GL: expose Buffer::data()/subData() on WebGL 2.0

Since glGetBufferSubData() is only exposed on Emscripten 2.0.17 and up,
both functions are not available on older versions. This is to avoid any
accidental foot guns since it explodes at compile time. The webgl2 CI
will be upgraded to 2.0.17 in a later commit.

src/Magnum/GL/Buffer.cpp

@@ -329,7 +329,7 @@ Int Buffer::size() {
     return size;
 }
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 Containers::Array<char> Buffer::data() {
     return subData(0, size());
 }
@@ -372,7 +372,7 @@ Buffer& Buffer::flushMappedRange(const GLintptr offset, const GLsizeiptr length)
 bool Buffer::unmap() { return (this->*Context::current().state().buffer.unmapImplementation)(); }
 #endif
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 Containers::Array<char> Buffer::subData(const GLintptr offset, const GLsizeiptr size) {
     Containers::Array<char> data(size);
     if(size) (this->*Context::current().state().buffer.getSubDataImplementation)(offset, size, data);
@@ -468,11 +468,13 @@ void Buffer::getParameterImplementationDSA(const GLenum value, GLint* const data
 }
 #endif
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 void Buffer::getSubDataImplementationDefault(const GLintptr offset, const GLsizeiptr size, GLvoid* const data) {
     glGetBufferSubData(GLenum(bindSomewhereInternal(_targetHint)), offset, size, data);
 }
+#endif
 
+#ifndef MAGNUM_TARGET_GLES
 void Buffer::getSubDataImplementationDSA(const GLintptr offset, const GLsizeiptr size, GLvoid* const data) {
     glGetNamedBufferSubData(_id, offset, size, data);
 }

src/Magnum/GL/Buffer.h

@@ -1089,7 +1089,7 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          */
         Int size();
 
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         /**
          * @brief Buffer data
          *
@@ -1101,9 +1101,11 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          *      eventually @fn_gl{BindBuffer} and @fn_gl{GetBufferParameter}
          *      with @def_gl{BUFFER_SIZE}, then @fn_gl2_keyword{GetNamedBufferSubData,GetBufferSubData},
          *      eventually @fn_gl_keyword{GetBufferSubData}
-         * @requires_gl Buffer data queries are not available in OpenGL ES and
-         *      WebGL. Use @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
-         *      in OpenGL ES instead.
+         * @requires_gl Buffer data queries are not available in OpenGL ES. Use
+         *      @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
+         *      instead.
+         * @requires_webgl20 Buffer data queries are not available in
+         *      WebGL 1.0. Emscripten 2.0.17 or higher is required in WebGL2.
          */
         Containers::Array<char> data();
 
@@ -1119,9 +1121,11 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          * @see @ref size(), @ref data(), @ref setSubData(), @ref setTargetHint(),
          *      @fn_gl2_keyword{GetNamedBufferSubData,GetBufferSubData},
          *      eventually @fn_gl{BindBuffer} and @fn_gl_keyword{GetBufferSubData}
-         * @requires_gl Buffer data queries are not available in OpenGL ES and
-         *      WebGL. Use @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
-         *      in OpenGL ES instead.
+         * @requires_gl Buffer data queries are not available in OpenGL ES. Use
+         *      @ref map(), @ref mapRead() or @ref DebugTools::bufferData() in
+         *      OpenGL ES instead.
+         * @requires_webgl20 Buffer data queries are not available in
+         *      WebGL 1.0. Emscripten 2.0.17 or higher is required in WebGL2.
          */
         Containers::Array<char> subData(GLintptr offset, GLsizeiptr size);
         #endif
@@ -1357,8 +1361,10 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
         void MAGNUM_GL_LOCAL getParameterImplementationDSA(GLenum value, GLint* data);
         #endif
 
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         void MAGNUM_GL_LOCAL getSubDataImplementationDefault(GLintptr offset, GLsizeiptr size, GLvoid* data);
+        #endif
+        #ifndef MAGNUM_TARGET_GLES
         void MAGNUM_GL_LOCAL getSubDataImplementationDSA(GLintptr offset, GLsizeiptr size, GLvoid* data);
         #endif
 

src/Magnum/GL/Implementation/BufferState.cpp

@@ -126,7 +126,7 @@ BufferState::BufferState(Context& context, Containers::StaticArrayView<Implement
         storageImplementation = &Buffer::storageImplementationDefault;
         #endif
         getParameterImplementation = &Buffer::getParameterImplementationDefault;
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         getSubDataImplementation = &Buffer::getSubDataImplementationDefault;
         #endif
         dataImplementation = &Buffer::dataImplementationDefault;

src/Magnum/GL/Implementation/BufferState.h

@@ -59,7 +59,7 @@ struct BufferState {
     void(Buffer::*storageImplementation)(Containers::ArrayView<const void>, Buffer::StorageFlags);
     #endif
     void(Buffer::*getParameterImplementation)(GLenum, GLint*);
-    #ifndef MAGNUM_TARGET_GLES2
+    #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
     void(Buffer::*getSubDataImplementation)(GLintptr, GLsizeiptr, GLvoid*);
     #endif
     void(Buffer::*dataImplementation)(GLsizeiptr, const GLvoid*, BufferUsage);