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.cpp

@@ -26,10 +26,13 @@
 #include "BufferData.h"
 
 #include <Corrade/Containers/Array.h>
-#include <Corrade/Utility/Algorithms.h>
 
 #include "Magnum/GL/Buffer.h"
 
+#if defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_BUILD_DEPRECATED)
+#include <Corrade/Utility/Algorithms.h>
+#endif
+
 namespace Magnum { namespace DebugTools {
 
 #ifdef MAGNUM_BUILD_DEPRECATED
@@ -46,12 +49,16 @@ void bufferSubData(GL::Buffer& buffer, GLintptr offset, GLsizeiptr size, void* o
 #endif
 
 Containers::Array<char> bufferSubData(GL::Buffer& buffer, GLintptr offset, GLsizeiptr size) {
+    #ifndef MAGNUM_TARGET_GLES
+    return buffer.subData(offset, size);
+    #else
     Containers::Array<char> data{NoInit, std::size_t(size)};
     if(size) {
         Utility::copy(buffer.mapRead(offset, size), data);
         buffer.unmap();
     }
     return data;
+    #endif
 }
 
 Containers::Array<char> bufferData(GL::Buffer& buffer) {

src/Magnum/DebugTools/BufferData.h

@@ -60,13 +60,13 @@ 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
     @ref building-features for more information.
 
-@requires_gl30 Extension @gl_extension{ARB,map_buffer_range}
 @requires_gles30 Extension @gl_extension{EXT,map_buffer_range} in OpenGL ES
     2.0.
 @requires_gles Buffer mapping is not available in WebGL.
@@ -97,13 +97,13 @@ template<class T> CORRADE_DEPRECATED("use non-templated bufferSubData() and Cont
 @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
     @ref building-features for more information.
 
-@requires_gl30 Extension @gl_extension{ARB,map_buffer_range}
 @requires_gles30 Extension @gl_extension{EXT,map_buffer_range} in OpenGL ES
     2.0.
 @requires_gles Buffer mapping is not available in WebGL.

src/Magnum/DebugTools/Test/BufferDataGLTest.cpp

@@ -49,10 +49,7 @@ BufferDataGLTest::BufferDataGLTest() {
 constexpr Int Data[] = {2, 7, 5, 13, 25};
 
 void BufferDataGLTest::data() {
-    #ifndef MAGNUM_TARGET_GLES
+    #ifdef MAGNUM_TARGET_GLES2
-    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)
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif
@@ -68,10 +65,7 @@ void BufferDataGLTest::data() {
 }
 
 void BufferDataGLTest::subData() {
-    #ifndef MAGNUM_TARGET_GLES
+    #ifdef MAGNUM_TARGET_GLES2
-    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)
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif