Mot [Lexaloffle Blog Feed]

Air Pico

Sat, 31 May 2025 09:51:53 UTC

UPDATE: Now with mouse support. Enable from the pause menu.

A cozy flight sim lite for PICO-8.

Become a pilot for Pico Air, a small air company operating between the islands of Pico Isles.
Perform deliveries, charter flights, crop dusting and other jobs to unlock new planes.

Features:

A 16km x 16km map to explore
3 different planes
External camera views
Photo mode

Controls

Arrows - Ailerons and elevator (roll and pitch)
O + Up/Down - Throttle
O + Left/Right - Rudder
X + Up/Down - Adjust elevator trim
X + Left/Right - Flaps

Or use player 2 controls for throttle and rudder.

Dashboard instruments from left to right are:

Speed in knots
Height in feet
Vertical speed in feet per minute
Flaps
Throttle

Photo mode

During a mission or free flight you can select "Photo mode" from the PICO-8 pause menu.
Photo mode allows pauses the game and allows you to move the camera independently from the plane.

During photo mode:

Arrows - Turns the camera
Player 2 arrows - Moves the camera
X (hold) - Move slowly
O (hold) - Move quickly
X+O (hold) - Move very quickly

Select "Back to game" from the pause menu to exit photo mode and return to the game.

Pico Isles

Find sfx not used by music patterns

Fri, 30 May 2025 01:52:42 UTC

Just a little snippet I use when looking sfx that haven't been used in the pattern editor.

p,s={},"" for a=0x3100,0x31ff do p[@a]=true end for i=0,63 do if not p[i] then s..=i.." " end end print(s)

Paste into the terminal and hit enter.

WARNING: This only shows sfx that are unused in any pattern. You are responsible for checking whether they are:

Used as sfx in the program
Used as instruments by another sfx (i.e. for sfx 0 to 7)
Used in some other way I haven't thought of

Experimental Flight Sim

Sun, 20 Apr 2025 01:22:32 UTC

mot_flightsim

by Mot

[Click to Play]

This is a work-in-progress flight simulator I've been working on.

The flight model is mostly implemented, but may need some tweaking. And I'm still to implement crashing into buildings and some sort of map or navigation aid.

I've never flown a plane, and only dabbled in flight sims, so I would really appreciate some feedback from anyone with more experience than me, so I can try to tweak the flight model parameters to be a bit more realistic.

The plane is based on the Cessna 172.

Controls

Arrows - ailerons/elevators
Player 2 up/down (E,D) - throttle
Player 2 left/right (S,F) - rudder

While holding down X

Up/down - adjust trim
Left/right - adjust flaps

You can also control it with a single controller by holding down circle to switch from ailerons/elevators to throttle/rudder.

When on the ground:

Dropping the throttle to 0 and continuing to press down activates the wheel brakes.
The rudder controls also control the nose wheel when your speed is less than 10 knots.

Instruments

From left to right the instruments/controls are:

Airspeed in knots
Altitude in feet
Vertical speed in feet per minute
Flaps
Throttle

Taking off

Leave flaps set to 0 (i.e. the default)
Set the throttle to full
Wait until the plane speed reaches 55 knots
Pull back slightly (down arrow) to raise the nose

Landing

Aim to approach at 4.5 degree glide slope and 65 knots.
Each airport has a coloured glideslope light:
- yellow = too high
- green = in range
- red = too low
Once you reach the runway:
a. level off at 10 feet above ground.
b. Try to slowly descend to 5 feet.
c. Drop the throttle to 0
d. Try to fly just above the runway for as long as possible until gravity takes over

(This is admittedly easier said than done with Pico-8 controls :-)

Aircraft damage

These things will damage the aircraft:

Heavy landings/crashes
Exceeding "never exceed speed" (158 knots)
Tight turns when exceeding "design maneuvering speed" (97 knots)
Taxiing on the wrong surface types

Flight model

If the game feels difficult, you can change the flight model in the pause menu.
"simple" disables stalls and damage due to stressing the airframe at high speeds.
"easy" disables all damage and lets you land on or take off from any surface.

Combat Chopper X

Sat, 05 Apr 2025 09:41:51 UTC

mot_chopperx

by Mot

[Click to Play]

This is an update of Combat Chopper to improve the resolution of the ground, at least close to the camera, using an enhanced version of the Whiplash Taxi Co ground drawing code.

See the original game for instructions on how to play.

I had to sacrifice a few things in order to squeeze the ground drawing code in, particularly the heads-up artificial horizon, and the targeting camera effects, and the menu is now in a separate cart. Also it drops down to 15 fps a bit more than I'd like, but it feels pretty playable regardless.

For comparison, here's shots with and without the new ground rendering:

.

Extended tline

Mon, 31 Mar 2025 10:11:01 UTC

Extended tline demo

by Mot

[Click to Play]

Update: Bug fixes

Here's a little line drawing routine I've used for Whiplash Taxi and some other work-in-progress carts.
I wanted to package it up like a drop in tline replacement.

It's equivalent to regular tline, but instead of drawing each tile it uses it to lookup a higher resolution 8x8 tile region and draws that instead. The result is a map with 8 times the detail (or 8 times the size, depending on how you look at it).

The demo is a simple go-cart example. You can press X to toggle between the new routine and the regular tline function.

The actual routine is in tab 1 and consumes 547 tokens.

To use it, you first create some 8x8 "textures" at the top left of your map region:

Then you create corresponding sprites in sprite page 1:

Then use the sprites in page 1 to draw on the map:

Then call the tlinex function to render the map, the same way you would call the regular tline.

Some caveats:

It's slower than tline, because it's calculating and performing multiple tline calls.
Especially if you zoom out a lot, it will slot down a lot (i.e. large values for the mdx,mdy parameters meaning the tline spans a lot of map cells)
It doesn't handle camera offsets.
It doesn't handle clip regions (and resets the clip region).
There are some occasional visual artifacts.

Perhaps someone will find this useful :)

Medieval world generator

Sat, 08 Feb 2025 09:14:56 UTC

mot_adv

by Mot

[Click to Play]

Here's a medieval procedural world generator I'm working on. It has a few different biomes, buildings and roads.
I'm thinking of turning it into some sort of Trial of the Sorcerer sequel.

Instructions

Give it a minute to generate the world, then open the pause menu and choose "explore world" to explore it in ray cast 3D.

There's no gameplay yet, just walk around and explore.

In the generator you can also use the direction pad to scroll around, and zoom in/out with X and O.

Variable Inspector

Sat, 02 Nov 2024 07:37:27 UTC

A quick port of my pico-8 variable inspector, I find useful for debugging.
It has a few more colours for readability, and can display userdata.

To use, hit Esc to break out of your program and enter:

dbg(v)

Where v is the value to inspect.

You can drill into values by clicking the "+" (or collapse them again by clicking "-").
Mouse wheel to scroll up and down.
Press Esc when done.

-- debug inspector

-- lines to display and scroll offset
local dbg_lines,dbg_s={},0,false

-- add item to display
function dadd(n,v,i,p)
	-- insertion sort in name order
	while p>1 
	and dbg_lines[p-1].i==i 
	and type(dbg_lines[p-1].n)==type(n) 
	and dbg_lines[p-1].n>n do 
		p-=1 
	end 
	add(dbg_lines,{n=n,v=v,x=(type(v)=="table" or type(v)=="userdata") and "+" or " ",i=i},p)
end

-- expand/collapse item
function dexp(l,p)
	if l.x=="+" then
		-- add item properties to expand
		if type(l.v)=="userdata" then
			if l.v:height() and l.v:height()>1 then
				for i=0,l.v:height()-1 do
					p+=1
					dadd(i,l.v:row(i),l.i.." ",p)
				end
			elseif l.v:width() then
				for i=0,l.v:width()-1 do
					p+=1
					dadd(i,l.v[i],l.i.." ",p)
				end			
			end
		else
			for n,v in pairs(l.v) do 
				p+=1 
				dadd(n,v,l.i.." ",p)
			end 
		end
		l.x="-"
	elseif l.x=="-" then
		-- delete nested lines to collapse
		while p<#dbg_lines and #dbg_lines[p+1].i>#dbg_lines[p].i do 
			deli(dbg_lines,p+1)
		end
		l.x="+" 
	end 
end

-- handle input
function dinp()

	-- get mouse state
	local x,y,b,_,w=mouse()

	-- handle mouse click
	local click=b==1
	if click and not dbg_click then 
		local i=(y-14)\9+1 
		local p=dbg_s+i 
		local l=dbg_lines[p]
		if l and(x-220)\5==#l.i then 
			dexp(l,p)
		end 
	end

	-- mouse wheel scrolls
	dbg_s=max(min(dbg_s-w*4,#dbg_lines-27),0) 

	dbg_click=click
end

function dtostr(v,nopreview)
	if type(v)=="userdata" then
		local w,h,t,d=v:attribs()
		local r=t
		if h==1 then
			r..="["..w.."]"
			if w<=16 and not nopreview then
				if t=="f64" then 	r..=" ("..string.format("%.2f",v[0])
				else					r..=" ("..v[0]
				end
				for i=1,w-1 do
					if t=="f64" then		r..=","..string.format("%.2f",v[i])
					else					r..=","..v[0]
					end
				end
				r..=")"				
			end
		else
			r..="["..w.."x"..h.."]"
		end
		return r
	elseif type(v)=="table" then
		if #v>0 then
			local r="["..#v.."]"
			if #v<=16 and not nopreview then
				r..=" ("..dtostr(v[1], true)
				for i=2,#v do
					r..=","..dtostr(v[i], true)
				end
				r..=")"
			end
			return r
		else
			return "{}"
		end
	else
		return tostr(v)
	end
end

-- draw UI
function dui()
	while true do 
		rectfill(220,10,470,260,1)
		for i=1,27 do 
			local l=dbg_lines[i+dbg_s]
			if l then 
				local x,y=220,(i-1)*9+14
				x+=#l.i*5
				local lx=x
				print(l.x,x,y,10)
				x+=5
				print(l.n,x,y,12)
				x=max(x+#tostr(l.n)*5,lx+25)
				print(sub(dtostr(l.v),1,(470-x)\5),x,y,7)
			end 
		end 
		dinp()
		flip()
	end 
end

function dbg(v,n)
	dadd(n or "value",v,"",#dbg_lines+1)
	cursor()
	pal()
	clip()
	dui()
end

min/max functions are expensive

Sun, 27 Oct 2024 11:11:23 UTC

I've noticed the min and max functions have a surprisingly high CPU cost.

For example

a=stat(1) for i=1,1000 do b=min(1,2) end print(stat(1)-a)

Outputs:0.103

Which is almost twice the CPU cost for sqrt()

a=stat(1) for i=1,1000 do b=sqrt(2) end print(stat(1)-a)

Outputs:0.054

And even if I define my own "min" function in lua, it's still a lot faster.

function mymin(a,b) return a<b and a or b end
a=stat(1) for i=1,1000 do b=mymin(1,2) end print(stat(1)-a)

Outputs:0.057

Is this a mistake?

CSV parser

Wed, 02 Oct 2024 08:42:34 UTC

Here's a basic CSV parser I use to save tokens in my games. It uses split for the heavy lifting.

Basic version

The most basic version is 66 tokens.

function data(str)
 local lines=split(str,"\n")
 local props,d=split(deli(lines,1)),{}
 for l in all(lines) do
  local o,v={},split(l)
  for i=1,#v do
   o[props[i]]=v[i]
  end
  if(o.name)d[o.name]=o
  add(d,o)
 end
 return d
end

It can be used like this (4 tokens):

spritetypes=data
[[name,sx,sy,sw,sh
alien,0,0,2,2
boss,4,0,4,4
player,0,2,4,2
bomb1,3,0,1,1
bomb2,2,1,1,1
bullet,2,0,1,1]]

The data function returns an array of objects, with properties that map to the CSV columns.

If objects have a name property, then they will be added as a property to the main object with that name.

Which means we can reference the "player" sprite type as:

print(spritetypes.player.sx)

References

This version allows you to reference objects defined in other CSV tables. It's 117 tokens.

glob={
 ["true"]=true,
 ["false"]=false
}

function data(str,globname)
 function fixval(v)
  if v=="" then
   return nil
  elseif glob[v]~=nil then
   return glob[v]
  end
  return v
 end  

 local lines=split(str,"\n")
 local props,d=split(deli(lines,1)),{}
 for l in all(lines) do
  local o,v={},split(l)
  for i=1,#v do
   o[props[i]]=fixval(v[i])
  end
  if o.name then
   d[o.name]=o
   if(globname)glob[globname.."."..o.name]=o
  end
  add(d,o)
 end
 return d
end

It can be used like this:

spritetypes=data(
[[name,sx,sy,sw,sh
alien,0,0,2,2
boss,4,0,4,4
player,0,2,4,2
bomb1,3,0,1,1
bomb2,2,1,1,1
bullet,2,0,1,1]],"spritetype")

enemytypes=data(
[[name,spritetype,health
boss,spritetype.boss,100
alien,spritetype.alien,10]],"enemytype")

enemies=data
[[typ,x,y,weapons
enemytype.boss,112,40
enemytype.alien,20,50
enemytype.alien,80,50]]

The routine maintains a glob variable containing objects that can be referenced, keyed by their name.

The second parameter tells data to add objects to the glob table, so that they can be referenced from other CSV tables. For example passing "spritetype" to data means that the "boss" sprite type will be added as "spritetype.boss".

This version also maps "true" and "false" as their corresponding boolean values.

Arrays

And if you need array properties, this final version supports them. It's 170 tokens.

glob={
 ["true"]=true,
 ["false"]=false
}

function maparray(a,fn)
 local r={}
 for e in all(a) do
  add(r,fn(e))
 end
 return r
end

function data(str,globname)
 function fixval(v)
  if v=="" then
   return nil
  elseif type(v)=="string" and sub(v,1,1)=="{" then
   return maparray(split(sub(v,2,#v-1),":"),fixval)
  elseif glob[v]~=nil then
   return glob[v]
  end
  return v
 end  

 local lines=split(str,"\n")
 local props,d=split(deli(lines,1)),{}
 for l in all(lines) do
  local o,v={},split(l)
  for i=1,#v do
   o[props[i]]=fixval(v[i])
  end
  if o.name then
   d[o.name]=o
   if(globname)glob[globname.."."..o.name]=o
  end
  add(d,o)
 end
 return d
end

It's used like so:

spritetypes=data(
[[name,sx,sy,sw,sh
alien,0,0,2,2
boss,4,0,4,4
player,0,2,4,2
bomb1,3,0,1,1
bomb2,2,1,1,1
bullet,2,0,1,1]],"spritetype")

enemytypes=data(
[[name,spritetype,weapons,health
boss,spritetype.boss,{spritetype.bomb1:spritetype.bomb2},100
alien,spritetype.alien,{spritetype.bullet},10]],"enemytype")

enemies=data
[[typ,x,y,weapons
enemytype.boss,112,40
enemytype.alien,20,50
enemytype.alien,80,50]]

Array values are enclosed in braces { }, and separated by semicolons :.
(Commas would have been nicer, but that would require handling nesting, which couldn't use split and would need way more code.)

I've used this routine pretty heavily in games like Trial of the Sorcerer and Combat Chopper, and it quickly pays for itself token wise. (Bonus if you can reuse the maparray function in other code.)

For large CSV tables in complex projects I even store them in a separate CSV file that can be edited with a CSV editor, and paste it back into the Pico-8 source after making any changes.

Titan

Sat, 03 Aug 2024 12:16:15 UTC

Titan

by Mot

[Click to Play]

I thought I'd upload this because I doubt I'll be able to finish it - at least as a Pico-8 game. Basically it was too ambitious and I ran out of space. Maybe I'll port it to Picotron someday, but for now it's basically a tech demo.

You wake up in an android body in a factory in a mining town on Saturn's largest moon, Titan. You have to solve the mystery of who you are and what happened, and maybe how you can put things right.

Or at least you would if the game was finished. For now there's a little puzzle about exiting the factory, and some dialog sequences. After that there's a car to drive, a slightly glitchy plane to fly and some empty buildings you can look inside.

It's intended to be a game about exploration and dialog.

Controls:

Arrows/mouse to aim
Controller 2 to move
When the crosshair turns yellow you can press X to interact.

Or you can switch it to single controller mode in the pause menu. (You can't strafe or look up/down, but that's not essential for this type of game.)

ChatGPT 4o

Sun, 19 May 2024 23:16:24 UTC

ChatGPT 4o seems pretty good at writing Pico-8 code. (At least for simple games).

I asked it:
"Can we try something different? Like a simple Space Invaders or Galaxians style game?
I have 4 sprites in slots 1,2,3,4 with a player ship, alien invader, player bullet and enemy bullet respectively. Could you make a simple game where the aliens move left and right in formation, and the player moves left to right along the bottom of the screen?"

I got this.

I pasted the gif into the chat window, and it said:

"Awesome! It looks like the basic mechanics are working. Let's add a few more features to make the game more interesting:

Enemy Bullets: Add bullets fired by the aliens.
Player Lives: Track the player's lives and end the game when they run out.
Score: Add a scoring system for each alien destroyed."

Then gave me an updated version that looks like this:

Then I got worried that AI is doing all the work and I'm going to turn into the spaceship inhabitants in WAL-E. So I asked it to quiz me on the code and check my answers.

It came up with questions like:

"Bullet Mechanics:

Q3: How does the player fire bullets? What happens when a bullet is fired?
Q4: How are player bullets updated and removed when they move off-screen?
Alien Movement:

Q5: How do the aliens move left and right in formation? What happens when they reach the edge of the screen?
Q6: How do the aliens move downwards after reaching the screen edge?"

Profiler

Fri, 08 Mar 2024 11:03:25 UTC

Here's a little profiler you can drop into an existing program - if you have 313 tokens to spare.
It instruments the global functions to count the number of calls and measure the CPU time spent inside them. Then it dumps it to a CSV file you can open in a spreadsheet viewer, and hopefully get some insight into where your program is spending the most time.

Instructions are in the comments at the top.

EDIT:

Count fn calls in a single 32bit integer (thanks @freds72).
Use "..." arguments syntax to support more than 9 arguments (thanks @Siapran)
Save uninstrumented fns to avoid calling the instrumented ones when dumping stats.

-->8
-- profiler

-- usage:
-- run your program
-- press esc to break
-- > _prof.begin()
-- > resume
-- run your program some more (to gather data)
-- press esc to break
-- > _prof.dump()
-- this will dump a profile.csv file to the cart's folder

-- notes:
-- profiling for more than 2-3 minutes could cause cpu measurements 
-- to overflow, and give incorrect results.
-- measures the amount of cpu spent in each function, where 1 is one whole frame
-- so divide by frame rate to get seconds (30, or 60 if using _update60).
-- profiling will slow down your program somewhat.

_prof={
	stats={},
	-- list of global functions to *not* instrument
	donttouch={flip=true,__flip=true,_startframe=true,_update_buttons=true,_get_menu_item_selected=true,_update_framerate=true,_map_display=true,_mark_cpu=true},
	-- original uninstrumented functions
	type=type,
	stat=stat,
	printh=printh,
	all=all,
	tostr=tostr,
	pairs=pairs
}

-- start profiling.
-- if called multiple times, will reset stats
_prof.begin=function()
	-- clear stats
	_prof.stats={}

	-- instrument functions
	if not _prof.instr then
		for n,v in _prof.pairs(_ENV) do
			if _prof.type(v)=="function" and not _prof.donttouch[n] then
				-- wrap function
				_ENV[n]=function(...)
					-- run and get cpu timing
					local cpuin=_prof.stat(1)
					return (function(...)
						-- update stats
						local cpuout=_prof.stat(1)
						local st=_prof.stats[n] or {ct=0,cpu=0}
						st.ct+=0x0.0001
						st.cpu+=cpuout-cpuin
						_prof.stats[n]=st
						return ...	
					end)(v(...))
				end
			end
		end
		_prof.instr=true
	end
end

-- dump profile stats to file
-- order is field to order by (name,ct,cpu,avg)
-- defaults to "cpu"
-- dst is printh destination
-- defaults to "profile.csv"
_prof.dump=function(order,dst)
	order = order or "cpu"
	dst = dst or "profile.csv"
	local rpt={}
 	for n,v in _prof.pairs(_prof.stats) do
		local cpu,ct,sh=v.cpu,v.ct,16

		-- average is cpu/(ct<<16), except that ct<<16 could
		-- overflow, in which case shift ct left as many bits 
		-- as possible and shift cpu right the remaining bits.
		while sh>0 and ct<0x4000 do		-- can't exceed 0x7fff as it would be treated as negative
			ct<<=1 sh-=1
		end
		cpu>>=sh

		-- create stat		
		local st={name=n,ct=v.ct,cpu=v.cpu,avg=cpu/ct}

		-- insert into rpt in order
  		local i=#rpt+1
  		while i>1 and (rpt[i-1][order]>st[order])==(order=="name") do
  			rpt[i]=rpt[i-1]
  			i-=1
  		end
	  	rpt[i]=st
	end

	-- print rpt
	_prof.printh("name,ct,cpu,avg",dst,true)
	for st in _prof.all(rpt) do
		_prof.printh(st.name..",".._prof.tostr(st.ct,2)..","..st.cpu..","..st.avg,dst)
	end
end

Here's an example of my 2D transforms demo.
For example you can see it spends a large amount of time in the "map" function (which would normally be suspicious except that the "2D transforms" replaces the standard "map" function with a custom version).

Render from RAM

Wed, 07 Feb 2024 04:13:04 UTC

mot_rendertest

by Mot

[Click to Play]

A little experiment with rendering directly from Pico-8 RAM using "peek".
Trying to use as few tokens as possible.

Mot's Animation System 2

Tue, 16 Jan 2024 00:34:26 UTC

Mot's Animation System 2

by Mot

[Click to Play]

This has been sitting on my drive for a year or so. I was meaning to write up some documentation for it, but I'm throwing it up as is for now. (Until I can remember how to use it.)

Basically it's a sequel to Mot's Animation System built on top of the 2D transforms library. The main improvement being that it supports rotation.

The basic idea is you create "sprite" animations based on frames on your tilemap. You can then combine them into "timeline" animations where position, rotation etc can be set at different points by creating keyframes.
There's also a "storyboard" animation type that simply plays other animations in order.

You can import gfx and tilemaps from other carts, save/load your projects. You can also export your animations to embed in your own projects if you wish. It's about 1700 tokens, although 1000 of that is the 2D transforms system. (I can post an example of this if anyone is interested.)

I'd write up some more, but I need to remember how it works myself :).

Maybe someone wants to have a play with it anyway.

EDIT:

Here's an example cart playing an exported image.
It uses tabs 2,3,4 of the editor, except I recovered about 200 tokens by stripping out some unused bits.

Animation System 2 test

by Mot

[Click to Play]

Whiplash Taxi Co

Sun, 30 Jul 2023 10:31:59 UTC

Whiplash Taxi Co

by Mot

[Click to Play]

UPDATE: Fixed suspension to lean towards the outside of turns, not the inside.

Welcome to the Whiplash Taxi Company, where our motto is "The slower you're there, the lower the fare!"

As a valued employee and taxi driver, your job is to pick up passengers and deliver them to their destination as fast as possible, by any means necessary.

Passengers are easy to spot, just look for the big red arrows over their heads.

Simply stop next to them so they can jump in!
Then follow the red destination indicator to the destination and stop when it says "stop!".

Repeat this as many times as possible in 5 minutes, and see how much $$$ you can bring in.

But beware, sometimes the direct route isn't the quickest.
To make it easier we have provide this giant map of Motsville. You may want to spend some time in "Free Explore" to get the layout. Or try some of the fully legitimate and not just driving-around-random-streets-way-too-fast street circuits, and maybe set a few lap records.

Remember, at Whiplash Taxis when we say "Break neck speeds", we mean it!
(Hopefully not literally. Hopefully.)

Taxi Game (maybe)

Sat, 08 Jul 2023 23:12:48 UTC

Taxi game

by Mot

[Click to Play]

This is basically a Wolfenstein-3D style ray-caster with floor tiles.
There's no gameplay or even collision detection so far.

The top right of the Pico-8 map region is used to layout the game, using the sprites in tab 3.

The sprites correspond to 8x8 regions in the top left of the map area, which represent the "texture" to draw.

SDF Ray Marcher v2

Wed, 08 Feb 2023 00:34:57 UTC

SDF Ray Marcher

by Mot

[Click to Play]

I updated my ray marcher to use RGB colours internally and random dither back to 16 colours.
This should allow me to add things like partially transparent surfaces, or atmospheric fog at some point.

Combat Chopper

Thu, 29 Dec 2022 00:01:03 UTC

Combat Chopper

by Mot

[Click to Play]

WARNING: This game attempts to emulate old 8-bit flight simulators from the 80s and 90s. The flight model leans towards realism rather than easy-to-pickup arcade gameplay (even if it's somewhat primitive compared to serious modern-day flight simulators). As such it's not an easy to pickup game - controlling the helicopter is challenging and takes practice. In combat, even more so.

Welcome to Combat Chopper, an 80s helicopter combat flight simulator for Pico-8!
Pilot your P8 64k Apachi armored attack helicopter on a series of missions destroying key targets in enemy territory.

Getting started

Training mode

Use the "Training" mode to practice controlling the helicopter before trying to take on any missions. You will need to be comfortable with keeping low, stopping and hovering, and landing, before attempting to engage in combat.
Training mode is exactly like career mode, except there are no objectives, and you cannot be shot down.

Flight controls

The helicopter and weapon systems can be fully controlled using a single controller.

When no button is held:

Up/down -> Pitch
Left/right -> Roll

When the circle button (Z) is held:

Up/down -> Collective
Left/right -> Tail rotor

To take off, hold circle (Z) and press the up arrow until the helicopter starts climbing.
A little bit of collective will make the helicopter hover just above the ground (due to the "ground cushion effect"). Adding more collective will cause the helicopter to continue climbing.

Once airborne, press the arrow keys (without holding circle) to tilt the helicopter, which will cause it to accelerate in that direction.

The cockpit gauges help you control your flight:

Player 2 controls (optional)

Although the game can be played with just one controller you can use a second controller for extra precision.
The player 2 arrow keys control the collective (up/down) and tail rotor (left/right).

Stopping

Being able to stop and hover is a useful skill.
Essentially this involves raising the nose and tilting backwards until your speed reduces to zero.
However, keep in mind that the helicopter has momentum and it takes some distance to brake from 100mph down to zero.
Also tilting backwards at speed will cause the helicopter to climb rapidly making you an easy target for SAM launchers. To avoid this, drop the collective down first before lifting the nose. Try to balance the collective and pitch angle to keep the vertical speed as close to zero as possible. When your speed is close to zero, quickly add collective to avoid dropping quickly.

Landing

Landing is tricky to master, but is an essential skill.

Use the map view to locate your base.

It will be at the coordinates you took off from! Alternatively look for the orange dot on the map.

Come to a hover next to your base, then turn to face it using the tail rotor controls.

Approach the the helipad slowly (~10mph) using the collective and vertical speed indicator to control the rate of descent.

As you reach the helipad, tilt the nose up slightly to come to a hover and lower the collective until you touch down onto the helipad.

Combat

As well as piloting your helicopter, you will also need to destroy enemy units.
This involves locating the enemy, targeting them, and selecting and firing the appropriate weapon.

Weapons and targeting

Hold cross (X) to access the weapon systems.
While held:

Up/down -> Cycles through available targets.
Left/right -> Select the weapon/countermeasure to fire.

Tap X to fire the selected weapon at the targeted unit.

From left-to-right the weapons are:
- No weapon. (I.e. safety on)
- Cannon. Effective against all unit types, but has limited range.
- Laser guided missile. Seeks the targeted unit. Ineffective against camps and outposts.
- Rockets. Fly straight forward. Effective against camps and outposts , but not other targets.
- Countermeasures. Used to counter surface to air missiles (SAMs).

In order to be targeted, an enemy unit must be visible (i.e. in front of you) and in range.
Range depends on your altitude - the higher up you are the greater your targeting range. Beware that this works both ways - enemies can also target you from further away when you are higher up.

When a unit is targeted a square reticle is displayed around it, and the unit is displayed in the targeting camera view. Enemy units have a red reticle and an "E" displayed in the bottom left corner of the target camera view. Friendly units have a blue/gray reticle and an "F" displayed.

Enemy fire

The main threat will be surface-to-air missiles (SAMs). Most units will fire these at you when they spot you.
Beware of SAM launchers as they fire more quickly and their missiles do greater damage.

The IR and SAM dashboard lights tell you when an enemy is aiming and firing at you.

If the IR light is lit an enemy is targeting you and getting ready to fire.
The SAM light means a missile has been fired and is actively seeking you, and you should take action to avoid being hit.
This might mean:

Dropping a countermeasure. This is the most effective way to avoid getting hit, but you only have a limited supply. Each countermeasure lasts for 10 seconds.
Dropping behind a hill is occasionally effective, if you have enough time.
Attempting to evade by turning tightly or rapidly dropping altitude. This is risky but can work.

The other threat is anti-aircraft (AA) guns.
These fire shells at you which, unlike SAMs, do not seek and have a shorter range. However there is no warning indicator for AA guns and they are particularly dangerous if they catch you at close range moving slowly, or if you try to take them head on.

Damage

Damage is displayed in the mission objective display as a red bar. If the bar is fully red then you have been shot down, and your helicopter will crash to the ground.
Damage also affects your engine and the amount of lift your rotors can generate.

You can repair your helicopter by landing at a friendly helipad, and dropping the collective down to zero. This will also restock your weapons.

Missions

In career mode you will be given missions.
Each involves destroying one or more enemy units at a specific location, then returning to and landing safely at your base.

The mission objective is displayed at the top of the dashboard.
Use the map to find your way to the objective coordinates. The objective is displayed as a red dot.

Once enough units have been destroyed at, or close to, the mission coordinates, the mission objective will change to "Return to Base", and display the base coordinates.

Tips

Some tips to help keep you in the air.

Keep low

Flying low is challenging. However keeping under 100 feet prevents you from being lit up like a Christmas tree to every SAM capable enemy unit.

Friendly space is to the west

If you need to retreat, head west.

Use the mountains

This is particularly important for missions deeper into enemy territory.
The basic approach is:

Fly to a mountain, keeping low, and come to a hover beside it. Ideally keeping it between you and enemy units.
"Pop up" to 200-300 feet and look around for enemy units. Then drop down again before they can fire at you.
Choose the next mountain.
Decide which enemy units to destroy or avoid in order to reach the next mountain.
Destroy the chosen units.

Repeat the process until you are within range of your objective.

Watch out for AA guns

Getting close to an anti-aircraft gun can quickly spoil your day.
Destroy them from range or avoid.

Helicopter flight sim

Wed, 09 Nov 2022 05:22:16 UTC

Chopper

by Mot

[Click to Play]

Update: Updated cart to latest version. This is probably close to what will be released.

A work-in-progress helicopter combat flight simulation. Loosely based on my memories of playing Gunship on C64 a few decades ago.

The heli can be controlled with player 1 input:

By default the arrow keys control the cyclic stick.
Hold down circle (z) to switch to collective (up/down) and tail rotor (left/right).
Hold down cross (x) for weapons mode, where up/down cycles between targets, and left/right selects the weapon.
Tap cross (x) quickly to fire.

So to take off, hold down circle (z) and up.

Alternatively you can use player 2 input (E,S,D,F in keyboard) for collective and tail rotor.

From left to right the weapons are:

None (i.e. safety on)
Cannon - auto aims. Effective against all unit types. Limited range.
Lazer guided missile - Seeks current target. Effective against tanks.
Unguided rockets - Fly straight ahead. Effective against infantry camps.
Countermeasures - Drop one of these to divert incoming missiles.

Walking Simulator

Sun, 25 Sep 2022 10:06:28 UTC

Walking Simulator

by Mot

[Click to Play]

A little texture-mapped graphics engine with BSP-tree models and fog shading.
Doesn't even try to maintain 30 FPS consistently :-)

Player one controls aim.
Player two controls strafe.
X/O moves up and down.

I still don't have a plan for this cart.