Neither multisample nor rectangle textures have mip levels.

Removed superfluous level parameter from related
Framebuffer::attachTexture{,Layer}() overloads (which should otherwise
be always set to 0).

src/Magnum/Framebuffer.cpp

@@ -186,13 +186,13 @@ Framebuffer& Framebuffer::attachTexture(const BufferAttachment attachment, Textu
 }
 
 #ifndef MAGNUM_TARGET_GLES
-Framebuffer& Framebuffer::attachTexture(const BufferAttachment attachment, RectangleTexture& texture, const Int level) {
-    (this->*Context::current()->state().framebuffer->texture2DImplementation)(attachment, GL_TEXTURE_RECTANGLE, texture.id(), level);
+Framebuffer& Framebuffer::attachTexture(const BufferAttachment attachment, RectangleTexture& texture) {
+    (this->*Context::current()->state().framebuffer->texture2DImplementation)(attachment, GL_TEXTURE_RECTANGLE, texture.id(), 0);
     return *this;
 }
 
-Framebuffer& Framebuffer::attachTexture(const BufferAttachment attachment, MultisampleTexture2D& texture, const Int level) {
-    (this->*Context::current()->state().framebuffer->texture2DImplementation)(attachment, GL_TEXTURE_2D_MULTISAMPLE, texture.id(), level);
+Framebuffer& Framebuffer::attachTexture(const BufferAttachment attachment, MultisampleTexture2D& texture) {
+    (this->*Context::current()->state().framebuffer->texture2DImplementation)(attachment, GL_TEXTURE_2D_MULTISAMPLE, texture.id(), 0);
     return *this;
 }
 #endif
@@ -227,8 +227,8 @@ Framebuffer& Framebuffer::attachTextureLayer(Framebuffer::BufferAttachment attac
     return *this;
 }
 
-Framebuffer& Framebuffer::attachTextureLayer(Framebuffer::BufferAttachment attachment, MultisampleTexture2DArray& texture, Int level, Int layer) {
-    (this->*Context::current()->state().framebuffer->textureLayerImplementation)(attachment, texture.id(), level, layer);
+Framebuffer& Framebuffer::attachTextureLayer(Framebuffer::BufferAttachment attachment, MultisampleTexture2DArray& texture, Int layer) {
+    (this->*Context::current()->state().framebuffer->textureLayerImplementation)(attachment, texture.id(), 0, layer);
     return *this;
 }
 #endif

src/Magnum/Framebuffer.h

@@ -522,13 +522,13 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
          * @requires_gl31 %Extension @extension{ARB,texture_rectangle}
          * @requires_gl Rectangle textures are not available in OpenGL ES.
          */
-        Framebuffer& attachTexture(BufferAttachment attachment, RectangleTexture& texture, Int level);
+        Framebuffer& attachTexture(BufferAttachment attachment, RectangleTexture& texture);
 
         /** @overload
          * @requires_gl32 %Extension @extension{ARB,texture_multisample}
          * @requires_gl Multisample textures are not available in OpenGL ES.
          */
-        Framebuffer& attachTexture(BufferAttachment attachment, MultisampleTexture2D& texture, Int level);
+        Framebuffer& attachTexture(BufferAttachment attachment, MultisampleTexture2D& texture);
         #endif
 
         /**
@@ -594,7 +594,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
          * @requires_gl32 %Extension @extension{ARB,texture_multisample}
          * @requires_gl Multisample textures are not available in OpenGL ES.
          */
-        Framebuffer& attachTextureLayer(BufferAttachment attachment, MultisampleTexture2DArray& texture, Int level, Int layer);
+        Framebuffer& attachTextureLayer(BufferAttachment attachment, MultisampleTexture2DArray& texture, Int layer);
         #endif
 
         #ifdef MAGNUM_BUILD_DEPRECATED

src/Magnum/Test/FramebufferGLTest.cpp

@@ -486,8 +486,8 @@ void FramebufferGLTest::attachRectangleTexture() {
     depthStencil.setStorage(TextureFormat::Depth24Stencil8, Vector2i(128));
 
     Framebuffer framebuffer({{}, Vector2i(128)});
-    framebuffer.attachTexture(Framebuffer::ColorAttachment(0), color, 0)
-               .attachTexture(Framebuffer::BufferAttachment::DepthStencil, depthStencil, 0);
+    framebuffer.attachTexture(Framebuffer::ColorAttachment(0), color)
+               .attachTexture(Framebuffer::BufferAttachment::DepthStencil, depthStencil);
 
     MAGNUM_VERIFY_NO_ERROR();
     CORRADE_COMPARE(framebuffer.checkStatus(FramebufferTarget::ReadDraw), Framebuffer::Status::Complete);