Pigment Mixing Function - GameCreators Forum

Author

Message

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 6th Jun 2013 03:13

Link

This function mixes two colours as if they were pigments (as in paint or ink) rather than light sources.

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(6)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu

set text opaque
sync on

w = screen width()/6
i# = 0.005
ratio# = 0.5   :`initial value

do
   rem adjust colour ratios
   mc = rightkey() + leftkey()*2
   if mc = 1 and ratio# < (1-i#) then inc ratio#, i#
   if mc = 2 and ratio# > i# then dec ratio#, i#

rem mix in-between colours
   for i = 1 to 5 step 2
      color(i) = mixPigment(color(i-1),color(i+1),ratio#)
   next i

rem draw colour bars
   for x = 0 to 5
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1
   next x

rem user info
   ink 0,-2
   text 0,0,"Use Left and Right keys to adjust colour ratios."
   text 0,16,str$(ratio#)
   sync
loop

end

function mixPigment(m,n,p#)
   mr = (255 - rgbr(m))*(1-p#)
   mg = (255 - rgbg(m))*(1-p#)
   mb = (255 - rgbb(m))*(1-p#)

nr = (255 - rgbr(n))*p#
   ng = (255 - rgbg(n))*p#
   nb = (255 - rgbb(n))*p#

r = 255 - (mr | nr)
   g = 255 - (mg | ng)
   b = 255 - (mb | nb)

c = rgb(r,g,b)
endfunction c

+ Code Snippet

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(6)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu

set text opaque
sync on

w = screen width()/6
i# = 0.005
ratio# = 0.5   :`initial value

do
   rem adjust colour ratios
   mc = rightkey() + leftkey()*2
   if mc = 1 and ratio# < (1-i#) then inc ratio#, i#
   if mc = 2 and ratio# > i# then dec ratio#, i#

   rem mix in-between colours
   for i = 1 to 5 step 2
      color(i) = mixPigment(color(i-1),color(i+1),ratio#)
   next i

   rem draw colour bars
   for x = 0 to 5
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1
   next x

   rem user info
   ink 0,-2
   text 0,0,"Use Left and Right keys to adjust colour ratios."
   text 0,16,str$(ratio#)
   sync
loop

end

function mixPigment(m,n,p#)
   mr = (255 - rgbr(m))*(1-p#)
   mg = (255 - rgbg(m))*(1-p#)
   mb = (255 - rgbb(m))*(1-p#)

   nr = (255 - rgbr(n))*p#
   ng = (255 - rgbg(n))*p#
   nb = (255 - rgbb(n))*p#

   r = 255 - (mr | nr)
   g = 255 - (mg | ng)
   b = 255 - (mb | nb)

   c = rgb(r,g,b)
endfunction c

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Back to top

Profile PM Email

Latch

17

Years of Service

User Offline

Joined: 23rd Jul 2006

Location:

Posted: 6th Jun 2013 05:06

Link

Neat. It's like an alpha blending routine.

Enjoy your day.

Back to top

Profile PM

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 6th Jun 2013 06:27 Edited at: 6th Jun 2013 07:17

Link

Hi Latch. You're right, I hadn't thought of it like that but it makes a lot of sense.

hmm... turns out it's the same as

+ Code Snippet

   mr = rgbr(m)*(1-p#)
   mg = rgbg(m)*(1-p#)
   mb = rgbb(m)*(1-p#)

   nr = rgbr(n)*p#
   ng = rgbg(n)*p#
   nb = rgbb(n)*p#

   r = mr+nr
   g = mg+ng
   b = mb+nb
   c = rgb(r,g,b)

I think I have this slightly wrong, I'm pretty sure magenta+yellow is supposed to make a primary red. Oh well, I'll just call this an alpha-transparency function for now.

Yeah I thought so, this is what I want:

I think it's just an AND... I'll try it. I think I actually tried this first but found difficulty getting different ratios, that's why I tried a negative OR, but it seems that was useless.

Inverting one of the colours and subtracting it from the other seems to have the same effect so maybe that's workable.

No that's not right, neither are right. White + Black would be Black instead of Grey like it should be. Ahh! This is harder than it looks.

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Back to top

Profile PM Email

Silverman

17

Years of Service

User Offline

Joined: 18th Jan 2007

Location: France

Posted: 6th Jun 2013 08:47 Edited at: 6th Jun 2013 12:27

Link

hi,
(I was wrong in this post, I re-edited)
If you want to find a solution by itself, does not look the snippet!

+ Code Snippet

sync on
sync rate 0


for value=255 to 255 step -1
   `color=AddColorAC( red(value) ,green(value))
   color=AddColorSC( magenta(value) ,yellow(value))
   cls
   ink color,0
   box 100,100,200,200
   wait 0
sync
next value

end
REM FUNCTIONS
function yellow(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*red)|(value*grn)
endfunction color

function magenta(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*red)|(value*blu)
endfunction color

function cyan(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*grn)|(value*grn)
endfunction color

function red(value)
   color=rgb(value,0,0)
endfunction color

function green(value)
   color=rgb(0,value,0)
endfunction color

function blue(value)
   color=rgb(0,0,value)
endfunction color

function AddColorSC(colorA,colorB)
`Subtractive color YMC
   color=colorA&colorB
endfunction color

function AddColorAC(colorA,colorB)
`Additive color RGB
   color=colorA|colorB
endfunction color

DirectX 9.0c (February 2010)/ DBClassic v1.20

Back to top

Profile PM

Pincho Paxton

21

Years of Service

User Offline

Joined: 8th Dec 2002

Location:

Posted: 6th Jun 2013 12:13 Edited at: 6th Jun 2013 12:15

Link

Magenta and yellow do make red if the paint is pure enough. I was watching an advert on TV where paint is allowed to spill into water, and mix together. It looks like lumpy clouds of colour. I wanted to make something like that in DBP. I don't know if it is possible in 3D however.

Back to top

Profile PM Email Website

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 6th Jun 2013 19:00 Edited at: 7th Jun 2013 02:59

Link

@Silverman - Thanks, I'll hold back from reading your solution but good to know it is there.

The trouble I'm having is it seems like the algorithm changes depending on the colours mixed. If we say that n is the maximum value for each component of RGB:

Magenta = n 0 n
+
Yellow = n n 0
=
Red = n 0 0

It's a simple & comparison. But look at this:

Red = n 0 0
+
Yellow = n n 0
=
Orange = n n/2 0

Why is the green element not discarded like it was in the previous example?

@Silverman - I had a look at your code but it has the same problem I mentioned above. It mixes magenta+yellow=red but it cannot mix red+yellow=orange.

sync on
sync rate 0

for value=255 to 0 step -1
   `color=AddColorAC( red(value) ,green(value))
   m = magenta(value)
   y = yellow(value)
   r = red(value)
   color = AddColorSC(r,y)
   cls
   ink r,0
   box 50,100,80,200
   ink y,0
   box 220,100,250,200
   ink color,0
   box 100,100,200,200
   wait 40
sync
next value

end
REM FUNCTIONS
function yellow(value)
   red = 65536
   grn = 256
   blu = 1

color=(value*red)|(value*grn)
endfunction color

function magenta(value)
   red = 65536
   grn = 256
   blu = 1

color=(value*red)|(value*blu)
endfunction color

function cyan(value)
   red = 65536
   grn = 256
   blu = 1

color=(value*grn)|(value*grn)
endfunction color

function red(value)
   color=65536*value
endfunction color

function green(value)
   color=256*value
endfunction color

function blue(value)
endfunction value

function AddColorSC(colorA,colorB)
`Subtractive color YMC
   color = colorA & colorB
endfunction color

function AddColorAC(colorA,colorB)
`Additive color RGB
   color=colorA|colorB
endfunction color

+ Code Snippet

sync on
sync rate 0


for value=255 to 0 step -1
   `color=AddColorAC( red(value) ,green(value))
   m = magenta(value)
   y = yellow(value)
   r = red(value)
   color = AddColorSC(r,y)
   cls
   ink r,0
   box 50,100,80,200
   ink y,0
   box 220,100,250,200
   ink color,0
   box 100,100,200,200
   wait 40
sync
next value

end
REM FUNCTIONS
function yellow(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*red)|(value*grn)
endfunction color

function magenta(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*red)|(value*blu)
endfunction color

function cyan(value)
   red = 65536
   grn = 256
   blu = 1

   color=(value*grn)|(value*grn)
endfunction color

function red(value)
   color=65536*value
endfunction color

function green(value)
   color=256*value
endfunction color

function blue(value)
endfunction value

function AddColorSC(colorA,colorB)
`Subtractive color YMC
   color = colorA & colorB
endfunction color

function AddColorAC(colorA,colorB)
`Additive color RGB
   color=colorA|colorB
endfunction color

I've made a colour mixing diagram that might help:

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Attachments

Login to view attachments

Back to top

Profile PM Email

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 7th Jun 2013 03:26 Edited at: 7th Jun 2013 09:16

Link

[edit: Removed the older versions of the function]
This is as streamlined as I can get it: (I changed the intensity value to an integer from 0 to 255)

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(6,1)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu

set text opaque
sync on

w = screen width()/6 :`color bar width
ival = 255
jval = 255

do
   rem adjust colour ratios
   mc = keystate(16) + keystate(30)*2
   nc = keystate(17) + keystate(31)*2
   if mc = 1 and ival < 255 then inc ival, 1
   if mc = 2 and ival > 0 then dec ival, 1
   if nc = 1 and jval < 255 then inc jval, 1
   if nc = 2 and jval > 0 then dec jval, 1

rem mix in-between colours
   for i = 1 to 5 step 2
      rem mix pigments
      color(i) = mixPigment(color(i-1),color(i+1),ival,jval)
      rem mix lights
      color(i,1) = mixLight(color(i-1),color(i+1),ival,jval)
   next i

rem draw colour bars
   for x = 0 to 5
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1

if x&1
         ink color(x,1),0
         box x*w,screen height()/2,(x+1)*w,screen height()-1
      endif
   next x

rem user info
   ink 0,-2
   text 0,0,"The top half of the screen mixes pigments, the bottom half mixes lights."
   text 0,16,"Use Q and A to adjust the intensity of the left-hand colour."
   text 0,32,"Use W and S to adjust the intensity of the right-hand colour."
   text 0,48,"L: "+str$(ival)+", R: "+str$(jval)

sync
loop

end

function mixPigment(i,j,ival,jval)
   `invert colours and apply intensity (65793 = 1 + 256 + 65536)
   i = (16777215 - i) & 65793 * ival
   j = (16777215 - j) & 65793 * jval
   `combine colours and reinvert
   k = 16777215 - (i|j)
endfunction k

function mixLight(i,j,ival,jval)
   `apply intensity (65793 = 1 + 256 + 65536)
   i = i & 65793 * ival
   j = j & 65793 * jval
   `combine colours
   k = i|j
endfunction i

+ Code Snippet

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(6,1)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu

set text opaque
sync on

w = screen width()/6 :`color bar width
ival = 255
jval = 255

do
   rem adjust colour ratios
   mc = keystate(16) + keystate(30)*2
   nc = keystate(17) + keystate(31)*2
   if mc = 1 and ival < 255 then inc ival, 1
   if mc = 2 and ival > 0 then dec ival, 1
   if nc = 1 and jval < 255 then inc jval, 1
   if nc = 2 and jval > 0 then dec jval, 1

   rem mix in-between colours
   for i = 1 to 5 step 2
      rem mix pigments
      color(i) = mixPigment(color(i-1),color(i+1),ival,jval)
      rem mix lights
      color(i,1) = mixLight(color(i-1),color(i+1),ival,jval)
   next i

   rem draw colour bars
   for x = 0 to 5
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1

      if x&1
         ink color(x,1),0
         box x*w,screen height()/2,(x+1)*w,screen height()-1
      endif
   next x

   rem user info
   ink 0,-2
   text 0,0,"The top half of the screen mixes pigments, the bottom half mixes lights."
   text 0,16,"Use Q and A to adjust the intensity of the left-hand colour."
   text 0,32,"Use W and S to adjust the intensity of the right-hand colour."
   text 0,48,"L: "+str$(ival)+", R: "+str$(jval)

   sync
loop

end

function mixPigment(i,j,ival,jval)
   `invert colours and apply intensity (65793 = 1 + 256 + 65536)
   i = (16777215 - i) & 65793 * ival
   j = (16777215 - j) & 65793 * jval
   `combine colours and reinvert
   k = 16777215 - (i|j)
endfunction k

function mixLight(i,j,ival,jval)
   `apply intensity (65793 = 1 + 256 + 65536)
   i = i & 65793 * ival
   j = j & 65793 * jval
   `combine colours
   k = i|j
endfunction i

I really don't understand why the mixLight function is messing up, it looks like it should work perfectly.

You may have noticed that I stumbled across a simple way to limit the brightness of a colour:

+ Code Snippet

color = 65535
hide mouse
sync rate 0
sync on
wait 2000

repeat
   for bri = 0 to 255
      cls colorBri(color,bri)
      sync
   next bri
until scancode()

function colorBri(col,bri)
   ret = col & 65793 * bri
endfunction ret

[edit]
Bugger, mixPigment still not working quite as it should. I tested Ped + Yellow and it gives Red.

[edit]
FINALLY! Wow that was surprisingly challenging. This can probably be simplified but it works just like paints:

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(12,1)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu
color(8) = red
color(10) = grn
color(12) = blu

set text opaque
sync on

w = screen width()/13 :`color bar width
ival = 0
jval = 0

do
   rem adjust colour ratios
   oldmc = mc
   oldnc = nc
   mc = keystate(16) + keystate(30)*2
   nc = keystate(17) + keystate(31)*2
   if mc > oldmc
      if mc = 1 and ival < 255 then inc ival, 1
      if mc = 2 and ival > 0 then dec ival, 1
   endif
   if nc > oldnc
      if nc = 1 and jval < 255 then inc jval, 1
      if nc = 2 and jval > 0 then dec jval, 1
   endif

rem mix in-between colours
   for i = 1 to 11 step 2
      rem mix pigments
      color(i) = mixPigment(color(i-1),color(i+1),ival,jval)
      rem mix lights
`      color(i,1) = mixLight(color(i-1),color(i+1),ival,jval)
   next i

rem draw colour bars
   for x = 0 to 12
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1

`      if x&1
`         ink color(x,1),0
`         box x*w,screen height()/2,(x+1)*w,screen height()-1
`      endif
   next x

rem user info
   ink 0,-2
`   text 0,0,"The top half of the screen mixes pigments, the bottom half mixes lights."
   text 0,16,"Use Q and A to adjust the amount of the left-hand colour."
   text 0,32,"Use W and S to adjust the amount of the right-hand colour."
   text 0,48,"L: "+str$(ival)+", R: "+str$(jval)

sync
loop

end

function mixPigment(i,j,ival,jval)
   i = 16777215 - i
   j = 16777215 - j

ir = rgbr(i)*ival
   ig = rgbg(i)*ival
   ib = rgbb(i)*ival

jr = rgbr(j)*jval
   jg = rgbg(j)*jval
   jb = rgbb(j)*jval

kr = ir+jr
   kg = ig+jg
   kb = ib+jb

x = kr
   if kg > x then x = kg
   if kb > x then x = kb

if x > 255
      y = x/255
      kr = kr/y
      kg = kg/y
      kb = kb/y
   endif

k = 16777215 - rgb(kr,kg,kb)
endfunction k

function mixLight(i,j,ival,jval)
   `apply intensity (65793 = 1 + 256 + 65536)
   i = i & 65793 * ival
   j = j & 65793 * jval
   `combine colours
   k = i|j
endfunction i

+ Code Snippet

set display mode 1024,768,32
hide mouse

red = 255*65536
grn = 255*256
blu = 255

dim color(12,1)
color(0) = red+blu
color(2) = red+grn
color(4) = blu+grn
color(6) = red+blu
color(8) = red
color(10) = grn
color(12) = blu

set text opaque
sync on

w = screen width()/13 :`color bar width
ival = 0
jval = 0

do
   rem adjust colour ratios
   oldmc = mc
   oldnc = nc
   mc = keystate(16) + keystate(30)*2
   nc = keystate(17) + keystate(31)*2
   if mc > oldmc
      if mc = 1 and ival < 255 then inc ival, 1
      if mc = 2 and ival > 0 then dec ival, 1
   endif
   if nc > oldnc
      if nc = 1 and jval < 255 then inc jval, 1
      if nc = 2 and jval > 0 then dec jval, 1
   endif

   rem mix in-between colours
   for i = 1 to 11 step 2
      rem mix pigments
      color(i) = mixPigment(color(i-1),color(i+1),ival,jval)
      rem mix lights
`      color(i,1) = mixLight(color(i-1),color(i+1),ival,jval)
   next i

   rem draw colour bars
   for x = 0 to 12
      ink color(x),0
      box x*w,0,(x+1)*w,screen height()-1

`      if x&1
`         ink color(x,1),0
`         box x*w,screen height()/2,(x+1)*w,screen height()-1
`      endif
   next x

   rem user info
   ink 0,-2
`   text 0,0,"The top half of the screen mixes pigments, the bottom half mixes lights."
   text 0,16,"Use Q and A to adjust the amount of the left-hand colour."
   text 0,32,"Use W and S to adjust the amount of the right-hand colour."
   text 0,48,"L: "+str$(ival)+", R: "+str$(jval)

   sync
loop

end

function mixPigment(i,j,ival,jval)
   i = 16777215 - i
   j = 16777215 - j

   ir = rgbr(i)*ival
   ig = rgbg(i)*ival
   ib = rgbb(i)*ival

   jr = rgbr(j)*jval
   jg = rgbg(j)*jval
   jb = rgbb(j)*jval

   kr = ir+jr
   kg = ig+jg
   kb = ib+jb

   x = kr
   if kg > x then x = kg
   if kb > x then x = kb

   if x > 255
      y = x/255
      kr = kr/y
      kg = kg/y
      kb = kb/y
   endif

   k = 16777215 - rgb(kr,kg,kb)
endfunction k

function mixLight(i,j,ival,jval)
   `apply intensity (65793 = 1 + 256 + 65536)
   i = i & 65793 * ival
   j = j & 65793 * jval
   `combine colours
   k = i|j
endfunction i

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Back to top

Profile PM Email

Pincho Paxton

21

Years of Service

User Offline

Joined: 8th Dec 2002

Location:

Posted: 7th Jun 2013 15:16

Link

I tried to test it in DBPro but it doesn't like & sign for some reason.

Back to top

Profile PM Email Website

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 7th Jun 2013 20:08

Link

@Pincho - DBP uses double symbols for bitwise comparisons, so && and ||.

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Back to top

Profile PM Email

Pincho Paxton

21

Years of Service

User Offline

Joined: 8th Dec 2002

Location:

Posted: 7th Jun 2013 20:13

Link

OK thanks!

Back to top

Profile PM Email Website

Silverman

17

Years of Service

User Offline

Joined: 18th Jan 2007

Location: France

Posted: 9th Jun 2013 12:34

Link

I made it like this:

+ Code Snippet

function SumColor(colorA,colorB)
   Sred=rgbr(colorA)+rgbr(colorB)
   Sgrn=rgbg(colorA)+rgbg(colorB)
   Sblu=rgbb(colorA)+rgbb(colorB)

   tmp=Sred
   if Sgrn>tmp then tmp=Sgrn
   if Sblu>tmp then tmp=Sblu

   red=(Sred*255)/tmp
   grn=(Sgrn*255)/tmp
   blu=(Sblu*255)/tmp

   color=rgb(red,grn,blu)
endfunction color

What's going on there if you makes: color = yellow + cyan, followed by: color = color + magenta ?
naturally white, but I'm not sure of the result with your code (and mine too). I think there is still something to improve(with mine

)

DirectX 9.0c (February 2010)/ DBClassic v1.20

Back to top

Profile PM

Libervurto

17

Years of Service

User Offline

Joined: 30th Jun 2006

Location: On Toast

Posted: 9th Jun 2013 22:25

Link

@Silverman - C+Y+M should be black when mixing pigments or white when mixing light.

The difficulty in learning is not acquiring new knowledge but relinquishing the old.

Back to top

Profile PM Email

Sorry your browser is not supported!

DarkBASIC Discussion / Pigment Mixing Function

Attachments