Primitives: use half length also in Cylinder primitive.

Everything is now consistent.

src/Primitives/Cylinder.cpp

@@ -31,27 +31,27 @@
 
 namespace Magnum { namespace Primitives {
 
-Trade::MeshData3D Cylinder::solid(UnsignedInt rings, UnsignedInt segments, Float length, Cylinder::Flags flags) {
+Trade::MeshData3D Cylinder::solid(const UnsignedInt rings, const UnsignedInt segments, const Float halfLength, const Flags flags) {
     CORRADE_ASSERT(rings >= 1 && segments >= 3, "Primitives::Cylinder::solid(): cylinder must have at least one ring and three segments", Trade::MeshData3D(Mesh::Primitive::Triangles, {}, {}, {}, {}));
 
     Implementation::Spheroid cylinder(segments, flags & Flag::GenerateTextureCoords ? Implementation::Spheroid::TextureCoords::Generate : Implementation::Spheroid::TextureCoords::DontGenerate);
 
-    Float y = length*0.5f;
-    Float textureCoordsV = flags & Flag::CapEnds ? 1.0f/(length+2.0f) : 0.0f;
+    const Float length = 2.0f*halfLength;
+    const Float textureCoordsV = flags & Flag::CapEnds ? 1.0f/(length+2.0f) : 0.0f;
 
     /* Bottom cap */
     if(flags & Flag::CapEnds) {
-        cylinder.capVertex(-y, -1.0f, 0.0f);
-        cylinder.capVertexRing(-y, textureCoordsV, Vector3::yAxis(-1.0f));
+        cylinder.capVertex(-halfLength, -1.0f, 0.0f);
+        cylinder.capVertexRing(-halfLength, textureCoordsV, Vector3::yAxis(-1.0f));
     }
 
     /* Vertex rings */
-    cylinder.cylinderVertexRings(rings+1, -y, length/rings, textureCoordsV, length/(rings*(flags & Flag::CapEnds ? length + 2.0f : length)));
+    cylinder.cylinderVertexRings(rings+1, -halfLength, length/rings, textureCoordsV, length/(rings*(flags & Flag::CapEnds ? length + 2.0f : length)));
 
     /* Top cap */
     if(flags & Flag::CapEnds) {
-        cylinder.capVertexRing(y, 1.0f - textureCoordsV, Vector3::yAxis(1.0f));
-        cylinder.capVertex(y, 1.0f, 1.0f);
+        cylinder.capVertexRing(halfLength, 1.0f - textureCoordsV, Vector3::yAxis(1.0f));
+        cylinder.capVertex(halfLength, 1.0f, 1.0f);
     }
 
     /* Faces */
@@ -62,16 +62,18 @@ Trade::MeshData3D Cylinder::solid(UnsignedInt rings, UnsignedInt segments, Float
     return cylinder.finalize();
 }
 
-Trade::MeshData3D Cylinder::wireframe(const UnsignedInt rings, const UnsignedInt segments, const Float length) {
+Trade::MeshData3D Cylinder::wireframe(const UnsignedInt rings, const UnsignedInt segments, const Float halfLength) {
     CORRADE_ASSERT(rings >= 1 && segments >= 4 && segments%4 == 0, "Primitives::Cylinder::wireframe(): improper parameters", Trade::MeshData3D(Mesh::Primitive::Lines, {}, {}, {}, {}));
 
     Implementation::WireframeSpheroid cylinder(segments/4);
 
+    const Float increment = 2*halfLength/rings;
+
     /* Rings */
-    cylinder.ring(-length/2);
+    cylinder.ring(-halfLength);
     for(UnsignedInt i = 0; i != rings; ++i) {
         cylinder.cylinder();
-        cylinder.ring(-length/2 + (i+1)*(length/rings));
+        cylinder.ring(-halfLength + (i+1)*increment);
     }
 
     return cylinder.finalize();

src/Primitives/Cylinder.h

@@ -62,7 +62,7 @@ class MAGNUM_PRIMITIVES_EXPORT Cylinder {
          *      equal to 1.
          * @param segments      Number of (face) segments. Must be larger or
          *      equal to 3.
-         * @param length        Cylinder length
+         * @param halfLength    Half the cylinder length
          * @param flags         Flags
          *
          * Indexed @ref Mesh::Primitive "Triangles" with normals, optional 2D
@@ -70,7 +70,7 @@ class MAGNUM_PRIMITIVES_EXPORT Cylinder {
          * are generated, vertices of one segment are duplicated for texture
          * wrapping.
          */
-        static Trade::MeshData3D solid(UnsignedInt rings, UnsignedInt segments, Float length, Flags flags = Flags());
+        static Trade::MeshData3D solid(UnsignedInt rings, UnsignedInt segments, Float halfLength, Flags flags = Flags());
 
         /**
          * @brief Wireframe cylinder
@@ -78,11 +78,11 @@ class MAGNUM_PRIMITIVES_EXPORT Cylinder {
          *      to 1.
          * @param segments      Number of (line) segments. Must be larger or
          *      equal to 4 and multiple of 4.
-         * @param length        Cylinder length
+         * @param halfLength    Half the cylinder length
          *
          * Indexed @ref Mesh::Primitive "Lines".
          */
-        static Trade::MeshData3D wireframe(UnsignedInt rings, UnsignedInt segments, Float length);
+        static Trade::MeshData3D wireframe(UnsignedInt rings, UnsignedInt segments, Float halfLength);
 };
 
 CORRADE_ENUMSET_OPERATORS(Cylinder::Flags)

src/Primitives/Test/CylinderTest.cpp

@@ -47,7 +47,7 @@ CylinderTest::CylinderTest() {
 }
 
 void CylinderTest::solidWithoutAnything() {
-    Trade::MeshData3D cylinder = Cylinder::solid(2, 3, 3.0f);
+    Trade::MeshData3D cylinder = Cylinder::solid(2, 3, 1.5f);
 
     CORRADE_COMPARE_AS(cylinder.positions(0), (std::vector<Vector3>{
         {0.0f, -1.5f, 1.0f},
@@ -84,7 +84,7 @@ void CylinderTest::solidWithoutAnything() {
 }
 
 void CylinderTest::solidWithTextureCoordsAndCaps() {
-    Trade::MeshData3D cylinder = Cylinder::solid(2, 3, 3.0f, Cylinder::Flag::GenerateTextureCoords|Cylinder::Flag::CapEnds);
+    Trade::MeshData3D cylinder = Cylinder::solid(2, 3, 1.5f, Cylinder::Flag::GenerateTextureCoords|Cylinder::Flag::CapEnds);
 
     CORRADE_COMPARE_AS(cylinder.positions(0), (std::vector<Vector3>{
         {0.0f, -1.5f, 0.0f},
@@ -188,7 +188,7 @@ void CylinderTest::solidWithTextureCoordsAndCaps() {
 }
 
 void CylinderTest::wireframe() {
-    Trade::MeshData3D cylinder = Cylinder::wireframe(2, 8, 1.0f);
+    Trade::MeshData3D cylinder = Cylinder::wireframe(2, 8, 0.5f);
 
     CORRADE_COMPARE_AS(cylinder.positions(0), (std::vector<Vector3>{
         {0.0f, -0.5f, 1.0f},