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#ifndef lint
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static const char RCSid[] = "$Id: bsdfinterp.c,v 2.21 2016/01/29 16:21:55 greg Exp $";
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#endif
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/*
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* Interpolate BSDF data from radial basis functions in advection mesh.
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*
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* G. Ward
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*/
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#define _USE_MATH_DEFINES
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include "bsdfrep.h"
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/* Insert vertex in ordered list */
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static void
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insert_vert(RBFNODE **vlist, RBFNODE *v)
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{
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int i, j;
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for (i = 0; vlist[i] != NULL; i++) {
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if (v == vlist[i])
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return;
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if (v->ord < vlist[i]->ord)
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break;
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}
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for (j = i; vlist[j] != NULL; j++)
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;
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while (j > i) {
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vlist[j] = vlist[j-1];
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--j;
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}
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vlist[i] = v;
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}
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/* Sort triangle edges in standard order */
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static int
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order_triangle(MIGRATION *miga[3])
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{
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RBFNODE *vert[7];
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MIGRATION *ord[3];
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int i;
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/* order vertices, first */
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memset(vert, 0, sizeof(vert));
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for (i = 3; i--; ) {
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if (miga[i] == NULL)
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return(0);
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insert_vert(vert, miga[i]->rbfv[0]);
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insert_vert(vert, miga[i]->rbfv[1]);
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}
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/* should be just 3 vertices */
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if ((vert[2] == NULL) | (vert[3] != NULL))
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return(0);
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/* identify edge 0 */
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for (i = 3; i--; )
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if (miga[i]->rbfv[0] == vert[0] &&
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miga[i]->rbfv[1] == vert[1]) {
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ord[0] = miga[i];
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break;
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}
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if (i < 0)
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return(0);
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/* identify edge 1 */
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for (i = 3; i--; )
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if (miga[i]->rbfv[0] == vert[1] &&
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miga[i]->rbfv[1] == vert[2]) {
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ord[1] = miga[i];
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break;
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}
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if (i < 0)
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return(0);
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/* identify edge 2 */
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for (i = 3; i--; )
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if (miga[i]->rbfv[0] == vert[0] &&
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miga[i]->rbfv[1] == vert[2]) {
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ord[2] = miga[i];
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break;
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}
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if (i < 0)
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return(0);
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/* reassign order */
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miga[0] = ord[0]; miga[1] = ord[1]; miga[2] = ord[2];
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return(1);
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}
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/* Determine if we are close enough to an edge */
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static int
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on_edge(const MIGRATION *ej, const FVECT ivec)
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{
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double cos_a, cos_b, cos_c, cos_aplusb;
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/* use triangle inequality */
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cos_a = DOT(ej->rbfv[0]->invec, ivec);
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if (cos_a <= 0)
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return(0);
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if (cos_a >= 1.) /* handles rounding error */
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return(1);
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cos_b = DOT(ej->rbfv[1]->invec, ivec);
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if (cos_b <= 0)
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return(0);
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if (cos_b >= 1.)
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return(1);
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cos_aplusb = cos_a*cos_b - sqrt((1.-cos_a*cos_a)*(1.-cos_b*cos_b));
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if (cos_aplusb <= 0)
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return(0);
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cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
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return(cos_c - cos_aplusb < .0002);
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}
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/* Determine if we are inside the given triangle */
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static int
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in_tri(const RBFNODE *v1, const RBFNODE *v2, const RBFNODE *v3, const FVECT p)
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{
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FVECT vc;
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int sgn1, sgn2, sgn3;
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/* signed volume test */
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VCROSS(vc, v1->invec, v2->invec);
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sgn1 = (DOT(p, vc) > 0);
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VCROSS(vc, v2->invec, v3->invec);
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sgn2 = (DOT(p, vc) > 0);
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if (sgn1 != sgn2)
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return(0);
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VCROSS(vc, v3->invec, v1->invec);
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sgn3 = (DOT(p, vc) > 0);
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return(sgn2 == sgn3);
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}
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/* Test (and set) bitmap for edge */
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static int
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check_edge(unsigned char *emap, int nedges, const MIGRATION *mig, int mark)
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{
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int ejndx, bit2check;
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if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
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ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
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else
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ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
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bit2check = 1<<(ejndx&07);
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if (emap[ejndx>>3] & bit2check)
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return(0);
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if (mark)
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emap[ejndx>>3] |= bit2check;
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return(1);
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}
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/* Compute intersection with the given position over remaining mesh */
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static int
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in_mesh(MIGRATION *miga[3], unsigned char *emap, int nedges,
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const FVECT ivec, MIGRATION *mig)
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{
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RBFNODE *tv[2];
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MIGRATION *sej[2], *dej[2];
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int i;
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/* check visitation record */
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if (!check_edge(emap, nedges, mig, 1))
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return(0);
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if (on_edge(mig, ivec)) {
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miga[0] = mig; /* close enough to edge */
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return(1);
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}
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if (!get_triangles(tv, mig)) /* do triangles either side? */
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return(0);
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for (i = 2; i--; ) { /* identify edges to check */
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MIGRATION *ej;
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sej[i] = dej[i] = NULL;
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if (tv[i] == NULL)
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continue;
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for (ej = tv[i]->ejl; ej != NULL; ej = nextedge(tv[i],ej)) {
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RBFNODE *rbfop = opp_rbf(tv[i],ej);
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if (rbfop == mig->rbfv[0]) {
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if (check_edge(emap, nedges, ej, 0))
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sej[i] = ej;
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} else if (rbfop == mig->rbfv[1]) {
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if (check_edge(emap, nedges, ej, 0))
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dej[i] = ej;
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}
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}
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}
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for (i = 2; i--; ) { /* check triangles just once */
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if (sej[i] != NULL && in_mesh(miga, emap, nedges, ivec, sej[i]))
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return(1);
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if (dej[i] != NULL && in_mesh(miga, emap, nedges, ivec, dej[i]))
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return(1);
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if ((sej[i] == NULL) | (dej[i] == NULL))
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continue;
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if (in_tri(mig->rbfv[0], mig->rbfv[1], tv[i], ivec)) {
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miga[0] = mig;
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miga[1] = sej[i];
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miga[2] = dej[i];
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return(1);
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}
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}
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return(0); /* not near this edge */
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}
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/* Find edge(s) for interpolating the given vector, applying symmetry */
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int
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get_interp(MIGRATION *miga[3], FVECT invec)
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{
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miga[0] = miga[1] = miga[2] = NULL;
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if (single_plane_incident) { /* isotropic BSDF? */
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RBFNODE *rbf; /* find edge we're on */
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for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
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if (input_orient*rbf->invec[2] < input_orient*invec[2]-FTINY)
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break;
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if (rbf->next != NULL && input_orient*rbf->next->invec[2] <
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input_orient*invec[2]+FTINY) {
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for (miga[0] = rbf->ejl; miga[0] != NULL;
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miga[0] = nextedge(rbf,miga[0]))
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if (opp_rbf(rbf,miga[0]) == rbf->next) {
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double nf = 1. -
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rbf->next->invec[2]*rbf->next->invec[2];
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if (nf > FTINY) { /* rotate to match */
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nf = sqrt((1.-invec[2]*invec[2])/nf);
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invec[0] = nf*rbf->next->invec[0];
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invec[1] = nf*rbf->next->invec[1];
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}
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return(0); /* rotational symmetry */
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}
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break;
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}
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}
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return(-1); /* outside range! */
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}
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{ /* else use triangle mesh */
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int sym = use_symmetry(invec);
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int nedges = 0;
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MIGRATION *mep;
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unsigned char *emap;
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/* clear visitation map */
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for (mep = mig_list; mep != NULL; mep = mep->next)
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++nedges;
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emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
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if (emap == NULL) {
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fprintf(stderr, "%s: Out of memory in get_interp()\n",
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progname);
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exit(1);
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}
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/* identify intersection */
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if (!in_mesh(miga, emap, nedges, invec, mig_list)) {
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#ifdef DEBUG
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fprintf(stderr,
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"Incident angle (%.1f,%.1f) deg. outside mesh\n",
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get_theta180(invec), get_phi360(invec));
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#endif
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sym = -1; /* outside mesh */
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} else if (miga[1] != NULL &&
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(miga[2] == NULL || !order_triangle(miga))) {
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| 255 |
#ifdef DEBUG
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| 256 |
fputs("Munged triangle in get_interp()\n", stderr);
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| 257 |
#endif
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sym = -1;
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}
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free(emap);
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return(sym); /* return in standard order */
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}
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}
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/* Advect between recorded incident angles and allocate new RBF */
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| 266 |
RBFNODE *
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advect_rbf(const FVECT invec, int lobe_lim)
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| 268 |
{
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| 269 |
double cthresh = FTINY;
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| 270 |
FVECT sivec;
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| 271 |
MIGRATION *miga[3];
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RBFNODE *rbf;
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int sym;
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| 274 |
float mbfact, mcfact;
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| 275 |
int n, i, j, k;
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| 276 |
FVECT v0, v1, v2;
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double s, t;
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| 278 |
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| 279 |
VCOPY(sivec, invec); /* find triangle/edge */
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| 280 |
sym = get_interp(miga, sivec);
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if (sym < 0) /* can't interpolate? */
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return(def_rbf_spec(invec));
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if (miga[1] == NULL) { /* advect along edge? */
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| 284 |
rbf = e_advect_rbf(miga[0], sivec, lobe_lim);
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if (single_plane_incident)
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| 286 |
rotate_rbf(rbf, invec);
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else
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| 288 |
rev_rbf_symmetry(rbf, sym);
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| 289 |
return(rbf);
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| 290 |
}
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| 291 |
#ifdef DEBUG
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| 292 |
if ((miga[0]->rbfv[0] != miga[2]->rbfv[0]) |
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| 293 |
(miga[0]->rbfv[1] != miga[1]->rbfv[0]) |
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(miga[1]->rbfv[1] != miga[2]->rbfv[1])) {
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| 295 |
fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
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| 296 |
exit(1);
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| 297 |
}
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| 298 |
#endif
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| 299 |
/* figure out position */
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| 300 |
fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
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| 301 |
normalize(v0);
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| 302 |
fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
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| 303 |
normalize(v2);
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| 304 |
fcross(v1, sivec, miga[1]->rbfv[1]->invec);
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| 305 |
normalize(v1);
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| 306 |
s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
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| 307 |
geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
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| 308 |
s, GEOD_REL);
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| 309 |
t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
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| 310 |
tryagain:
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| 311 |
n = 0; /* count migrating particles */
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| 312 |
for (i = 0; i < mtx_nrows(miga[0]); i++)
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| 313 |
for (j = 0; j < mtx_ncols(miga[0]); j++)
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| 314 |
for (k = (mtx_coef(miga[0],i,j) > cthresh) *
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| 315 |
mtx_ncols(miga[2]); k--; )
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| 316 |
n += (mtx_coef(miga[2],i,k) > cthresh ||
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| 317 |
mtx_coef(miga[1],j,k) > cthresh);
|
| 318 |
/* are we over our limit? */
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| 319 |
if ((lobe_lim > 0) & (n > lobe_lim)) {
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| 320 |
cthresh = cthresh*2. + 10.*FTINY;
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| 321 |
goto tryagain;
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| 322 |
}
|
| 323 |
#ifdef DEBUG
|
| 324 |
fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
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| 325 |
miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
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| 326 |
miga[2]->rbfv[1]->nrbf, n);
|
| 327 |
#endif
|
| 328 |
rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
|
| 329 |
if (rbf == NULL) {
|
| 330 |
fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
|
| 331 |
exit(1);
|
| 332 |
}
|
| 333 |
rbf->next = NULL; rbf->ejl = NULL;
|
| 334 |
VCOPY(rbf->invec, sivec);
|
| 335 |
rbf->nrbf = n;
|
| 336 |
n = 0; /* compute RBF lobes */
|
| 337 |
mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
|
| 338 |
(1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
|
| 339 |
mcfact = (1.-s) *
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| 340 |
(1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
|
| 341 |
for (i = 0; i < mtx_nrows(miga[0]); i++) {
|
| 342 |
const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
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| 343 |
const float w0i = rbf0i->peak;
|
| 344 |
const double rad0i = R2ANG(rbf0i->crad);
|
| 345 |
C_COLOR cc0;
|
| 346 |
ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
|
| 347 |
c_decodeChroma(&cc0, rbf0i->chroma);
|
| 348 |
for (j = 0; j < mtx_ncols(miga[0]); j++) {
|
| 349 |
const float ma = mtx_coef(miga[0],i,j);
|
| 350 |
const RBFVAL *rbf1j;
|
| 351 |
C_COLOR ccs;
|
| 352 |
double srad2;
|
| 353 |
if (ma <= cthresh)
|
| 354 |
continue;
|
| 355 |
rbf1j = &miga[0]->rbfv[1]->rbfa[j];
|
| 356 |
c_decodeChroma(&ccs, rbf1j->chroma);
|
| 357 |
c_cmix(&ccs, 1.-s, &cc0, s, &ccs);
|
| 358 |
srad2 = R2ANG(rbf1j->crad);
|
| 359 |
srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*srad2*srad2;
|
| 360 |
ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
|
| 361 |
geodesic(v1, v0, v1, s, GEOD_REL);
|
| 362 |
for (k = 0; k < mtx_ncols(miga[2]); k++) {
|
| 363 |
float mb = mtx_coef(miga[1],j,k);
|
| 364 |
float mc = mtx_coef(miga[2],i,k);
|
| 365 |
const RBFVAL *rbf2k;
|
| 366 |
double rad2;
|
| 367 |
int pos[2];
|
| 368 |
if ((mb <= cthresh) & (mc <= cthresh))
|
| 369 |
continue;
|
| 370 |
rbf2k = &miga[2]->rbfv[1]->rbfa[k];
|
| 371 |
rad2 = R2ANG(rbf2k->crad);
|
| 372 |
rad2 = srad2 + t*rad2*rad2;
|
| 373 |
rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact) *
|
| 374 |
rad0i*rad0i/rad2;
|
| 375 |
if (rbf_colorimetry == RBCtristimulus) {
|
| 376 |
C_COLOR cres;
|
| 377 |
c_decodeChroma(&cres, rbf2k->chroma);
|
| 378 |
c_cmix(&cres, 1.-t, &ccs, t, &cres);
|
| 379 |
rbf->rbfa[n].chroma = c_encodeChroma(&cres);
|
| 380 |
} else
|
| 381 |
rbf->rbfa[n].chroma = c_dfchroma;
|
| 382 |
rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
|
| 383 |
ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
|
| 384 |
geodesic(v2, v1, v2, t, GEOD_REL);
|
| 385 |
pos_from_vec(pos, v2);
|
| 386 |
rbf->rbfa[n].gx = pos[0];
|
| 387 |
rbf->rbfa[n].gy = pos[1];
|
| 388 |
++n;
|
| 389 |
}
|
| 390 |
}
|
| 391 |
}
|
| 392 |
rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
|
| 393 |
rev_rbf_symmetry(rbf, sym);
|
| 394 |
return(rbf);
|
| 395 |
}
|
