star-gs

commit 50aef149568be0cf7583097bea7bf08a7c61e0a4
parent 9b0fd6fd923b31d78a6d31dc65d1776db546de7e
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Mon, 26 Apr 2021 22:06:43 +0200

Add the sgs_geometry_sample function

Diffstat:
M
src/sgs_geometry.c
 | 
34
++++++++++++++++++++++++++++++++++
M
src/sgs_geometry.h
 | 
10
+++++++++-

2 files changed, 43 insertions(+), 1 deletion(-)
diff --git a/src/sgs_geometry.c b/src/sgs_geometry.c
@@ -23,6 +23,7 @@
 #include "sgs_log.h"
 
 #include <star/s3d.h>
+#include <star/ssp.h>
 
 #include <rsys/cstr.h>
 #include <rsys/float2.h>
@@ -270,6 +271,39 @@ sgs_geometry_trace_ray
   }
 }
 
+extern LOCAL_SYM void
+sgs_geometry_sample
+  (const struct sgs_geometry* geom,
+   struct ssp_rng* rng,
+   struct sgs_fragment* frag)
+{
+  struct s3d_primitive prim = S3D_PRIMITIVE_NULL;
+  struct s3d_attrib position;
+  struct s3d_attrib normal;
+  float r0, r1, r2;
+  float st[2];
+  ASSERT(geom && rng && frag);
+
+  /* Sample the geometry */
+  r0 = ssp_rng_canonical_float(rng);
+  r1 = ssp_rng_canonical_float(rng);
+  r2 = ssp_rng_canonical_float(rng);
+  S3D(scene_view_sample(geom->view_sp, r0, r1, r2, &prim, st));
+
+  /* Retrieve sampling point attributes */
+  S3D(primitive_get_attrib(&prim, S3D_POSITION, st, &position));
+  S3D(primitive_get_attrib(&prim, S3D_GEOMETRY_NORMAL, st, &normal));
+
+  /* Setup the output variable */
+  d3_set_f3(frag->position, position.value);
+  d3_set_f3(frag->normal, normal.value);
+  d3_normalize(frag->normal, frag->normal);
+  frag->surface_type = darray_int_cdata_get(&geom->tris_type)[prim.prim_id];
+  frag->s3d_pos.prim = prim;
+  frag->s3d_pos.st[0] = st[0];
+  frag->s3d_pos.st[1] = st[1];
+}
+
 res_T
 sgs_geometry_dump_vtk(const struct sgs_geometry* geom, FILE* stream)
 {
diff --git a/src/sgs_geometry.h b/src/sgs_geometry.h
@@ -152,9 +152,9 @@ static const struct sgs_hit SGS_HIT_NULL = SGS_HIT_NULL__;
 #define SGS_HIT_NONE(Hit) ((Hit)->distance >= FLT_MAX)
 
 /* Forward declaration */
-struct s3d_hit;
 struct sgs;
 struct sgs_geometry;
+struct ssp_rng;
 
 /*******************************************************************************
  * Geometry API
@@ -194,6 +194,14 @@ sgs_geometry_trace_ray
    const struct sgs_s3d_position* pos_from, /* To avoid self hit. May be NULL */
    struct sgs_hit* hit);
 
+/* Uniformly sample a point onto the faces of the geometry defined in the
+ * sampling_mask on geometry creation */
+extern LOCAL_SYM void
+sgs_geometry_sample
+  (const struct sgs_geometry* geom,
+   struct ssp_rng* rng,
+   struct sgs_fragment* frag);
+
 extern LOCAL_SYM res_T
 sgs_geometry_dump_vtk
   (const struct sgs_geometry* geom,