Added separate stencil formats to Renderbuffer.

src/Renderbuffer.h

@@ -68,7 +68,7 @@ class Renderbuffer {
          *
          * Like AbstractTexture::Format without
          * AbstractTexture::Format::RGB9Intensity5, three-component and
-         * compressed formats.
+         * compressed formats, but with added separate stencil index.
          */
         enum class Format: GLenum {
             #ifndef MAGNUM_TARGET_GLES
@@ -93,21 +93,64 @@ class Renderbuffer {
             #endif
 
             #ifndef MAGNUM_TARGET_GLES
-            Depth = GL_DEPTH_COMPONENT, DepthStencil = GL_DEPTH_STENCIL,
+            /**
+             * Depth component, at least 16bit.
+             *
+             * Prefer to use the exactly specified version of this format, in
+             * this case e.g. `Format::%Depth16`.
+             * @requires_gl Use exactly specified format <tt>Format::%Depth16</tt> instead.
+             */
+            Depth = GL_DEPTH_COMPONENT,
+
+            DepthStencil = GL_DEPTH_STENCIL,
             #endif
 
-            Depth16 = GL_DEPTH_COMPONENT16
+            Depth16 = GL_DEPTH_COMPONENT16,
 
             #ifndef MAGNUM_TARGET_GLES
-            ,
-
             Depth24 = GL_DEPTH_COMPONENT24,
             DepthFloat = GL_DEPTH_COMPONENT32F,
+
+            /**
+             * Stencil index (unspecified size).
+             *
+             * Prefer to use the exactly specified version of this format, in
+             * this case e.g. `Format::%Stencil8`.
+             * @requires_gl Use exactly specified format <tt>Format::%Stencil8</tt> instead.
+             */
+            Stencil = GL_STENCIL_INDEX,
+
+            /**
+             * 1-bit stencil index.
+             *
+             * @requires_gl Use <tt>Format::%Stencil8</tt> instead.
+             */
+            Stencil1 = GL_STENCIL_INDEX1,
+
+            /**
+             * 4-bit stencil index.
+             *
+             * @requires_gl Use <tt>Format::%Stencil8</tt> instead.
+             */
+            Stencil4 = GL_STENCIL_INDEX4,
+            #endif
+
+            /** 8-bit stencil index. */
+            Stencil8 = GL_STENCIL_INDEX8
+
+            #ifndef MAGNUM_TARGET_GLES
+            ,
+
+            /**
+             * 16-bit stencil index.
+             *
+             * @requires_gl Use <tt>Format::%Stencil8</tt> instead.
+             */
+            Stencil16 = GL_STENCIL_INDEX1,
+
             Depth24Stencil8 = GL_DEPTH24_STENCIL8,
             DepthFloatStencil8 = GL_DEPTH32F_STENCIL8
             #endif
-
-            /** @todo GL_STENCIL_INDEX1 - GL_STENCIL_INDEX16 (renderbuffer only) */
         };
 
         /** @copydoc AbstractTexture::InternalFormat */