Revision: 29239
http://projects.blender.org/plugins/scmsvn/viewcvs.php?view=rev&root=bf-blender&revision=29239
Author: blendix
Date: 2010-06-05 16:35:07 +0200 (Sat, 05 Jun 2010)
Log Message:
-----------
Render Branch: improve least squares reconstruction for irradiance cache,
in cases where it is underdetermined (few samples points). Hopefully solves
flickering in some of the mountains that we have here.
Modified Paths:
--------------
branches/render25/source/blender/render/intern/source/cache.c
Modified: branches/render25/source/blender/render/intern/source/cache.c
===================================================================
--- branches/render25/source/blender/render/intern/source/cache.c
2010-06-05 12:55:32 UTC (rev 29238)
+++ branches/render25/source/blender/render/intern/source/cache.c
2010-06-05 14:35:07 UTC (rev 29239)
@@ -438,6 +438,13 @@
struct IrrCacheNode *children[8]; /* child nodes */
} IrrCacheNode;
+typedef struct Lsq4DFit {
+ float (*A)[4];
+ float (*B)[MAX_CACHE_DIMENSION];
+ float (*w);
+ int tot, alloc;
+} Lsq4DFit;
+
struct IrrCache {
/* irradiance cache */
IrrCacheNode root; /* root node of the tree */
@@ -460,30 +467,53 @@
int locked;
int dimension;
int use_light_dir;
+
+ /* least squares reconstruction */
+ Lsq4DFit lsq;
/* test: a stable global coordinate system may help */
};
-typedef struct Lsq4DFit {
- float AtA[4][4];
- float AtB[MAX_CACHE_DIMENSION][4];
-} Lsq4DFit;
+/* Least Squares fit to hyperplane for better interpolation of samples, this
+ helps especially at tile borders or visibility boundaries, as it allows us
+ to extrapolate rather than just interpolate. */
+void lsq_4D_alloc(Lsq4DFit *lsq)
+{
+ lsq->alloc = 25;
+ lsq->A = MEM_callocN(sizeof(*lsq->A)*lsq->alloc, "lsq->A");
+ lsq->B = MEM_callocN(sizeof(*lsq->B)*lsq->alloc, "lsq->B");
+ lsq->w = MEM_callocN(sizeof(*lsq->w)*lsq->alloc, "lsq->w");
+}
+
+void lsq_4D_free(Lsq4DFit *lsq)
+{
+ MEM_freeN(lsq->A);
+ MEM_freeN(lsq->B);
+ MEM_freeN(lsq->w);
+}
+
+void lsq_4D_init(Lsq4DFit *lsq)
+{
+ lsq->tot = 0;
+}
+
void lsq_4D_add(Lsq4DFit *lsq, float a[4], float *b, int dimension, float
weight)
{
- float (*AtA)[4]= lsq->AtA;
- float (*AtB)[4]= lsq->AtB;
- int i, j;
+ int i;
- /* build AtA and AtB directly from rows of A and
- corresponding right hand side b */
- for(i=0; i<4; i++)
- for(j=0; j<4; j++)
- AtA[i][j] += weight*a[i]*a[j];
-
+ if(lsq->tot >= lsq->alloc) {
+ lsq->alloc *= 2;
+ lsq->A = MEM_reallocN(lsq->A, sizeof(*lsq->A)*lsq->alloc);
+ lsq->B = MEM_reallocN(lsq->B, sizeof(*lsq->B)*lsq->alloc);
+ lsq->w = MEM_reallocN(lsq->w, sizeof(*lsq->w)*lsq->alloc);
+ }
+
+ copy_v4_v4(lsq->A[lsq->tot], a);
for(i=0; i<dimension; i++)
- for(j=0; j<4; j++)
- AtB[i][j] += weight*a[j]*b[i];
+ lsq->B[lsq->tot][i] = b[i];
+ lsq->w[lsq->tot] = weight;
+ lsq->tot++;
}
void TNT_svd(float m[][4], float *w, float u[][4]);
@@ -508,14 +538,46 @@
void lsq_4D_solve(Lsq4DFit *lsq, float *solution, int dimension)
{
- float AtAinv[4][4], x[4];
- int i;
+ float AtA[4][4], AtAinv[4][4], AtB[MAX_CACHE_DIMENSION][4];
+ float x[4], meanB[MAX_CACHE_DIMENSION], totw;
+ float (*A)[4]= lsq->A, (*B)[MAX_CACHE_DIMENSION] = lsq->B, *w = lsq->w;
+ int i, j, k;
- svd_invert_m4_m4(AtAinv, lsq->AtA);
+ memset(AtA, 0, sizeof(AtA));
+ memset(AtB, 0, sizeof(AtB));
+ memset(meanB, 0, sizeof(meanB));
+ totw = 0.0f;
+ /* computed weighted mean B, to do least squares on (B-meanB),
+ this works better on underdetermined systems where lsq will
+ minimize ||x||, which is not what we want */
+ for(k=0; k<lsq->tot; k++) {
+ for(i=0; i<dimension; i++)
+ meanB[i] += B[k][i]*w[k];
+ totw += w[k];
+ }
+
+ for(i=0; i<dimension; i++)
+ meanB[i] /= totw;
+
+ /* build AtA and AtB from A and B */
+ for(k=0; k<lsq->tot; k++) {
+ for(i=0; i<4; i++)
+ for(j=0; j<4; j++)
+ AtA[i][j] += w[k]*A[k][i]*A[k][j];
+
+ for(i=0; i<dimension; i++)
+ for(j=0; j<4; j++)
+ AtB[i][j] += w[k]*A[k][j]*(B[k][i] - meanB[i]);
+
+ }
+
+ /* use SVD for stable inverting of AtA */
+ svd_invert_m4_m4(AtAinv, AtA);
+
for(i=0; i<dimension; i++) {
- mul_v4_m4v4(x, AtAinv, lsq->AtB[i]);
- solution[i]= x[3];
+ mul_v4_m4v4(x, AtAinv, AtB[i]);
+ solution[i]= meanB[i] + x[3];
}
}
@@ -547,6 +609,9 @@
/* options */
cache->lsq_reconstruction= 1;
cache->neighbour_clamp= 1;
+
+ if(cache->lsq_reconstruction)
+ lsq_4D_alloc(&cache->lsq);
if(re->db.wrld.mode & WO_AMB_OCC)
cache->dimension++;
@@ -566,6 +631,9 @@
if(G.f & G_DEBUG)
printf("irr cache stats: %d samples, %d lookups, post %d,
%.4f.\n", cache->totsample, cache->totlookup, cache->totpost,
(float)cache->totsample/(float)cache->totlookup);
+ if(cache->lsq_reconstruction)
+ lsq_4D_free(&cache->lsq);
+
BLI_memarena_free(cache->arena);
MEM_freeN(cache->stack);
MEM_freeN(cache);
@@ -849,7 +917,7 @@
float accum[MAX_CACHE_DIMENSION], P[3], dPdu[3], dPdv[3], N[3],
bumpN[3], totw;
float discard_weight, maxdist, distfac;
int i, added= 0, totfound= 0, use_lsq, dimension;
- Lsq4DFit lsq;
+ Lsq4DFit *lsq= &cache->lsq;
/* XXX check how often this is called! */
/* XXX can identical samples end up in the cache now? */
@@ -899,7 +967,7 @@
dimension= cache->dimension;
if(use_lsq)
- memset(&lsq, 0, sizeof(lsq));
+ lsq_4D_init(lsq);
else
memset(accum, 0, sizeof(accum));
@@ -959,7 +1027,7 @@
if(use_lsq) {
float a[4]= {D[0], D[1], D[2],
1.0f};
- lsq_4D_add(&lsq, a, C,
dimension, w);
+ lsq_4D_add(lsq, a, C,
dimension, w);
}
else {
for(i=0; i<dimension; i++)
@@ -985,7 +1053,7 @@
if(totw > EPSILON && totfound >= 1) {
if(!preprocess) {
if(use_lsq) {
- lsq_4D_solve(&lsq, accum, dimension);
+ lsq_4D_solve(lsq, accum, dimension);
}
else {
float invw= 1.0/totw;
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