finished sample rework

glow-extras @ 38ce73ea

-Subproject commit d24f6bfa89995994ecec1b7fb7a4791b3de7fd7a
+Subproject commit 38ce73ea211cc54f861caa10778d903f94f508b5

polymesh @ ee575532

-Subproject commit 422b371894d4326a41d6dcc81ed5a998c7406b25
+Subproject commit ee575532d0eba2da77b672219bbda8082638e657

samples/basic/viewer/main.cc

@@ -146,8 +146,77 @@ void advanced_objects(pm::vertex_attribute<tg::pos3> const& pos)
 
 void advanced_visualization(pm::vertex_attribute<tg::pos3> const& pos)
 {
-    // gv::opaque, gv::transparent
-    // colors, textures, mappings
+    // the args in gv::view(obj, args) do not only configure the viewer but also change how the renderable is visualized
+
+    pm::Mesh const& m = pos.mesh();
+
+    // RNG for creating some random sample values
+    tg::rng rng;
+
+    // colors
+    {
+        auto g = gv::grid();
+
+        // generate some random color attributes
+        pm::face_attribute<tg::color3> random_face_colors = m.faces().map([&](pm::face_handle) { return tg::uniform<tg::color3>(rng); });
+        pm::vertex_attribute<tg::color3> random_vertex_colors = m.vertices().map([&](pm::vertex_handle) { return tg::uniform<tg::color3>(rng); });
+
+        // map positions to colors
+        pm::vertex_attribute<tg::color3> vcolors = m.vertices().map([&](pm::vertex_handle v) { return tg::color3(pos[v] * 0.5f + 0.5f); });
+
+        gv::view(pos, tg::color3::red, "solid color for whole mesh");
+        gv::view(pos, random_face_colors, "random face colors");
+        gv::view(pos, random_vertex_colors, "random vertex colors");
+        gv::view(gv::points(pos), vcolors, "point cloud with xyz colors");
+    }
+
+    // data mapping
+    {
+        auto g = gv::grid();
+
+        // a scalar field consisting of vertex y coordinate
+        pm::vertex_attribute<float> vdata = pos.map([](tg::pos3 v) { return v.y; });
+        // a scalar field consisting of face areas
+        pm::face_attribute<float> fdata = m.faces().map([&](pm::face_handle f) { return pm::face_area(f, pos); });
+
+        // map vertex data to black-red, from 0.1 .. 0.3 (repeats outside)
+        gv::view(pos, gv::mapping(vdata).linear(tg::color3::black, tg::color3::red, 0.1f, 0.3f), "vertex data");
+
+        // map face data to red (small) to green (big) from 0.05 .. 0.5 (data outside this range is clamped)
+        gv::view(pos, gv::mapping(fdata).linear(tg::color3::red, tg::color3::green, 0.05f, 0.5f).clamped(), "face data");
+    }
+
+    // textures
+    {
+        auto g = gv::grid();
+
+        // taking xy as UV for now
+        // NOTE: halfedge attributes also work
+        pm::vertex_attribute<tg::pos2> uv = pos.map([](tg::pos3 v) { return tg::pos2(v.x, v.y); });
+
+        // textures can be loaded directly or async
+        // TODO: gv::textured with a filename (and color space)
+        glow::SharedTexture2D tex = glow::Texture2D::createFromFile(dataPath + "textures/tiles.color.png", glow::ColorSpace::sRGB);
+        glow::AsyncTexture2D atex = glow::AsyncTextureLoader::load2D(dataPath + "textures/tiles.color.png", glow::ColorSpace::sRGB);
+
+        gv::view(pos, gv::textured(uv, tex), "textured");
+        gv::view(pos, gv::textured(uv, atex), "textured (async)");
+        gv::view(pos, gv::textured(uv, tex).flip(), "flipped y axis");
+        gv::view(pos, gv::textured(uv, tex).transform(tg::scaling(3.0f, 0.5f)), "transformed UVs");
+    }
+
+    // transparency
+    {
+        auto g = gv::grid();
+
+        // if colors with alpha < 1 are provided, transparency is enabled
+        gv::view(pos, tg::color4(0, 0.4f, 0.3f, 0.2f), "transparency with fresnel");
+        gv::view(pos, tg::color4(0, 0.4f, 0.3f, 0.2f), gv::no_fresnel, "transparency without fresnel");
+
+        // it can be explicitly controlled via gv::transparent and gv::opaque
+        gv::view(pos, tg::color4(0.3f, 0.1f, 0.3f, 0.5f), gv::transparent, "explicitly transparent");
+        gv::view(pos, tg::color4(0.3f, 0.1f, 0.3f, 0.2f), gv::opaque, "transparent color but disabled transparency");
+    }
 
     // TODO: complex material (e.g. PBR)
 }
@@ -431,30 +500,18 @@ void special_use_cases(pm::vertex_attribute<tg::pos3> const& pos)
 
 int main()
 {
-    // Create a context
+    // create a rendering context
     glow::glfw::GlfwContext ctx;
 
     tg::rng rng;
 
-    // Load a sample polymesh mesh
+    // load a sample polymesh mesh
     pm::Mesh m;
     auto pos = m.vertices().make_attribute<tg::pos3>();
     load(dataPath + "suzanne.obj", m, pos);
     normalize(pos); // make it -1..1
 
-    // prepare some data
-    pm::vertex_attribute<glm::vec2> uv = pos.map([](tg::pos3 v) { return glm::vec2(v.x, v.y); });
-    pm::vertex_attribute<float> vdata = pos.map([](tg::pos3 v) { return v.y; });
-    pm::vertex_attribute<tg::vec3> vnormals = vertex_normals_by_area(pos);
-    pm::face_attribute<float> fdata = m.faces().map([&](pm::face_handle f) { return f.vertices().avg(pos).z; });
-    glow::SharedTexture2D tex = glow::Texture2D::createFromFile(dataPath + "textures/tiles.color.png", glow::ColorSpace::sRGB);
-    glow::AsyncTexture2D atex = glow::AsyncTextureLoader::load2D(dataPath + "textures/tiles.color.png", glow::ColorSpace::sRGB);
-    pm::face_attribute<tg::color3> fcolors = m.faces().map([&](pm::face_handle) { return tg::uniform<tg::color3>(rng); });
-    pm::vertex_attribute<tg::color3> vcolors = attribute(m.vertices(), tg::color3(1, 0, 0));
-    pm::edge_attribute<float> edge_lengths = m.edges().map([&](pm::edge_handle e) { return edge_length(e, pos); });
-    pm::vertex_attribute<float> ptsize = m.vertices().map([&](pm::vertex_handle v) { return v.edges().avg(edge_lengths); });
-
-    // basics demos
+    // basic demos
     {
         simple_view(pos);
 
@@ -487,38 +544,5 @@ int main()
         headless_screenshot(pos);
     }
 
-    // Grid of examples
-    {
-        // Configuration nesting
-        {
-            // Colored faces
-            gv::view(pos, fcolors, "colored faces");
-
-            {
-                // Colored vertices
-                gv::view(pos, vcolors, "colored vertices");
-            }
-        }
-
-        // Mapped 1D vertex data
-        gv::view(pos, gv::mapping(vdata).linear({0, 0, 0}, {1, 0, 0}, 0.1f, 0.3f), "vertex data");
-
-        // Mapped 1D face data
-        gv::view(pos, gv::mapping(fdata).linear({0, 1, 0}, {0, 0, 1}, -0.5f, 0.5f).clamped(), "face data");
-
-        // Textured mesh
-        gv::view(pos, gv::textured(uv, tex), "textured");
-
-        // Textured mesh (async texture)
-        gv::view(pos, gv::textured(uv, atex), "textured (async)");
-
-        // transparencies
-        gv::view(pos, tg::color4(0, 0.4f, 0.3f, 0.2f), "transparency with fresnel");
-        gv::view(pos, tg::color4(0, 0.4f, 0.3f, 0.2f), gv::no_fresnel, "transparency without fresnel");
-
-        {
-        }
-    }
-
-    return 0;
+    return EXIT_SUCCESS;
 }