hypothete [Lexaloffle Blog Feed]

Sparkle Team

Tue, 28 Sep 2021 15:58:49 UTC

Sparkle Team

by hypothete

[Click to Play]

This is a half-completed demake of the Sega Genesis title Shining Force. I played the game for the first time early this year, and I found myself fascinated with the turn-based battle system. My biggest annoyance with Shining Force was that characters take a movement turn on the map, then combat takes place in a battle screen for only one turn. As enjoyable as it is to see higher quality graphics of the characters and terrain on the battle screen, there's a lot of time wasted moving between the two views in larger battles. I decided to write a similar battle system, but have all combat take place on the map instead.

Here's how combat works: Characters on the map are sorted by their speed to determine turn order, then each character gets a movement and action turn. Playable characters have HP and MP bars that appear at the bottom of the screen during their turn. Depending on their class, a character may have ranged or melee attacks, as well as one or more magic spells. There are also potions hidden on the map, which characters can pick up by standing on them, and can drink as an action. There isn't a win condition implemented, but I found it fun to try and get my party to the castle in the center of the map while testing the mechanics.

Writing this cart was a great way to get comfortable with coroutines, and hopefully the code will prove helpful for other people writing turn-based battle systems. Let me know what you think!

GMagic: a vector art drawing program

Sat, 02 Feb 2019 18:26:27 UTC

Hi all,

I'm writing a short graphical text adventure for the PICO-8, and a few weeks ago I determined that I needed a vector graphics editor capable of outputting PICO-8 code. I've created a web app called GMagic that lets you make vector drawings on a canvas, then export Lua functions for drawing them. I also provide the functions for drawing polygons and polylines:

ptstr() (needed for the functions):

Polygon:

Polyline:

If you want to read more about GMagic or check out some sample screenshots, you can view the Github repository here. If you end up using GMagic for a cart, I'd love to hear about it!

EDIT 6/24: I can't believe I forgot to include ptstr()! I've added it above, and to the Lua sample in the repo.

World of Pico: a GPIO experiment

Sun, 06 Jan 2019 00:29:46 UTC

Hi all, I wanted to share with you an experiment I've been working on called World of Pico. It uses the GPIO pins to transfer map data from a JavaScript context to the cart, allowing for essentially unlimited maps for exploration when the cart is hosted on a webpage. The demo has 3 maps, but I can see this technique being used in combination with a map server, and eventually allowing for interactivity between the client and server.

The method of data transfer is very similar to how P8T by seleb works. Different values on pin 0 of the GPIO tell the JS app or the cart whose turn it is to read and update the following pin values. If you want to explore the source code or read more about the transfer technique, please check out the GitHub repo.

Thanks for taking a look!

Fill pattern dithering

Sat, 11 Nov 2017 02:11:38 UTC

Fill pattern dither

by hypothete

[Click to Play]

This is a demo using the fill patterns introduced in 0.1.11 as a way of dithering between two or more colors. Use the buttons to adjust spread of the gradient, the number of sample circles drawn per frame, and the radius of the circles.

The way it works is I have a gradient table, a fill pattern table, and a spread value. I'm going to draw 500 circles randomly each screen refresh, and each circle is going to use two colors and a fill pattern as its fill. The circle's colors are determined by the nearest and next nearest colors on the gradient based on some measurement, in this case the proportion of the spread to the shortest distance from a circle to one of three bouncing points.

I set up a table of fill patterns that I generated from a 4x4 ordered dithering matrix. There's a good description of ordered dithering here. Here's the matrix I used:

 1   9   3  11
13   5  15   7
 4  12   2  10
16   8  14   6

To make a table of fill pattern values, I iterated over the 4x4 matrix 16 times, and if each cell was higher than the count i, I flipped a corresponding bit in a 16-bit binary number. This gives us 16 binary numbers to pass to the fillpattern method:

pat={
  0b1111111111111111,
  0b0111111111111111,
  0b0111111111011111,
  0b0101111111011111,
  0b0101111101011111,
  0b0101101101011111,
  0b0101101101011110,
  0b0101101001011110,
  0b0101101001011010,
  0b0001101001011010,
  0b0001101001001010,
  0b0000101001001010,
  0b0000101000001010,
  0b0000001000001010,
  0b0000001000001000
}

The fill pattern for each circle is then determined by the circle's position between one color and the next along the gradient. So if the circle lands between two colors, it will use pat[7] or pat[8], but if it's centered on a color it uses pat[1].

Voronoi diagram generator

Mon, 05 Sep 2016 19:57:24 UTC

Voronoi diagram generator

by hypothete

[Click to Play]

Simple Voronoi diagram generator. I was trying to see if I could get a speed boost from writing pixel values directly to the video RAM, but regardless the fill walking through all the pixels is still very slow. Any ideas on how I could speed things up?

--voronoi diagram
--by hypothete
points={}

function makepoints()
    for i=1,16 do
        e=rnd(128)
        f=rnd(128)
        add(points,{
            x=e,
            y=f,
            c=rnd(255)
        })
    end
end

function jitter()
    for i=1,#points do
        p=points[i]
        p.x+=rnd(2)-1
        p.y+=rnd(2)-1
    end
end

function near(pts,b)
    nt=nil --nearest pt
    nd=4096--dist to nt
    for i=1,#pts do
        a=pts[i]
        nl=(b.x-a.x)^2 + (b.y-a.y)^2
        --dist leaving off sqrt
        if(nl<nd)then
            nd=nl
            nt=a
        end
    end
    return nt
end

function drawvoro()
    for i=0,63 do
        for j=0,127 do
            k=i+64*j --x+y*w = 1d position
            z={x=i*2,y=j}
            np=near(points,z)
            if(np) then
                memset(0x6000+k,np.c,0x1)
            end
        end
    end
end

function _init()
    makepoints()
    drawvoro()
end

function _update()
    if(btnp(5)) then
        jitter()
        drawvoro()
    end
end

Bracewell Probe Simulator

Sun, 04 Sep 2016 13:27:51 UTC

Bracewell Probe Simulator

by hypothete

[Click to Play]

This is a simple simulation of Bracewell probes, AI-guided spacecraft that explore star clusters, looking for life and intelligence. Most of what I experimented with in this cartridge was depth-based sorting for drawing and hacky 3D projection techniques.

Wizard of the Golden Hat

Sun, 28 Aug 2016 17:56:35 UTC

Wizard of the Golden Hat 0.0.1

by hypothete

[Click to Play]

Hi all, this is my unfinished Ludum Dare 36 submission (http://ludumdare.com/compo/ludum-dare-36/?uid=20847). I started building the game with the day/night system and text menus; by the time I was 40 hours in I realized that I hadn't found the game mechanic and decided to call it quits. Still learned a ton, though.

Quick shout out to geckojsc for the lua coroutine dialog system tutorial: https://www.lexaloffle.com/bbs/?tid=3833 I used a lot of the work here with a few tweaks to build the textboxes and in-game menu. One issue I'd like to address in the future is a more terse way of setting up actors and conditional scripts. I feel like when Pico-8 cartridges reach a length of ~1000 chars or so, things start to get really messy in terms of source code organization. Additionally, there were a few functions that I had trouble "hoisting" and I couldn't figure out why. If anyone has pointers on how to simplify the data structures I'm using or specifically better use of tables, please let me know. Thanks for taking a look!