ETC Unison Mosaic Designer v1.11.0 - Manual (Page 232)

Unison Mosaic Designer User Manual
Earlier in this document, we stated that the pixel function should return 3 numbers, representing the red, green
and blue components of a colour. This was not the entire truth. We are also allowed to return a single variable of
type colour. This function is therefore equivalent to Listing 8:
Listing 9
function pixel(frame,x,y)
local c = colour.new(255,0,0)
return c
end
Once again, we return to our vertical band example and use colour variables to specify the band colour and the
background colour:
Listing 10
-- width of the bands in pixels
band_width = 4
-- space between bands in pixels
band_spacing = 1
-- the colour of the band
band_colour = colour.new(255,0,0)
-- the colour of the space between bands
background_colour = colour.new(0,0,255)
-- get the combined width of band and separator
local total_band_width = band_width+band_spacing
-- get the number of visible bands
local bands = width/total_band_width
-- modulo operator (a%b)
function mod(a,b)
return a - math.floor(a/b)*b
end
-- the pixel function
function pixel(frame,x,y)
if (mod(x,total_band_width)>=band_width) then
-- in band separator
return background_colour
end
-- get the band in which this pixel falls
local band = math.floor(x/total_band_width)
-- get the fraction through the effect
local t = frame/frames
-- get the height of the band in which this pixel falls
local band_height = (math.sin((band/bands+t)*math.pi*2)+1)/4
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