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root/radiance/ray/src/common/bsdf.h
Revision: 2.11
Committed: Tue Apr 19 21:31:22 2011 UTC (13 years ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.10: +8 -6 lines
Log Message:
Fixed interface for determining BSDF solid angles

File Contents

# User Rev Content
1 greg 2.11 /* RCSid $Id: bsdf.h,v 2.10 2011/04/11 03:47:46 greg Exp $ */
2 greg 2.4 /*
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 greg 2.8 * 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 greg 2.4 * BSDF vectors always oriented away from surface, even when "incident."
18     *
19     * Created by Greg Ward on 1/10/11.
20     *
21     */
22    
23     #ifndef _BSDF_H_
24     #define _BSDF_H_
25    
26     #include "fvect.h"
27     #include "ccolor.h"
28    
29     #ifdef __cplusplus
30     extern "C" {
31     #endif
32    
33     #define SDnameLn 128 /* maximum BSDF name length */
34     #define SDmaxCh 3 /* maximum # spectral channels */
35    
36 greg 2.9 /* Component flags for SDsampBSDF() and SDdirectHemi() */
37 greg 2.4 #define SDsampR 0x1 /* include reflection */
38     #define SDsampT 0x2 /* include transmission */
39     #define SDsampS 0x3 /* include scattering (R+T) */
40     #define SDsampSp 0x4 /* include non-diffuse portion */
41     #define SDsampDf 0x8 /* include diffuse portion */
42     #define SDsampSpR 0x5 /* include non-diffuse reflection */
43     #define SDsampSpT 0x6 /* include non-diffuse transmission */
44     #define SDsampSpS 0x7 /* include non-diffuse scattering */
45     #define SDsampAll 0xF /* include everything */
46    
47 greg 2.9 /* Projected solid angle query flags for SDsizeBSDF() */
48 greg 2.7 #define SDqueryVal 0x0 /* query single value */
49     #define SDqueryMin 0x1 /* query minimum proj. solid angle */
50     #define SDqueryMax 0x2 /* query maximum proj. solid angle */
51 greg 2.4
52     /* Error codes: normal return, out of memory, file i/o, file format, bad argument,
53     bad data, unsupported feature, internal error, unknown error */
54     typedef enum {SDEnone=0, SDEmemory, SDEfile, SDEformat, SDEargument,
55     SDEdata, SDEsupport, SDEinternal, SDEunknown} SDError;
56    
57     /* English ASCII strings corresponding to ennumerated errors */
58     extern const char *SDerrorEnglish[];
59    
60     /* Additional information on last error (ASCII English) */
61     extern char SDerrorDetail[];
62    
63     /* Holder for BSDF value and spectral color */
64     typedef struct {
65     double cieY; /* photopic BSDF (Y) value */
66     C_COLOR spec; /* spectral and (x,y) color */
67     } SDValue;
68    
69     /* Cached, encoded, cumulative distribution for one incident (solid) angle */
70     #define SD_CDIST_BASE double cTotal; \
71     struct SDCDst_s *next
72     typedef struct SDCDst_s {
73     SD_CDIST_BASE; /* base fields first */
74     /* ...encoded distribution extends struct */
75     } SDCDst;
76    
77     /* Forward declaration of BSDF component */
78     typedef struct SDComp_s SDComponent;
79    
80     /* Methods needed to handle BSDF components (nothing is optional) */
81     typedef const struct {
82     /* return non-diffuse BSDF */
83     int (*getBSDFs)(float coef[SDmaxCh], const FVECT outVec,
84     const FVECT inVec, const void *dist);
85     /* query non-diffuse PSA for vector */
86 greg 2.11 SDError (*queryProjSA)(double *psa, const FVECT v1,
87     const RREAL *v2, int qflags,
88     const void *dist);
89 greg 2.4 /* get cumulative distribution */
90     const SDCDst *(*getCDist)(const FVECT inVec, SDComponent *sdc);
91     /* sample cumulative distribution */
92     SDError (*sampCDist)(FVECT outVec, double randX,
93     const SDCDst *cdp);
94     /* free a spectral BSDF component */
95     void (*freeSC)(void *dist);
96     } SDFunc;
97    
98     /* Structure to hold a spectral BSDF component (typedef SDComponent above) */
99     struct SDComp_s {
100     C_COLOR cspec[SDmaxCh]; /* component spectral bases */
101     SDFunc *func; /* methods for this component */
102     void *dist; /* loaded distribution data */
103     SDCDst *cdList; /* cumulative distribution cache */
104     };
105    
106     /* Container for non-diffuse BSDF components */
107     typedef struct {
108     double minProjSA; /* minimum projected solid angle */
109     double maxHemi; /* maximum directional hemispherical */
110     int ncomp; /* number of separate components */
111     SDComponent comp[1]; /* BSDF components (extends struct) */
112     } SDSpectralDF;
113    
114     /* Loaded BSDF data */
115     typedef struct {
116     char name[SDnameLn]; /* BSDF name (derived from file) */
117     char *mgf; /* geometric description (if any) */
118     float dim[3]; /* width, height, thickness (meters) */
119     SDValue rLambFront; /* diffuse front reflectance */
120     SDValue rLambBack; /* diffuse rear reflectance */
121     SDValue tLamb; /* diffuse transmission */
122     SDSpectralDF *rf, *rb, *tf; /* non-diffuse BSDF components */
123     } SDData;
124    
125     /* List of loaded BSDFs */
126     extern struct SDCache_s {
127     SDData bsdf; /* BSDF data */
128     unsigned refcnt; /* how many callers are using us? */
129     struct SDCache_s /* next in cache list */
130     *next;
131     } *SDcacheList; /* Global BSDF cache */
132    
133     /* BSDF cache retention preference */
134     #define SDretainNone 0 /* free unreferenced data (default) */
135     #define SDretainBSDFs 1 /* keep loaded BSDFs in cache */
136     #define SDretainAll 2 /* also keep cumulative cache data */
137    
138     extern int SDretainSet; /* set to SDretainNone by default */
139    
140     /*****************************************************************
141     * The following routines are less commonly used by applications.
142     */
143    
144 greg 2.6 #define SDisLoaded(sd) ((sd)->rLambFront.spec.flags != 0)
145 greg 2.4
146     /* Report an error to the indicated stream (in English) */
147     extern SDError SDreportEnglish(SDError ec, FILE *fp);
148    
149     /* Shorten file path to useable BSDF name, removing suffix */
150     extern void SDclipName(char res[SDnameLn], const char *fname);
151    
152     /* Allocate new spectral distribution function */
153     extern SDSpectralDF *SDnewSpectralDF(int nc);
154    
155     /* Free a spectral distribution function */
156     extern void SDfreeSpectralDF(SDSpectralDF *df);
157    
158 greg 2.10 /* Initialize an unused BSDF struct and assign name (calls SDclipName) */
159     extern void SDclearBSDF(SDData *sd, const char *fname);
160 greg 2.4
161     /* Load a BSDF struct from the given file (keeps name unchanged) */
162     extern SDError SDloadFile(SDData *sd, const char *fname);
163    
164     /* Free data associated with BSDF struct */
165     extern void SDfreeBSDF(SDData *sd);
166    
167     /* Find writeable BSDF by name, or allocate new cache entry if absent */
168     extern SDData *SDgetCache(const char *bname);
169    
170     /* Free cached cumulative distributions for BSDF component */
171     extern void SDfreeCumulativeCache(SDSpectralDF *df);
172    
173     /* Sample an individual BSDF component */
174     extern SDError SDsampComponent(SDValue *sv, FVECT outVec,
175     const FVECT inVec, double randX,
176     SDComponent *sdc);
177    
178     /* Convert 1-dimensional random variable to N-dimensional */
179     extern void SDmultiSamp(double t[], int n, double randX);
180    
181     /* Map a [0,1]^2 square to a unit radius disk */
182     void SDsquare2disk(double ds[2], double seedx, double seedy);
183    
184     /* Map point on unit disk to a unit square in [0,1]^2 range */
185     void SDdisk2square(double sq[2], double diskx, double disky);
186    
187     /*****************************************************************
188     * The calls below are the ones most applications require.
189     * All directions are assumed to be unit vectors.
190     */
191    
192     /* Get BSDF from cache (or load and cache it on first call) */
193     /* Report any problems to stderr and return NULL on failure */
194     extern const SDData *SDcacheFile(const char *fname);
195    
196     /* Free a BSDF from our cache (clear all if NULL) */
197     extern void SDfreeCache(const SDData *sd);
198    
199 greg 2.11 /* Query projected solid angle resolution for non-diffuse BSDF direction(s) */
200     extern SDError SDsizeBSDF(double *projSA, const FVECT v1,
201     const RREAL *v2, int qflags,
202     const SDData *sd);
203 greg 2.4
204     /* Return BSDF for the given incident and scattered ray vectors */
205     extern SDError SDevalBSDF(SDValue *sv, const FVECT outVec,
206     const FVECT inVec, const SDData *sd);
207    
208     /* Compute directional hemispherical scattering at given incident angle */
209     extern double SDdirectHemi(const FVECT inVec,
210     int sflags, const SDData *sd);
211    
212     /* Sample BSDF direction based on the given random variable */
213     extern SDError SDsampBSDF(SDValue *sv, FVECT outVec,
214     const FVECT inVec, double randX,
215     int sflags, const SDData *sd);
216    
217     /*****************************************************************
218     * Vector math for getting between world and local BSDF coordinates.
219     * Directions may be passed unnormalized to these routines.
220     */
221    
222     /* Compute World->BSDF transform from surface normal and up (Y) vector */
223     extern SDError SDcompXform(RREAL vMtx[3][3], const FVECT sNrm,
224     const FVECT uVec);
225    
226     /* Compute inverse transform */
227     extern SDError SDinvXform(RREAL iMtx[3][3], RREAL vMtx[3][3]);
228    
229     /* Transform and normalize direction (column) vector */
230     extern SDError SDmapDir(FVECT resVec, RREAL vMtx[3][3],
231     const FVECT inpVec);
232    
233 greg 2.5 /* System-specific BSDF loading routine (not part of our library) */
234     extern SDData *loadBSDF(char *name);
235    
236     /* System-specific BSDF error translator (not part of our library) */
237     extern char *transSDError(SDError ec);
238    
239 greg 2.4 /*################################################################*/
240     /*######### DEPRECATED DEFINITIONS AWAITING PERMANENT REMOVAL #######*/
241 greg 2.1 /*
242     * Header for BSDF i/o and access routines
243     */
244 greg 2.2
245 greg 2.4 #include "mat4.h"
246 greg 2.1 /* up directions */
247     typedef enum {
248     UDzneg=-3,
249     UDyneg=-2,
250     UDxneg=-1,
251     UDunknown=0,
252     UDxpos=1,
253     UDypos=2,
254     UDzpos=3
255     } UpDir;
256     /* BSDF coordinate calculation routines */
257     /* vectors always point away from surface */
258 greg 2.4
259     typedef int b_vecf2(FVECT v, int n, void *cd);
260     typedef int b_ndxf2(FVECT v, void *cd);
261     typedef double b_radf2(int n, void *cd);
262 greg 2.1
263     /* Bidirectional Scattering Distribution Function */
264     struct BSDF_data {
265     int ninc; /* number of incoming directions */
266     int nout; /* number of outgoing directions */
267 greg 2.3 float dim[3]; /* width, height, thickness (meters) */
268     char *mgf; /* geometric description (if any) */
269 greg 2.1 void *ib_priv; /* input basis private data */
270 greg 2.4 b_vecf2 *ib_vec; /* get input vector from index */
271     b_ndxf2 *ib_ndx; /* get input index from vector */
272     b_radf2 *ib_ohm; /* get input radius for index */
273 greg 2.1 void *ob_priv; /* output basis private data */
274 greg 2.4 b_vecf2 *ob_vec; /* get output vector from index */
275     b_ndxf2 *ob_ndx; /* get output index from vector */
276     b_radf2 *ob_ohm; /* get output radius for index */
277 greg 2.1 float *bsdf; /* scattering distribution data */
278     }; /* bidirectional scattering distrib. func. */
279    
280     #define getBSDF_incvec(v,b,i) (*(b)->ib_vec)(v,i,(b)->ib_priv)
281     #define getBSDF_incndx(b,v) (*(b)->ib_ndx)(v,(b)->ib_priv)
282     #define getBSDF_incohm(b,i) (*(b)->ib_ohm)(i,(b)->ib_priv)
283     #define getBSDF_outvec(v,b,o) (*(b)->ob_vec)(v,o,(b)->ob_priv)
284     #define getBSDF_outndx(b,v) (*(b)->ob_ndx)(v,(b)->ob_priv)
285     #define getBSDF_outohm(b,o) (*(b)->ob_ohm)(o,(b)->ob_priv)
286     #define BSDF_value(b,i,o) (b)->bsdf[(o)*(b)->ninc + (i)]
287    
288     extern struct BSDF_data *load_BSDF(char *fname);
289     extern void free_BSDF(struct BSDF_data *b);
290     extern int r_BSDF_incvec(FVECT v, struct BSDF_data *b, int i,
291     double rv, MAT4 xm);
292     extern int r_BSDF_outvec(FVECT v, struct BSDF_data *b, int o,
293     double rv, MAT4 xm);
294 greg 2.3 extern int getBSDF_xfm(MAT4 xm, FVECT nrm, UpDir ud, char *xfbuf);
295 greg 2.2
296 greg 2.4 /*######### END DEPRECATED DEFINITIONS #######*/
297     /*################################################################*/
298    
299     #ifdef __cplusplus
300     }
301     #endif
302     #endif /* ! _BSDF_H_ */