3D textures _are_ available in OpenGL ES 3.0.

doc/opengl-support.dox

@@ -250,6 +250,7 @@ supported.
 @es_extension{OES,depth24}                   | done
 @es_extension{OES,element_index_uint}        | done
 @es_extension{OES,rgb8_rgba8}                | done (desktop-compatible subset)
+@es_extension{OES,texture_3D}                | missing limit query
 @es_extension2{OES,texture_half_float_linear,OES_texture_float_linear} | done
 @es_extension{OES,texture_float_linear}      | done
 @es_extension2{OES,texture_half_float,OES_texture_float} | done
@@ -286,7 +287,6 @@ Only extensions not already listed in above tables are included here.
 @es_extension{OES,mapbuffer}                 | done
 @es_extension{OES,stencil1}                  | done
 @es_extension{OES,stencil4}                  | done
-@es_extension{OES,texture_3D}                | missing limit query
 
 @section opengl-unsupported Unsupported OpenGL features
 

src/Magnum/Context.cpp

@@ -214,8 +214,7 @@ const std::vector<Extension>& Extension::extensions(Version version) {
         _extension(GL,OES,depth32),
         _extension(GL,OES,mapbuffer),
         _extension(GL,OES,stencil1),
-        _extension(GL,OES,stencil4),
+        _extension(GL,OES,stencil4)};
-        _extension(GL,OES,texture_3D)};
     #ifdef MAGNUM_TARGET_GLES2
     static const std::vector<Extension> extensionsES300{
         _extension(GL,ANGLE,framebuffer_blit),
@@ -238,6 +237,7 @@ const std::vector<Extension>& Extension::extensions(Version version) {
         _extension(GL,OES,depth24),
         _extension(GL,OES,element_index_uint),
         _extension(GL,OES,rgb8_rgba8),
+        _extension(GL,OES,texture_3D),
         _extension(GL,OES,texture_half_float_linear),
         _extension(GL,OES,texture_float_linear),
         _extension(GL,OES,texture_half_float),
@@ -468,7 +468,6 @@ Context::Context() {
     _disable(GL,KHR,debug)
     _disable(GL,NV,read_buffer_front)
     _disable(GL,OES,mapbuffer)
-    _disable(GL,OES,texture_3D)
     #ifdef MAGNUM_TARGET_GLES2
     _disable(GL,ANGLE,framebuffer_blit)
     _disable(GL,ANGLE,framebuffer_multisample)
@@ -484,6 +483,7 @@ Context::Context() {
     _disable(GL,NV,fbo_color_attachments) // ??
     _disable(GL,NV,read_buffer)
     _disable(GL,NV,framebuffer_multisample)
+    _disable(GL,OES,texture_3D)
     _disable(GL,OES,vertex_array_object)
     #endif
     #undef _disable

src/Magnum/Extensions.h

@@ -276,8 +276,8 @@ namespace GL {
         #endif
         _extension(GL,OES,stencil1,                 GLES200,    None) // #31
         _extension(GL,OES,stencil4,                 GLES200,    None) // #32
-        _extension(GL,OES,texture_3D,               GLES200,    None) // #34
         #ifdef MAGNUM_TARGET_GLES2
+        _extension(GL,OES,texture_3D,               GLES200, GLES300) // #34
         _extension(GL,OES,texture_half_float_linear, GLES200, GLES300) // #35
         _extension(GL,OES,texture_float_linear,     GLES200, GLES300) // #35
         _extension(GL,OES,texture_half_float,       GLES200, GLES300) // #36