star-stl

commit 17718c31beb6c6872c03ba59b54e3ceda7eade08
parent 78211c56742c8117f183c745b08db73933da329b
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu,  3 Jul 2025 14:16:51 +0200

Add desc API to facilitate access to mesh data

Diffstat:
M
src/sstl.h
 | 
50
++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 50 insertions(+), 0 deletions(-)
diff --git a/src/sstl.h b/src/sstl.h
@@ -162,6 +162,56 @@ sstl_get_desc
    struct sstl_desc* desc);
 
 /*******************************************************************************
+ * Descriptor API. This is a set of help functions for retrieving mesh data from
+ * their raw representation.
+ ******************************************************************************/
+static INLINE res_T
+sstl_desc_get_triangle_ids
+  (const struct sstl_desc* desc,
+   const size_t itri,
+   unsigned ids[3])
+{
+  if(!desc || !ids || itri >= desc->triangles_count) return RES_BAD_ARG;
+  ids[0] = desc->indices[itri*3/*#ids per triangle*/ + 0];
+  ids[1] = desc->indices[itri*3/*#ids per triangle*/ + 1];
+  ids[2] = desc->indices[itri*3/*#ids per triangle*/ + 2];
+  return RES_OK;
+}
+
+static INLINE res_T
+sstl_desc_get_vertex_coords
+  (const struct sstl_desc* desc,
+   const size_t ivtx,
+   float coords[3])
+{
+  if(!desc || !coords || ivtx >= desc->vertices_count) return RES_BAD_ARG;
+  coords[0] = desc->vertices[ivtx*3/*#coords per vertex*/ + 0];
+  coords[1] = desc->vertices[ivtx*3/*#coords per vertex*/ + 1];
+  coords[2] = desc->vertices[ivtx*3/*#coords per vertex*/ + 2];
+  return RES_OK;
+}
+
+static INLINE res_T
+sstl_desc_get_facet
+  (const struct sstl_desc* desc,
+   const size_t itri,
+   struct sstl_facet* facet)
+{
+  unsigned ids[3] = {0,0,0};
+
+  if(!desc || !facet || itri >= desc->triangles_count) return RES_BAD_ARG;
+
+  #define CALL(Func) {res_T res; if((res = Func) != RES_OK) return res;} (void)0
+  CALL(sstl_desc_get_triangle_ids(desc, itri, ids));
+  CALL(sstl_desc_get_vertex_coords(desc, ids[0], facet->vertices[0]));
+  CALL(sstl_desc_get_vertex_coords(desc, ids[1], facet->vertices[1]));
+  CALL(sstl_desc_get_vertex_coords(desc, ids[2], facet->vertices[2]));
+  #undef CALL
+
+  return RES_OK;
+}
+
+/*******************************************************************************
  * Writer API
  ******************************************************************************/
 SSTL_API res_T