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Taichi_Moxi.py
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import taichi as ti
import matplotlib.image as mpig
@ti.data_oriented
class Taichi_Moxi:
def __init__(self, res=512) -> None:
self.k = (0, 3, 4, 1, 2, 7, 8, 5, 6)
self.res = res
self.alpha = 0.2
self.omiga = 0.1
self.q = ti.field(float, shape=3)
self.pigment_flow_rate = ti.field(float, shape=())
self.paper_dryness = ti.field(float, shape=())
self.currntColor = ti.field(float, shape=4)
self.activated_gravity = ti.field(ti.i32, shape=())
self.cursor = ti.field(float, shape=2)
self.Pigment_Surface_c = ti.Vector.field(
3, dtype=float, shape=(res, res))
self.Pigment_Surface_a = ti.field(dtype=float, shape=(res, res))
self.FrameBuffer = ti.Vector.field(3, dtype=float, shape=(res, res))
self.BackgrounLayer = ti.Vector.field(3, dtype=float, shape=(res, res))
self.Water_Surface = ti.field(float, shape=(res, res))
self.kappa_avg = ti.Vector.field(9, dtype=float, shape=(res, res))
self.sigma = ti.field(float, shape=(res, res))
self.kappa = ti.field(dtype=float, shape=(res, res))
self.paper = ti.field(dtype=float, shape=(res, res))
self.fibers = ti.field(dtype=float, shape=(res, res))
self.w = ti.Vector.field(9, dtype=float, shape=2)
self.Pigment_flow_c = ti.Vector.field(3, dtype=float)
self.Pigment_flow_a = ti.field(dtype=float)
self.Pigment_flow_star_c = ti.Vector.field(3, dtype=float)
self.Pigment_flow_star_a = ti.field(dtype=float)
self.Flow = ti.Vector.field(9, dtype=float)
self.FlowNext = ti.Vector.field(9, dtype=float)
self.Feq = ti.Vector.field(9, dtype=float)
self.rho = ti.field(float)
self.FlowVelocity = ti.Vector.field(2, dtype=float)
self.s0 = ti.root
self.s1 = self.s0.dense(ti.ij, int(self.res/32))
self.s2 = self.s1.dense(ti.ij, 8)
self.s3 = self.s2.dense(ti.ij, 4)
self.s3.place(self.Pigment_flow_c, self.Pigment_flow_a)
self.s3.place(self.Pigment_flow_star_c, self.Pigment_flow_star_a)
self.s3.place(self.Flow, self.Feq, self.FlowNext)
self.s3.place(self.rho)
self.s3.place(self.FlowVelocity)
self.w[0] = ti.Vector([4.0/9.0, 1.0/9.0, 1.0/9.0, 1.0/9.0, 1.0 /
9.0, 1.0/36.0, 1.0/36.0, 1.0/36.0, 1.0/36.0])
self.w[1] = ti.Vector([4.0/9.0, 0.95/9.0, 1.0/9.0, 1.05/9.0, 1.0 /
9.0, 1.0/36.0, 1.0/36.0, 1.0/36.0, 1.0/36.0])
self.e = ti.Vector.field(2, dtype=int, shape=9)
self.e[0] = ti.Vector([0, 0])
self.e[1] = ti.Vector([0, 1])
self.e[2] = ti.Vector([-1, 0])
self.e[3] = ti.Vector([0, -1])
self.e[4] = ti.Vector([1, 0])
self.e[5] = ti.Vector([1, 1])
self.e[6] = ti.Vector([-1, 1])
self.e[7] = ti.Vector([-1, -1])
self.e[8] = ti.Vector([1, -1])
self._paper = ti.field(float, shape=(512, 512))
self._paper.from_numpy(mpig.imread("paper_512_2.png")[:, :, 0])
self._fibers = ti.field(float, shape=(512, 512))
self._fibers.from_numpy(mpig.imread("fibers_512_2.png")[:, :, 0])
self.init_paper_and_fibers()
self.pigment_flow_rate[None] = 4
self.paper_dryness[None] = 0.5
self.activated_gravity[None] = 0
self.Pigment_flow_c.fill(1)
self.ini_k()
self.update_kappa_avg()
self.set_edge_parameters(q1=0.01, q2=.07, q3=0.2)
self.update_sigma()
self.BackgrounLayer.fill(1.0)
@ti.kernel
def init_paper_and_fibers(self):
for i, j in ti.ndrange(self.res, self.res):
self.paper[i, j] = self._paper[i % 512, j % 512]
self.fibers[i, j] = self._fibers[i % 512, j % 512]
@ti.kernel
def ini_k(self):
for P in ti.grouped(self.kappa):
self.kappa[P] = self.paper[P]
@ti.kernel
def update_kappa_avg(self):
for P in ti.grouped(self.kappa_avg):
for i in ti.static(range(1, 9)):
self.kappa_avg[P][i] = 0.5 * \
(self.kappa[P]+self.kappa[P+self.e[i]])
@ti.kernel
def update_sigma(self):
for P in ti.grouped(self.sigma):
self.sigma[P] = self.q[0]+self.q[1] * \
self.fibers[P]+self.q[2]*self.paper[P]
@ti.kernel
def update_k_for_pinning(self):
for P in ti.grouped(self.rho):
if (self.rho[P] < 1e-6 and
self.rho[P+self.e[1]] < self.sigma[P+self.e[1]] and
self.rho[P+self.e[2]] < self.sigma[P+self.e[2]] and
self.rho[P+self.e[3]] < self.sigma[P+self.e[3]] and
self.rho[P+self.e[4]] < self.sigma[P+self.e[4]] and
self.rho[P+self.e[5]] < (self.sigma[P+self.e[5]]*1.41421356) and
self.rho[P+self.e[6]] < (self.sigma[P+self.e[6]]*1.41421356) and
self.rho[P+self.e[7]] < (self.sigma[P+self.e[7]]*1.41421356) and
self.rho[P+self.e[8]] < (self.sigma[P+self.e[8]]*1.41421356)):
self.kappa[P] = self.paper_dryness[None]
@ti.kernel
def update_rho(self):
for P in ti.grouped(self.Flow):
self.rho[P] = self.Flow[P].sum()*0.995
@ti.kernel
def update_FlowNext(self):
for P in ti.grouped(self.Flow):
for i in ti.static(range(9)):
prePos = clamp(P-self.e[i], 0, self.res-1)
self.FlowNext[P][i] = mix(
self.Feq[prePos][i], self.Flow[prePos][i], self.omiga)
@ti.kernel
def update_flow(self):
for P in ti.grouped(self.FlowNext):
for i in ti.static(range(9)):
prePos = clamp(P-self.e[i], 0, self.res-1)
self.Flow[P][i] = self.kappa_avg[P][i] * \
(self.FlowNext[P][self.k[i]] - self.FlowNext[prePos][i]) + \
self.FlowNext[prePos][i]
@ti.kernel
def update_Feq(self):
for P in ti.grouped(self.rho):
if self.rho[P] > 1e-6:
self.FlowVelocity[P] = self.Flow[P][1]*self.e[1] +\
self.Flow[P][2]*self.e[2] +\
self.Flow[P][3]*self.e[3] +\
self.Flow[P][4]*self.e[4] +\
self.Flow[P][5]*self.e[5] +\
self.Flow[P][6]*self.e[6] +\
self.Flow[P][7]*self.e[7] +\
self.Flow[P][8]*self.e[8]
for i in ti.static(range(9)):
self.Feq[P][i] = self.w[self.activated_gravity[None]][i]*(self.rho[P] + smoothstep(self.rho[P], 0, self.alpha)*(3 * self.e[i].dot(self.FlowVelocity[P]) +
4.5 * (self.e[i].dot(self.FlowVelocity[P]))**2 - 1.5 * self.FlowVelocity[P].dot(self.FlowVelocity[P])))
@ti.kernel
def drawStrok(self, brushRadius: float, brush_wetness: float, softness: float):
center = ti.Vector([self.cursor[0], self.cursor[1]])
r = brushRadius**2
for i, j in ti.ndrange((int(self.res*(center[0] - r)), int(self.res*(center[0] + r))), (int(self.res*(center[1] - r)), int(self.res*(center[1] + r)))):
dis = (ti.Vector([i, j])/self.res-center).norm()
if dis < r:
brush_tip = smoothstep(0, softness, 1-dis/r)
water_mask = max(1-self.rho[i, j]/0.5, 0.1)
self.Water_Surface[i, j] += water_mask
self.Water_Surface[i, j] = clamp(
self.Water_Surface[i, j], 0, 2*brush_wetness)
self.Pigment_Surface_c[i, j] = ti.Vector(
[self.currntColor[0], self.currntColor[1], self.currntColor[2]])
self.Pigment_Surface_a[i, j] += brush_tip*self.currntColor[3]
self.Pigment_Surface_a[i, j] = clamp(
self.Pigment_Surface_a[i, j])
self.kappa[i, j] = self.paper[i, j]
@ti.kernel
def water_pigment_surface_to_flow(self):
for P in ti.grouped(self.Water_Surface):
if self.Water_Surface[P] > 0:
phi = clamp(
self.Water_Surface[P], 0, 1.0-self.rho[P])
self.Flow[P][0] += phi
b = phi/self.Water_Surface[P]*self.Pigment_Surface_a[P]
self.Water_Surface[P] -= phi
if b > 0:
self.Pigment_flow_c[P] = (self.Pigment_flow_c[P]*self.Pigment_flow_a[P] +
self.Pigment_Surface_c[P]*b) / (self.Pigment_flow_a[P]+b)
self.Pigment_flow_a[P] = clamp(
self.Pigment_flow_a[P]+b, 0, 1)
self.Pigment_Surface_a[P] = clamp(
self.Pigment_Surface_a[P]-b, 0, 1)
@ti.kernel
def update_Pf_star(self):
for P in ti.grouped(self.Pigment_flow_c):
Ppre = P-self.pigment_flow_rate[None]*self.FlowVelocity[P]
self.Pigment_flow_star_c[P] = bilerp(
self.Pigment_flow_c, Ppre)
self.Pigment_flow_star_a[P] = bilerp(
self.Pigment_flow_a, Ppre)
@ti.kernel
def update_Pf(self):
for P in ti.grouped(self.Pigment_flow_c):
gama_star = mix(1, 0.005, smoothstep(
self.FlowVelocity[P].norm()*self.pigment_flow_rate[None], 0, 0.001))
self.Pigment_flow_a[P] = (self.Pigment_flow_a[P]-self.Pigment_flow_star_a[P]
)*gama_star+self.Pigment_flow_star_a[P]
self.Pigment_flow_c[P] = (self.Pigment_flow_c[P]-self.Pigment_flow_star_c[P]
)*gama_star+self.Pigment_flow_star_c[P]
@ti.kernel
def render(self):
for i, j in ti.ndrange(self.res, self.res):
# s_index = ti.rescale_index(self.Flow, self.s1, [i, j])
# if (ti.is_active(self.s1, s_index)):
self.FrameBuffer[i, j] = mix(
self.BackgrounLayer[i, j], self.Pigment_flow_c[i, j], self.Pigment_flow_a[i, j])
self.FrameBuffer[i, j] = mix(
self.FrameBuffer[i, j], self.Pigment_Surface_c[i, j], self.Pigment_Surface_a[i, j])
# self.FrameBuffer[i, j] = mix(
# self.FrameBuffer[i, j], ti.Vector([0.0, 0.2, 0.6]), self.rho[i, j]*0.5)
def update(self):
self.water_pigment_surface_to_flow()
self.update_rho()
self.update_Feq()
self.update_FlowNext()
self.update_flow()
self.update_Pf_star()
self.update_Pf()
self.update_k_for_pinning()
self.update_kappa_avg()
def setCurrentColor(self, r=0.0, g=0.0, b=0.0, a=0.0):
self.currntColor[0] = r
self.currntColor[1] = g
self.currntColor[2] = b
self.currntColor[3] = a
def setCursor(self, x, y):
self.cursor[0] = x
self.cursor[1] = y
def set_edge_parameters(self, q1=-0.05, q2=0.9, q3=0.9):
self.q[0] = q1
self.q[1] = q2
self.q[2] = q3
def clear(self):
self.Pigment_flow_a.fill(0)
self.Pigment_flow_c.fill(1)
self.Pigment_Surface_a.fill(0)
self.Pigment_Surface_c.fill(0)
self.dry()
def dry(self):
self.Water_Surface.fill(0)
self.Flow.fill(0)
def save(self, filename):
ti.imwrite(self.FrameBuffer.to_numpy(), filename)
@ti.func
def bilerp(filed, pos):
"bilinear insertion"
x, y = pos[0], pos[1]
x0 = int(x)
y0 = int(y)
x1 = x0 + 1
y1 = y0 + 1
x = x - x0
y = y - y0
return mix(mix(filed[x0, y0], filed[x1, y0], x),
mix(filed[x0, y1], filed[x1, y1], x), y)
@ti.func
def clamp(x, a=0.0, b=1.0):
return ti.max(a, ti.min(b, x))
@ti.func
def smoothstep(edge0, edge1, x):
t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0)
return t * t * (3.0 - 2.0 * t)
@ti.func
def mix(a, b, x):
return a * (1.0 - x) + b * x