as a reference.

yeah i guess ill post in the support topic then. might as well.

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