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RadiancePmap/pmapsrc.h
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pmapsrc.h
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/* RCSid $Id: pmapsrc.h,v 2.7 2020/08/07 01:21:13 rschregle Exp $ */
/*
======================================================================
Photon map support routines for emission from light sources
Roland Schregle (roland.schregle@{hslu.ch, gmail.com})
(c) Fraunhofer Institute for Solar Energy Systems,
supported by the German Research Foundation
(DFG LU-204/10-2, "Fassadenintegrierte Regelsysteme" (FARESYS))
(c) Lucerne University of Applied Sciences and Arts,
supported by the Swiss National Science Foundation
(SNSF #147053, "Daylight Redirecting Components")
(c) Tokyo University of Science,
supported by the JSPS Grants-in-Aid for Scientific Research
(KAKENHI JP19KK0115, "Three-Dimensional Light Flow")
======================================================================
$Id: pmapsrc.h,v 2.7 2020/08/07 01:21:13 rschregle Exp $
*/
#ifndef PMAPSRC_H
#define PMAPSRC_H
#include "ray.h"
#include "source.h"
/* Data structures for photon emission */
typedef struct {
unsigned theta, phi; /* Direction indices */
COLOR pdf; /* Probability of emission in this
direction per RGB */
float cdf; /* Cumulative probability up to
this sample */
} EmissionSample;
typedef struct {
unsigned numTheta, numPhi; /* Num divisions in theta & phi */
double dCosTheta, dPhi; /* Increments for above */
RREAL cosThetaMax; /* cos(source aperture) */
FVECT uh, vh, wh; /* Emission aperture axes at origin,
w is normal*/
FVECT us, vs, ws; /* Source surface axes at origin,
w is normal */
FVECT photonOrg; /* Current photon origin */
EmissionSample *samples; /* PDF samples for photon emission
directions */
unsigned long numPartitions; /* Number of surface partitions */
RREAL partArea; /* Area covered by each partition */
SRCREC *src, *port; /* Current source and port */
unsigned long partitionCnt, /* Current surface partition */
maxPartitions, /* Max allocated partitions */
numSamples; /* Number of PDF samples */
unsigned char* partitions; /* Source surface partitions */
COLOR partFlux; /* Total flux emitted by partition */
float cdf; /* Cumulative probability */
} EmissionMap;
/* Photon port flags (orientation relative to surface normal):
* Forward, backward, both (bidirectional). */
#define PMAP_PORTFWD 1
#define PMAP_PORTBWD 2
#define PMAP_PORTBI (PMAP_PORTFWD | PMAP_PORTBWD)
/* Photon ports for emission from geometry en lieu of light sources */
extern char *photonPortList [MAXSET + 1];
extern SRCREC *photonPorts;
extern unsigned numPhotonPorts;
/* Dispatch tables for partitioning light source surfaces and generating
an origin for photon emission */
extern int (*photonPartition []) (EmissionMap*);
extern int (*photonOrigin []) (EmissionMap*);
void getPhotonPorts (char **portList);
/* Find geometry declared as photon ports from modifiers in portList */
void initPhotonEmissionFuncs ();
/* Init photonPartition[] and photonOrigin[] dispatch tables with source
specific emission routines */
void initPhotonEmission (EmissionMap *emap, float numPdfSamples);
/* Initialize photon emission from partitioned light source emap -> src;
* this involves integrating the flux emitted from the current photon
* origin emap -> photonOrg and setting up a PDF to sample the emission
* distribution with numPdfSamples samples */
int emitPhoton (const EmissionMap*, RAY* ray);
/* Emit photon from current source partition based on emission
distribution and return new photon ray.
Also returns an acceptance/rejection flag: 1 if origin lies within
the emitting source/port, else 0 if it lies outside, in which case
the emitted photon should be rejected. */
void multDirectPmap (RAY *r);
/* Factor irradiance from direct photons into r -> rcol; interface to
* direct() */
void inscatterVolumePmap (RAY *r, COLOR inscatter);
/* Add inscattering from volume photon map; interface to srcscatter() */
#endif
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