Rétro-Actif

Rétro, blog, prog.

A year of Pico-8 sketches

-

Sphere
A WIP version of Sphere. One of my favorites sketches.1

Hello everyone and happy new year! 2017 has been a hectic year, yet during this year, I got a few good things, such as finally getting a job in gamedev and getting inspired to make Pico-8 sketches.

I'm not going to introduce again (beware, french inside) that little fantasy console, but those last months, it got a few updates which sparked a new interest in me to write down some small carts for it.

After storing them in a folder I would regulary update with the latest sketch, I wondered what to do with them after a while. Only sharing them via GIFs on social networks is fine, but I also wanted to have them available to everyone to inspire themselves do better than me (that should be easy, that said, people like Rez or [Trasevol_Dog][traseveol] do miracles on the same platform!)

So, after zipping the sketch folder up and uploading, here are my Pico-8 sketches of the year 2017 : [link]

Best of 9
A small selection of the year's sketches.

They're licenced under Creative Commons Attribution-NonCommercial-ShareAlike 4.0, which means as long as you mention me (and the other people that did some of the routines I used such as electricGryphon) and don't use them in commercial stuff, you're allowed (and encouraged) to share and remix under the same licence.

To make stuff a bit easier for you, I'll provide in the bottom of this post the source for the matrix and vector libraries I did over the year to allow me to easily make 3D scenes. I haven't documented it yet, but it should get easy to do work with it. Have a look at how I used it through sketches to see how it's used (mostly vec() and mat() calls with some vector/matrix maths.). Note that I created some utility functions like mat.scale to easily create transformation matrices. If you have basic knowledge about the 3D projection process, you should be fine! :D

3D wave
The last sketch of year, only touched up a bit today

Anyway, I sure had fun making all those sketches, I hope I'll be able to top this and make a better batch this year and why not?- a few bigger projects! Have a nice day and, again, a happy new year! See ya!

Link to 2017's archive : [link]


As promised, here's the matrix/vector library, released as CC0, designed for Pico-8.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
-- vec3 and matrix44 library
-- Released as CC0 (https://creativecommons.org/publicdomain/zero/1.0/)
-- Adding a mention would be nice but not needed. o/

------------
-- vector --
------------
local vec = (function()
 local vec_mt = {}
 local function new(x,y,z)
    local vec={t="vec",x=x,y=y,z=z,
        str=function(v)
            return "("..v.x..","..v.y..","..v.z..")"
        end,
        dot=function(v,v2)
            return v.x*v2.x + v.y*v2.y + v.z*v2.z
        end,
        lensq=function(v)
            return (v.x*v.x) + (v.y*v.y) + (v.z*v.z)
        end,
        len=function(v)
            return sqrt(v:lensq())
        end,
        norm=function(v)
            local vmax = v
            return vmax/vmax:len()
        end
    }
    setmetatable(vec,vec_mt)
    return vec
 end
 vec_mt = {
    __add = function(v,o)
        if type(o) == "number" then
            return new(v.x+o,v.y+o,v.z+o)
        end
        return new(v.x+o.x,v.y+o.y,v.z+o.z)
    end,
    __sub = function(v,o)
        if type(o) == "number" then
            return new(v.x-o,v.y-o,v.z-o)
        end
        return new(v.x-o.x,v.y-o.y,v.z-o.z)
    end,
    __mul = function(v,s)
        return new(v.x*s,v.y*s,v.z*s)
        end,
    __div = function(v,s)
        return new(v.x/s,v.y/s,v.z/s)
        end,
 }
 local unit_x = new(1,0,0)
 local unit_y = new(0,1,0)
 local unit_z = new(0,0,1)  
 local zero = new(0,0,0)
    return setmetatable({
        new=new,
        z=zero,
        ux=unit_x,
        uy=unit_y,
        uz=unit_z
    },{__call=function(_,x,y,z) return new(x,y,z) end})
end)()

----------------------
-- matrix (m[y][x]) --
----------------------
local mat = (function()
local new = nil
local mat_mt = {}
-- v[y][x]
local function mat_each(lmbda)
    local a = {}
    for y=1,4 do
        a[y] = {}
        for x=1,4 do
            a[y][x] = lmbda(x,y)
        end
    end
    return a
end

local function mat_i()
    return new({
 {1,0,0,0},
 {0,1,0,0},
 {0,0,1,0},
 {0,0,0,1}})
end

local function mat_z()
    return new({
 {0,0,0,0},
 {0,0,0,0},
 {0,0,0,0},
 {0,0,0,0}})
end
local function mat_det(m)
    return (
     m[1][1]*m[2][2]*m[3][3]*m[4][4] + m[1][1]*m[2][3]*m[3][4]*m[4][2] + m[1][1]*m[2][4]*m[3][2]*m[4][3]
+ m[1][2]*m[2][1]*m[3][4]*m[4][3] + m[1][2]*m[2][3]*m[3][1]*m[4][4] + m[1][2]*m[2][4]*m[3][3]*m[4][1]
+ m[1][3]*m[2][1]*m[3][2]*m[4][4] + m[1][3]*m[2][2]*m[3][4]*m[4][1] + m[1][3]*m[2][4]*m[3][1]*m[4][2]
+ m[1][4]*m[2][1]*m[3][3]*m[4][2] + m[1][4]*m[2][2]*m[3][1]*m[4][3] + m[1][4]*m[2][3]*m[3][2]*m[4][1]
- m[1][1]*m[2][2]*m[3][4]*m[4][3] - m[1][1]*m[2][3]*m[3][2]*m[4][4] - m[1][1]*m[2][4]*m[3][3]*m[4][2]
- m[1][2]*m[2][1]*m[3][3]*m[4][4] - m[1][2]*m[2][3]*m[3][4]*m[4][1] - m[1][2]*m[2][4]*m[3][1]*m[4][3]
- m[1][3]*m[2][1]*m[3][4]*m[4][2] - m[1][3]*m[2][2]*m[3][1]*m[4][4] - m[1][3]*m[2][4]*m[3][2]*m[4][1]
- m[1][4]*m[2][1]*m[3][2]*m[4][3] - m[1][4]*m[2][2]*m[3][3]*m[4][1] - m[1][4]*m[2][3]*m[3][1]*m[4][2])
end

local function mat_inv(m)
    local d = m:det()
    if d == 0 then return m end
    local o = mat_i()
    local m11,m12,m13,m14=m[1][1],m[1][2],m[1][3],m[1][4]
    local m21,m22,m23,m24=m[2][1],m[2][2],m[2][3],m[2][4]
    local m31,m32,m33,m34=m[3][1],m[3][2],m[3][3],m[3][4]
    local m41,m42,m43,m44=m[4][1],m[4][2],m[4][3],m[4][4]

    o[1][1] = (m22*m33*m44 + m23*m34*m42 + m24*m32*m43 - m22*m34*m43 - m23*m32*m44 - m24*m33*m42)
    o[1][2] = (m12*m34*m43 + m13*m32*m44 + m14*m33*m42 - m12*m33*m44 - m13*m34*m42 - m14*m32*m43)
    o[1][3] = (m12*m23*m44 + m13*m24*m42 + m14*m22*m43 - m12*m24*m43 - m13*m22*m44 - m14*m23*m42)
    o[1][4] = (m12*m24*m33 + m13*m22*m34 + m14*m23*m32 - m12*m23*m34 - m13*m24*m32 - m14*m22*m33)

    o[2][1] = (m21*m34*m43 + m23*m31*m44 + m24*m33*m41 - m21*m33*m44 - m23*m34*m41 - m24*m31*m43)
    o[2][2] = (m11*m33*m44 + m13*m34*m41 + m14*m31*m43 - m11*m34*m43 - m13*m31*m44 - m14*m33*m41)
    o[2][3] = (m11*m24*m43 + m13*m21*m44 + m14*m23*m41 - m11*m23*m44 - m13*m24*m41 - m14*m21*m43)
    o[2][4] = (m11*m23*m34 + m13*m24*m31 + m14*m21*m33 - m11*m24*m33 - m13*m21*m34 - m14*m23*m31)

    o[3][1] = (m21*m32*m44 + m22*m34*m41 + m24*m31*m42 - m21*m34*m42 - m22*m31*m44 - m24*m32*m41)
    o[3][2] = (m11*m34*m42 + m12*m31*m44 + m14*m32*m41 - m11*m32*m44 - m12*m34*m41 - m14*m31*m42)
    o[3][3] = (m11*m22*m44 + m12*m24*m41 + m14*m21*m42 - m11*m24*m42 - m12*m21*m44 - m14*m22*m41)
    o[3][4] = (m11*m24*m32 + m12*m21*m34 + m14*m22*m31 - m11*m22*m34 - m12*m24*m31 - m14*m21*m32)

    o[4][1] = (m21*m33*m42 + m22*m31*m43 + m23*m32*m41 - m21*m32*m43 - m22*m33*m41 - m23*m31*m42)
    o[4][2] = (m11*m32*m43 + m12*m33*m41 + m13*m31*m42 - m11*m33*m42 - m12*m31*m43 - m13*m32*m41)
    o[4][3] = (m11*m23*m42 + m12*m21*m43 + m13*m22*m41 - m11*m22*m43 - m12*m23*m41 - m13*m21*m42)
    o[4][4] = (m11*m22*m33 + m12*m23*m31 + m13*m21*m32 - m11*m23*m32 - m12*m21*m33 - m13*m22*m31)
    return o/d
end

local function mat_mul_vec(m,v,res)
    local function slice(m,v,y)
        return m[y][1]*v.x+m[y][2]*v.y+m[y][3]*v.z+m[y][4]*1
    end
    local vr = res or vec(0,0,0)
    vr.x = slice(m,v,1)
    vr.y = slice(m,v,2)
    vr.z = slice(m,v,3)
    return vr,slice(m,v,4)
end

local function mat_mul(m,m2)
    local function mult(m,m2,x,y)
        local acc = 0
        for i=1,4 do
            acc = acc+m[y][i]*m2[i][x]
        end
        return acc
    end
    local a = mat_z()
    for y=1,4 do
        a[y]={}
        for x=1,4 do
            a[y][x] = mult(m,m2,x,y)
        end
    end
    return a
end

local function mat_scale(sx,sy,sz)
    local m = mat_i()
    m[1][1]=sx
    m[2][2]=sy
    m[3][3]=sz
    return m
end

local function mat_trns(tx,ty,tz)
    local m = mat_i()
    m[1][4]=tx
    m[2][4]=ty
    m[3][4]=tz
    return m
end

local function mat_rot(ax,ay,az)
    local a = cos(ax)
    local b = sin(ax)
    local c = cos(ay)
    local d = sin(ay)
    local e = cos(az)
    local f = sin(az)
    local ad = a*d
    local bd = b*d
    local m = mat_z()

    m[1][1] = c*e
    m[1][2] = -c*f
    m[1][3] = d
    m[2][1] = bd*e+a*f
    m[2][2] = -bd*f+a*e
    m[2][3] = -b*c
    m[3][1] = -ad*e+b*f
    m[3][2] = ad*f+b*e
    m[3][3] = a*c
    m[4][4] = 1
    return m
end


local function mat_proj(nr,fr, fov)
    -- /180 because converting degrees to pico
    local a = fov and (fov/360)/2
    --local t = sin(a)/cos(a) s= 1/t
    local s = fov and cos(a)/sin(a) or 1
    local m = mat_z()
    m[1][1],m[2][2] = s,s
    m[3][3]=-(fr+nr)/(fr-nr)
    m[3][4]=-(fr*nr)/(fr-nr)
    m[4][3]=-1
    return m
end


mat_mt = {
    __add = function(m,m2)
        return new(mat_each(function(x,y) return m[y][x]+m2[y][x] end))
    end,
    __sub = function(m,m2)
        return new(mat_each(function(x,y) return m[y][x]-m2[y][x] end))
    end,
    __mul = function(m,o)
        local t = type(o)
        if t == "number" then
            return new(mat_each(function(x,y) return m[y][x]*o end))        
        elseif t == "table" then
            if o.t == "mat" then
                return mat_mul(m,o)
            elseif o.t == "vec" then
                return mat_mul_vec(m,o)
            end
        end
        flip()
        return m
    end,
    __div = function(m,o)
        local t = type(o)
        if t == "number" then
            return new(mat_each(function(x,y) return m[y][x]/o end))        
        end
        return m
    end
    }

new = function(arr)
    arr.det=mat_det
    arr.inv=mat_inv
    arr.t="mat"
    arr.str = function(m)
        local s = "["
        for y=1,4 do
            s = s..m[y][1]
            for x=2,4 do
                s = s.." "..m[y][x]
            end
            if y<4 then s = s.."\n" end
        end
        s = s.."]"
        return s
    end

    setmetatable(arr, mat_mt)
    return arr
end 

return setmetatable({
    new=new,
    i=mat_i,
    z=mat_z,
    trans=mat_trns,
    rot=mat_rot,
    scale=mat_scale,
    proj=mat_proj;
    mul_vec=mat_mul_vec
},{__call=function(t,arr) return new(arr) end})

end)()

  1. I ported the final sketch over Love2D to have a widescreen version, I'm pretty happy how it turned out, I should make a post about it. 


Tags