star-cpr

commit 46e8dfae2032995927a7950a3a94e8e93037e0a0
parent d710029da754b33bb63b40e32c9d913a583827f1
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri, 26 Aug 2016 15:49:57 +0200

Clip only the triangles that intersect the clip polygon AABB

Diffstat:
M
src/cpr_mesh.c
 | 
67
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----

1 file changed, 63 insertions(+), 4 deletions(-)
diff --git a/src/cpr_mesh.c b/src/cpr_mesh.c
@@ -83,6 +83,21 @@ cInt_to_double(const ClipperLib::cInt i, const double scale)
 }
 
 static INLINE int
+aabb_intersect
+  (const double lower0[2],
+   const double upper0[2],
+   const double lower1[2],
+   const double upper1[2])
+{
+  ASSERT(lower0 && upper0 && lower1 && upper1);
+  return lower0[0] < upper1[0]
+      && lower0[1] < upper1[1]
+      && lower1[0] < upper0[0]
+      && lower1[1] < upper0[1];
+}
+
+
+static INLINE int
 aabb_is_degenerated(const double lower[2], const double upper[2])
 {
   ASSERT(lower && upper);
@@ -136,6 +151,23 @@ error:
   goto exit;
 }
 
+static void
+triangle_compute_aabb
+  (double tri[3][2],
+   double lower[2],
+   double upper[2])
+{
+  size_t ivert;
+  ASSERT(tri && lower && upper);
+
+  d2_splat(lower, DBL_MAX);
+  d2_splat(upper,-DBL_MAX);
+  FOR_EACH(ivert, 0, 3) {
+    d2_min(lower, lower, tri[ivert]);
+    d2_max(upper, upper, tri[ivert]);
+  }
+}
+
 static res_T
 register_vertex
   (const double pos[2],
@@ -179,6 +211,24 @@ error:
   goto exit;
 }
 
+static FINLINE res_T
+register_triangle
+  (double tri[3][2],
+   struct darray_double* coords, /* Vertex buffer */
+   struct darray_size_t* indices, /* Index buffer */
+   struct htable_vertex* vertices) /* Map a vertex to its index */
+{
+  size_t ivert;
+  res_T res = RES_OK;
+  ASSERT(tri && coords && indices && vertices);
+  FOR_EACH(ivert, 0, 3) {
+    res = register_vertex(tri[ivert], coords, indices, vertices);
+    if(res != RES_OK) return res;
+  }
+  return RES_OK;
+}
+
+
 static res_T
 register_paths
   (const ClipperLib::Paths& paths,
@@ -478,17 +528,26 @@ cpr_mesh_clip(struct cpr_mesh* mesh, struct cpr_polygon* poly_desc)
   CPR(mesh_get_triangles_count(mesh, &ntris));
   FOR_EACH(itri, 0, ntris) {
     size_t ids[3];
+    double tri[3][2];
 
     CPR(mesh_get_indices(mesh, itri, ids));
+    CPR(mesh_get_position(mesh, ids[0], tri[0]));
+    CPR(mesh_get_position(mesh, ids[1], tri[1]));
+    CPR(mesh_get_position(mesh, ids[2], tri[2]));
+    triangle_compute_aabb(tri, lower, upper);
+
+    if(!aabb_intersect(lower, upper, poly.lower, poly.upper)) {
+      res = register_triangle(tri, &coords, &indices, &vertices);
+      if(res != RES_OK) goto error;
+      continue;
+    }
 
     /* Setup the candidate path */
     cand_path.clear();
     FOR_EACH(ivert, 0, 3) {
-      double pos[2];
       ClipperLib::IntPoint pt;
-      CPR(mesh_get_position(mesh, ids[ivert], pos));
-      pt.X = double_to_cInt(pos[0], extend[0]);
-      pt.Y = double_to_cInt(pos[1], extend[1]);
+      pt.X = double_to_cInt(tri[ivert][0], extend[0]);
+      pt.Y = double_to_cInt(tri[ivert][1], extend[1]);
       cand_path.push_back(pt);
     }