commit f1c4a9deeccef5f8002e1be8258e101fdff37aa6
parent a54d9fadc2a53e775dcdbc3291f018158f06cbd8
Author: Vincent Forest <vincent.forest@meso-star.com>
Date: Thu, 2 Aug 2018 11:19:10 +0200
Fix the SVX scattering/transmissivity filter function
The distance to traverse into the voxel was wrong
Diffstat:
3 files changed, 41 insertions(+), 26 deletions(-)
diff --git a/src/htrdr.c b/src/htrdr.c
@@ -321,7 +321,8 @@ htrdr_init
htrdr_log_err(htrdr, "could not create the BSDF of the ground.\n");
goto error;
}
- SSF(lambertian_reflection_setup(htrdr->bsdf, 1));
+ SSF(lambertian_reflection_setup(htrdr->bsdf, 0.02));
+/* SSF(lambertian_reflection_setup(htrdr->bsdf, 1));*/
res = ssf_phase_create(htrdr->allocator, &ssf_phase_hg, &htrdr->phase_hg);
if(res != RES_OK) {
diff --git a/src/htrdr_args.c b/src/htrdr_args.c
@@ -292,7 +292,7 @@ htrdr_args_init(struct htrdr_args* args, int argc, char** argv)
*args = HTRDR_ARGS_DEFAULT;
- while((opt = getopt(argc, argv, "C:c:D:dfhi:m:o:t:v")) != -1) {
+ while((opt = getopt(argc, argv, "C:c:D:dfg:hi:m:o:t:v")) != -1) {
switch(opt) {
case 'C':
res = parse_multiple_parameters
diff --git a/src/htrdr_compute_radiance_sw.c b/src/htrdr_compute_radiance_sw.c
@@ -67,6 +67,7 @@ scattering_hit_filter
void* context)
{
struct scattering_context* ctx = context;
+ double vox_dst; /* Distance to traverse into the voxel */
double ks_max;
int pursue_traversal = 1;
ASSERT(hit && ctx && !SVX_HIT_NONE(hit) && org && dir && range);
@@ -75,21 +76,22 @@ scattering_hit_filter
ks_max = htrdr_sky_fetch_svx_voxel_property(ctx->sky, HTRDR_Ks,
HTRDR_SVX_MAX, HTRDR_ALL_COMPONENTS, ctx->wavelength, &hit->voxel);
- for(;;) {
- double dst;
- double T;
+ /* Compute the distance to traverse into the voxel */
+ vox_dst = hit->distance[1] - hit->distance[0];
- dst = hit->distance[1] - ctx->traversal_dst;
- T = dst * ks_max; /* Compute tau for the current leaf */
+ /* Iterate until a collision occurs into the voxel or until the ray
+ * does not collide the voxel */
+ for(;;) {
+ const double T = vox_dst * ks_max; /* Compute tau for the current leaf */
- /* A collision occurs behind `dst' */
+ /* A collision occurs behind `vox_dst' */
if(ctx->Ts > T) {
ctx->Ts -= T;
ctx->traversal_dst = hit->distance[1];
pursue_traversal = 1;
break;
- /* A real/null collision occurs before `dst' */
+ /* A real/null collision occurs before `vox_dst' */
} else {
double pos[3];
double proba;
@@ -97,13 +99,14 @@ scattering_hit_filter
const double collision_dst = ctx->Ts / ks_max;
/* Compute the traversed distance up to the challenged collision */
- dst = ctx->traversal_dst + collision_dst;
- ctx->traversal_dst = dst;
+ ctx->traversal_dst = hit->distance[0] + collision_dst;
+ ASSERT(ctx->traversal_dst >= hit->distance[0]);
+ ASSERT(ctx->traversal_dst <= hit->distance[1]);
/* Compute the world space position where a collision may occur */
- pos[0] = org[0] + dst * dir[0];
- pos[1] = org[1] + dst * dir[1];
- pos[2] = org[2] + dst * dir[2];
+ pos[0] = org[0] + ctx->traversal_dst * dir[0];
+ pos[1] = org[1] + ctx->traversal_dst * dir[1];
+ pos[2] = org[2] + ctx->traversal_dst * dir[2];
/* TODO use a per wavelength getter that will precompute the interpolated
* cross sections for a wavelength to improve the fetch efficiency */
@@ -118,6 +121,8 @@ scattering_hit_filter
break;
} else { /* Null collision */
ctx->Ts = ssp_ran_exp(ctx->rng, 1); /* Sample a new optical thickness */
+ /* Compute the remaining distance to traverse into the voxel */
+ vox_dst = hit->distance[1] - ctx->traversal_dst;
}
}
}
@@ -133,7 +138,7 @@ transmissivity_hit_filter
void* context)
{
struct transmissivity_context* ctx = context;
- double dst;
+ double vox_dst; /* Distance to traverse into the voxel */
double k_max;
double k_min;
int pursue_traversal = 1;
@@ -146,20 +151,23 @@ transmissivity_hit_filter
HTRDR_SVX_MAX, HTRDR_ALL_COMPONENTS, ctx->wavelength, &hit->voxel);
ASSERT(k_min <= k_max);
- dst = hit->distance[1] - ctx->traversal_dst;
- ctx->Tmin += dst * k_min;
+ /* Compute the distance to traverse into the voxel */
+ vox_dst = hit->distance[1] - hit->distance[0];
+ ctx->Tmin += vox_dst * k_min;
+ /* Iterate until a collision occurs into the voxel or until the ray
+ * does not collide the voxel */
for(;;) {
- const double Tdif = dst * (k_max-k_min);
+ const double Tdif = vox_dst * (k_max-k_min);
- /* A collision occurs behind `dst' */
+ /* A collision occurs behind `vox_dst' */
if(ctx->Ts > Tdif) {
ctx->Ts -= Tdif;
ctx->traversal_dst = hit->distance[1];
pursue_traversal = 1;
break;
- /* A real/null collision occurs before `dst' */
+ /* A real/null collision occurs before `vox_dst' */
} else {
double x[3];
double k;
@@ -167,13 +175,14 @@ transmissivity_hit_filter
double collision_dst = ctx->Ts / (k_max - k_min);
/* Compute the traversed distance up to the challenged collision */
- dst = ctx->traversal_dst + collision_dst;
- ctx->traversal_dst = dst;
+ ctx->traversal_dst = hit->distance[0] + collision_dst;
+ ASSERT(ctx->traversal_dst >= hit->distance[0]);
+ ASSERT(ctx->traversal_dst <= hit->distance[1]);
/* Compute the world space position where a collision may occur */
- x[0] = org[0] + dst * dir[0];
- x[1] = org[1] + dst * dir[1];
- x[2] = org[2] + dst * dir[2];
+ x[0] = org[0] + ctx->traversal_dst * dir[0];
+ x[1] = org[1] + ctx->traversal_dst * dir[1];
+ x[2] = org[2] + ctx->traversal_dst * dir[2];
/* TODO use a per wavelength getter that will precompute the interpolated
* cross sections for a wavelength to improve the fetch efficiency */
@@ -189,7 +198,8 @@ transmissivity_hit_filter
break;
} else { /* Null collision */
ctx->Ts = ssp_ran_exp(ctx->rng, 1); /* Sample a new optical thickness */
- dst = hit->distance[1] - ctx->traversal_dst;
+ /* Compute the remaining distance to traverse into the voxel */
+ vox_dst = hit->distance[1] - ctx->traversal_dst;
}
}
}
@@ -351,6 +361,9 @@ htrdr_compute_radiance_sw
w *= ksi;
break;
}
+ ASSERT(SVX_HIT_NONE(&svx_hit)
+ || ( svx_hit.distance[0] <= scattering_ctx.traversal_dst
+ && svx_hit.distance[1] >= scattering_ctx.traversal_dst));
/* Negative the incoming dir to match the convention of the SSF library */
d3_minus(wo, dir);
@@ -380,6 +393,7 @@ htrdr_compute_radiance_sw
int type;
d3_normalize(N, d3_set_f3(N, s3d_hit.normal));
+ if(d3_dot(N, wo) < 0) d3_minus(N, N);
reflectivity = ssf_bsdf_sample
(htrdr->bsdf, rng, wo, N, dir_next, &type, &pdf);
if(ssp_rng_canonical(rng) > reflectivity) break; /* Russian roulette */
