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root/radiance/ray/src/common/bsdf.h
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Comparing ray/src/common/bsdf.h (file contents):
Revision 2.2 by greg, Mon Jun 14 22:02:22 2010 UTC vs.
Revision 2.22 by greg, Sun Apr 21 21:36:23 2013 UTC

# Line 1 | Line 1
1   /* RCSid $Id$ */
2   /*
3 < * Header for BSDF i/o and access routines
3 > *  bsdf.h
4 > *  
5 > *  Declarations for bidirectional scattering distribution functions.
6 > *  Assumes <stdio.h> already included.
7 > *
8 > *  A material is oriented in right-hand coordinate system with X-axis
9 > *      in the surface plane pointed to the right as seen from the front.
10 > *      This means the Y-axis is "up" and the Z-axis is the surface normal.
11 > *
12 > *  Note that we reverse the identification of "front" and "back" from
13 > *      the conventions used in WINDOW 6.  "Front" in our library points
14 > *      in the +Z direction, towards the interior of the space rather
15 > *      than the exterior.
16 > *
17 > *  BSDF incident & exiting vectors are always oriented away from surface.
18 > *
19 > *  Created by Greg Ward on 1/10/11.
20 > *
21   */
22  
23 < #ifndef _RAD_BSDF_H_
24 < #define _RAD_BSDF_H_
8 <                                /* up directions */
9 < typedef enum {
10 <        UDzneg=-3,
11 <        UDyneg=-2,
12 <        UDxneg=-1,
13 <        UDunknown=0,
14 <        UDxpos=1,
15 <        UDypos=2,
16 <        UDzpos=3
17 < } UpDir;
18 <                                /* BSDF coordinate calculation routines */
19 <                                /* vectors always point away from surface */
20 < typedef int     b_vecf(FVECT, int, void *);
21 < typedef int     b_ndxf(FVECT, void *);
22 < typedef double  b_radf(int, void *);
23 > #ifndef _BSDF_H_
24 > #define _BSDF_H_
25  
26 < /* Bidirectional Scattering Distribution Function */
27 < struct BSDF_data {
26 <        int     ninc;                   /* number of incoming directions */
27 <        int     nout;                   /* number of outgoing directions */
28 <        void    *ib_priv;               /* input basis private data */
29 <        b_vecf  *ib_vec;                /* get input vector from index */
30 <        b_ndxf  *ib_ndx;                /* get input index from vector */
31 <        b_radf  *ib_ohm;                /* get input radius for index */
32 <        void    *ob_priv;               /* output basis private data */
33 <        b_vecf  *ob_vec;                /* get output vector from index */
34 <        b_ndxf  *ob_ndx;                /* get output index from vector */
35 <        b_radf  *ob_ohm;                /* get output radius for index */
36 <        float   *bsdf;                  /* scattering distribution data */
37 < };                              /* bidirectional scattering distrib. func. */
26 > #include "fvect.h"
27 > #include "ccolor.h"
28  
29 < #define getBSDF_incvec(v,b,i)   (*(b)->ib_vec)(v,i,(b)->ib_priv)
30 < #define getBSDF_incndx(b,v)     (*(b)->ib_ndx)(v,(b)->ib_priv)
31 < #define getBSDF_incohm(b,i)     (*(b)->ib_ohm)(i,(b)->ib_priv)
42 < #define getBSDF_outvec(v,b,o)   (*(b)->ob_vec)(v,o,(b)->ob_priv)
43 < #define getBSDF_outndx(b,v)     (*(b)->ob_ndx)(v,(b)->ob_priv)
44 < #define getBSDF_outohm(b,o)     (*(b)->ob_ohm)(o,(b)->ob_priv)
45 < #define BSDF_value(b,i,o)       (b)->bsdf[(o)*(b)->ninc + (i)]
29 > #ifdef __cplusplus
30 > extern "C" {
31 > #endif
32  
33 < extern struct BSDF_data *load_BSDF(char *fname);
34 < extern void free_BSDF(struct BSDF_data *b);
35 < extern int r_BSDF_incvec(FVECT v, struct BSDF_data *b, int i,
50 <                                double rv, MAT4 xm);
51 < extern int r_BSDF_outvec(FVECT v, struct BSDF_data *b, int o,
52 <                                double rv, MAT4 xm);
53 < extern int getBSDF_xfm(MAT4 xm, FVECT nrm, UpDir ud);
33 > #ifdef _WIN32
34 > #define strcasecmp      stricmp
35 > #endif
36  
37 < #endif  /* ! _RAD_BSDF_H_ */
37 > #define SDnameLn        128             /* maximum BSDF name length */
38 > #define SDmaxCh         3               /* maximum # spectral channels */
39 >
40 > /* Component flags for SDsampBSDF() and SDdirectHemi() */
41 > #define SDsampR         0x1             /* include reflection */
42 > #define SDsampT         0x2             /* include transmission */
43 > #define SDsampS         0x3             /* include scattering (R+T) */
44 > #define SDsampSp        0x4             /* include non-diffuse portion */
45 > #define SDsampDf        0x8             /* include diffuse portion */
46 > #define SDsampSpR       0x5             /* include non-diffuse reflection */
47 > #define SDsampSpT       0x6             /* include non-diffuse transmission */
48 > #define SDsampSpS       0x7             /* include non-diffuse scattering */
49 > #define SDsampAll       0xF             /* include everything */
50 >
51 > /* Projected solid angle query flags for SDsizeBSDF() */
52 > #define SDqueryVal      0x0             /* query single value */
53 > #define SDqueryMin      0x1             /* query minimum proj. solid angle */
54 > #define SDqueryMax      0x2             /* query maximum proj. solid angle */
55 >
56 > /* Error codes: normal return, out of memory, file i/o, file format, bad argument,
57 >                 bad data, unsupported feature, internal error, unknown error */
58 > typedef enum {SDEnone=0, SDEmemory, SDEfile, SDEformat, SDEargument,
59 >                SDEdata, SDEsupport, SDEinternal, SDEunknown} SDError;
60 >
61 > /* English strings corresponding to ennumerated errors */
62 > extern const char       *SDerrorEnglish[];
63 >
64 > /* Pointer to error list in preferred language */
65 > extern const char       **SDerrorList;
66 >
67 > /* Additional information on last error (generally in English) */
68 > extern char             SDerrorDetail[];
69 >
70 > /* Holder for BSDF value and spectral color */
71 > typedef struct {
72 >        double          cieY;           /* photopic BSDF (Y) value */
73 >        C_COLOR         spec;           /* spectral and (x,y) color */
74 > } SDValue;
75 >
76 > /* Cached, encoded, cumulative distribution for one incident (solid) angle */
77 > #define SD_CDIST_BASE(styp)     double          cTotal; \
78 >                                struct styp     *next
79 > typedef struct SDCDst_s {
80 >        SD_CDIST_BASE(SDCDst_s);        /* base fields first */
81 >        /* ...encoded distribution extends struct */
82 > } SDCDst;
83 >
84 > extern const SDCDst     SDemptyCD;      /* empty distribution */
85 >
86 > /* Forward declaration of BSDF component */
87 > typedef struct SDComp_s SDComponent;
88 >
89 > /* Methods needed to handle BSDF components (nothing is optional) */
90 > typedef const struct {
91 >                                        /* return non-diffuse BSDF */
92 >        int             (*getBSDFs)(float coef[SDmaxCh], const FVECT outVec,
93 >                                    const FVECT inVec, SDComponent *sdc);
94 >                                        /* query non-diffuse PSA for vector */
95 >        SDError         (*queryProjSA)(double *psa, const FVECT v1,
96 >                                                const RREAL *v2, int qflags,
97 >                                                SDComponent *sdc);
98 >                                        /* get cumulative distribution */
99 >        const SDCDst    *(*getCDist)(const FVECT inVec, SDComponent *sdc);
100 >                                        /* sample cumulative distribution */
101 >        SDError         (*sampCDist)(FVECT ioVec, double randX,
102 >                                                const SDCDst *cdp);
103 >                                        /* free a spectral BSDF component */
104 >        void            (*freeSC)(void *dist);
105 > } SDFunc;
106 >
107 > /* Structure to hold a spectral BSDF component (typedef SDComponent above) */
108 > struct SDComp_s {
109 >        C_COLOR         cspec[SDmaxCh]; /* component spectral bases */
110 >        SDFunc          *func;          /* methods for this component */
111 >        void            *dist;          /* loaded distribution data */
112 >        SDCDst          *cdList;        /* cumulative distribution cache */
113 > };
114 >
115 > /* Container for non-diffuse BSDF components */
116 > typedef struct {
117 >        double          minProjSA;      /* minimum projected solid angle */
118 >        double          maxHemi;        /* maximum directional hemispherical */
119 >        int             ncomp;          /* number of separate components */
120 >        SDComponent     comp[1];        /* BSDF components (extends struct) */
121 > } SDSpectralDF;
122 >
123 > /* Loaded BSDF data */
124 > typedef struct {
125 >        char            name[SDnameLn]; /* BSDF name (usu. derived from file) */
126 >        char            matn[SDnameLn]; /* material name */
127 >        char            makr[SDnameLn]; /* manufacturer */
128 >        char            *mgf;           /* geometric description (if any) */
129 >        float           dim[3];         /* width, height, thickness (meters) */
130 >        SDValue         rLambFront;     /* diffuse front reflectance */
131 >        SDValue         rLambBack;      /* diffuse rear reflectance */
132 >        SDValue         tLamb;          /* diffuse transmission */
133 >        SDSpectralDF    *rf, *rb;       /* non-diffuse BRDF components */
134 >        SDSpectralDF    *tf, *tb;       /* non-diffuse BTDF components */
135 > } SDData;
136 >
137 > /* List of loaded BSDFs */
138 > extern struct SDCache_s {
139 >        SDData          bsdf;           /* BSDF data */
140 >        unsigned        refcnt;         /* how many callers are using us? */
141 >        struct SDCache_s                /* next in cache list */
142 >                        *next;
143 > } *SDcacheList;         /* Global BSDF cache */
144 >
145 > /* BSDF cache retention policies */
146 > #define SDretainNone    0               /* free unreferenced BSDF data */
147 > #define SDretainBSDFs   1               /* keep loaded BSDFs in memory */
148 > #define SDretainAll     2               /* also keep cumulative cache data */
149 >
150 > extern int              SDretainSet;    /* =SDretainNone by default */
151 >
152 > /*****************************************************************
153 > * The following routines are less commonly used by applications.
154 > */
155 >
156 > #define SDisLoaded(sd)  ((sd)->rLambFront.spec.flags != 0)
157 >
158 > /* Report an error to the indicated stream */
159 > extern SDError          SDreportError(SDError ec, FILE *fp);
160 >
161 > /* Shorten file path to useable BSDF name, removing suffix */
162 > extern void             SDclipName(char res[SDnameLn], const char *fname);
163 >
164 > /* Allocate new spectral distribution function */
165 > extern SDSpectralDF     *SDnewSpectralDF(int nc);
166 >
167 > /* Add component(s) to spectral distribution function */
168 > extern SDSpectralDF     *SDaddComponent(SDSpectralDF *odf, int nadd);
169 >
170 > /* Free a spectral distribution function */
171 > extern void             SDfreeSpectralDF(SDSpectralDF *df);
172 >
173 > /* Initialize an unused BSDF struct and assign name (calls SDclipName) */
174 > extern void             SDclearBSDF(SDData *sd, const char *fname);
175 >
176 > /* Load a BSDF struct from the given file (keeps name unchanged) */
177 > extern SDError          SDloadFile(SDData *sd, const char *fname);
178 >
179 > /* Free data associated with BSDF struct */
180 > extern void             SDfreeBSDF(SDData *sd);
181 >
182 > /* Find writeable BSDF by name, or allocate new cache entry if absent */
183 > extern SDData           *SDgetCache(const char *bname);
184 >
185 > /* Free cached cumulative distributions for BSDF component */
186 > extern void             SDfreeCumulativeCache(SDSpectralDF *df);
187 >
188 > /* Sample an individual BSDF component */
189 > extern SDError          SDsampComponent(SDValue *sv, FVECT ioVec,
190 >                                        double randX, SDComponent *sdc);
191 >
192 > /* Convert 1-dimensional random variable to N-dimensional */
193 > extern void             SDmultiSamp(double t[], int n, double randX);
194 >
195 > /* Map a [0,1]^2 square to a unit radius disk */
196 > extern void             SDsquare2disk(double ds[2], double seedx, double seedy);
197 >
198 > /* Map point on unit disk to a unit square in [0,1]^2 range */
199 > extern void             SDdisk2square(double sq[2], double diskx, double disky);
200 >
201 > /*****************************************************************
202 > * The calls below are the ones most applications require.
203 > * All directions are assumed to be unit vectors.
204 > */
205 >
206 > /* Get BSDF from cache (or load and cache it on first call) */
207 > /* Report any problems to stderr, return NULL on failure */
208 > extern const SDData     *SDcacheFile(const char *fname);
209 >
210 > /* Free a BSDF from our cache (clear all if sd==NULL) */
211 > extern void             SDfreeCache(const SDData *sd);
212 >
213 > /* Query projected solid angle resolution for non-diffuse BSDF direction(s) */
214 > extern SDError          SDsizeBSDF(double *projSA, const FVECT v1,
215 >                                        const RREAL *v2, int qflags,
216 >                                        const SDData *sd);
217 >
218 > /* Return BSDF for the given incident and scattered ray vectors */
219 > extern SDError          SDevalBSDF(SDValue *sv, const FVECT outVec,
220 >                                        const FVECT inVec, const SDData *sd);
221 >
222 > /* Compute directional hemispherical scattering at given incident angle */
223 > extern double           SDdirectHemi(const FVECT inVec,
224 >                                        int sflags, const SDData *sd);
225 >
226 > /* Sample BSDF direction based on the given random variable */
227 > extern SDError          SDsampBSDF(SDValue *sv, FVECT ioVec, double randX,
228 >                                        int sflags, const SDData *sd);
229 >
230 > /*****************************************************************
231 > * Vector math for getting between world and local BSDF coordinates.
232 > * Directions may be passed unnormalized to these routines.
233 > */
234 >
235 > /* Compute World->BSDF transform from surface normal and BSDF up vector */
236 > extern SDError          SDcompXform(RREAL vMtx[3][3], const FVECT sNrm,
237 >                                        const FVECT uVec);
238 >
239 > /* Compute inverse transform */
240 > extern SDError          SDinvXform(RREAL iMtx[3][3], RREAL vMtx[3][3]);
241 >
242 > /* Transform and normalize direction (column) vector */
243 > extern SDError          SDmapDir(FVECT resVec, RREAL vMtx[3][3],
244 >                                        const FVECT inpVec);
245 >
246 > /* Application-specific BSDF loading routine (not part of our library) */
247 > extern SDData           *loadBSDF(char *name);
248 >
249 > /* Application-specific BSDF error translator (not part of our library) */
250 > extern char             *transSDError(SDError ec);
251 >
252 > #ifdef __cplusplus
253 > }
254 > #endif
255 > #endif  /* ! _BSDF_H_ */

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