jumper1k_breakdown.p8

--[[

1k jump
by andy wallace
@andy_makes
andymakes.com

you can play the game here: https://andymakes.itch.io/1k-jump
that page has the original 1013 byte code as well

this is a breakdown of the code where i add whitespace and a lot of comments
with one or two small exceptions, this code is identical to the 1024 byte version

i made this game as an entry for pico-1k jam
hosted by paul nicholas (@liquidream)
https://itch.io/jam/pico-1k
thank for setting it up!

if you dig this, you might like my #tweetcarts, which are just 280 chars
https://twitter.com/search?q=%40andy_makes%20%23tweetcart&src=typed_query

]]

--setting color palette 
--7 is the "active" color for the game. all live elements will use it
--13, 136, 141 are the background colors that spread while the game is played
--the title and game over also use 5 for gret, but i got lucky in that i had exactly 4 earlier colors so i did not need to add it to my palette
pal({7,13,136,141},1)

--the number of resets since the game started
--this is used to kick the game into the title screen when it first launches
a=0

--shortening some function names
b=btn
r=rnd

--reset game values
::_r::  --this flag is used by a goto when the player presses x to reset

g=1 --game/game over. 1 means playing, 0 means game over
t=0 --time, goes up by 1 each tick
n=0 --time for next platform spawn
s=0 --score

w=128 --width of the screen

--player values
x=64
y=60
v=-1  --y velocity

--array for the platforms
o={}

--increment the number of attempts
a+=1

--play a beep. this is weird! it's a print function that plays audio via an escape char!
--https://www.lexaloffle.com/dl/docs/pico-8_manual.html#audio_
?"\ab"

--clear the screen
cls()

--game loop
--this flag is used by a goto to return to this point and create frames
::_::

--"clearing" the screen by setting pixels to black
--this affects 1500 randomly selected pixels each frame
for i=0,1500 do
  --grab a random x and y position
  d = r(w)
  e = r(w)
  --see what color it is
  c = pget(d,e)
  --if it is the base color, set it to 0 (black)
  if(c==1)  pset(d, e, 0)
  --if it is one of the background colors, expand it to a nearby pixel
  if(c>1)   pset(d+r(2)-1, e+r(2)-1, c)
end

--main physics/game loop
--the runs m times per frame, allowing the game to get faster over time
--the game speeds up every 7 points
--the maximum is 12 ticks per frame (i've never gotten this far)
--if g is 0 (game over), the physics loop will not run at all
m = min(12, 2+s/7) * g

for j=1,m do
  --move player x position from button input
  --based on https://gist.github.com/kometbomb/7ab11b8383d3ac94cbfe1be5fb859785#example-how-to-move-left-and-right-in-minimal-chars
  --max(.3,-v*1.2) modulates the speed based on the y velocity
  --the player moves faster when going up
  if(b()>0 and b()<3) x+=(b()*2-3) * max(.3,-v*1.2)
  
  --update y position of the player
  v+=.01  --gravity
  y+=v    --add the velocity to the y position

  --go through all platforms
  --z represents the platform object for each iteration of the loop
  for k,z in pairs(o)do
    --move platform up
    z.y-=.14  --this value is very small because it will happen m times per frame
    
    c=1 --assume the platform will use the default color

    --rectangular hit detection on the player
    if abs(x-z.x)<9 and abs(y-z.y)<7 then
      --increase the color to one of the background colors
      c = 2+s%3
      --set the player velocity go upward
      v = -0.9
      --increase the score
      s+=1
      --play a little sound
      ?"\as"..flr(m).."c.e.-g"
    end

    --draw the rectangle for the platform
    --this happens multiple times each frame, but that's fine
    rect(z.x-4,z.y-3,z.x+4,z.y+3,c)

    --if the color is above 1, it got set when the player hit the platform and we can remove it from the list
    if(c>1) del(o,z)
  end

  --t is the timer, n is the time for the next spawn
  --if t is greater than n, it's time for a new platform
  if t>n then 
    --add a new platform at a random x position and a y that is just past the bottom of the screen
    add(o,{x=r(128),y=w+4})
    
    --increase the next time to spawn a platform
    --as the game goes on and m gets bigger, the random range increases
    n+=120+r(m*15)
  end

  --increase the timer
  t+=1
end
--end of the physics loop

--this next part deals with drawing the title/instructions and player

--the decoration escape string that multiple text draws use
--https://www.lexaloffle.com/dl/docs/pico-8_manual.html#rendering_mode_options__
f = "\#5\^t\^w" 

--although g controls if game is over, i set this based on if the player's y is greater than 128 or lower than 0 (meaning they are off screen)
if y>w or y<0 then
  --if g is still 1 and this isn't the first time we've reached this screen (a>1) play a little sound
  if(g>0and a>1)  print("\af#..f#..e7..e7")

  --set g to 0 to make it game over
  g=0

  --a lot of this text uses the "?" version of the print command
  --you can find some info about it here: https://demoman.net/?a=optimizing-for-tweetcarts

  --draw the score using the formatting saved as f earlier
  ?f..s,57,48,1

  --draw the instructions
  ?"\#5⬅️ & ➡️ to move",35,72
  ?"\#5❎ to start",43,82

  --if the user presses x, go to ::_r:: to reset the game
  if(b(5))  goto _r

--things we draw if the game is still going
else
  --the player is a mess of trig to allow it to spin, so i shortened the names of cos() and sin() to save chars
  c=cos
  z=sin

  --draw a dot at the top of the screen randomly. this is to show the dangerous border on the top of the screen
  ?".",r(128),0,1

  --drawing a player that rotates as it moves was the last thing i did
  --it's a little sloppy because i had some chars to spare and thought it would be fun

  --this is a mess of bad variable names. pretty much just the next single letter name i had available
  e = -x/30     --the current angle to rotate the player. based on their x position
  j = x+c(e)*3  --x1 for the line that makes the player's arm
  k = y+z(e)*3  --y1 for the line that makes the player's arm
  u = x-c(e)*3  --x2 for the line that makes the player's arm
  h = y-z(e)*3  --y2 for the line that makes the player's arm

  --draw the line for the player arm
  line(j,k,u,h)
  
  --the "body" is a set of lines that run perpendicular to the arm line
  
  --first, change the angle to add 90 degrees (pi/2 radians)
  e += .25

  --this loop draws lines from 25% of the arm line to 75%
  for i=-1,1,.25 do
    p = .5 + i/4   --get the percentage

    --get the x and y position of the base point along the arm line
    --more bad variable names
    l = p*j + u*(1-p)     --x
    m = p*k + h*(1-p)     --y
    
    --by default, the vertical line for the body will extend 3 pixels in either direciton
    d=3 
    --if this point is in the center, i don't have it extend down
    if(abs(i)<.8) d=0

    --draw a vertical line around the center point from the arm line
    line( l+c(e)*3, m+z(e)*3, l-c(e)*d, m-z(e)*d )
  end

  --give the player a head in the form of a circle
  circ( x+c(e)*4, y+z(e)*4, 2)

  --draw the score in the top left of the screen
  ?s,1,8
end

--if the game just started, instead of playing i want to be on the title screen
--this is a slight mod on the game over screen

--if a is 1, that means the game just started and we should end the round
if a<2 then
  --move the player off screen to kill them
  y=-1

  --write the game title over the score
  ?f.."\#41k jump",37,48

  --add in some credits so we know who made this thing!
  ?"by @andy_makes",36,99
end

--draw everything to the screen
flip()

--return to the ::_:: and reapeat everything for next frame!
goto _