handcram.p8

pico-8 cartridge // http://www.pico-8.com
version 29
__lua__

--hand cram
--by @andy_makes
--playable at https://andymakes.itch.io/hand-cram

--**********************************
--original, 557 char code
--**********************************
--[[
t=0g=0r=rnd
w=128b=abs
o=circ::_::if g>0then
pal({5,2},1)print("score:"..t,9,9,7)
if(btn(5))t,g=0,0
else
if(t<1)a={9,9,88,0,40,0,0,0,0,0,40,0,88}
i=btn()pal({7,8},1)t+=1
for k=0,200do
o(r(w),r(w),5,0)end
for k=0,10do
s=2^k
l=s*2
a[k+3]+=band(i,l)/l-band(i,s)/s
end
for k=0,1do
x=a[3+k*8]y=a[5+k*8]s=a[k+1]o(x,y,s,1+k)o(x,y,s+2,1+k)
for c=0,w do
srand(c+t)if r(8)<1then
p=1+flr(r(2))z=r(w)o(c,z,4,p)
if(sqrt((x-c)^2+(y-z)^2)<s)a[k+1]+=b(1+k-p)/5-.01end
end
if(k==1 and sqrt((x-a[3])^2+(y-a[5])^2)<s+a[1])g=1
if(b(64-x)>66or 66<b(64-y))g=1end
end
flip()goto _
--]]

--**********************************
--expanded, commented code
--**********************************

--this is the exact same code as above, but with whitespace and line breaks added
--and a ton of comments to try to explain what it's doing

--variables that change and track game-state
t=0   --elapsed time
g=0   --game-over. if this is anything other than 0, the game has ended

--constants
w=128 --screen width. this value comes up enough that it saves chars to define it

--functions i use enough that it saves characters to to give them single-letter names
r=rnd
b=abs
o=circ

--this is the identifer that goto() will use.
--this marks the start of the game loop
::_:: 

--game over stuff
--g gets set to 1 when the game ends
if g>0 then
  --using pal to change the colors of what has been drawn to "fade" the shapes and highlight the score text
  pal({5,2},1)
  
  --drawing the score. i found out later that i could have saved chars by using "?" instead of print
  print("score:"..t,9,9,7)

  --if x is pressed, i reset the game by setting g and time back to 0
  --g is an int instead of a bool to save a few characters
  if(btn(5))  t,g=0,0

  --whenever possible, i shoot for single line if statements because they do not require "then" and "end"

--if g is 0, we play the game
--this is the main game loop
else
  --if t is 0, that means we're on the first frame and i need to "initialize" the game
  --this array stores all of the game values for the two circles
  --slots 1 and 2 are used for the sizes (both start at 9)
  --most of the rest of it is unused because my input loop creates garbage data
  --but four of the remaining slots represent the x and y of each circle (set to 40 or 88 to give them starting positions on screen)
  if(t<1) a={9,9,88,0,40,0,0,0,0,0,40,0,88}
  --btw, i use "<1" instead of "==0" because it saves a char
  
  --getting the input as a bitfield 
  --you can see the docs for this here: https://pico-8.fandom.com/wiki/btn
  --more on this when we get to input
  i=btn()

  --setting the palette used during the game
  --this does not need to happen every frame
  --but putting it in the above if statement would require making it multi-line, which require "then" and "end"
  pal({7,8},1)

  --advance the time
  --this acts as the score, but is also used to generate the positions of the dots that move across the screen
  t+=1

  --clearing the screen
  --i did not use cls() because i wanted some visual noise
  --this loop draws 200 black circles in random positions
  --this covers most of the screen, but not all of it, creating trails
  for k=0,200 do
    o(r(w),r(w),5,0)
  end

  --munro hoberman's work introduced me to this technique
  --he uses is a lot and to great effect in his tweetcarts
  --exmaple: https://twitter.com/munrohoberman/status/1345134334232113157


  --input
  --this is probably the most confusing part of the code
  --i highly recomend reading this post by eli piilonen (@2darray) to get a better understanding of how to read the btn bitfield
  --https://pastebin.com/MVhr16td

  --this loop runs through 11 of the 13 bits in the input value
  --the last two don't matter to me so i don't bother
  --there are other irrelevant values in the middle, but i need to get through them to get the ones the i care about
  for k=0,10 do
    s=2^k     --getting a power of two to do a binary and comparison to isolate a single bit for each button that pico-8 tracks
    l=s*2     --getting the value of the next bit
    a[k+3]+=band(i,l)/l-band(i,s)/s   --comparing these values and modifying the number stored in the array
    --most of the slots in the array are garbage because we don't care about most pairs of inputs
    --but a few are important like right-arrow minus left-arrow or down-arrow minus up-arrow
    --the slots we care about wind up representing the x and y positions of the player circles
  end

  --this loop checks both player circles
  --k==0 is the first player circle, k==1 is the second
  for k=0,1 do
    --grab the array values we care about for this circle
    --and store them in names that are shorter and more readable
    x=a[3+k*8]
    y=a[5+k*8]
    s=a[k+1]    --size of the circle

    --draw the circle twice
    --the second one is two pixels bigger than the actual size
    --i just thought this looked nice and helped differentiate the player circles from the obstacles
    --i redefined circ() as o() at the top
    o(x,y,s,1+k)
    o(x,y,s+2,1+k)

    --this loop goes through each pixel on the screen left to right
    --it will create obstacles and move them across the screen
    --the seed for each cycle is set by the x position plus the time
    --this creates the effect of the "random" obstacles moving cleanly across the screen without needing to make objects
    --shoutout to alex mckendry (fuzzydunlop) on the wonderville discord for introducing me to this
    for c=0,w do    --c is the x position
      --reseed random using the x position plus the time
      srand(c+t)

      --there is a 1/8 chance of having an obstacle in this column
      --up at the top i redefined rnd() as r()
      if r(8)<1 then
        --p represents the color. this can be 1 or 2
        p=1+flr(r(2))
        --z is the y position ("y" is already used for the player circle position)
        z=r(w)

        --draw the circle
        o(c,z,4,p)

        --hit detection
        --getting this to work as single-line if statement was very handy, but it is a dense line!
        if(sqrt((x-c)^2+(y-z)^2)<s) a[k+1] += b(1+k-p)/5-.01
        --the first part is a distance function, getting the distance using the pythagorean theorem
          -- sqrt((x-c)^2+(y-z)^2) < s
        --the second part adjusts the circle's size
          -- i have to use "a[k+1]" instead of "s" because i need to modify the array, not my copy of the value
        --so i'm adding to a[k+1] but "b(1+k-p)/5-.01" is also confusing
        --i previously redifed abs as b, so it's taking the absolute value of 1+k (the circle's color) minus p (the obstacle's color) and then dividing it by 5
        --so if it matches it will add 0 divided by 5 (0), if it doesn't match it will add 1/5 (0.2)
        --but then i subtract 0.01 to give a slight reduction in size if the colors match
        --so what it actually comes out to is adding 0.2-.01 (0.19) if they don't match and subtracting 0.01 if they do
      end

    end
    --this whole loop runs twice, once for each player circle
    --this means all obstacles are drawn twice, which is unnecessary and a little wasteful, but it saves characters

    --finally we check if the game has ended
    --there are two ways this can happen

    --the first is the two player circles touching
    --i only check this in the loop for the second circle (k==1) (note: just realized i could have saved a char by using k>0)
    --i do the same distance check as above using my x,y values for this player circle, and the array locations of those values for the other player circle
    --if their distance is less than their combined radius, it's game over, menaing i set g to 1
    if(k==1 and sqrt((x-a[3])^2+(y-a[5])^2)<s+a[1]) g=1
    
    --the other way you can lose is by going off the screen
    --i check this by taking the absolute value of the x and y position to the center of the screen
    if(b(64-x)>66or 66<b(64-y)) g=1
    
  --that is the end of the code that runs for each player circle  
  end

--and that's the end of the game loop as well!
end

--all that's left to do is draw everything to the screen using flip()
flip()

--and use goto to hop back to ::_::
goto _