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# Crossing

edited March 2015 in Examples Posts: 11
``````-- crossing

-- Use this function to perform your initial setup
function setup()
displayMode(OVERLAY)

dataNum = 100

print("Hello World!")
displayMode(FULLSCREEN)
--   backingMode(RETAINED)
frame = 1
done = false

data={}
dataBuf={}
for n=1,dataNum do
table.insert(dataBuf,n)
end
for n=1,dataNum do
n = table.remove(dataBuf,math.random(1,#dataBuf))
table.insert(data,
{
num = n,
col= randomColor(),
pnt={},
velocity=math.random(20,100)
})
end
calcAllCrossingPoint()
end

-- x1 = {s=n, e=n}
function calcCrossingPoint(x1,y1,x2,y2)
mA = matrix(
-(y1.e - y1.s),      x1.e - x1.s,  0, 0,
-(y2.e - y2.s),      x2.e - x2.s,  0, 0,
0,0,1,0,
0,0,0,1
)
invA = mA:inverse()
mB = matrix(
x1.e * y1.s - y1.e * x1.s   , 0,0,0,
x2.e * y2.s - y2.e * x2.s   , 0,0,0,
0,0,0,0,
0,0,0,0
)
mAns = invA * mB
return mAns[1], mAns[5]
end

function randomColor()
local col= color(
math.random(128,255),
math.random(64,128),
math.random(64,128))
return col
end

function setParam()
local hMargin = 0.9
local vMargin = 0.9
local param = {
h = HEIGHT * vMargin,
posy = HEIGHT * (1 - vMargin)/2,
l = WIDTH * (1 - hMargin)/2,
r = WIDTH * ((1 - hMargin)/2 + hMargin),
step = WIDTH * hMargin/dataNum
}
return param
end

function draw()
if done == true then
--      return
end
frame = frame + 1
--   background(40, 40, 50)
strokeWidth(4)
stroke(158, 183, 39, 255)
local param = setParam()
line(param.l, param.posy, param.r, param.posy)
line(param.l, param.posy + param.h, param.r, param.posy + param.h)
strokeWidth(1)

local x1,y1,x2,y2={s=0,e=0},{s=0,e=0},{s=0,e=0},{s=0,e=0}
for k,v in ipairs(data) do
--  if (frame % dataNum) > k then
--    if (frame          ) > k then
stroke(v.col)
fill(242, 24, 24, 255)
strokeWidth(1)
x1, y1 = calcPos(k, v.num,param)
line(x1.s, y1.s, x1.e, y1.e)
for i,o in ipairs(v.pnt) do
strokeWidth(0)
fill(randomColor())
ellipse(o.x, o.y, math.random(2,12))
--       o.y = o.y - v.velocity
if o.y < param.posy then
v.velocity = 0
end
end
--  end
end
done = true
end

function calcAllCrossingPoint()
local param = setParam()
local x1,y1,x2,y2={s=0,e=0},{s=0,e=0},{s=0,e=0},{s=0,e=0}
for k,v in ipairs(data) do
x1, y1 = calcPos(k, v.num,param)
v.x1y1 = {x1=x1, y1=y1}
for n=k+1,dataNum do
if v.num > data[n].num then
x2, y2 = calcPos(n, data[n].num, param)
local x,y=calcCrossingPoint(x1,y1,x2,y2)
table.insert(v.pnt, {x=x,y=y})
end
end
end
end

function calcPos(s, e, param)
local x = {s = param.l + s * param.step,
e = param.l+ e * param.step}
local y = {s = param.posy,e = param.posy+param.h}
return x, y
end

-- This function gets called once every frame
``````

• Mod
Posts: 5,396

pretty! =D>

• Mod
Posts: 9,457

@cuvota I like the effect you created. I have something similar I wrote long ago, but I like the way yours looks a lot better.

``````displayMode(FULLSCREEN)

function setup()
tab={}
tab1={}
tab2={}
for z=1,15 do
table.insert(tab,vec4(math.random(WIDTH),HEIGHT,math.random(WIDTH),0))
table.insert(tab1,vec4(0,math.random(HEIGHT),WIDTH,math.random(HEIGHT)))
end
end

function draw()
background(30, 60, 74, 255)
stroke(255)
strokeWidth(2)
for a,b in pairs(tab) do
line(b.x,b.y,b.z,b.w)
b.x=b.x+1
if b.x>WIDTH then
b.x=0
end
b.z=b.z+1
if b.z>WIDTH then
b.z=0
end
end
for a,b in pairs(tab1) do
line(b.x,b.y,b.z,b.w)
b.y=b.y+1
if b.y>HEIGHT then
b.y=0
end
b.w=b.w+1
if b.w>HEIGHT then
b.w=0
end
end
tab2={}
for a,b in pairs(tab) do
for c,d in pairs(tab1) do
calc(vec2(b.x,b.y),vec2(b.z,b.w),vec2(d.x,d.y),vec2(d.z,d.w))
end
end
for a,b in pairs(tab) do
for c,d in pairs(tab) do
calc(vec2(b.x,b.y),vec2(b.z,b.w),vec2(d.x,d.y),vec2(d.z,d.w))
end
end
for a,b in pairs(tab1) do
for c,d in pairs(tab1) do
calc(vec2(b.x,b.y),vec2(b.z,b.w),vec2(d.x,d.y),vec2(d.z,d.w))
end
end
noStroke()
for a,b in pairs(tab2) do
fill(math.random(255),math.random(255),math.random(255))
ellipse(b.x,b.y,20)
end
end

function calc(a,b,c,d)    -- calculate intercept point
x1=a.x y1=a.y x2=b.x y2=b.y x3=c.x y3=c.y x4=d.x y4=d.y
x12=x1-x2 y12=y1-y2 x34=x3-x4 y34=y3-y4
c=x12*y34-y12*x34
if math.abs(c) > 0.01 then
a=x1*y2-y1*x2 b=x3*y4-y3*x4 x=(a*x34-b*x12)/c y=(a*y34-b*y12)/c
end
if x>math.min(x1,x2) and x<math.max(x1,x2) and
y>math.min(y1,y2) and y<math.max(y1,y2) and
x>math.min(x3,x4) and x<math.max(x3,x4) and
y>math.min(y3,y4) and y<math.max(y3,y4) then
table.insert(tab2,vec2(x,y))
end
end

``````
• Mod
Posts: 9,457

@cuvota An interesting effect with your program is to set dataNum=10, run the program, and then keep pressing the replay button.

• Posts: 11

I found wonderful and fantastic figure, thank you for your comment.
also taking snapshot makes another effect. I fully enjoyed.

• Mod
Posts: 3,297

change the beginning of setup for this

``````function setup()
displayMode(OVERLAY)

dataNum = 10

tween.delay(1,restart)
``````