Replicube - Boat and Ocean

boat_ocean.vox

-- params for the scene
waterBaseColor = 13
boatColor = 15
boatLength = 14
boatWidthBase = 4
mastHeight = 10
timeOffset = 2

-- define the water shape and color with sin waves
waterY = -5
height = sin((x + t + timeOffset) * 0.3) * 1.7
height = height + sin((z * 0.5) * 0.2) * 1
water = y < height + waterY and 1 or 0
waterColor = waterBaseColor + clamp(height, -1, 1)
if abs(x) == extent or abs(y) == extent or abs(z) == extent then
	waterColor = waterBaseColor
end

-- start defining the extents and position of the boat
PI = 3.141
boatX =1
boatY = sin((boatX + t + timeOffset) * 0.3) * 1.7 + waterY + 1
boatFront = boatX + boatLength / 2
boatBack = boatX - boatLength / 2

-- useful to have a t value along the length of the boat
boatT = clamp((x - boatBack) / (boatLength), 0, 1)
boatInvT = 1 - boatT

-- taper the hull along the length of the boat
boatTaperStartT = 0.6
boatWidth = boatWidthBase - clamp((boatT - boatTaperStartT) / (1 - boatTaperStartT), 0, 1) * boatWidthBase
if x == boatBack then boatWidth = boatWidth - 1 end
boatBottom = boatY - 2 + max(0, (boatT - 0.6) / 0.4) * 3
boatBottom = boatBottom + max(0, (boatInvT - 0.75) / 0.25) * 2
boatBottom = boatBottom + abs(z * 0.5)

-- add some vertical variation to the deck
boatTop = boatY +  3
if boatT > 0.2 and boatT < boatTaperStartT then boatTop = boatTop - 1 end
if boatT < 0.3 then boatTop = boatTop + 1 end

-- define the sail using a similar technique
sailBottom = boatTop + 1
sailTop = boatTop + mastHeight - 2
sailT = clamp((y - sailBottom) / (sailTop - sailBottom), 0, 1)
sailCurve = clamp(1 - (abs(sailT - 0.5) / 0.5), 0, 1) * 6
boatSail = abs(x - (boatX + 1 + sailCurve * 0.5)) < 1 and abs(z) < boatWidthBase and y > sailBottom and y < sailTop and 1 or 0

-- inset the deck into the top of the hull
-- important to do after the sail so it doesn't affect it
if abs(z) < boatWidth - 1 and boatT > 0 then boatTop = boatTop - 1 end

-- define the  boat and mast as a volume within the bounds we setup
boat = x >= boatBack and x <= boatFront and y > boatBottom and y < boatTop and abs(z) < boatWidth and 1 or 0
boatMast = x == boatX and z == 0 and y > boatBottom and y < boatTop + mastHeight and 1 or 0

-- sum everything up into a final color
return water * waterColor + min(1, boat + boatMast) * boatColor + boatSail