htrdr

commit d978bcea7156dda07113a67043ccf6292ba06931
parent 67b9637ccf210ace9423d6c3866e40d34714eb3e
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri, 18 Nov 2022 11:44:59 +0100

htrdr-planeto: accelerate compute with rnatm update

An update to the rnatm API allows you to query the BVH of the tetrahedra
once and to reuse the returned cells in each function that use the same
input position

Diffstat:
M
src/planeto/htrdr_planeto_compute_radiance.c
 | 
45
+++++++++++++++++++++++++++++----------------

1 file changed, 29 insertions(+), 16 deletions(-)
diff --git a/src/planeto/htrdr_planeto_compute_radiance.c b/src/planeto/htrdr_planeto_compute_radiance.c
@@ -42,9 +42,14 @@ struct scattering {
    * normalized and looks towards the incoming direction */
   double normal[3];
 
-  double distance;
+  /* Cells in which the scattering position is located */
+  struct rnatm_cell_pos cells[RNATM_MAX_COMPONENTS_COUNT];
+
+  double distance; /* Distance from ray origin to scattering position */
 };
-#define SCATTERING_NULL__ {S3D_HIT_NULL__, {0,0,0}, DBL_MAX}
+#define SCATTERING_NULL__ {                                                    \
+  S3D_HIT_NULL__, {0,0,0}, {RNATM_CELL_POS_NULL__}, DBL_MAX                    \
+}
 static const struct scattering SCATTERING_NULL = SCATTERING_NULL__;
 
 /* Arguments of the filtering function used to sample a position */
@@ -58,10 +63,11 @@ struct sample_distance_context {
   double Ts; /* Sample optical thickness */
 
   /* Output data */
+  struct rnatm_cell_pos* cells;
   double distance;
 };
 #define SAMPLE_DISTANCE_CONTEXT_NULL__ {                                       \
-  NULL, NULL, 0, 0, 0, RNATM_RADCOEFS_COUNT__, 0, DBL_MAX                      \
+  NULL, NULL, 0, 0, 0, RNATM_RADCOEFS_COUNT__, 0, NULL, DBL_MAX                \
 }
 static const struct sample_distance_context SAMPLE_DISTANCE_CONTEXT_NULL =
   SAMPLE_DISTANCE_CONTEXT_NULL__;
@@ -132,6 +138,7 @@ sample_position_hit_filter
 
   /* Configure the common input arguments to retrieve the radiative coefficient
    * of a given position */
+  get_k_args.cells = ctx->cells;
   get_k_args.iband = ctx->iband;
   get_k_args.iquad = ctx->iquad;
   get_k_args.radcoef = ctx->radcoef;
@@ -152,15 +159,17 @@ sample_position_hit_filter
     /* A collision occurs in the voxel */
     } else {
       const double vox_dst_collision = ctx->Ts / k_max;
+      double pos[3];
       double  k, r;
 
       /* Calculate the distance travelled to the collision to be queried */
       dst_travelled += vox_dst_collision;
 
       /* Retrieve the radiative coefficient at the collision position */
-      get_k_args.pos[0] = org[0] + dst_travelled * dir[0];
-      get_k_args.pos[1] = org[1] + dst_travelled * dir[1];
-      get_k_args.pos[2] = org[2] + dst_travelled * dir[2];
+      pos[0] = org[0] + dst_travelled * dir[0];
+      pos[1] = org[1] + dst_travelled * dir[1];
+      pos[2] = org[2] + dst_travelled * dir[2];
+      RNATM(fetch_cell_list(ctx->atmosphere, pos, get_k_args.cells, NULL));
       RNATM(get_radcoef(ctx->atmosphere, &get_k_args, &k));
 
       r = ssp_rng_canonical(ctx->rng);
@@ -185,6 +194,7 @@ static double
 sample_distance
   (struct htrdr_planeto* cmd,
    const struct planeto_compute_radiance_args* args,
+   struct rnatm_cell_pos* cells,
    const enum rnatm_radcoef radcoef,
    const double pos[3],
    const double dir[3],
@@ -193,7 +203,7 @@ sample_distance
   struct rnatm_trace_ray_args rt = RNATM_TRACE_RAY_ARGS_NULL;
   struct sample_distance_context ctx = SAMPLE_DISTANCE_CONTEXT_NULL;
   struct svx_hit hit;
-  ASSERT(cmd && args && pos && dir && d3_is_normalized(dir) && range);
+  ASSERT(cmd && args && cells && pos && dir && d3_is_normalized(dir) && range);
   ASSERT((unsigned)radcoef < RNATM_RADCOEFS_COUNT__);
   ASSERT(range[0] < range[1]);
 
@@ -207,6 +217,7 @@ sample_distance
   ctx.iquad = args->iquad;
   ctx.wavelength = args->wlen;
   ctx.radcoef = radcoef;
+  ctx.cells = cells;
 
   /* Trace the ray into the atmosphere */
   d3_set(rt.ray_org, pos);
@@ -235,13 +246,14 @@ transmissivity
    const double dir[3],
    const double range_max)
 {
+  struct rnatm_cell_pos cells[RNATM_MAX_COMPONENTS_COUNT];
   double range[2];
   double dst = 0;
   ASSERT(range_max >= 0);
 
   range[0] = 0;
   range[1] = range_max;
-  dst = sample_distance(cmd, args, radcoef, pos, dir, range);
+  dst = sample_distance(cmd, args, cells, radcoef, pos, dir, range);
 
   if(DISTANCE_NONE(dst)) {
     return 1.0; /* No collision in the medium */
@@ -308,7 +320,7 @@ sample_scattering
   /* Look for an atmospheric collision */
   range[0] = 0;
   range[1] = hit.distance;
-  dst = sample_distance(cmd, args, RNATM_RADCOEF_Ks, pos, dir, range);
+  dst = sample_distance(cmd, args, sc->cells, RNATM_RADCOEF_Ks, pos, dir, range);
 
   /* Scattering in volume */
   if(!DISTANCE_NONE(dst)) {
@@ -357,7 +369,7 @@ static INLINE struct ssf_phase*
 create_phase_fn
   (struct htrdr_planeto* cmd,
    const struct planeto_compute_radiance_args* args,
-   const double pos[3]) /* Scattering position */
+   const struct rnatm_cell_pos* cells) /* Cells in which scattering occurs */
 {
   struct rnatm_sample_component_args sample_args =
     RNATM_SAMPLE_COMPONENT_ARGS_NULL;
@@ -365,10 +377,10 @@ create_phase_fn
     RNATM_CELL_CREATE_PHASE_FN_ARGS_NULL;
   struct ssf_phase* phase = NULL;
   size_t cpnt;
-  ASSERT(cmd && args && pos);
+  ASSERT(cmd && args && cells);
 
   /* Sample the atmospheric scattering component */
-  d3_set(sample_args.pos, pos);
+  sample_args.cells = cells;
   sample_args.iband = args->iband;
   sample_args.iquad = args->iquad;
   sample_args.radcoef = RNATM_RADCOEF_Ks;
@@ -376,7 +388,7 @@ create_phase_fn
   RNATM(sample_component(cmd->atmosphere, &sample_args, &cpnt));
 
   /* Retrieve the component cell in which the scattering position is located */
-  RNATM(fetch_cell(cmd->atmosphere, pos, cpnt, &phase_fn_args.cell));
+  phase_fn_args.cell = RNATM_GET_COMPONENT_CELL(cells, cpnt);
   ASSERT(!SUVM_PRIMITIVE_NONE(&phase_fn_args.cell.prim));
 
   /* Retrieve the component phase function */
@@ -459,6 +471,7 @@ static INLINE double
 volume_scattering
   (struct htrdr_planeto* cmd,
    const struct planeto_compute_radiance_args* args,
+   const struct scattering* sc,
    const double sc_pos[3], /* Scattering position */
    const double in_dir[3], /* Incident direction */
    double sc_dir[3]) /* Sampled scattering direction */
@@ -470,9 +483,9 @@ volume_scattering
   double pdf = 0;
   double rho = 0;
   double Ld = 0;
-  ASSERT(cmd && args && sc_pos && in_dir && sc_dir);
+  ASSERT(cmd && args && sc && sc_pos && in_dir && sc_dir);
 
-  phase = create_phase_fn(cmd, args, sc_pos);
+  phase = create_phase_fn(cmd, args, sc->cells);
   d3_minus(wo, in_dir); /* Match StarSF convention */
 
   ssf_phase_sample(phase, args->rng, wo, sc_dir, NULL);
@@ -535,7 +548,7 @@ planeto_compute_radiance
     /* Scattering in volume */
     if(!SURFACE_SCATTERING(&sc)) {
       double Ls; /* Direct contribution at the scattering position */
-      Ls = volume_scattering(cmd, args, sc_pos, dir, sc_dir);
+      Ls = volume_scattering(cmd, args, &sc, sc_pos, dir, sc_dir);
       L += Tr_abs * Ls;
 
       /* Reset surface intersection */