GenerateRichPresence calls rc_runtime_get_richpresence in rhceevos on the achievement runtime to get the current Rich Presence string, a description of the player's current in-game state based on its memory as fed into a custom-developed script downloaded via FetchGameData. This gets passed into PingRichPresence, but is separated into its own method so it can be used elsewhere locally.
MemoryPeeker is a function passed by pointer into rcheevos DoFrame functionality that forms the lynchpin of the rcheevos runtime - it provides the interface by which rcheevos accesses memory and determines if the fields provided by achievement, leaderboard, and rich presence definitions are meeting the criteria needed.
AchievementEventHandler simply checks which kind of event is triggered and calls the appropriate function. Its primary purpose is as a function to be pointed to.
HandleAchievementTriggeredEvent is an asynchronous method that processes an event and places a synchronous AwardAchievement call on the work queue. In the process, it also updates the unlock map and makes the ActivateDeactivateAchievement call to determine and adjust the achievement's current active state.
PingRichPresence makes a "ping" API request to the RetroAchievements website with the provided RichPresence string parameter. While there has been talk about tying ping in with session, in its current state the primary purpose of ping is to send the player's Rich Presence to the website.
AwardAchievement performs the API call to notify the site that an achievement has been unlocked. As one of the parameters is the game hash (something I overlooked previously; I thought it was the game ID) this change also moves the game hash into a member field.
This fixes a crash I found in the Request function of AchievementManager where under certain conditions init_request would return an api_request with null post data, and Post would crash if it attempted to access it. Now the function aborts before the Post and returns an INVALID_REQUEST response type.
PR #11183 regressed the lookup table reconstruction and, for some reason, added an else clause that clobbered the dCache whenever dCache emulation is turned on.
RetroAchievements Rich Presence is a script that is run periodically on a game's memory to provide a detailed text description of what the player is doing. Existing Discord presence on Dolphin would update a player's Discord status to say not just that they are using Dolphin but that they are playing, for example, Sonic Adventure 2 Battle; Rich Presence would detail that the player is in City Escape with 5 lives and 142 rings.
Activating this in the runtime simply entails loading that text script, as returned by the FetchGameData API call, into the runtime, here only determined by whether rich presence is enabled in the achievement settings. Deactivating this is done via the same rcheevos method by setting the rich presence to an empty string.
