DebugTools: make bufferData()/bufferSubData() default to Buffer::subData()

This avoids requiring any Desktop GL extensions and allows forwarding to
Buffer::subData() also on WebGL 2.0 (in a follow-up commit)

src/Magnum/DebugTools/BufferData.h

@@ -47,7 +47,8 @@ namespace Implementation {
 @brief Buffer subdata
 
 Emulates @ref GL::Buffer::subData() call on platforms that don't support it
-(such as OpenGL ES) by using @ref GL::Buffer::map().
+(such as OpenGL ES) by using @ref GL::Buffer::mapRead(). On desktop GL it's
+just an alias to @ref GL::Buffer::subData().
 
 @note This function is available only if Magnum is compiled with
     @ref MAGNUM_TARGET_GL "TARGET_GL" enabled (done by default). See
@@ -58,16 +59,23 @@ Emulates @ref GL::Buffer::subData() call on platforms that don't support it
 @requires_gles Buffer mapping is not available in WebGL.
 */
 template<class T> Containers::Array<T> inline bufferSubData(GL::Buffer& buffer, GLintptr offset, GLsizeiptr size) {
+    #ifndef MAGNUM_TARGET_GLES
+    Containers::Array<char> data = buffer.subData(offset, size*sizeof(T));
+    CORRADE_INTERNAL_ASSERT(!data.deleter());
+    return Containers::Array<T>{reinterpret_cast<T*>(data.release()), std::size_t(size)};
+    #else
     Containers::Array<T> data{std::size_t(size)};
     if(size) Implementation::bufferSubData(buffer, offset, size*sizeof(T), data);
     return data;
+    #endif
 }
 
 /**
 @brief Buffer data
 
 Emulates @ref GL::Buffer::data() call on platforms that don't support it (such
-as OpenGL ES) by using @ref GL::Buffer::map().
+as OpenGL ES) by using @ref GL::Buffer::mapRead(). On desktop GL it's just an
+alias to @ref GL::Buffer::data().
 
 @note This function is available only if Magnum is compiled with
     @ref MAGNUM_TARGET_GL "TARGET_GL" enabled (done by default). See

src/Magnum/DebugTools/Test/BufferDataGLTest.cpp

@@ -47,10 +47,7 @@ BufferDataGLTest::BufferDataGLTest() {
 constexpr Int Data[] = {2, 7, 5, 13, 25};
 
 void BufferDataGLTest::data() {
-    #ifndef MAGNUM_TARGET_GLES
-    if(!GL::Context::current().isExtensionSupported<GL::Extensions::ARB::map_buffer_range>())
-        CORRADE_SKIP(GL::Extensions::ARB::map_buffer_range::string() << "is not supported.");
-    #elif defined(MAGNUM_TARGET_GLES2)
+    #ifdef MAGNUM_TARGET_GLES2
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif
@@ -64,10 +61,7 @@ void BufferDataGLTest::data() {
 }
 
 void BufferDataGLTest::subData() {
-    #ifndef MAGNUM_TARGET_GLES
-    if(!GL::Context::current().isExtensionSupported<GL::Extensions::ARB::map_buffer_range>())
-        CORRADE_SKIP(GL::Extensions::ARB::map_buffer_range::string() << "is not supported.");
-    #elif defined(MAGNUM_TARGET_GLES2)
+    #ifdef MAGNUM_TARGET_GLES2
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif