Various improvements to existing examples

samples/basic/viewer/main.cc

@@ -107,7 +107,7 @@ void advanced_objects(pm::vertex_attribute<tg::pos3> const& pos)
         auto g = gv::grid();
 
         pm::vertex_attribute<tg::vec3> vnormals = pm::vertex_normals_by_area(pos);
-        pm::vertex_attribute<float> line_widths = pos.map([](tg::pos3 p) { return 0.01f * tg::abs(p.x); });
+        pm::edge_attribute<float> line_widths = m.edges().map([&](pm::edge_handle e) { return 0.25f * distance(pos(e.vertexA()), pos(e.vertexB())); });
 
         gv::view(gv::lines(pos).line_width_world(0.01f).normals(vnormals), "oriented billboard lines");
         gv::view(gv::lines(pos).line_width_px(10), "10px line width");
@@ -289,6 +289,12 @@ void typed_geometry_objects()
     gv::view(gv::lines(tg::aabb3({-0.3f, 0, -0.4f}, {0.2f, 0.5f, 0.1f})), "lines(tg::aabb)");
 
     // vector versions
+    {
+        std::vector<tg::pos3> pts;
+        for (auto i = 0; i < 500; ++i)
+            pts.push_back(uniform(rng, tg::sphere3::unit));
+        gv::view(pts, "point cloud");
+    }
     {
         std::vector<tg::segment3> segs;
         for (auto i = 0; i < 20; ++i)
@@ -301,12 +307,6 @@ void typed_geometry_objects()
             tris.emplace_back(uniform(rng, tg::sphere3::unit), uniform(rng, tg::sphere3::unit), uniform(rng, tg::sphere3::unit));
         gv::view(tris, "tg::triangle soup");
     }
-    {
-        std::vector<tg::pos3> pts;
-        for (auto i = 0; i < 500; ++i)
-            pts.push_back(uniform(rng, tg::sphere3::unit));
-        gv::view(pts, "point cloud");
-    }
     {
         std::vector<tg::box3> bbs;
         for (auto i = 0; i < 4; ++i)
@@ -323,8 +323,8 @@ void typed_geometry_objects()
             bbs.push_back(tg::box3(c, {e0, e1, e2}));
         }
 
-        gv::view(gv::lines(bbs), "tg::box frames");
         gv::view(bbs, "tg::box soup");
+        gv::view(gv::lines(bbs), "tg::box frames");
     }
 }
 
@@ -508,8 +508,12 @@ void headless_screenshot(pm::vertex_attribute<tg::pos3> const& pos)
 void special_use_cases(pm::vertex_attribute<tg::pos3> const& pos)
 {
     // TODO: decoupled camera
-
-    gv::view(pos, gv::maybe_empty, "allows empty renderable");
+    {
+        auto g = gv::grid();
+        std::vector<tg::triangle3> tris;
+        gv::view(tris, gv::maybe_empty, "allows empty renderable");
+        gv::view(pos, gv::maybe_empty, "but does not necessarily have to be empty if specified");
+    }
 
     gv::view(pos, gv::infinite_accumulation, "progressive rendering is not stopped early");
 
@@ -564,9 +568,9 @@ void special_use_cases(pm::vertex_attribute<tg::pos3> const& pos)
         gv::view(pos, "built-in camera");
         gv::view(pos, "built-in camera");
         gv::view(pos, camA, "custom camera A");
-        gv::view(pos, camA, "custom camera A");
-        gv::view(pos, camB, "custom camera B");
+        gv::view(tg::aabb3::unit_centered, camA, "custom camera A");
         gv::view(pos, camB, "custom camera B");
+        gv::view(gv::lines(pos), camB, "custom camera B");
     }
 
     // per default, the camera is reset for each new view (and fit to the scene)
@@ -574,7 +578,7 @@ void special_use_cases(pm::vertex_attribute<tg::pos3> const& pos)
     // configuring gv::reuse_camera means that the current view will use the last camera
     // these can be chained indefinitely
     {
-        gv::view(pos, gv::preserve_camera, "next view uses the same camera");
+        gv::view(pos, gv::preserve_camera, "next view will use the same camera");
         gv::view(pos);
         gv::view(pos, gv::reuse_camera, "re-used previous camera");
         gv::view(pos, gv::reuse_camera, "re-used previous camera (again)");