Add colors(...) to tri_ref and line_ref

viewer/glow-extras/viewer/canvas.hh

@@ -382,6 +382,17 @@ protected:
         line_ref& color(float r, float g, float b, float a = 1) { return color(tg::color4(r, g, b, a)); }
         line_ref& color(std::string_view color_str);
 
+        /// sets the two vertex colors (for all lines, probably only useful for add_line(line))
+        line_ref& colors(tg::color4 const& c0, tg::color4 const& c1)
+        {
+            for (auto& l : _lines)
+            {
+                l.p0.color = c0;
+                l.p1.color = c1;
+            }
+            return *this;
+        }
+
         /// sets the size of all added lines
         /// NOTE: world size or px size is determined by canvas state and cannot be changed!
         line_ref& size(float s)
@@ -498,6 +509,18 @@ protected:
         triangle_ref& color(float r, float g, float b, float a = 1) { return color(tg::color4(r, g, b, a)); }
         triangle_ref& color(std::string_view color_str);
 
+        /// sets the three vertex colors (for all triangles, probably only useful for add_face(tri))
+        triangle_ref& colors(tg::color4 const& c0, tg::color4 const& c1, tg::color4 const& c2)
+        {
+            for (auto& t : _triangles)
+            {
+                t.color[0] = c0;
+                t.color[1] = c1;
+                t.color[2] = c2;
+            }
+            return *this;
+        }
+
         /// sets the triangle normal of all triangles
         triangle_ref& normal(tg::vec3 const& n)
         {