Documented required OpenGL version for some functionality.

The requirements are cross-referenced to dedicated page, similarly to
TODO and bug lists.

Also updated / improved documentation for some texture / image formats.

Doxyfile

@@ -193,7 +193,14 @@ TAB_SIZE               = 8
 # will result in a user-defined paragraph with heading "Side Effects:".
 # You can put \n's in the value part of an alias to insert newlines.
 
-ALIASES                =
+ALIASES                = \
+    "requires_gl30=@xrefitem RequiresGL30 \"Requires OpenGL 3.0\" \"Functionality requiring OpenGL 3.0\"" \
+    "requires_gl31=@xrefitem RequiresGL31 \"Requires OpenGL 3.1\" \"Functionality requiring OpenGL 3.1\"" \
+    "requires_gl32=@xrefitem RequiresGL32 \"Requires OpenGL 3.2\" \"Functionality requiring OpenGL 3.2\"" \
+    "requires_gl33=@xrefitem RequiresGL33 \"Requires OpenGL 3.3\" \"Functionality requiring OpenGL 3.3\"" \
+    "requires_gl40=@xrefitem RequiresGL40 \"Requires OpenGL 4.0\" \"Functionality requiring OpenGL 4.0\"" \
+    "requires_gl41=@xrefitem RequiresGL41 \"Requires OpenGL 4.1\" \"Functionality requiring OpenGL 4.1\"" \
+    "requires_gl42=@xrefitem RequiresGL42 \"Requires OpenGL 4.2\" \"Functionality requiring OpenGL 4.2\""
 
 # This tag can be used to specify a number of word-keyword mappings (TCL only).
 # A mapping has the form "name=value". For example adding

doc/MainPage.dox

@@ -16,6 +16,10 @@ Features:
   Collection of pre-made @ref Primitives "graphic primitives" and
   @ref Shaders "shaders" for testing purposes.
 
+The engine is meant to be run on OpenGL 3 capable hardware, but most of the
+functionality is working on OpenGL 2.1 hardware too. See also
+@ref RequiredExtensions.
+
 @section BuildingLink Building Magnum
 
 Guide @ref Building "how to build Magnum" on different platforms.

doc/RequiredExtensions.dox

@@ -0,0 +1,28 @@
+/** @page RequiredExtensions Functionality requiring specific OpenGL version or extensions
+
+The engine is meant to be run on OpenGL 3 capable hardware, but most of the
+functionality is working in OpenGL 2.1 hardware too (i.e. integrated Intel
+GPUs), unless stated otherwise. Following are lists of functionality requiring
+specific OpenGL version. In most cases it is also specified which extension is
+required for given functionality, so if given hardware supports required
+extension, it doesn't need to have required OpenGL version too (e.g.
+`APPLE_vertex_array_object` is supported on Intel GPUs even if they are
+capable of OpenGL 2.1 only).
+
+- @subpage RequiresGL30
+- @subpage RequiresGL31
+- @subpage RequiresGL32
+- @subpage RequiresGL33
+- @subpage RequiresGL40
+- @subpage RequiresGL41
+- @subpage RequiresGL42
+
+@page RequiresGL30 Functionality requiring OpenGL 3.0
+@page RequiresGL31 Functionality requiring OpenGL 3.1
+@page RequiresGL32 Functionality requiring OpenGL 3.2
+@page RequiresGL33 Functionality requiring OpenGL 3.3
+@page RequiresGL40 Functionality requiring OpenGL 4.0
+@page RequiresGL41 Functionality requiring OpenGL 4.1
+@page RequiresGL42 Functionality requiring OpenGL 4.2
+
+*/

src/AbstractImage.h

@@ -67,7 +67,11 @@ class MAGNUM_EXPORT AbstractImage {
             /** Stencil index. For framebuffer reading only. */
             StencilIndex = GL_STENCIL_INDEX,
 
-            /** Depth and stencil component. For framebuffer reading only. */
+            /**
+             * Depth and stencil component. For framebuffer reading only.
+             *
+             * @requires_gl30 Extension <tt>EXT_packed_depth_stencil</tt>
+             */
             DepthStencil = GL_DEPTH_STENCIL
         };
 
@@ -80,7 +84,11 @@ class MAGNUM_EXPORT AbstractImage {
             UnsignedInt = GL_UNSIGNED_INT,  /**< Each component unsigned int */
             Int = GL_INT,                   /**< Each component int */
 
-            /** Each component half float (16bit). For framebuffer reading only. */
+            /**
+             * Each component half float (16bit). For framebuffer reading only.
+             *
+             * @requires_gl30 Extension <tt>NV_half_float</tt> / <tt>ARB_half_float_pixel</tt>
+             */
             HalfFloat = GL_HALF_FLOAT,
 
             Float = GL_FLOAT,               /**< Each component float (32bit) */
@@ -160,6 +168,8 @@ class MAGNUM_EXPORT AbstractImage {
             /**
              * Three-component BGR, float, red and green 11bit, blue 10bit,
              * 32bit total. For framebuffer reading only.
+             *
+             * @requires_gl30 Extension <tt>EXT_packed_float</tt>
              */
             B10GR11Float = GL_UNSIGNED_INT_10F_11F_11F_REV,
 
@@ -167,18 +177,24 @@ class MAGNUM_EXPORT AbstractImage {
              * Three-component BGR, unsigned integers with exponent, each
              * component 9bit, exponent 5bit, 32bit total. For framebuffer
              * reading only.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_shared_exponent</tt>
              */
             Exponent5RGB9 = GL_UNSIGNED_INT_5_9_9_9_REV,
 
             /**
              * 24bit depth and 8bit stencil component, 32bit total. For
              * framebuffer reading only.
+             *
+             * @requires_gl30 Extension <tt>EXT_packed_depth_stencil</tt>
              */
             Depth24Stencil8 = GL_UNSIGNED_INT_24_8,
 
             /**
              * 32bit float depth component and 8bit stencil component, 64bit
              * total. For framebuffer reading only.
+             *
+             * @requires_gl30 Extension <tt>ARB_depth_buffer_float</tt>
              */
             Depth32FloatStencil8 = GL_FLOAT_32_UNSIGNED_INT_24_8_REV
         };

src/AbstractShaderProgram.h

@@ -154,6 +154,8 @@ class MAGNUM_EXPORT AbstractShaderProgram {
          *
          * @note This function should be called between loadShader() calls
          * and link().
+         *
+         * @requires_gl30 Extension <tt>EXT_gpu_shader4</tt>
          */
         void bindFragmentDataLocation(GLuint location, const std::string& name);
 
@@ -184,7 +186,11 @@ class MAGNUM_EXPORT AbstractShaderProgram {
             glUniform1i(location, value);
         }
 
-        /** @copydoc setUniform(GLint, GLint) */
+        /**
+         * @copydoc setUniform(GLint, GLint)
+         *
+         * @requires_gl30 Extension <tt>EXT_gpu_shader4</tt>
+         */
         void setUniform(GLint location, GLuint value) {
             glUniform1ui(location, value);
         }

src/AbstractTexture.h

@@ -116,14 +116,61 @@ class MAGNUM_EXPORT AbstractTexture {
 
         /** @brief Type of data per each component */
         enum class ComponentType {
-            UnsignedByte,   /**< Unsigned byte (char) */
+            /**
-            Byte,           /**< Byte (char) */
+             * (Non-normalized) unsigned byte
-            UnsignedShort,  /**< Unsigned short */
+             *
-            Short,          /**< Short */
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
-            UnsignedInt,    /**< Unsigned integer */
+             */
-            Int,            /**< Integer */
+            UnsignedByte,
-            Half,           /**< Half float (16 bit) */
+
-            Float,          /**< Float (32 bit) */
+            /**
+             * (Non-normalized) byte
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
+             */
+            Byte,
+
+            /**
+             * (Non-normalized) unsigned short
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
+             */
+            UnsignedShort,
+
+            /**
+             * (Non-normalized) short
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
+             */
+            Short,
+
+            /**
+             * (Non-normalized) unsigned integer
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
+             */
+            UnsignedInt,
+
+            /**
+             * (Non-normalized) integer
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_integer</tt>
+             */
+            Int,
+
+            /**
+             * Half float (16 bit)
+             *
+             * @requires_gl30 Extension <tt>ARB_texture_float</tt>
+             */
+            Half,
+
+            /**
+             * Float (32 bit)
+             *
+             * @requires_gl30 Extension <tt>ARB_texture_float</tt>
+             */
+            Float,
 
             /**
              * Normalized unsigned byte, i.e. values from range
@@ -134,6 +181,8 @@ class MAGNUM_EXPORT AbstractTexture {
             /**
              * Normalized byte, i.e. values from range
              * @f$ [-128; 127] @f$ are converted to range @f$ [0.0; 1.0] @f$.
+             *
+             * @requires_gl31 (no extension providing this functionality)
              */
             NormalizedByte,
 
@@ -146,6 +195,8 @@ class MAGNUM_EXPORT AbstractTexture {
             /**
              * Normalized short, i.e. values from range
              * @f$ [-32768; 32767] @f$ are converted to range @f$ [0.0; 1.0] @f$.
+             *
+             * @requires_gl31 (no extension providing this functionality)
              */
             NormalizedShort
         };
@@ -160,12 +211,16 @@ class MAGNUM_EXPORT AbstractTexture {
             /**
              * One-component (red channel), unsigned normalized, probably
              * 8bit.
+             *
+             * @requires_gl30 (no extension providing this functionality)
              */
             Red = GL_RED,
 
             /**
              * Two-component (red and green channel), unsigned normalized,
              * each component probably 8bit, 16bit total.
+             *
+             * @requires_gl30 (no extension providing this functionality)
              */
             RedGreen = GL_RG,
 
@@ -212,8 +267,10 @@ class MAGNUM_EXPORT AbstractTexture {
             RGB10Alpha2 = GL_RGB10_A2,
 
             /**
-             * Four-component RGBA, unsigned integers, each RGB component
+             * Four-component RGBA, unsigned non-normalized, each RGB
-             * 10bit, alpha channel 2bit, 32bit total.
+             * component 10bit, alpha channel 2bit, 32bit total.
+             *
+             * @requires_gl33 Extension <tt>ARB_texture_rgb10_a2ui</tt>
              */
             RGB10Alpha2Unsigned = GL_RGB10_A2UI,
 
@@ -232,6 +289,8 @@ class MAGNUM_EXPORT AbstractTexture {
             /**
              * Three-component RGB, float, red and green 11bit, blue 10bit,
              * 32bit total.
+             *
+             * @requires_gl30 Extension <tt>EXT_packed_float</tt>
              */
             RG11B10Float = GL_R11F_G11F_B10F,
 
@@ -244,8 +303,10 @@ class MAGNUM_EXPORT AbstractTexture {
             #endif
 
             /**
-             * Three-component RGB, unsigned integers with exponent, each
+             * Three-component RGB, unsigned with exponent, each component
-             * component 9bit, exponent 5bit, 32bit total.
+             * 9bit, exponent 5bit, 32bit total.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_shared_exponent</tt>
              */
             RGB9Exponent5 = GL_RGB9_E5,
 
@@ -261,29 +322,61 @@ class MAGNUM_EXPORT AbstractTexture {
             /** Compressed RGBA, unsigned normalized. */
             CompressedRGBA = GL_COMPRESSED_RGBA,
 
-            /** RTGC compressed red channel, unsigned normalized. */
+            /**
+             * RTGC compressed red channel, unsigned normalized.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_compression_rgtc</tt>
+             */
             CompressedRtgcRed = GL_COMPRESSED_RED_RGTC1,
 
-            /** RTGC compressed red channel, signed normalized. */
+            /**
+             * RTGC compressed red channel, signed normalized.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_compression_rgtc</tt>
+             */
             CompressedRtgcSignedRed = GL_COMPRESSED_SIGNED_RED_RGTC1,
 
-            /** RTGC compressed red and green channel, unsigned normalized. */
+            /**
+             * RTGC compressed red and green channel, unsigned normalized.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_compression_rgtc</tt>
+             */
             CompressedRtgcRedGreen = GL_COMPRESSED_RG_RGTC2,
 
-            /** RTGC compressed red and green channel, signed normalized. */
+            /**
+             * RTGC compressed red and green channel, signed normalized.
+             *
+             * @requires_gl30 Extension <tt>EXT_texture_compression_rgtc</tt>
+             */
             CompressedRtgcSignedRedGreen = GL_COMPRESSED_SIGNED_RG_RGTC2,
 
             #if defined(GL_COMPRESSED_RGBA_BPTC_UNORM) || defined(DOXYGEN_GENERATING_OUTPUT)
-            /** BTPC compressed RGBA, unsigned normalized. */
+            /**
+             * BTPC compressed RGBA, unsigned normalized.
+             *
+             * @requires_gl42 Extension <tt>ARB_texture_compression_btpc</tt>
+             */
             CompressedBtpcRGBA = GL_COMPRESSED_RGBA_BPTC_UNORM,
 
-            /** BTPC compressed sRGBA, unsigned normalized. */
+            /**
+             * BTPC compressed sRGBA, unsigned normalized.
+             *
+             * @requires_gl42 Extension <tt>ARB_texture_compression_btpc</tt>
+             */
             CompressedBtpcSRGBA = GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM,
 
-            /** BTPC compressed RGB, signed float. */
+            /**
+             * BTPC compressed RGB, signed float.
+             *
+             * @requires_gl42 Extension <tt>ARB_texture_compression_btpc</tt>
+             */
             CompressedBtpcRGBSignedFloat = GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT,
 
-            /** BTPC compressed RGB, unsigned float. */
+            /**
+             * BTPC compressed RGB, unsigned float.
+             *
+             * @requires_gl42 Extension <tt>ARB_texture_compression_btpc</tt>
+             */
             CompressedBtpcRGBUnsignedFloat = GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT,
             #endif
 
@@ -299,13 +392,25 @@ class MAGNUM_EXPORT AbstractTexture {
             /** 24bit depth component. */
             Depth24 = GL_DEPTH_COMPONENT24,
 
-            /** 32bit float depth component. */
+            /**
+             * 32bit float depth component.
+             *
+             * @requires_gl30 Extension <tt>ARB_depth_buffer_float</tt>
+             */
             Depth32Float = GL_DEPTH_COMPONENT32F,
 
-            /** 24bit depth and 8bit stencil component.  */
+            /**
+             * 24bit depth and 8bit stencil component.
+             *
+             * @requires_gl30 Extension <tt>EXT_packed_depth_stencil</tt>
+             */
             Depth24Stencil8 = GL_DEPTH24_STENCIL8,
 
-            /** 32bit float depth component and 8bit stencil component. */
+            /**
+             * 32bit float depth component and 8bit stencil component.
+             *
+             * @requires_gl30 Extension <tt>ARB_depth_buffer_float</tt>
+             */
             Depth32FloatStencil8 = GL_DEPTH32F_STENCIL8
         };
 
@@ -420,13 +525,32 @@ class MAGNUM_EXPORT AbstractTexture {
              * Each dimension has its own unique subset of these targets.
              */
             enum class Target: GLenum {
-                Texture1D = GL_TEXTURE_1D,
+                Texture1D = GL_TEXTURE_1D, /**< One-dimensional texture */
-                Texture2D = GL_TEXTURE_2D,
+                Texture2D = GL_TEXTURE_2D, /**< Two-dimensional texture */
-                Texture3D = GL_TEXTURE_3D,
+                Texture3D = GL_TEXTURE_3D, /**< Three-dimensional texture */
+
+                /**
+                 * Array of one-dimensional textures
+                 *
+                 * @requires_gl30 Extension <tt>EXT_texture_array</tt>
+                 */
                 Array1D = GL_TEXTURE_1D_ARRAY,
+
+                /**
+                 * Array of two-dimensional textures
+                 *
+                 * @requires_gl30 Extension <tt>EXT_texture_array</tt>
+                 */
                 Array2D = GL_TEXTURE_2D_ARRAY,
+
+                /**
+                 * Rectangle texture
+                 *
+                 * @requires_gl31 Extension <tt>ARB_texture_rectangle</tt>
+                 */
                 Rectangle = GL_TEXTURE_RECTANGLE,
-                CubeMap = GL_TEXTURE_CUBE_MAP,
+
+                CubeMap = GL_TEXTURE_CUBE_MAP /**< Cube map texture */
             };
 
             /**

src/Buffer.h

@@ -38,10 +38,18 @@ class Buffer {
             /** Used for storing vertex attributes. */
             Array = GL_ARRAY_BUFFER,
 
-            /** Source for copies. */
+            /**
+             * Source for copies.
+             *
+             * @requires_gl31 Extension <tt>ARB_copy_buffer</tt>
+             */
             CopyRead = GL_COPY_READ_BUFFER,
 
-            /** Target for copies. */
+            /**
+             * Target for copies.
+             *
+             * @requires_gl31 Extension <tt>ARB_copy_buffer</tt>
+             */
             CopyWrite = GL_COPY_WRITE_BUFFER,
 
             /** Used for storing vertex indices. */
@@ -53,13 +61,26 @@ class Buffer {
             /** Target for pixel pack operations. */
             PixelPack = GL_PIXEL_PACK_BUFFER,
 
-            /** Source for texel fetches. */
+            /**
+             * Source for texel fetches.
+             *
+             * @see BufferedTexture
+             * @requires_gl31 Extension <tt>ARB_texture_buffer_object</tt>
+             */
             Texture = GL_TEXTURE_BUFFER,
 
-            /** Target for transform feedback. */
+            /**
+             * Target for transform feedback.
+             *
+             * @requires_gl30 Extension <tt>EXT_transform_feedback</tt>
+             */
             TransformFeedback = GL_TRANSFORM_FEEDBACK_BUFFER,
 
-            /** Used for storing uniforms. */
+            /**
+             * Used for storing uniforms.
+             *
+             * @requires_gl31 Extension <tt>ARB_uniform_buffer_object</tt>
+             */
             Uniform = GL_UNIFORM_BUFFER
         };
 

src/BufferedTexture.h

@@ -35,6 +35,8 @@ using data setting functions in Buffer itself.
 
 When using buffered texture in the shader, use `samplerBuffer` and fetch the
 data using integer coordinates in `texelFetch()`.
+
+@requires_gl31 Extension <tt>ARB_texture_buffer_object</tt>
 */
 class BufferedTexture {
     BufferedTexture(const BufferedTexture& other) = delete;

src/CubeMapTexture.h

@@ -59,6 +59,8 @@ class CubeMapTexture: public Texture2D {
 
         /**
          * @brief Enable/disable seamless cube map textures
+         *
+         * @requires_gl32 Extension <tt>ARB_seamless_cube_map</tt>
          */
         inline static void setSeamless(bool enabled) {
             enabled ? glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS) : glDisable(GL_TEXTURE_CUBE_MAP_SEAMLESS);

src/Framebuffer.h

@@ -28,6 +28,8 @@ namespace Magnum {
 
 /**
 @brief %Framebuffer
+
+@requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
 */
 class MAGNUM_EXPORT Framebuffer {
     Framebuffer(const Framebuffer& other) = delete;
@@ -38,8 +40,19 @@ class MAGNUM_EXPORT Framebuffer {
     public:
         /** @brief %Framebuffer target */
         enum class Target: GLenum {
-            Read = GL_READ_FRAMEBUFFER,     /**< For reading only. */
+            /**
-            Draw = GL_DRAW_FRAMEBUFFER,     /**< For drawing only. */
+             * For reading only.
+             *
+             * @requires_gl30 Extension <tt>EXT_framebuffer_blit</tt>
+             */
+            Read = GL_READ_FRAMEBUFFER,
+
+            /**
+             * For drawing only.
+             *
+             * @requires_gl30 Extension <tt>EXT_framebuffer_blit</tt>
+             */
+            Draw = GL_DRAW_FRAMEBUFFER,
             ReadDraw = GL_FRAMEBUFFER       /**< For both reading and drawing. */
         };
 
@@ -146,6 +159,8 @@ class MAGNUM_EXPORT Framebuffer {
          * mapDefaultForDraw() for binding particular framebuffer for reading
          * and drawing. If multiple attachments are specified in mapForDraw()
          * / mapDefaultForDraw(), the data are written to each of them.
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_blit</tt>
          */
         inline static void blit(const Math::Vector2<GLint>& bottomLeft, const Math::Vector2<GLint>& topRight, const Math::Vector2<GLint>& destinationBottomLeft, const Math::Vector2<GLint>& destinationTopRight, BlitMask blitMask, AbstractTexture::Filter filter) {
             glBlitFramebuffer(bottomLeft.x(), bottomLeft.y(), topRight.x(), topRight.y(), destinationBottomLeft.x(), destinationBottomLeft.y(), destinationTopRight.x(), destinationTopRight.y(), static_cast<GLbitfield>(blitMask), static_cast<GLenum>(filter));
@@ -164,6 +179,8 @@ class MAGNUM_EXPORT Framebuffer {
          * no interpolation is needed and thus
          * AbstractTexture::Filter::NearestNeighbor filtering is used by
          * default.
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_blit</tt>
          */
         inline static void blit(const Math::Vector2<GLint>& bottomLeft, const Math::Vector2<GLint>& topRight, BlitMask blitMask) {
             glBlitFramebuffer(bottomLeft.x(), bottomLeft.y(), topRight.x(), topRight.y(), bottomLeft.x(), bottomLeft.y(), topRight.x(), topRight.y(), static_cast<GLbitfield>(blitMask), static_cast<GLenum>(AbstractTexture::Filter::NearestNeighbor));
@@ -266,6 +283,8 @@ class MAGNUM_EXPORT Framebuffer {
          * @param depthStencilAttachment Depth/stencil attachment
          * @param texture           1D texture
          * @param mipLevel          Mip level
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture1D(Target target, DepthStencilAttachment depthStencilAttachment, Texture1D* texture, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -280,6 +299,8 @@ class MAGNUM_EXPORT Framebuffer {
          * @param colorAttachment   Color attachment ID (number between 0 and 15)
          * @param texture           1D texture
          * @param mipLevel          Mip level
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture1D(Target target, unsigned int colorAttachment, Texture1D* texture, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -297,6 +318,7 @@ class MAGNUM_EXPORT Framebuffer {
          *      should be always 0.
          *
          * @see attachCubeMapTexture()
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture2D(Target target, DepthStencilAttachment depthStencilAttachment, Texture2D* texture, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -314,6 +336,7 @@ class MAGNUM_EXPORT Framebuffer {
          *      should be always 0.
          *
          * @see attachCubeMapTexture()
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture2D(Target target, unsigned int colorAttachment, Texture2D* texture, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -331,6 +354,7 @@ class MAGNUM_EXPORT Framebuffer {
          * @param mipLevel          Mip level
          *
          * @see attachTexture2D()
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachCubeMapTexture(Target target, DepthStencilAttachment depthStencilAttachment, CubeMapTexture* texture, CubeMapTexture::Coordinate coordinate, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -347,6 +371,7 @@ class MAGNUM_EXPORT Framebuffer {
          * @param mipLevel          Mip level
          *
          * @see attachTexture2D()
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachCubeMapTexture(Target target, unsigned int colorAttachment, CubeMapTexture* texture, CubeMapTexture::Coordinate coordinate, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -361,6 +386,8 @@ class MAGNUM_EXPORT Framebuffer {
          * @param texture           3D texture
          * @param mipLevel          Mip level
          * @param layer             Layer of 2D image within a 3D texture
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture3D(Target target, DepthStencilAttachment depthStencilAttachment, Texture3D* texture, GLint mipLevel, GLint layer) {
             /** @todo Check for internal format compatibility */
@@ -376,6 +403,8 @@ class MAGNUM_EXPORT Framebuffer {
          * @param texture           3D texture
          * @param mipLevel          Mip level
          * @param layer             Layer of 2D image within a 3D texture.
+         *
+         * @requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
          */
         inline void attachTexture3D(Target target, unsigned int colorAttachment, Texture3D* texture, GLint mipLevel, GLint layer) {
             /** @todo Check for internal format compatibility */

src/Mesh.h

@@ -31,10 +31,13 @@ namespace Magnum {
 class Buffer;
 
 /**
- * @brief Base class for managing non-indexed meshes
+@brief Base class for managing non-indexed meshes
- *
+
- * @todo Support for normalized values (e.g. for color as char[4] passed to
+@todo Support for normalized values (e.g. for color as char[4] passed to
- *      shader as floating-point vec4)
+     shader as floating-point vec4)
+
+@requires_gl30 Extension <tt>APPLE_vertex_array_object</tt>
+@requires_gl30 Extension <tt>EXT_gpu_shader4</tt> (for unsigned integer attributes)
  */
 class MAGNUM_EXPORT Mesh {
     Mesh(const Mesh& other) = delete;

src/Query.h

@@ -56,6 +56,8 @@ class MAGNUM_EXPORT AbstractQuery {
          *
          * Note that this function is blocking until the result is available.
          * See resultAvailable().
+         *
+         * @requires_gl33 Extension <tt>ARB_timer_query</tt> (64bit integers)
          */
         template<class T> T result() = delete;
 
@@ -105,7 +107,11 @@ class MAGNUM_EXPORT Query: public AbstractQuery {
             /** Count of primitives written to transform feedback buffer. */
             TransformFeedbackPrimitivesWritten = GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN,
 
-            /** Elapsed time */
+            /**
+             * Elapsed time
+             *
+             * @requires_gl33 Extension <tt>ARB_timer_query</tt>
+             */
             TimeElapsed = GL_TIME_ELAPSED
         };
 
@@ -173,7 +179,11 @@ class MAGNUM_EXPORT SampleQuery: public AbstractQuery {
             /** Count of samples passed from fragment shader */
             SamplesPassed = GL_SAMPLES_PASSED,
 
-            /** Whether any samples passed from fragment shader */
+            /**
+             * Whether any samples passed from fragment shader
+             *
+             * @requires_gl33 Extension <tt>ARB_occlusion_query2</tt>
+             */
             AnySamplesPassed = GL_ANY_SAMPLES_PASSED
         };
 
@@ -258,6 +268,8 @@ GLuint timeElapsed1 = tmp-q1.result<GLuint>();
 GLuint timeElapsed2 = q3.result<GLuint>()-tmp;
 @endcode
 Using this query results in fewer OpenGL calls when doing more measures.
+
+@requires_gl33 Extension <tt>ARB_timer_query</tt>
 */
 class TimeQuery: public AbstractQuery {
     public:

src/Renderbuffer.h

@@ -27,6 +27,8 @@ namespace Magnum {
 @brief %Renderbuffer
 
 Attachable to Framebuffer as render target.
+
+@requires_gl30 Extension <tt>EXT_framebuffer_object</tt>
 */
 class Renderbuffer {
     Renderbuffer(const Renderbuffer& other) = delete;

src/Shader.h

@@ -42,9 +42,16 @@ class MAGNUM_EXPORT Shader {
     public:
         /** @brief %Shader type */
         enum Type {
-            Vertex = GL_VERTEX_SHADER,      /**< @brief Vertex shader */
+            Vertex = GL_VERTEX_SHADER,      /**< Vertex shader */
-            Geometry = GL_GEOMETRY_SHADER,  /**< @brief Geometry shader */
+
-            Fragment = GL_FRAGMENT_SHADER   /**< @brief Fragment shader */
+            /**
+             * Geometry shader
+             *
+             * @requires_gl32 Extension <tt>ARB_geometry_shader4</tt>
+             */
+            Geometry = GL_GEOMETRY_SHADER,
+
+            Fragment = GL_FRAGMENT_SHADER   /**< Fragment shader */
         };
 
         /** @brief %Shader state */

src/Shaders/PhongShader.h

@@ -23,7 +23,12 @@
 
 namespace Magnum { namespace Shaders {
 
-/** @brief Phong shader */
+/**
+@brief Phong shader
+
+@requires_gl33 The shader is written in GLSL 3.3, although it should be trivial
+    to port it to older versions.
+*/
 class PhongShader: public AbstractShaderProgram {
     public:
         typedef Attribute<0, Vector4> Vertex;   /**< @brief Vertex position */

src/Texture.h

@@ -47,6 +47,8 @@ between 0 and `textureSizeInGivenDirection-1`. Note that rectangle textures
 don't support mipmapping and repeating wrapping modes, see @ref Texture::Filter
 "Filter", @ref Texture::Mipmap "Mipmap" and generateMipmap() documentation
 for more information.
+
+@requires_gl31 Extension <tt>ARB_texture_rectangle</tt> (rectangle textures)
  */
 template<size_t textureDimensions> class Texture: public AbstractTexture {
     public: