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WIP: result correct.
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enigmahe committed Jun 24, 2024
1 parent d85208e commit 1146ba4
Showing 1 changed file with 29 additions and 43 deletions.
72 changes: 29 additions & 43 deletions bxdf/volume.py
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Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,6 @@ class GridVolume_np:
__type_mapping = {"none": NONE, "mono": MONO, "rgb": RGB}
def __init__(self, elem: xet.Element):
self.albedo = np.ones(3, np.float32)
self.par = np.zeros(3, np.float32)
self.pdf = np.float32([1., 0., 0.])
self.phase_type_id = -1
self.phase_type = "hg"
self.type_name = "none"
Expand Down Expand Up @@ -117,15 +115,24 @@ def setup_volume(self, path:str):
CONSOLE.log(f"[red]Error :skull:[/red]: {path} contains no valid volume file.")
raise RuntimeError("Volume file not found.")
density_grid, (self.xres, self.yres, self.zres, self.channel) = vol_file_to_numpy(path, FORCE_MONO_COLOR)
density_grid = GridVolume_np.make_rgb_volume_from_monocolor(density_grid)
self.channel = 3
if FORCE_MONO_COLOR:
CONSOLE.log(f"[yellow]Warning[/yellow]: FORCE_MONO_COLOR is True. This only makes sense when we are testing the code.")
return density_grid.reshape((self.zres, self.yres, self.xres, self.channel))

density_grid = density_grid.reshape((self.zres, self.yres, self.xres, self.channel))
density_grid = GridVolume_np.make_colorful_volume(density_grid, self.xres, self.yres, self.zres)
self.channel = 3
return density_grid

@staticmethod
def make_rgb_volume_from_monocolor(density_grid):
density_grid = np.stack([density_grid, density_grid * 0.2, density_grid * 0.2], axis = -1)
def make_colorful_volume(density_grid: np.ndarray, xres: int, yres: int, zres: int):
z_coords = np.linspace(0, 0.9, zres, dtype = np.float32).reshape(-1, 1, 1, 1) + 0.1
y_coords = np.linspace(0, 0.9, yres, dtype = np.float32).reshape(1, -1, 1, 1) + 0.1
x_coords = np.linspace(0, 0.9, xres, dtype = np.float32).reshape(1, 1, -1, 1) + 0.1
density_grid = np.concatenate([
density_grid * z_coords,
density_grid * y_coords,
density_grid * x_coords
], axis = -1)
return density_grid

def get_shape(self) -> Tuple[int, int, int]:
Expand All @@ -135,7 +142,9 @@ def export(self):
if self.type_id == GridVolume_np.NONE:
return GridVolume(_type = 0)
aabb_mini, aabb_maxi = self.get_aabb()
maj = self.density_grid.max(axis = (0, 1, 2)) # the shape of density grid: (zres, yres, xres, channels)
maj = self.density_grid.max(axis = (0, 1, 2))
majorant = vec3(maj) if self.type_id == GridVolume_np.RGB else vec3([maj, maj, maj])
# the shape of density grid: (zres, yres, xres, channels)
return GridVolume(
_type = self.type_id,
albedo = vec3(self.albedo),
Expand All @@ -144,7 +153,8 @@ def export(self):
mini = vec3(aabb_mini),
maxi = vec3(aabb_maxi),
max_idxs = vec3i([self.xres, self.yres, self.zres]),
majorant = vec3(maj) if self.type_id == GridVolume_np.RGB else vec3([maj, maj, maj]),
majorant = majorant,
pdf = majorant / majorant.sum(),
ph = PhaseFunction(_type = self.phase_type_id, par = vec3(self.par), pdf = vec3(self.pdf))
)

Expand Down Expand Up @@ -348,18 +358,19 @@ def sample_new_rays(self, incid: vec3):
def sample_distance_delta_tracking_3d(self, grid: ti.template(), ray_ol: vec3, ray_dl: vec3, near_far: vec2) -> vec4:
result = vec4([1, 1, 1, -1])
if self._type:
# mis_pdf = ONES_V3

# Step 1: choose one element according to the majorant
channel = 2
maj = self.majorant[2]
channel = 0
maj = 1.0
val = ti.random(float)
if val < self.pdf[0]:
maj = self.majorant[0]
channel = 0
elif val < self.pdf[0] + self.pdf[1]:
maj = self.majorant[1]
channel = 1
else:
channel = 2
maj = self.majorant[2]
inv_maj = 1.0 / maj

t = near_far[0]
Expand All @@ -376,60 +387,39 @@ def sample_distance_delta_tracking_3d(self, grid: ti.template(), ray_ol: vec3, r
if ti.random(float) < n_s * inv_maj:
result[:3] *= self.albedo
result[3] = t
# mis_pdf *= d / ti.max(EPSL_V3, self.majorant)
break

maj_tr = ti.exp(-self.majorant * dist)
result[:3] *= maj_tr / ti.exp(- dist * maj)
# mis_pdf *= maj_tr
dist = -ti.log(1.0 - ti.random(float)) * inv_maj
if t + dist >= near_far[1]:
dist = near_far[1] - t

maj_tr = ti.exp(-self.majorant * dist)
result[:3] *= maj_tr / ti.exp(- dist * maj)
# mis_pdf *= maj_tr

# MIS
# mis_numerator = rgb_select(mis_pdf, channel)
# result[:3] *= mis_numerator / mis_pdf.sum()
return result

@ti.func
def eval_tr_ratio_tracking_3d(self, grid: ti.template(), ray_ol: vec3, ray_dl: vec3, near_far: vec2) -> vec3:
Tr = ONES_V3
if self._type:
# mis_pdf = ONES_V3

# Step 1: choose one element according to the majorant
channel = 2
maj = self.majorant[2]
maj = 1.0
val = ti.random(float)
if val < self.pdf[0]:
maj = self.majorant[0]
channel = 0
elif val < self.pdf[0] + self.pdf[1]:
maj = self.majorant[1]
channel = 1
else:
maj = self.majorant[2]
inv_maj = 1.0 / maj

t = near_far[0]
while True:
dist = -ti.log(1.0 - ti.random(float)) * inv_maj

if t + dist >= near_far[1]:
dist = near_far[1] - t # get the actual optical length
Tr *= ti.exp(- self.majorant * dist) / ti.exp(- dist * maj)
break
if t + dist >= near_far[1]: break
t += dist
# for mono-chromatic medium, this is 1
d = self.density_lookup_3d(grid, ray_ol + t * ray_dl, vec3([
ti.random(float), ti.random(float), ti.random(float)
]))

majorant_tr = ti.exp(- self.majorant * dist)
Tr *= ti.max(ZERO_V3, 1.0 - d * inv_maj) * majorant_tr / ti.exp(- dist * maj)
# mis_pdf *= d * majorant_tr * self.pdf
Tr *= ti.max(ZERO_V3, 1.0 - d * inv_maj)

# Russian Roulette
if Tr.max() < 0.1:
Expand All @@ -438,9 +428,5 @@ def eval_tr_ratio_tracking_3d(self, grid: ti.template(), ray_ol: vec3, ray_dl: v
Tr.fill(0)
break
Tr /= rr_max_val

# evaluate MIS weight
# mis_numerator = rgb_select(mis_pdf, channel)
# Tr *= mis_numerator / mis_pdf.sum()
return Tr

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