src/rt/rayinit.cal

{ SCCSid "$SunId$ LBL" }

{
        Initialization file for Radiance.

        The following are predefined:

        Dx, Dy, Dz                      - ray direction
        Nx, Ny, Nz                      - surface normal
        Px, Py, Pz                      - intersection point
        T                               - distance from start
        Ts                              - single ray (shadow) distance
        Rdot                            - ray dot product
        S                               - world scale
        Tx, Ty, Tz                      - world origin
        Ix, Iy, Iz                      - world i unit vector
        Jx, Jy, Jz                      - world j unit vector
        Kx, Ky, Kz                      - world k unit vector
        arg(n)                          - real arguments, arg(0) is count

        For brdf functions, the following are also available:

        NxP, NyP, NzP                   - perturbed surface normal
        RdotP                           - perturbed ray dot product
        CrP, CgP, CbP                   - perturbed material color

        Library functions:

        if(a, b, c)                     - if a positive, return b, else c

        select(N, a1, a2, ..)           - return aN

        sqrt(x)                         - square root function

        sin(x), cos(x), tan(x),
        asin(x), acos(x),
        atan(x), atan2(y,x)             - standard trig functions

        floor(x), ceil(x)               - g.l.b. & l.u.b.

        exp(x), log(x), log10(x)        - exponent and log functions

        erf(z), erfc(z)                 - error functions

        rand(x)                         - pseudo-random function (0 to 1)

        hermite(p0,p1,r0,r1,t)          - 1-dimensional hermite polynomial

        noise3(x,y,z), noise3a(x,y,z),
        noise3b(x,y,z), noise3c(x,y,z)  - noise function with gradient (-1 to 1)

        fnoise3(x,y,z)                  - fractal noise function (-1 to 1)
}

                        { Backward compatibility }
AC = arg(0);
A1 = arg(1); A2 = arg(2); A3 = arg(3); A4 = arg(4); A5 = arg(5);
A6 = arg(6); A7 = arg(7); A8 = arg(8); A9 = arg(9); A10 = arg(10);

                        { Forward compatibility (?) }
D(i) = select(i, Dx, Dy, Dz);
N(i) = select(i, Nx, Ny, Nz);
P(i) = select(i, Px, Py, Pz);
noise3d(i,x,y,z) = select(i, noise3a(x,y,z), noise3b(x,y,z), noise3c(x,y,z));

                        { More robust versions of library functions }
bound(a,x,b) : if(a-x, a, if(x-b, b, x));
Acos(x) : acos(bound(-1,x,1));
Asin(x) : asin(bound(-1,x,1));
Atan2(y,x) : if(x*x+y*y, atan2(y,x), 0);
Exp(x) : if(-x-100, 0, exp(x));
Sqrt(x) : if(x, sqrt(x), 0);

                        { Useful constants }
PI : 3.14159265358979323846;
DEGREE : PI/180;
FTINY : 1e-7;

                        { Useful functions }
and(a,b) : if( a, b, a );
or(a,b) : if( a, a, b );
not(a) : if( a, -1, 1 );
abs(x) : if( x, x, -x );
sgn(x) : if( x, 1, if(-x, -1, 0) );
sq(x) : x*x;
max(a,b) : if( a-b, a, b );
min(a,b) : if( a-b, b, a );
inside(a,x,b) : and(x-a,b-x);
frac(x) : x - floor(x);
mod(n,d) : n - floor(n/d)*d;
tri(n,d) : abs( d - mod(n-d,2*d) );
linterp(t,p0,p1) : (1-t)*p0 + t*p1;

noop(v) = v;
clip(v) = bound(0,v,1);
noneg(v) = if(v,v,0);
red(r,g,b) = if(r,r,0);
green(r,g,b) = if(g,g,0);
blue(r,g,b) = if(b,b,0);
grey(r,g,b) = noneg(.263*r + .655*g + .082*b);
clip_r(r,g,b) = bound(0,r,1);
clip_g(r,g,b) = bound(0,g,1);
clip_b(r,g,b) = bound(0,b,1);
clipgrey(r,g,b) = min(grey(r,g,b),1);

dot(v1,v2) : v1(1)*v2(1) + v1(2)*v2(2) + v1(3)*v2(3);
cross(i,v1,v2) : select(i,      v1(2)*v2(3) - v1(3)*v2(2),
                                v1(3)*v2(1) - v1(1)*v2(3),
                                v1(1)*v2(2) - v1(2)*v2(1));

fade(near_val,far_val,dist) = far_val +
                if (16-dist, (near_val-far_val)/(1+dist*dist), 0);

bezier(p1, p2, p3, p4, t) =     p1 * (1+t*(-3+t*(3-t))) +
                                p2 * 3*t*(1+t*(-2+t)) +
                                p3 * 3*t*t*(1-t) +
                                p4 * t*t*t ;

bspline(pp, p0, p1, pn, t) =    pp * (1/6+t*(-.5+t*(.5-1/6*t))) +
                                p0 * (2/3+t*t*(-1+.5*t)) +
                                p1 * (1/6+t*(.5+t*(.5-.5*t))) +
                                pn * (1/6*t*t*t) ;

turbulence(x,y,z,s) = if( s-1.01, 0, abs(noise3(x/s,y/s,z/s)*s) +
                                                turbulence(x,y,z,2*s) );
turbulencea(x,y,z,s) = if( s-1.01, 0,
                        sgn(noise3(x/s,y/s,z/s))*noise3a(x/s,y/s,z/s) +
                        turbulencea(x,y,z,2*s) );
turbulenceb(x,y,z,s) = if( s-1.01, 0,
                        sgn(noise3(x/s,y/s,z/s))*noise3b(x/s,y/s,z/s) +
                        turbulenceb(x,y,z,2*s) );
turbulencec(x,y,z,s) = if( s-1.01, 0,
                        sgn(noise3(x/s,y/s,z/s))*noise3c(x/s,y/s,z/s) +
                        turbulencec(x,y,z,2*s) );

                        { Normal distribution from uniform range (0,1) }

un2`private(t) : t - (2.515517+t*(.802853+t*.010328))/
                (1+t*(1.432788+t*(.189269+t*.001308))) ;
un1`private(p) : un2`private(sqrt(-2*log(p))) ;

unif2norm(p) : if( .5-p, -un1`private(p), un1`private(1-p) ) ;

nrand(x) = unif2norm(rand(x));

                        { Local (u,v) coordinates for planar surfaces }
crosslen`private = Nx*Nx + Ny*Ny;
                        { U is distance from projected Z-axis }
U = if( crosslen`private - FTINY,
                (Py*Nx - Px*Ny)/crosslen`private,
                Px);
                        { V is defined so that N = U x V }
V = if( crosslen`private - FTINY,
                Pz - Nz*(Px*Nx + Py*Ny)/crosslen`private,
                Py);
Revision:	2.8
Committed:	Thu Dec 9 16:56:28 1993 UTC (30 years, 4 months ago) by greg
Branch:	MAIN
Changes since 2.7:	+1 -0 lines
Log Message:	added Atan2(y,x) function for machines that barf on atan2(0,0)
#	User	Rev	Content
1	greg	1.1	{ SCCSid "$SunId$ LBL" }
2
3			{
4			Initialization file for Radiance.
5
6			The following are predefined:
7
8			Dx, Dy, Dz - ray direction
9			Nx, Ny, Nz - surface normal
10			Px, Py, Pz - intersection point
11			T - distance from start
12	greg	2.3	Ts - single ray (shadow) distance
13	greg	1.1	Rdot - ray dot product
14			S - world scale
15			Tx, Ty, Tz - world origin
16			Ix, Iy, Iz - world i unit vector
17			Jx, Jy, Jz - world j unit vector
18			Kx, Ky, Kz - world k unit vector
19			arg(n) - real arguments, arg(0) is count
20
21			For brdf functions, the following are also available:
22
23			NxP, NyP, NzP - perturbed surface normal
24			RdotP - perturbed ray dot product
25			CrP, CgP, CbP - perturbed material color
26
27			Library functions:
28
29			if(a, b, c) - if a positive, return b, else c
30
31			select(N, a1, a2, ..) - return aN
32
33			sqrt(x) - square root function
34
35			sin(x), cos(x), tan(x),
36			asin(x), acos(x),
37			atan(x), atan2(y,x) - standard trig functions
38
39			floor(x), ceil(x) - g.l.b. & l.u.b.
40
41			exp(x), log(x), log10(x) - exponent and log functions
42
43			erf(z), erfc(z) - error functions
44
45			rand(x) - pseudo-random function (0 to 1)
46
47			hermite(p0,p1,r0,r1,t) - 1-dimensional hermite polynomial
48
49			noise3(x,y,z), noise3a(x,y,z),
50			noise3b(x,y,z), noise3c(x,y,z) - noise function with gradient (-1 to 1)
51
52			fnoise3(x,y,z) - fractal noise function (-1 to 1)
53			}
54
55			{ Backward compatibility }
56			AC = arg(0);
57			A1 = arg(1); A2 = arg(2); A3 = arg(3); A4 = arg(4); A5 = arg(5);
58			A6 = arg(6); A7 = arg(7); A8 = arg(8); A9 = arg(9); A10 = arg(10);
59
60			{ Forward compatibility (?) }
61			D(i) = select(i, Dx, Dy, Dz);
62			N(i) = select(i, Nx, Ny, Nz);
63			P(i) = select(i, Px, Py, Pz);
64			noise3d(i,x,y,z) = select(i, noise3a(x,y,z), noise3b(x,y,z), noise3c(x,y,z));
65
66			{ More robust versions of library functions }
67			bound(a,x,b) : if(a-x, a, if(x-b, b, x));
68			Acos(x) : acos(bound(-1,x,1));
69			Asin(x) : asin(bound(-1,x,1));
70	greg	2.8	Atan2(y,x) : if(xx+yy, atan2(y,x), 0);
71	greg	2.2	Exp(x) : if(-x-100, 0, exp(x));
72	greg	1.1	Sqrt(x) : if(x, sqrt(x), 0);
73
74			{ Useful constants }
75			PI : 3.14159265358979323846;
76			DEGREE : PI/180;
77			FTINY : 1e-7;
78
79			{ Useful functions }
80			and(a,b) : if( a, b, a );
81			or(a,b) : if( a, a, b );
82			not(a) : if( a, -1, 1 );
83			abs(x) : if( x, x, -x );
84			sgn(x) : if( x, 1, if(-x, -1, 0) );
85			sq(x) : x*x;
86			max(a,b) : if( a-b, a, b );
87			min(a,b) : if( a-b, b, a );
88			inside(a,x,b) : and(x-a,b-x);
89			frac(x) : x - floor(x);
90			mod(n,d) : n - floor(n/d)*d;
91			tri(n,d) : abs( d - mod(n-d,2*d) );
92			linterp(t,p0,p1) : (1-t)p0 + tp1;
93
94			noop(v) = v;
95			clip(v) = bound(0,v,1);
96	greg	1.4	noneg(v) = if(v,v,0);
97			red(r,g,b) = if(r,r,0);
98			green(r,g,b) = if(g,g,0);
99			blue(r,g,b) = if(b,b,0);
100	greg	2.4	grey(r,g,b) = noneg(.263r + .655g + .082*b);
101	greg	1.1	clip_r(r,g,b) = bound(0,r,1);
102			clip_g(r,g,b) = bound(0,g,1);
103			clip_b(r,g,b) = bound(0,b,1);
104	greg	2.5	clipgrey(r,g,b) = min(grey(r,g,b),1);
105	greg	1.1
106			dot(v1,v2) : v1(1)v2(1) + v1(2)v2(2) + v1(3)*v2(3);
107			cross(i,v1,v2) : select(i, v1(2)v2(3) - v1(3)v2(2),
108			v1(3)v2(1) - v1(1)v2(3),
109			v1(1)v2(2) - v1(2)v2(1));
110
111			fade(near_val,far_val,dist) = far_val +
112			if (16-dist, (near_val-far_val)/(1+dist*dist), 0);
113
114			bezier(p1, p2, p3, p4, t) = p1 * (1+t(-3+t(3-t))) +
115			p2 * 3t(1+t*(-2+t)) +
116			p3 * 3tt*(1-t) +
117			p4 * ttt ;
118
119			bspline(pp, p0, p1, pn, t) = pp * (1/6+t(-.5+t(.5-1/6*t))) +
120			p0 * (2/3+tt(-1+.5*t)) +
121			p1 * (1/6+t(.5+t(.5-.5*t))) +
122			pn * (1/6tt*t) ;
123
124			turbulence(x,y,z,s) = if( s-1.01, 0, abs(noise3(x/s,y/s,z/s)*s) +
125			turbulence(x,y,z,2*s) );
126			turbulencea(x,y,z,s) = if( s-1.01, 0,
127			sgn(noise3(x/s,y/s,z/s))*noise3a(x/s,y/s,z/s) +
128			turbulencea(x,y,z,2*s) );
129			turbulenceb(x,y,z,s) = if( s-1.01, 0,
130			sgn(noise3(x/s,y/s,z/s))*noise3b(x/s,y/s,z/s) +
131			turbulenceb(x,y,z,2*s) );
132			turbulencec(x,y,z,s) = if( s-1.01, 0,
133			sgn(noise3(x/s,y/s,z/s))*noise3c(x/s,y/s,z/s) +
134			turbulencec(x,y,z,2*s) );
135	greg	1.2
136	greg	1.3	{ Normal distribution from uniform range (0,1) }
137
138			un2`private(t) : t - (2.515517+t(.802853+t.010328))/
139			(1+t(1.432788+t(.189269+t*.001308))) ;
140	greg	2.2	un1`private(p) : un2`private(sqrt(-2*log(p))) ;
141	greg	1.3
142	greg	2.6	unif2norm(p) : if( .5-p, -un1`private(p), un1`private(1-p) ) ;
143	greg	1.3
144			nrand(x) = unif2norm(rand(x));
145
146	greg	1.2	{ Local (u,v) coordinates for planar surfaces }
147			crosslen`private = NxNx + NyNy;
148	greg	2.7	{ U is distance from projected Z-axis }
149	greg	1.2	U = if( crosslen`private - FTINY,
150			(PyNx - PxNy)/crosslen`private,
151			Px);
152			{ V is defined so that N = U x V }
153			V = if( crosslen`private - FTINY,
154			Pz - Nz(PxNx + Py*Ny)/crosslen`private,
155			Py);