Merge branch 'master' into compatibility

src/MeshTools/FullScreenTriangle.cpp

@@ -32,25 +32,28 @@
 
 namespace Magnum { namespace MeshTools {
 
-std::pair<Buffer, Mesh> fullScreenTriangle() {
+std::pair<Buffer*, Mesh> fullScreenTriangle() {
     Mesh mesh;
     mesh.setPrimitive(Mesh::Primitive::Triangles)
         .setVertexCount(3);
 
-    Buffer buffer;
+    Buffer* buffer = nullptr;
     #ifndef MAGNUM_TARGET_GLES
     if(!Context::current()->isVersionSupported(Version::GL300))
     #else
     if(!Context::current()->isVersionSupported(Version::GLES300))
     #endif
     {
+        buffer = new Buffer;
         constexpr Vector2 triangle[] = {
             Vector2(-1.0,  1.0),
             Vector2(-1.0, -3.0),
             Vector2( 3.0,  1.0)
         };
-        buffer.setData(triangle, Buffer::Usage::StaticDraw);
-        mesh.addVertexBuffer(buffer, 0, AbstractShaderProgram::Attribute<0, Vector2>());
+        buffer->setData(triangle, Buffer::Usage::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, AbstractShaderProgram::Attribute<0, Vector2>());
     }
 
     return {std::move(buffer), std::move(mesh)};

src/MeshTools/FullScreenTriangle.h

@@ -52,8 +52,8 @@ computed from them. The vertex positions are, in order:
 On OpenGL 2.1 and OpenGL ES 2.0 the vertex positions are passed explicitly as
 attribute `0`, contained in the buffer. On OpenGL 3.0+ and OpenGL ES 3.0+ the
 mesh is attribute-less and the vertex positions can be computed using
-`gl_VertexID` builtin shader variable, thus the returned vertex buffer is empty
-and basically useless.
+`gl_VertexID` builtin shader variable, thus `nullptr` is returned instead of
+vertex buffer.
 
 Computing positions in vertex shader in a portable way might be done like this.
 For OpenGL 2.1 and OpenGL ES 2.0 you then need to bind the location of `position`
@@ -80,7 +80,7 @@ void main() {
 @attention The implementation needs to check OpenGL version, so it expects
     active context.
 */
-std::pair<Buffer, Mesh> MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle();
+std::pair<Buffer*, Mesh> MAGNUM_MESHTOOLS_EXPORT fullScreenTriangle();
 
 }}