SDL_GLattr: formatted wiki documentation to be wikiheaders-friendly.

Reference https://github.com/libsdl-org/sdlwiki/issues/544

include/SDL_video.h

@@ -221,35 +221,65 @@ typedef enum SDL_FlashOperation
 typedef void *SDL_GLContext;
 
 /**
- * OpenGL configuration attributes
+ * OpenGL configuration attributes.
+ *
+ * While you can set most OpenGL attributes normally, the attributes listed
+ * above must be known before SDL creates the window that will be used with
+ * the OpenGL context. These attributes are set and read with
+ * SDL_GL_SetAttribute and SDL_GL_GetAttribute.
+ *
+ * In some cases, these attributes are minimum requests; the GL does not
+ * promise to give you exactly what you asked for. It's possible to ask for a
+ * 16-bit depth buffer and get a 24-bit one instead, for example, or to ask
+ * for no stencil buffer and still have one available. Context creation should
+ * fail if the GL can't provide your requested attributes at a minimum, but
+ * you should check to see exactly what you got.
+ *
+ *
+ * [Multisample anti-aliasing](http://en.wikipedia.org/wiki/Multisample_anti-aliasing)
+ * is a type of full screen anti-aliasing. Multipsampling defaults to off but
+ * can be turned on by setting SDL_GL_MULTISAMPLEBUFFERS to 1 and
+ * SDL_GL_MULTISAMPLESAMPLES to a value greater than 0. Typical values are 2
+ * and 4.
+ *
+ * SDL_GL_CONTEXT_PROFILE_MASK determines the type of context created, while
+ * both SDL_GL_CONTEXT_MAJOR_VERSION and SDL_GL_CONTEXT_MINOR_VERSION
+ * determine which version. All three attributes must be set prior to creating
+ * the first window, and in general you can't change the value of
+ * SDL_GL_CONTEXT_PROFILE_MASK without first destroying all windows created
+ * with the previous setting.
+ *
+ * SDL_GL_CONTEXT_RELEASE_BEHAVIOR can be set to
+ * SDL_GL_CONTEXT_RELEASE_BEHAVIOR_NONE or
+ * SDL_GL_CONTEXT_RELEASE_BEHAVIOR_FLUSH.
  */
 typedef enum SDL_GLattr
 {
-    SDL_GL_RED_SIZE,
-    SDL_GL_GREEN_SIZE,
-    SDL_GL_BLUE_SIZE,
-    SDL_GL_ALPHA_SIZE,
-    SDL_GL_BUFFER_SIZE,
-    SDL_GL_DOUBLEBUFFER,
-    SDL_GL_DEPTH_SIZE,
-    SDL_GL_STENCIL_SIZE,
-    SDL_GL_ACCUM_RED_SIZE,
-    SDL_GL_ACCUM_GREEN_SIZE,
-    SDL_GL_ACCUM_BLUE_SIZE,
-    SDL_GL_ACCUM_ALPHA_SIZE,
-    SDL_GL_STEREO,
-    SDL_GL_MULTISAMPLEBUFFERS,
-    SDL_GL_MULTISAMPLESAMPLES,
-    SDL_GL_ACCELERATED_VISUAL,
-    SDL_GL_RETAINED_BACKING,
-    SDL_GL_CONTEXT_MAJOR_VERSION,
-    SDL_GL_CONTEXT_MINOR_VERSION,
-    SDL_GL_CONTEXT_EGL,
-    SDL_GL_CONTEXT_FLAGS,
-    SDL_GL_CONTEXT_PROFILE_MASK,
-    SDL_GL_SHARE_WITH_CURRENT_CONTEXT,
-    SDL_GL_FRAMEBUFFER_SRGB_CAPABLE,
-    SDL_GL_CONTEXT_RELEASE_BEHAVIOR,
+    SDL_GL_RED_SIZE,                    /**< the minimum number of bits for the red channel of the color buffer; defaults to 3. */
+    SDL_GL_GREEN_SIZE,                  /**< the minimum number of bits for the green channel of the color buffer; defaults to 3. */
+    SDL_GL_BLUE_SIZE,                   /**< the minimum number of bits for the blue channel of the color buffer; defaults to 2. */
+    SDL_GL_ALPHA_SIZE,                  /**< the minimum number of bits for the alpha channel of the color buffer; defaults to 0. */
+    SDL_GL_BUFFER_SIZE,                 /**< the minimum number of bits for frame buffer size; defaults to 0. */
+    SDL_GL_DOUBLEBUFFER,                /**< whether the output is single or double buffered; defaults to double buffering on. */
+    SDL_GL_DEPTH_SIZE,                  /**< the minimum number of bits in the depth buffer; defaults to 16. */
+    SDL_GL_STENCIL_SIZE,                /**< the minimum number of bits in the stencil buffer; defaults to 0. */
+    SDL_GL_ACCUM_RED_SIZE,              /**< the minimum number of bits for the red channel of the accumulation buffer; defaults to 0. */
+    SDL_GL_ACCUM_GREEN_SIZE,            /**< the minimum number of bits for the green channel of the accumulation buffer; defaults to 0. */
+    SDL_GL_ACCUM_BLUE_SIZE,             /**< the minimum number of bits for the blue channel of the accumulation buffer; defaults to 0. */
+    SDL_GL_ACCUM_ALPHA_SIZE,            /**< the minimum number of bits for the alpha channel of the accumulation buffer; defaults to 0. */
+    SDL_GL_STEREO,                      /**< whether the output is stereo 3D; defaults to off. */
+    SDL_GL_MULTISAMPLEBUFFERS,          /**< the number of buffers used for multisample anti-aliasing; defaults to 0. */
+    SDL_GL_MULTISAMPLESAMPLES,          /**< the number of samples used around the current pixel used for multisample anti-aliasing. */
+    SDL_GL_ACCELERATED_VISUAL,          /**< set to 1 to require hardware acceleration, set to 0 to force software rendering; defaults to allow either. */
+    SDL_GL_RETAINED_BACKING,            /**< not used (deprecated). */
+    SDL_GL_CONTEXT_MAJOR_VERSION,       /**< OpenGL context major version. */
+    SDL_GL_CONTEXT_MINOR_VERSION,       /**< OpenGL context minor version. */
+    SDL_GL_CONTEXT_EGL,                 /**< deprecated: set SDL_GL_CONTEXT_PROFILE_MASK to SDL_GL_CONTEXT_PROFILE_ES to enable instead. */
+    SDL_GL_CONTEXT_FLAGS,               /**< some combination of 0 or more of elements of the SDL_GLcontextFlag enumeration; defaults to 0. */
+    SDL_GL_CONTEXT_PROFILE_MASK,        /**< type of GL context (Core, Compatibility, ES). See SDL_GLprofile; default value depends on platform. */
+    SDL_GL_SHARE_WITH_CURRENT_CONTEXT,  /**< OpenGL context sharing; defaults to 0. */
+    SDL_GL_FRAMEBUFFER_SRGB_CAPABLE,    /**< requests sRGB capable visual; defaults to 0. (>= SDL 2.0.1) */
+    SDL_GL_CONTEXT_RELEASE_BEHAVIOR,    /**< sets context the release behavior; defaults to 1. (>= SDL 2.0.4) */
     SDL_GL_CONTEXT_RESET_NOTIFICATION,
     SDL_GL_CONTEXT_NO_ERROR,
     SDL_GL_FLOATBUFFERS