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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
|
# AO render benchmark
# Original program (C) Syoyo Fujita in Javascript (and other languages)
# https://code.google.com/p/aobench/
# Ruby(yarv2llvm) version by Hideki Miura
#
IMAGE_WIDTH = 256
IMAGE_HEIGHT = 256
NSUBSAMPLES = 2
NAO_SAMPLES = 8
class Vec
def initialize(x, y, z)
@x = x
@y = y
@z = z
end
attr_accessor :x, :y, :z
def vadd(b)
Vec.new(@x + b.x, @y + b.y, @z + b.z)
end
def vsub(b)
Vec.new(@x - b.x, @y - b.y, @z - b.z)
end
def vcross(b)
Vec.new(@y * b.z - @z * b.y,
@z * b.x - @x * b.z,
@x * b.y - @y * b.x)
end
def vdot(b)
@x * b.x + @y * b.y + @z * b.z
end
def vlength
Math.sqrt(@x * @x + @y * @y + @z * @z)
end
def vnormalize
len = vlength
v = Vec.new(@x, @y, @z)
if len > 1.0e-17 then
v.x = v.x / len
v.y = v.y / len
v.z = v.z / len
end
v
end
end
class Sphere
def initialize(center, radius)
@center = center
@radius = radius
end
attr_reader :center, :radius
def intersect(ray, isect)
rs = ray.org.vsub(@center)
b = rs.vdot(ray.dir)
c = rs.vdot(rs) - (@radius * @radius)
d = b * b - c
if d > 0.0 then
t = - b - Math.sqrt(d)
if t > 0.0 and t < isect.t then
isect.t = t
isect.hit = true
isect.pl = Vec.new(ray.org.x + ray.dir.x * t,
ray.org.y + ray.dir.y * t,
ray.org.z + ray.dir.z * t)
n = isect.pl.vsub(@center)
isect.n = n.vnormalize
else
0.0
end
end
nil
end
end
class Plane
def initialize(p, n)
@p = p
@n = n
end
def intersect(ray, isect)
d = -@p.vdot(@n)
v = ray.dir.vdot(@n)
v0 = v
if v < 0.0 then
v0 = -v
end
if v0 < 1.0e-17 then
return
end
t = -(ray.org.vdot(@n) + d) / v
if t > 0.0 and t < isect.t then
isect.hit = true
isect.t = t
isect.n = @n
isect.pl = Vec.new(ray.org.x + t * ray.dir.x,
ray.org.y + t * ray.dir.y,
ray.org.z + t * ray.dir.z)
end
nil
end
end
class Ray
def initialize(org, dir)
@org = org
@dir = dir
end
attr_accessor :org, :dir
end
class Isect
def initialize
@t = 10000000.0
@hit = false
@pl = Vec.new(0.0, 0.0, 0.0)
@n = Vec.new(0.0, 0.0, 0.0)
end
attr_accessor :t, :hit, :pl, :n
end
def clamp(f)
i = f * 255.5
if i > 255.0 then
i = 255.0
end
if i < 0.0 then
i = 0.0
end
i.to_i
end
def otherBasis(basis, n)
basis[2] = Vec.new(n.x, n.y, n.z)
basis[1] = Vec.new(0.0, 0.0, 0.0)
if n.x < 0.6 and n.x > -0.6 then
basis[1].x = 1.0
elsif n.y < 0.6 and n.y > -0.6 then
basis[1].y = 1.0
elsif n.z < 0.6 and n.z > -0.6 then
basis[1].z = 1.0
else
basis[1].x = 1.0
end
basis[0] = basis[1].vcross(basis[2])
basis[0] = basis[0].vnormalize
basis[1] = basis[2].vcross(basis[0])
basis[1] = basis[1].vnormalize
end
class Scene
def initialize
@spheres = Array.new
@spheres[0] = Sphere.new(Vec.new(-2.0, 0.0, -3.5), 0.5)
@spheres[1] = Sphere.new(Vec.new(-0.5, 0.0, -3.0), 0.5)
@spheres[2] = Sphere.new(Vec.new(1.0, 0.0, -2.2), 0.5)
@plane = Plane.new(Vec.new(0.0, -0.5, 0.0), Vec.new(0.0, 1.0, 0.0))
end
def ambient_occlusion(isect)
basis = Array.new
otherBasis(basis, isect.n)
ntheta = NAO_SAMPLES
nphi = NAO_SAMPLES
eps = 0.0001
occlusion = 0.0
p0 = Vec.new(isect.pl.x + eps * isect.n.x,
isect.pl.y + eps * isect.n.y,
isect.pl.z + eps * isect.n.z)
nphi.times do |j|
ntheta.times do |i|
r = rand
phi = 2.0 * 3.14159265 * rand
x = Math.cos(phi) * Math.sqrt(1.0 - r)
y = Math.sin(phi) * Math.sqrt(1.0 - r)
z = Math.sqrt(r)
rx = x * basis[0].x + y * basis[1].x + z * basis[2].x
ry = x * basis[0].y + y * basis[1].y + z * basis[2].y
rz = x * basis[0].z + y * basis[1].z + z * basis[2].z
raydir = Vec.new(rx, ry, rz)
ray = Ray.new(p0, raydir)
occisect = Isect.new
@spheres[0].intersect(ray, occisect)
@spheres[1].intersect(ray, occisect)
@spheres[2].intersect(ray, occisect)
@plane.intersect(ray, occisect)
if occisect.hit then
occlusion = occlusion + 1.0
else
0.0
end
end
end
occlusion = (ntheta.to_f * nphi.to_f - occlusion) / (ntheta.to_f * nphi.to_f)
Vec.new(occlusion, occlusion, occlusion)
end
def render(w, h, nsubsamples)
cnt = 0
nsf = nsubsamples.to_f
h.times do |y|
w.times do |x|
rad = Vec.new(0.0, 0.0, 0.0)
# Subsmpling
nsubsamples.times do |v|
nsubsamples.times do |u|
cnt = cnt + 1
wf = w.to_f
hf = h.to_f
xf = x.to_f
yf = y.to_f
uf = u.to_f
vf = v.to_f
px = (xf + (uf / nsf) - (wf / 2.0)) / (wf / 2.0)
py = -(yf + (vf / nsf) - (hf / 2.0)) / (hf / 2.0)
eye = Vec.new(px, py, -1.0).vnormalize
ray = Ray.new(Vec.new(0.0, 0.0, 0.0), eye)
isect = Isect.new
@spheres[0].intersect(ray, isect)
@spheres[1].intersect(ray, isect)
@spheres[2].intersect(ray, isect)
@plane.intersect(ray, isect)
if isect.hit then
col = ambient_occlusion(isect)
rad.x = rad.x + col.x
rad.y = rad.y + col.y
rad.z = rad.z + col.z
end
end
end
r = rad.x / (nsf * nsf)
g = rad.y / (nsf * nsf)
b = rad.z / (nsf * nsf)
printf("%c", clamp(r))
printf("%c", clamp(g))
printf("%c", clamp(b))
end
nil
end
nil
end
end
alias printf_orig printf
def printf *args
end
# File.open("ao.ppm", "w") do |fp|
printf("P6\n")
printf("%d %d\n", IMAGE_WIDTH, IMAGE_HEIGHT)
printf("255\n", IMAGE_WIDTH, IMAGE_HEIGHT)
Scene.new.render(IMAGE_WIDTH, IMAGE_HEIGHT, NSUBSAMPLES)
# end
undef printf
alias printf printf_orig
|
