Primitives: textured circle primitive.

doc/changelog.dox

@@ -207,6 +207,11 @@ See also:
     bootstrap project for using Magnum together with wxWidgets (see
     [mosra/magnum-bootstrap#19](https://github.com/mosra/magnum-bootstrap/pull/19))
 
+@subsubsection changelog-latest-new-primitives Primitives library
+
+-   @ref Primitives::circle2DSolid() and @ref Primitives::circle3DSolid()
+    can now generate a textured mesh
+
 @subsubsection changelog-latest-new-scenegraph SceneGraph library
 
 -   Added @ref SceneGraph::AbstractObject::Type /

src/Magnum/Primitives/Circle.cpp

@@ -33,15 +33,21 @@
 
 namespace Magnum { namespace Primitives {
 
-Trade::MeshData2D circle2DSolid(const UnsignedInt segments) {
+Trade::MeshData2D circle2DSolid(const UnsignedInt segments, CircleTextureCoords textureCoords) {
     CORRADE_ASSERT(segments >= 3, "Primitives::circle2DSolid(): segments must be >= 3",
         (Trade::MeshData2D{MeshPrimitive::TriangleFan, {}, {}, {}, {}, nullptr}));
 
     std::vector<Vector2> positions;
     positions.reserve(segments + 2);
 
+    std::vector<std::vector<Vector2>> textureCoordinates;
+    if(textureCoords == CircleTextureCoords::Generate)
+        textureCoordinates.emplace_back();
+
     /* Central point */
     positions.emplace_back();
+    if(textureCoords == CircleTextureCoords::Generate)
+        textureCoordinates.front().emplace_back(0.5f, 0.5f);
 
     /* Points on circle. The first/last point is here twice to close the circle
        properly. */
@@ -49,10 +55,14 @@ Trade::MeshData2D circle2DSolid(const UnsignedInt segments) {
     for(UnsignedInt i = 0; i != segments + 1; ++i) {
         const Rad angle(Float(i)*angleIncrement);
         const std::pair<Float, Float> sincos = Math::sincos(angle);
-        positions.emplace_back(sincos.second, sincos.first);
+        Vector2 position{sincos.second, sincos.first};
+        positions.emplace_back(position);
+
+        if(textureCoords == CircleTextureCoords::Generate)
+            textureCoordinates.front().emplace_back(position*0.5f + Vector2{0.5f});
     }
 
-    return Trade::MeshData2D{MeshPrimitive::TriangleFan, {}, {std::move(positions)}, {}, {}, nullptr};
+    return Trade::MeshData2D{MeshPrimitive::TriangleFan, {}, {std::move(positions)}, std::move(textureCoordinates), {}, nullptr};
 }
 
 Trade::MeshData2D circle2DWireframe(const UnsignedInt segments) {
@@ -73,15 +83,21 @@ Trade::MeshData2D circle2DWireframe(const UnsignedInt segments) {
     return Trade::MeshData2D{MeshPrimitive::LineLoop, {}, {std::move(positions)}, {}, {}, nullptr};
 }
 
-Trade::MeshData3D circle3DSolid(const UnsignedInt segments) {
+Trade::MeshData3D circle3DSolid(const UnsignedInt segments, CircleTextureCoords textureCoords) {
     CORRADE_ASSERT(segments >= 3, "Primitives::circle3DSolid(): segments must be >= 3",
         (Trade::MeshData3D{MeshPrimitive::TriangleFan, {}, {}, {}, {}, {}, nullptr}));
 
     std::vector<Vector3> positions;
     positions.reserve(segments + 2);
 
+    std::vector<std::vector<Vector2>> textureCoordinates;
+    if(textureCoords == CircleTextureCoords::Generate)
+        textureCoordinates.emplace_back();
+
     /* Central point */
     positions.emplace_back();
+    if(textureCoords == CircleTextureCoords::Generate)
+        textureCoordinates.front().emplace_back(0.5f, 0.5f);
 
     /* Points on circle. The first/last point is here twice to close the circle
        properly. */
@@ -89,13 +105,17 @@ Trade::MeshData3D circle3DSolid(const UnsignedInt segments) {
     for(UnsignedInt i = 0; i != segments + 1; ++i) {
         const Rad angle(Float(i)*angleIncrement);
         const std::pair<Float, Float> sincos = Math::sincos(angle);
-        positions.emplace_back(sincos.second, sincos.first, 0.0f);
+        Vector3 position{sincos.second, sincos.first, 0.0f};
+        positions.emplace_back(position);
+
+        if(textureCoords == CircleTextureCoords::Generate)
+            textureCoordinates.front().emplace_back(position.xy()*0.5f + Vector2{0.5f});
     }
 
     /* Normals. All pointing in the same direction. */
     std::vector<Vector3> normals{segments + 2, Vector3::zAxis(1.0f)};
 
-    return Trade::MeshData3D{MeshPrimitive::TriangleFan, {}, {std::move(positions)}, {std::move(normals)}, {}, {}, nullptr};
+    return Trade::MeshData3D{MeshPrimitive::TriangleFan, {}, {std::move(positions)}, {std::move(normals)}, std::move(textureCoordinates), {}, nullptr};
 }
 
 Trade::MeshData3D circle3DWireframe(const UnsignedInt segments) {

src/Magnum/Primitives/Circle.h

@@ -34,9 +34,21 @@
 
 namespace Magnum { namespace Primitives {
 
+/**
+@brief Whether to generate circle texture coordinates
+
+@see @ref circle2DSolid(), @ref circle3DSolid()
+*/
+enum class CircleTextureCoords: UnsignedByte {
+    DontGenerate,       /**< Don't generate texture coordinates */
+    Generate            /**< Generate texture coordinates */
+};
+
 /**
 @brief Solid 2D circle
-@param segments  Number of segments. Must be greater or equal to @cpp 3 @ce.
+@param segments         Number of segments. Must be greater or equal to
+    @cpp 3 @ce.
+@param textureCoords    Whether to generate texture coordinates
 
 Circle with radius @cpp 1.0f @ce. Non-indexed @ref MeshPrimitive::TriangleFan.
 
@@ -44,11 +56,12 @@ Circle with radius @cpp 1.0f @ce. Non-indexed @ref MeshPrimitive::TriangleFan.
 
 @see @ref circle2DWireframe(), @ref circle3DSolid()
 */
-MAGNUM_PRIMITIVES_EXPORT Trade::MeshData2D circle2DSolid(UnsignedInt segments);
+MAGNUM_PRIMITIVES_EXPORT Trade::MeshData2D circle2DSolid(UnsignedInt segments, CircleTextureCoords textureCoords = CircleTextureCoords::DontGenerate);
 
 /**
 @brief Wireframe 2D circle
-@param segments  Number of segments. Must be greater or equal to @cpp 3 @ce.
+@param segments         Number of segments. Must be greater or equal to
+    @cpp 3 @ce.
 
 Circle with radius @cpp 1.0f @ce. Non-indexed @ref MeshPrimitive::LineLoop.
 
@@ -60,7 +73,9 @@ MAGNUM_PRIMITIVES_EXPORT Trade::MeshData2D circle2DWireframe(UnsignedInt segment
 
 /**
 @brief Solid 3D circle
-@param segments  Number of segments. Must be greater or equal to @cpp 3 @ce.
+@param segments         Number of segments. Must be greater or equal to
+    @cpp 3 @ce.
+@param textureCoords    Whether to generate texture coordinates
 
 Circle on the XY plane with radius @cpp 1.0f @ce. Non-indexed
 @ref MeshPrimitive::TriangleFan with normals in positive Z direction.
@@ -69,7 +84,7 @@ Circle on the XY plane with radius @cpp 1.0f @ce. Non-indexed
 
 @see @ref circle3DWireframe(), @ref circle2DSolid()
 */
-MAGNUM_PRIMITIVES_EXPORT Trade::MeshData3D circle3DSolid(UnsignedInt segments);
+MAGNUM_PRIMITIVES_EXPORT Trade::MeshData3D circle3DSolid(UnsignedInt segments, CircleTextureCoords textureCoords = CircleTextureCoords::DontGenerate);
 
 /**
 @brief Wireframe 3D circle

src/Magnum/Primitives/Test/CircleTest.cpp

@@ -38,14 +38,22 @@ struct CircleTest: TestSuite::Tester {
     explicit CircleTest();
 
     void solid2D();
+    void solid2DTextureCoords();
+
     void solid3D();
+    void solid3DTextureCoords();
+
     void wireframe2D();
     void wireframe3D();
 };
 
 CircleTest::CircleTest() {
     addTests({&CircleTest::solid2D,
+              &CircleTest::solid2DTextureCoords,
+
               &CircleTest::solid3D,
+              &CircleTest::solid3DTextureCoords,
+
               &CircleTest::wireframe2D,
               &CircleTest::wireframe3D});
 }
@@ -63,6 +71,31 @@ void CircleTest::solid2D() {
         { 0.0f, -1.0f}, { Constants::sqrt2()/2.0f, -Constants::sqrt2()/2.0f},
         { 1.0f,  0.0f}
     }), TestSuite::Compare::Container);
+    CORRADE_COMPARE(circle.textureCoords2DArrayCount(), 0);
+}
+
+void CircleTest::solid2DTextureCoords() {
+    Trade::MeshData2D circle = Primitives::circle2DSolid(8, Primitives::CircleTextureCoords::Generate);
+
+    CORRADE_VERIFY(!circle.isIndexed());
+    CORRADE_COMPARE(circle.primitive(), MeshPrimitive::TriangleFan);
+    CORRADE_COMPARE_AS(circle.positions(0), (std::vector<Vector2>{
+        { 0.0f,  0.0f},
+        { 1.0f,  0.0f}, { Constants::sqrt2()/2.0f,  Constants::sqrt2()/2.0f},
+        { 0.0f,  1.0f}, {-Constants::sqrt2()/2.0f,  Constants::sqrt2()/2.0f},
+        {-1.0f,  0.0f}, {-Constants::sqrt2()/2.0f, -Constants::sqrt2()/2.0f},
+        { 0.0f, -1.0f}, { Constants::sqrt2()/2.0f, -Constants::sqrt2()/2.0f},
+        { 1.0f,  0.0f}
+    }), TestSuite::Compare::Container);
+    CORRADE_COMPARE(circle.textureCoords2DArrayCount(), 1);
+    CORRADE_COMPARE_AS(circle.textureCoords2D(0), (std::vector<Vector2>{
+        {0.5f, 0.5f},
+        {1.0f, 0.5f}, {0.5f + Constants::sqrt2()/4.0f, 0.5f + Constants::sqrt2()/4.0f},
+        {0.5f, 1.0f}, {0.5f - Constants::sqrt2()/4.0f, 0.5f + Constants::sqrt2()/4.0f},
+        {0.0f, 0.5f}, {0.5f - Constants::sqrt2()/4.0f, 0.5f - Constants::sqrt2()/4.0f},
+        {0.5f, 0.0f}, {0.5f + Constants::sqrt2()/4.0f, 0.5f - Constants::sqrt2()/4.0f},
+        {1.0f, 0.5f}
+    }), TestSuite::Compare::Container);
 }
 
 void CircleTest::solid3D() {
@@ -90,6 +123,43 @@ void CircleTest::solid3D() {
         { 0.0f,  0.0f, 1.0f},
         { 0.0f,  0.0f, 1.0f}
     }), TestSuite::Compare::Container);
+    CORRADE_COMPARE(circle.textureCoords2DArrayCount(), 0);
+}
+
+void CircleTest::solid3DTextureCoords() {
+    Trade::MeshData3D circle = Primitives::circle3DSolid(8, Primitives::CircleTextureCoords::Generate);
+
+    CORRADE_VERIFY(!circle.isIndexed());
+    CORRADE_COMPARE(circle.primitive(), MeshPrimitive::TriangleFan);
+    CORRADE_COMPARE_AS(circle.positions(0), (std::vector<Vector3>{
+        { 0.0f,  0.0f, 0.0f},
+        { 1.0f,  0.0f, 0.0f}, { Constants::sqrt2()/2.0f,  Constants::sqrt2()/2.0f, 0.0f},
+        { 0.0f,  1.0f, 0.0f}, {-Constants::sqrt2()/2.0f,  Constants::sqrt2()/2.0f, 0.0f},
+        {-1.0f,  0.0f, 0.0f}, {-Constants::sqrt2()/2.0f, -Constants::sqrt2()/2.0f, 0.0f},
+        { 0.0f, -1.0f, 0.0f}, { Constants::sqrt2()/2.0f, -Constants::sqrt2()/2.0f, 0.0f},
+        { 1.0f,  0.0f, 0.0f}
+    }), TestSuite::Compare::Container);
+    CORRADE_COMPARE_AS(circle.normals(0), (std::vector<Vector3>{
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f},
+        { 0.0f,  0.0f, 1.0f}
+    }), TestSuite::Compare::Container);
+    CORRADE_COMPARE(circle.textureCoords2DArrayCount(), 1);
+    CORRADE_COMPARE_AS(circle.textureCoords2D(0), (std::vector<Vector2>{
+        {0.5f, 0.5f},
+        {1.0f, 0.5f}, {0.5f + Constants::sqrt2()/4.0f, 0.5f + Constants::sqrt2()/4.0f},
+        {0.5f, 1.0f}, {0.5f - Constants::sqrt2()/4.0f, 0.5f + Constants::sqrt2()/4.0f},
+        {0.0f, 0.5f}, {0.5f - Constants::sqrt2()/4.0f, 0.5f - Constants::sqrt2()/4.0f},
+        {0.5f, 0.0f}, {0.5f + Constants::sqrt2()/4.0f, 0.5f - Constants::sqrt2()/4.0f},
+        {1.0f, 0.5f}
+    }), TestSuite::Compare::Container);
 }
 
 void CircleTest::wireframe2D() {