Question about effect!

Alex

Hi,


I have question about this effect in this link

(http://www.tcax.org/forum.php?mo ... &extra=page%3D1)

I think he used curve to make this effect, so my question is how can we make this effect by using Lua ?

I'm not good in Python to understand his code and rewrite in Lua

milkyjing

this demo is simpler http://www.tcax.org/forum.php?mod=viewthread&tid=382
it may help you understand the concept behind the effect.

p.s. this is a popular effect, and I think there do be some nice guy had already wrote a Lua version.

Alex

Thank u Bro

Alex

I understand some things ..I will try the to do it
but If there is lua example (simple) it will be better, or if u can tell that man who wrote a LUA version

Regards

Alex

Ok
I came with question

1. max(pt_num, maxi)

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max here it same like interpolate function in auto.4 right?

1. function interpolate(pct, min, max)

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milkyjing

Alex 发表于 2013-9-7 14:34
Ok
I came with questionmax here it same like interpolate function in auto.4 right?

Nope, it means to return the larger one of pt_num and maxi

milkyjing

Alex 发表于 2013-9-7 01:54
I understand some things ..I will try the to do it
but If there is lua example (simple) it will be b ...

Yep, I had already sent your request to some members who both knew python and Lua, but I'm not sure whether they have enough interest or time to rewrite.

I think the better way is by your side, digging into the demo, try to understand the concept, if not, come to post here with your specific question, and we will try to give an explanation. Then you're able to write your own.

Alex

Yep, I had already sent your request to some members who both knew python and Lua, but I'm not sure whether they have enough interest or time to rewrite.

I really appreciate that, if they cant at less i need them help

and I really try to understand ur demo script and I'm trying to write by myself, if i have question i will ask you
question i will put here with my code

thanks

Alex

this is my  simple code, but i didn't get the right result  (NyuFx)

1.         local l = table.copy(line)
   
2.         for si,syl in pairs(line.syls) do
   
3. 
   
4.                    for pi, pixel in ipairs(convert.text_to_pixels(syl.text, line.styleref, syl.left % 1,  y % 1)) do   
   
5. 
   
6.                 local x, y = syl.left + pixel.x,syl.y + pixel.y
   
7. 
   
8.                 local points = {
   
9.                                 {x, y},
   
10.                                 {x + rand(50,50), y+rand(-30,40)},
    
11.                                 {x + rand(50,50), y+rand(30,90)},
    
12.                                 {x + rand(-100,100), y + rand(-50,50)},
    
13.                                 {x + rand(-50,50), y + rand(-70,70)},
    
14.                                 {x + rand(-70,70), y + rand(-40,40) }
    
15.                               }
    
16. 
    
17.                 local  start_t = line.start_time + syl.start_time
    
18.                 local  end_t = line.start_time + syl.start_time + 400
    
19. 
    
20.                         local tt = Interpolate(#pixel,start_t, end_t)
    
21.                         local x_cur, y_cur = bezier_curve(#pixel, points)
    
22. 
    
23.                         l.start_time = tt
    
24.                         l.end_time = tt + 300
    
25.                         l.text = string.format("{\\an7\\pos("..x_cur..","..y_cur..")\\bord0\\1c&Hffffff&\\fscx150\\fscy150\\p1}").."m 0 0 l 1 0 l 1 1 l 0 1 l 0 0 "
    
26.                         Output(l)
    
27. 
    
28.                   end
    
29.         end

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-

depending on your experience, what are the things missing?

milkyjing

Alex 发表于 2013-9-7 18:13
this is my  simple code, but i didn't get the right result  (NyuFx)
-

Sorry, I'm not so familiar with NyuFX, I've sent your request to showjim, a nice guy who is good at NyuFX.

showjim

Alex 发表于 2013-9-7 20:13
this is my  simple code, but i didn't get the right result  (NyuFx)
-

Hi mate,

I just looked through your code roughly, the only thing I did is to check the grammar of Lua. I find there are two functions you used not properly. They are "Interpolate" and "bezier_curve". Commonly, the "pct" coefficient in these two functions should range from 0 to 1. In your code, what you used is "#pixel", this is to get the index of current pixel, the value is larger or equal to 1 in Lua. Or maybe the functions you used are not the way I said. Could you show the code of these two functions?
I do not have NyuFX on my current computer. I'll check & run your code in the next few days.

Regards,
showjim

Alex

thank you showjim, I appreciate that

this is the both function

1. function bezier_curve(pct, p)
   
2. 
   
3.         local function fac(n)
   
4.                 local k = 1
   
5.                 if n > 1 then
   
6.                         for i=2, n do
   
7.                                 k = k * i
   
8.                         end
   
9.                 end
   
10.                 return k
    
11.         end
    
12. 
    
13.         local function bin(i, n)
    
14.                 return fac(n) / (fac(i) * fac(n-i))
    
15.         end
    
16. 
    
17.         local function bernstein(pct, i, n)
    
18.                 return bin(i, n) * math.pow(pct,i) * math.pow((1 - pct), n - i)
    
19.         end
    
20. 
    
21. 
    
22.         if pct < 0 or pct > 1 or table.maxn(p) < 2 then
    
23.                 return nil
    
24.         end
    
25.         for i, v in ipairs(p) do
    
26.                 if type(v[1]) ~= "number" or type(v[2]) ~= "number" then
    
27.                         return nil
    
28.                 end
    
29.         end
    
30. 
    
31.         local x, y, z = 0, 0, 0
    
32.         local n = table.maxn(p) - 1
    
33.         for i=0, n do
    
34.                 local bern = bernstein(pct, i, n)
    
35.                 x = x + p[i+1][1] * bern
    
36.                 y = y + p[i+1][2] * bern
    
37.                 z = z + (p[i+1][3] or 0) * bern
    
38.         end
    
39.         return x, y, z
    
40. end

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other one

1. function math.bezier(pct, p)
   
2.         if type(pct) ~= "number" or type(p) ~= "table" then
   
3.                 error("number and table expected", 2)
   
4.         elseif pct < 0 or pct > 1 or #p < 2 then
   
5.                 error("invalid arguments", 2)
   
6.         end
   
7.         for i, v in ipairs(p) do
   
8.                 if type(v[1]) ~= "number" or type(v[2]) ~= "number" or (type(v[3]) ~= "number" and type(v[3]) ~= "nil") then
   
9.                         error("invalid table content", 2)
   
10.                 end
    
11.         end
    
12.         --Factorial
    
13.         local function fac(n)
    
14.                 local k = 1
    
15.                 if n > 1 then
    
16.                         for i=2, n do
    
17.                                 k = k * i
    
18.                         end
    
19.                 end
    
20.                 return k
    
21.         end
    
22.         --Binomial coefficient
    
23.         local function bin(i, n)
    
24.                 return fac(n) / (fac(i) * fac(n-i))
    
25.         end
    
26.         --Bernstein polynom
    
27.         local function bernstein(pct, i, n)
    
28.                 return bin(i, n) * pct^i * (1 - pct)^(n - i)
    
29.         end
    
30.         --Calculate coordinate
    
31.         local point = {0, 0, 0}
    
32.         local n = #p - 1
    
33.         for i=0, n do
    
34.                 local bern = bernstein(pct, i, n)
    
35.                 point[1] = point[1] + p[i+1][1] * bern
    
36.                 point[2] = point[2] + p[i+1][2] * bern
    
37.                 point[3] = point[3] + (p[i+1][3] or 0) * bern
    
38.         end
    
39.         return point
    
40. end

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Interpolate function

1. function utils.interpolate(pct, val1, val2, calc)
   
2.         if type(pct) ~= "number" or
   
3.         not (
   
4.                 (type(val1) == "number" and type(val2) == "number") or
   
5.                 (type(val1) == "string" and type(val2) == "string")
   
6.         ) or
   
7.         (type(calc) ~= "string" and type(calc) ~= "number" and type(calc) ~= "nil") then
   
8.                 error("number and 2 numbers or 2 strings and optional string expected", 2)
   
9.         end
   
10.         -- Calculate percent value depending on calculation mode
    
11.         if calc ~= nil then
    
12.                 if type(calc) == "number" then
    
13.                         pct = pct^calc
    
14.                 elseif calc == "curve_up" then
    
15.                         pct = (math.sin( -math.pi/2 + pct * math.pi*2) + 1) / 2
    
16.                 elseif calc == "curve_down" then
    
17.                         pct = 1 - (math.sin( -math.pi/2 + pct * math.pi*2) + 1) / 2
    
18.                 else
    
19.                         error("valid last value expected", 2)
    
20.                 end
    
21.         end
    
22.         -- Interpolate numbers
    
23.         if type(val1) == "number" then
    
24.                 return val1 + (val2 - val1) * pct
    
25.         -- Interpolate strings
    
26.         else
    
27.                 -- RGB
    
28.                 local r1, g1, b1 = convert.ass_to_rgb(val1)
    
29.                 local r2, g2, b2 = convert.ass_to_rgb(val2)
    
30.                 if b1 and b2 then
    
31.                         return convert.rgb_to_ass((r2 - r1) * pct + r1, (g2 - g1) * pct + g1, (b2 - b1) * pct + b1)
    
32.                 end
    
33.                 -- Alpha
    
34.                 local a1 = convert.ass_to_a(val1)
    
35.                 local a2 = convert.ass_to_a(val2)
    
36.                 if a1 and a2 then
    
37.                         return convert.a_to_ass((a2 - a1) * pct + a1)
    
38.                 end
    
39.                 -- Invalid string
    
40.                 error("invalid strings", 2)
    
41.         end
    
42. end

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saiyaku

                        l.text = string.format("{\\an7\\pos("..x_cur..","..y_cur..")\\bord0\\1c&Hffffff&\\fscx150\\fscy150\\p1}").."m 0 0 l 1 0 l 1 1 l 0 1 l 0 0 "

I don't know lua, but maybe the 'pos' should be 'move' ,I think.

Alex

No,
we can do curve effect by using pos tag, no need move tag

milkyjing

Alex 发表于 2013-9-10 05:40
No,
we can do curve effect by using pos tag, no need move tag

but I suppose that maybe we should use move instead of pos, since in this effect the points moves from the text to the bezier.

Alex

I used before but the result was same, i will try again soon with move tag
and I hope to get a satisfactory result