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
|
\documentclass{article}
\usepackage{axiom}
\begin{document}
\title{\$SPAD/src/graph/view3D illuminate3d.c}
\author{The Axiom Team}
\maketitle
\begin{abstract}
\end{abstract}
\eject
\tableofcontents
\eject
\section{License}
<<license>>=
/*
Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
- Neither the name of The Numerical ALgorithms Group Ltd. nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
@
<<*>>=
<<license>>
#define _ILLUMINATE3D_C
#include "axiom-c-macros.h"
#include <math.h>
#include "header.h"
#include "draw.h"
#include "all_3d.H1"
/***********************
* void phong(pt,N) *
* *
* a general routine *
* for determining the *
* intensity values at *
* a particular point *
* using the Phong *
* illumination model *
* with Phong shading *
***********************/
float
#ifdef _NO_PROTO
phong(pt,N)
triple pt;
float N[3];
#else
phong(triple pt,float N[3])
#endif
{
float dotLN, dotHN, H[3], E[3], P[3], NM[3], L[3];
float color, diffuse, specular;
diffuse = 0.0; specular = 0.0;
/* renormalize average normal vector for the point */
normalizeVector(N);
/* temporary norm, in case the sign is switched */
NM[0] = N[0]; NM[1] = N[1]; NM[2] = N[2];
P[0] = pt.x; P[1] = pt.y; P[2] = pt.z;
normalizeVector(P);
/* vector from infinite light source */
L[0] = viewport->lightVector[0];
L[1] = viewport->lightVector[1];
L[2] = viewport->lightVector[2];
normalizeVector(L);
/* vector from point to observers eye */
normalizeVector(eyePoint);
E[0] = 8.0*eyePoint[0] - P[0];
E[1] = 8.0*eyePoint[1] - P[1];
E[2] = 8.0*eyePoint[2] - P[2];
normalizeVector(E);
/* light returned even if normal faces away from light source */
dotLN = L[0]*NM[0] + L[1]*NM[1] + L[2]*NM[2];
if (dotLN < 0.0) dotLN = -dotLN;
diffuse = dotLN*lightIntensity;
/* calculate specular highlight if surface faces light source */
if (dotLN > 0.0) {
H[0] = E[0] + L[0];
H[1] = E[1] + L[1];
H[2] = E[2] + L[2];
normalizeVector(H);
dotHN = NM[0]*H[0]+NM[1]*H[1]+NM[2]*H[2];
if (dotHN < 0.0) dotHN = -dotHN;
specular = pow((double)dotHN,coeff)*lightIntensity;
}
/* return intensity value from 0.0 to 1.0 */
color = Camb + diffuse*Cdiff + specular*Cspec;
if (color > 1.0) color = 1.0;
if (color < 0.0) color = 0.0;
return(color);
}
int
#ifdef _NO_PROTO
hueValue(val)
float val;
#else
hueValue(float val)
#endif
{
int hue;
hue = floor(absolute(val) * viewport->numberOfHues) + viewport->hueOffset;
if (hue > 26) hue = 26;
return hue;
}
int
#ifdef _NO_PROTO
getHue(val)
float val;
#else
getHue(float val)
#endif
{
int hue;
hue = hueValue(val);
if (hue < 11)
hue *= 6;
else
if (hue > 10 && hue < 16)
hue = hue*20 - 140;
else
hue = hue*12 - 12;
return hue;
}
/**** Conversion functions for different color models ****/
float
#ifdef _NO_PROTO
Value(n1, n2, hue)
float n1, n2, hue;
#else
Value(float n1, float n2, float hue)
#endif
{
float v;
if (hue > 360.0) hue -= 360.0;
if (hue < 0.0) hue += 360.0;
if (hue < 60.0) {
v = n1 + (n2-n1)*hue/60.0;
} else {
if (hue < 180.0) {
v = n2;
} else {
if (hue < 240.0) {
v = n1 + (n2-n1)*(240.0-hue)/60.0;
} else {
v = n1;
}
}
}
return(v);
}
RGB
#ifdef _NO_PROTO
hlsTOrgb(h,l,s)
float h, l, s;
#else
hlsTOrgb(float h,float l,float s)
#endif
{
RGB rgb;
float m1, m2;
if (l <= 0.5) {
m2 = l*(1.0+s);
}
else {
m2 = l+s-l*s;
}
m1 = 2.0*l-m2;
rgb.r = Value(m1,m2,h+120.0);
rgb.g = Value(m1,m2,h);
rgb.b = Value(m1,m2,h-120.0);
return(rgb);
}
@
\eject
\begin{thebibliography}{99}
\bibitem{1} nothing
\end{thebibliography}
\end{document}
|
