MeshTools: return just a mesh from fullScreenTriangle().

Backwards-incompatible change, sorry.

doc/changelog.dox

@@ -186,6 +186,10 @@ See also:
 
 @subsection changelog-latest-compatibility Potential compatibility breakages, removed APIs
 
+-   The @ref MeshTools::fullScreenTriangle() function now returns just a
+    @ref GL::Mesh instead of @ref std::pair of a mesh and a buffer, as the
+    buffer is now owned by the mesh. This change was not possible to be done in
+    a backwards-compatible way.
 -   Removed deprecated implicit conversion @ref Corrade::Containers::Optional
     to @cpp std::optional @ce, deprecated in January 2018. The class now
     contains an *explicit* and opt-in STL compatibility, see its documentation

src/Magnum/MeshTools/FullScreenTriangle.cpp

@@ -34,34 +34,31 @@
 
 namespace Magnum { namespace MeshTools {
 
-std::pair<std::unique_ptr<GL::Buffer>, GL::Mesh> fullScreenTriangle(GL::Version version) {
+GL::Mesh fullScreenTriangle(const GL::Version version) {
     GL::Mesh mesh;
     mesh.setPrimitive(GL::MeshPrimitive::Triangles)
         .setCount(3);
 
-    std::unique_ptr<GL::Buffer> buffer;
     #ifndef MAGNUM_TARGET_GLES
     if(version < GL::Version::GL300)
     #else
     if(version < GL::Version::GLES300)
     #endif
     {
-        buffer.reset(new GL::Buffer);
-        constexpr Vector2 triangle[] = {
+        constexpr Vector2 triangle[]{
             {-1.0f,  1.0f},
             {-1.0f, -3.0f},
             { 3.0f,  1.0f}
         };
-        buffer->setData(triangle, GL::BufferUsage::StaticDraw);
-        /** @todo Is it possible to attach moveable buffer here to avoid heap
-           allocation? OTOH this is more effective in most (modern) cases */
-        mesh.addVertexBuffer(*buffer, 0, GL::Attribute<0, Vector2>{});
+        GL::Buffer buffer{GL::Buffer::TargetHint::Array};
+        buffer.setData(triangle, GL::BufferUsage::StaticDraw);
+        mesh.addVertexBuffer(std::move(buffer), 0, GL::Attribute<0, Vector2>{});
     }
 
-    return {std::move(buffer), std::move(mesh)};
+    return mesh;
 }
 
-std::pair<std::unique_ptr<GL::Buffer>, GL::Mesh> fullScreenTriangle() {
+GL::Mesh fullScreenTriangle() {
     return fullScreenTriangle(GL::Context::current().version());
 }
 

src/Magnum/MeshTools/FullScreenTriangle.h

@@ -34,9 +34,6 @@
 #include "Magnum/configure.h"
 
 #ifdef MAGNUM_TARGET_GL
-#include <memory>
-#include <utility>
-
 #include "Magnum/GL/GL.h"
 #include "Magnum/MeshTools/visibility.h"
 
@@ -89,7 +86,7 @@ void main() {
     @ref MAGNUM_TARGET_GL enabled (done by default). See @ref building-features
     for more information.
 */
-std::pair<std::unique_ptr<GL::Buffer>, GL::Mesh> MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle(GL::Version version);
+GL::Mesh MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle(GL::Version version);
 
 /** @overload
 
@@ -99,7 +96,7 @@ This function implicitly uses current context version.
     @ref MAGNUM_TARGET_GL enabled (done by default). See @ref building-features
     for more information.
 */
-std::pair<std::unique_ptr<GL::Buffer>, GL::Mesh> MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle();
+GL::Mesh MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle();
 #else
 #error this header is available only in the OpenGL build
 #endif