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66c9c8a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 | # Copyright (c) 2022 NVIDIA CORPORATION. All rights reserved.
# NVIDIA CORPORATION and its licensors retain all intellectual property
# and proprietary rights in and to this software, related documentation
# and any modifications thereto. Any use, reproduction, disclosure or
# distribution of this software and related documentation without an express
# license agreement from NVIDIA CORPORATION is strictly prohibited.
###########################################################################
# Example Ray March
#
# Shows how to implement an SDF ray marching based renderer. Please see
# https://iquilezles.org/www/articles/distfunctions/distfunctions.htm
# for reference on different distance functions.
#
###########################################################################
import warp as wp
wp.init()
@wp.func
def sdf_sphere(p: wp.vec3, r: float):
return wp.length(p) - r
@wp.func
def sdf_box(upper: wp.vec3, p: wp.vec3):
qx = wp.abs(p[0]) - upper[0]
qy = wp.abs(p[1]) - upper[1]
qz = wp.abs(p[2]) - upper[2]
e = wp.vec3(wp.max(qx, 0.0), wp.max(qy, 0.0), wp.max(qz, 0.0))
return wp.length(e) + wp.min(wp.max(qx, wp.max(qy, qz)), 0.0)
@wp.func
def sdf_plane(p: wp.vec3, plane: wp.vec4):
return plane[0] * p[0] + plane[1] * p[1] + plane[2] * p[2] + plane[3]
@wp.func
def op_union(d1: float, d2: float):
return wp.min(d1, d2)
@wp.func
def op_subtract(d1: float, d2: float):
return wp.max(-d1, d2)
@wp.func
def op_intersect(d1: float, d2: float):
return wp.max(d1, d2)
# simple scene
@wp.func
def sdf(p: wp.vec3):
sphere_1 = wp.vec3(0.0, 0.75, 0.0)
d = op_subtract(sdf_sphere(p - sphere_1, 0.75), sdf_box(wp.vec3(1.0, 0.5, 0.5), p))
# ground plane
d = op_union(d, sdf_plane(p, wp.vec4(0.0, 1.0, 0.0, 1.0)))
return d
@wp.func
def normal(p: wp.vec3):
eps = 1.0e-5
# compute gradient of the SDF using finite differences
dx = sdf(p + wp.vec3(eps, 0.0, 0.0)) - sdf(p - wp.vec3(eps, 0.0, 0.0))
dy = sdf(p + wp.vec3(0.0, eps, 0.0)) - sdf(p - wp.vec3(0.0, eps, 0.0))
dz = sdf(p + wp.vec3(0.0, 0.0, eps)) - sdf(p - wp.vec3(0.0, 0.0, eps))
return wp.normalize(wp.vec3(dx, dy, dz))
@wp.func
def shadow(ro: wp.vec3, rd: wp.vec3):
t = float(0.0)
s = float(1.0)
for _ in range(64):
d = sdf(ro + t * rd)
t = t + wp.clamp(d, 0.0001, 2.0)
h = wp.clamp(4.0 * d / t, 0.0, 1.0)
s = wp.min(s, h * h * (3.0 - 2.0 * h))
if t > 8.0:
return 1.0
return s
@wp.kernel
def draw(cam_pos: wp.vec3, cam_rot: wp.quat, width: int, height: int, pixels: wp.array(dtype=wp.vec3)):
tid = wp.tid()
x = tid % width
y = tid // width
# compute pixel coordinates
sx = (2.0 * float(x) - float(width)) / float(height)
sy = (2.0 * float(y) - float(height)) / float(height)
# compute view ray
ro = cam_pos
rd = wp.quat_rotate(cam_rot, wp.normalize(wp.vec3(sx, sy, -2.0)))
t = float(0.0)
# ray march
for _ in range(128):
d = sdf(ro + rd * t)
t = t + d
if d < 0.01:
p = ro + rd * t
n = normal(p)
l = wp.normalize(wp.vec3(0.6, 0.4, 0.5))
# half-vector
h = wp.normalize(l - rd)
diffuse = wp.dot(n, l)
specular = wp.clamp(wp.dot(n, h), 0.0, 1.0) ** 80.0
fresnel = 0.04 + 0.96 * wp.clamp(1.0 - wp.dot(h, l), 0.0, 1.0) ** 5.0
intensity = 2.0
result = (
wp.vec3(0.6, 0.6, 0.59) * (diffuse * (1.0 - fresnel) + specular * fresnel * 10.0) * shadow(p, l) * intensity
)
# gamma
pixels[tid] = wp.vec3(result[0] ** 2.2, result[1] ** 2.2, result[2] ** 2.2)
else:
pixels[tid] = wp.vec3(0.4, 0.45, 0.5) * 1.5
class Example:
def __init__(self, **kwargs):
self.width = 2048
self.height = 1024
self.cam_pos = (-1.25, 1.0, 2.0)
self.cam_rot = wp.quat_rpy(-0.5, -0.5, 0.0)
self.pixels = wp.zeros(self.width * self.height, dtype=wp.vec3)
def update(self):
pass
def render(self):
with wp.ScopedTimer("render"):
wp.launch(
kernel=draw,
dim=self.width * self.height,
inputs=[self.cam_pos, self.cam_rot, self.width, self.height, self.pixels],
)
if __name__ == "__main__":
import matplotlib.pyplot as plt
example = Example()
example.render()
plt.imshow(
example.pixels.numpy().reshape((example.height, example.width, 3)), origin="lower", interpolation="antialiased"
)
plt.show()
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