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/* RCSid $Id: bsdf.h,v 2.9 2011/02/23 21:58:31 greg Exp $ */ |
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/* |
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* bsdf.h |
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* |
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* Declarations for bidirectional scattering distribution functions. |
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* Assumes <stdio.h> already included. |
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* |
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* A material is oriented in right-hand coordinate system with X-axis |
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* in the surface plane pointed to the right as seen from the front. |
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* This means the Y-axis is "up" and the Z-axis is the surface normal. |
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* |
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* Note that we reverse the identification of "front" and "back" from |
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* the conventions used in WINDOW 6. "Front" in our library points |
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* in the +Z direction, towards the interior of the space rather |
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* than the exterior. |
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* |
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* BSDF vectors always oriented away from surface, even when "incident." |
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* |
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* Created by Greg Ward on 1/10/11. |
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* |
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*/ |
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|
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#ifndef _BSDF_H_ |
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#define _BSDF_H_ |
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|
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#include "fvect.h" |
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#include "ccolor.h" |
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|
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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|
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#define SDnameLn 128 /* maximum BSDF name length */ |
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#define SDmaxCh 3 /* maximum # spectral channels */ |
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|
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/* Component flags for SDsampBSDF() and SDdirectHemi() */ |
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#define SDsampR 0x1 /* include reflection */ |
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#define SDsampT 0x2 /* include transmission */ |
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#define SDsampS 0x3 /* include scattering (R+T) */ |
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#define SDsampSp 0x4 /* include non-diffuse portion */ |
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#define SDsampDf 0x8 /* include diffuse portion */ |
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#define SDsampSpR 0x5 /* include non-diffuse reflection */ |
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#define SDsampSpT 0x6 /* include non-diffuse transmission */ |
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#define SDsampSpS 0x7 /* include non-diffuse scattering */ |
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#define SDsampAll 0xF /* include everything */ |
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|
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/* Projected solid angle query flags for SDsizeBSDF() */ |
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#define SDqueryVal 0x0 /* query single value */ |
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#define SDqueryMin 0x1 /* query minimum proj. solid angle */ |
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#define SDqueryMax 0x2 /* query maximum proj. solid angle */ |
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|
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/* Error codes: normal return, out of memory, file i/o, file format, bad argument, |
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bad data, unsupported feature, internal error, unknown error */ |
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typedef enum {SDEnone=0, SDEmemory, SDEfile, SDEformat, SDEargument, |
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SDEdata, SDEsupport, SDEinternal, SDEunknown} SDError; |
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|
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/* English ASCII strings corresponding to ennumerated errors */ |
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extern const char *SDerrorEnglish[]; |
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|
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/* Additional information on last error (ASCII English) */ |
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extern char SDerrorDetail[]; |
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|
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/* Holder for BSDF value and spectral color */ |
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typedef struct { |
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double cieY; /* photopic BSDF (Y) value */ |
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C_COLOR spec; /* spectral and (x,y) color */ |
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} SDValue; |
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|
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/* Cached, encoded, cumulative distribution for one incident (solid) angle */ |
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#define SD_CDIST_BASE double cTotal; \ |
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struct SDCDst_s *next |
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typedef struct SDCDst_s { |
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SD_CDIST_BASE; /* base fields first */ |
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/* ...encoded distribution extends struct */ |
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} SDCDst; |
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|
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/* Forward declaration of BSDF component */ |
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typedef struct SDComp_s SDComponent; |
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|
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/* Methods needed to handle BSDF components (nothing is optional) */ |
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typedef const struct { |
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/* return non-diffuse BSDF */ |
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int (*getBSDFs)(float coef[SDmaxCh], const FVECT outVec, |
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const FVECT inVec, const void *dist); |
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/* query non-diffuse PSA for vector */ |
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SDError (*queryProjSA)(double *psa, const FVECT vec, |
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int qflags, const void *dist); |
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/* get cumulative distribution */ |
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const SDCDst *(*getCDist)(const FVECT inVec, SDComponent *sdc); |
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/* sample cumulative distribution */ |
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SDError (*sampCDist)(FVECT outVec, double randX, |
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const SDCDst *cdp); |
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/* free a spectral BSDF component */ |
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void (*freeSC)(void *dist); |
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} SDFunc; |
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|
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/* Structure to hold a spectral BSDF component (typedef SDComponent above) */ |
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struct SDComp_s { |
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C_COLOR cspec[SDmaxCh]; /* component spectral bases */ |
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SDFunc *func; /* methods for this component */ |
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void *dist; /* loaded distribution data */ |
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SDCDst *cdList; /* cumulative distribution cache */ |
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}; |
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|
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/* Container for non-diffuse BSDF components */ |
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typedef struct { |
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double minProjSA; /* minimum projected solid angle */ |
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double maxHemi; /* maximum directional hemispherical */ |
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int ncomp; /* number of separate components */ |
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SDComponent comp[1]; /* BSDF components (extends struct) */ |
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} SDSpectralDF; |
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|
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/* Loaded BSDF data */ |
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typedef struct { |
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char name[SDnameLn]; /* BSDF name (derived from file) */ |
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char *mgf; /* geometric description (if any) */ |
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float dim[3]; /* width, height, thickness (meters) */ |
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SDValue rLambFront; /* diffuse front reflectance */ |
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SDValue rLambBack; /* diffuse rear reflectance */ |
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SDValue tLamb; /* diffuse transmission */ |
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SDSpectralDF *rf, *rb, *tf; /* non-diffuse BSDF components */ |
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} SDData; |
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|
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/* List of loaded BSDFs */ |
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extern struct SDCache_s { |
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SDData bsdf; /* BSDF data */ |
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unsigned refcnt; /* how many callers are using us? */ |
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struct SDCache_s /* next in cache list */ |
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*next; |
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} *SDcacheList; /* Global BSDF cache */ |
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|
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/* BSDF cache retention preference */ |
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#define SDretainNone 0 /* free unreferenced data (default) */ |
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#define SDretainBSDFs 1 /* keep loaded BSDFs in cache */ |
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#define SDretainAll 2 /* also keep cumulative cache data */ |
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|
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extern int SDretainSet; /* set to SDretainNone by default */ |
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|
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/***************************************************************** |
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* The following routines are less commonly used by applications. |
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*/ |
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|
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#define SDisLoaded(sd) ((sd)->rLambFront.spec.flags != 0) |
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|
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/* Report an error to the indicated stream (in English) */ |
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extern SDError SDreportEnglish(SDError ec, FILE *fp); |
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|
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/* Shorten file path to useable BSDF name, removing suffix */ |
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extern void SDclipName(char res[SDnameLn], const char *fname); |
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|
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/* Allocate new spectral distribution function */ |
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extern SDSpectralDF *SDnewSpectralDF(int nc); |
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|
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/* Free a spectral distribution function */ |
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extern void SDfreeSpectralDF(SDSpectralDF *df); |
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|
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/* Initialize an unused BSDF struct and assign name (calls SDclipName) */ |
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extern void SDclearBSDF(SDData *sd, const char *fname); |
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|
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/* Load a BSDF struct from the given file (keeps name unchanged) */ |
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extern SDError SDloadFile(SDData *sd, const char *fname); |
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|
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/* Free data associated with BSDF struct */ |
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extern void SDfreeBSDF(SDData *sd); |
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|
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/* Find writeable BSDF by name, or allocate new cache entry if absent */ |
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extern SDData *SDgetCache(const char *bname); |
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|
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/* Free cached cumulative distributions for BSDF component */ |
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extern void SDfreeCumulativeCache(SDSpectralDF *df); |
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|
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/* Sample an individual BSDF component */ |
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extern SDError SDsampComponent(SDValue *sv, FVECT outVec, |
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const FVECT inVec, double randX, |
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SDComponent *sdc); |
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|
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/* Convert 1-dimensional random variable to N-dimensional */ |
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extern void SDmultiSamp(double t[], int n, double randX); |
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|
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/* Map a [0,1]^2 square to a unit radius disk */ |
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void SDsquare2disk(double ds[2], double seedx, double seedy); |
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|
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/* Map point on unit disk to a unit square in [0,1]^2 range */ |
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void SDdisk2square(double sq[2], double diskx, double disky); |
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|
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/***************************************************************** |
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* The calls below are the ones most applications require. |
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* All directions are assumed to be unit vectors. |
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*/ |
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|
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/* Get BSDF from cache (or load and cache it on first call) */ |
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/* Report any problems to stderr and return NULL on failure */ |
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extern const SDData *SDcacheFile(const char *fname); |
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|
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/* Free a BSDF from our cache (clear all if NULL) */ |
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extern void SDfreeCache(const SDData *sd); |
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|
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/* Query projected solid angle resolution for non-diffuse BSDF direction */ |
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extern SDError SDsizeBSDF(double *projSA, const FVECT vec, |
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int qflags, const SDData *sd); |
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|
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/* Return BSDF for the given incident and scattered ray vectors */ |
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extern SDError SDevalBSDF(SDValue *sv, const FVECT outVec, |
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const FVECT inVec, const SDData *sd); |
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|
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/* Compute directional hemispherical scattering at given incident angle */ |
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extern double SDdirectHemi(const FVECT inVec, |
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int sflags, const SDData *sd); |
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|
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/* Sample BSDF direction based on the given random variable */ |
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extern SDError SDsampBSDF(SDValue *sv, FVECT outVec, |
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const FVECT inVec, double randX, |
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int sflags, const SDData *sd); |
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|
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/***************************************************************** |
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* Vector math for getting between world and local BSDF coordinates. |
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* Directions may be passed unnormalized to these routines. |
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*/ |
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|
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/* Compute World->BSDF transform from surface normal and up (Y) vector */ |
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extern SDError SDcompXform(RREAL vMtx[3][3], const FVECT sNrm, |
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const FVECT uVec); |
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|
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/* Compute inverse transform */ |
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extern SDError SDinvXform(RREAL iMtx[3][3], RREAL vMtx[3][3]); |
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|
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/* Transform and normalize direction (column) vector */ |
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extern SDError SDmapDir(FVECT resVec, RREAL vMtx[3][3], |
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const FVECT inpVec); |
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|
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/* System-specific BSDF loading routine (not part of our library) */ |
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extern SDData *loadBSDF(char *name); |
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|
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/* System-specific BSDF error translator (not part of our library) */ |
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extern char *transSDError(SDError ec); |
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|
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/*################################################################*/ |
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/*######### DEPRECATED DEFINITIONS AWAITING PERMANENT REMOVAL #######*/ |
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/* |
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* Header for BSDF i/o and access routines |
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*/ |
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|
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#include "mat4.h" |
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/* up directions */ |
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typedef enum { |
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UDzneg=-3, |
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UDyneg=-2, |
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UDxneg=-1, |
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UDunknown=0, |
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UDxpos=1, |
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UDypos=2, |
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UDzpos=3 |
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} UpDir; |
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/* BSDF coordinate calculation routines */ |
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/* vectors always point away from surface */ |
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|
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typedef int b_vecf2(FVECT v, int n, void *cd); |
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typedef int b_ndxf2(FVECT v, void *cd); |
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typedef double b_radf2(int n, void *cd); |
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|
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/* Bidirectional Scattering Distribution Function */ |
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struct BSDF_data { |
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int ninc; /* number of incoming directions */ |
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int nout; /* number of outgoing directions */ |
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float dim[3]; /* width, height, thickness (meters) */ |
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char *mgf; /* geometric description (if any) */ |
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void *ib_priv; /* input basis private data */ |
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b_vecf2 *ib_vec; /* get input vector from index */ |
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b_ndxf2 *ib_ndx; /* get input index from vector */ |
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b_radf2 *ib_ohm; /* get input radius for index */ |
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void *ob_priv; /* output basis private data */ |
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b_vecf2 *ob_vec; /* get output vector from index */ |
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b_ndxf2 *ob_ndx; /* get output index from vector */ |
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b_radf2 *ob_ohm; /* get output radius for index */ |
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float *bsdf; /* scattering distribution data */ |
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}; /* bidirectional scattering distrib. func. */ |
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|
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#define getBSDF_incvec(v,b,i) (*(b)->ib_vec)(v,i,(b)->ib_priv) |
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#define getBSDF_incndx(b,v) (*(b)->ib_ndx)(v,(b)->ib_priv) |
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#define getBSDF_incohm(b,i) (*(b)->ib_ohm)(i,(b)->ib_priv) |
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#define getBSDF_outvec(v,b,o) (*(b)->ob_vec)(v,o,(b)->ob_priv) |
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#define getBSDF_outndx(b,v) (*(b)->ob_ndx)(v,(b)->ob_priv) |
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#define getBSDF_outohm(b,o) (*(b)->ob_ohm)(o,(b)->ob_priv) |
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#define BSDF_value(b,i,o) (b)->bsdf[(o)*(b)->ninc + (i)] |
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|
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extern struct BSDF_data *load_BSDF(char *fname); |
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extern void free_BSDF(struct BSDF_data *b); |
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extern int r_BSDF_incvec(FVECT v, struct BSDF_data *b, int i, |
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double rv, MAT4 xm); |
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extern int r_BSDF_outvec(FVECT v, struct BSDF_data *b, int o, |
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double rv, MAT4 xm); |
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extern int getBSDF_xfm(MAT4 xm, FVECT nrm, UpDir ud, char *xfbuf); |
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|
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/*######### END DEPRECATED DEFINITIONS #######*/ |
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/*################################################################*/ |
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|
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#ifdef __cplusplus |
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} |
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#endif |
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#endif /* ! _BSDF_H_ */ |
