revert triangulation changes of Circle

Author: ffreyer

src/meshes.jl

@@ -20,13 +20,15 @@ function mesh(primitive::AbstractGeometry; pointtype=Point, facetype=GLTriangleF
         _fs = positions.faces
         isnothing(faces(primitive)) || @error("A primitive should not define `faces` and use a FaceView for `coordinates()`. Using faces from FaceView.")
     else
-        _fs = faces(primitive)
+        # This tries `faces(prim)` first, then triangulation with the natural
+        # position type of the primitive.
+        _fs = decompose(facetype, primitive)
     end
 
     # If faces returns nothing for primitive, we try to triangulate!
     if isnothing(_fs)
         if eltype(positions) <: Point2
-            # triangulation.jl
+            # try triangulation with the converted positions as a last attempt
             fs = decompose(facetype, positions)
         else
             error("No triangulation for $(typeof(primitive))")

src/primitives/spheres.jl

@@ -43,18 +43,20 @@ end
 
 function coordinates(s::Circle, nvertices=64)
     r = radius(s); o = origin(s)
-    ps = [r * Point(cos(phi), sin(phi)) + o for phi in LinRange(0, 2pi, nvertices+1)]
-    ps[end] = o
+    ps = [r * Point(cos(phi), sin(phi)) + o for phi in LinRange(0, 2pi, nvertices)]
+    # ps[end] = o
     return ps
 end
 
 function texturecoordinates(::Circle, nvertices=64)
     return coordinates(Circle(Point2f(0.5), 0.5f0), nvertices)
 end
 
-function faces(::Circle, nvertices=64)
-    return [GLTriangleFace(nvertices+1, i, mod1(i+1, nvertices)) for i in 1:nvertices]
-end
+# TODO: Consider generating meshes for circles with a point in the center so 
+#       that the triangles are more regular
+# function faces(::Circle, nvertices=64)
+#     return [GLTriangleFace(nvertices+1, i, mod1(i+1, nvertices)) for i in 1:nvertices]
+# end
 
 
 function coordinates(s::Sphere, nvertices=24)

test/geometrytypes.jl

@@ -183,7 +183,7 @@ end
     @test f == face_target
     circle = Circle(Point2f(0), 1.0f0)
     points = decompose(Point2f, Tesselation(circle, 20))
-    @test length(points) == 21
+    @test length(points) == 20
     tess_circle = Tesselation(circle, 32)
     mesh = triangle_mesh(tess_circle)
     @test decompose(Point2f, mesh) ≈ decompose(Point2f, tess_circle)

test/polygons.jl

@@ -13,14 +13,11 @@
     @test poly1.exterior == decompose(Point2f, rect)
     @test poly1.interiors == [decompose(Point2f, hole)]
 
-    fs = GLTriangleFace[
-        (1, 9, 8), (5, 13, 12), (10, 9, 1), (4, 1, 8), (11, 10, 1), (3, 4, 8), 
-        (12, 11, 1), (3, 8, 7), (12, 1, 2), (3, 7, 6), (5, 12, 2), (2, 3, 6), (6, 5, 2)]
-    @test fs == faces(poly1)
+    # triangulation is inconsistent...
+    @test length(faces(poly1)) == 11
     ps = vcat(decompose(Point2f, rect), decompose(Point2f, hole))
     @test coordinates(poly1) == ps
 
-
     fs = GeometryBasics.earcut_triangulate([poly1.exterior[[1, 2, 3, 4, 1]]])
     @test fs == GLTriangleFace[(4,1,2), (2,3,4)]