XR Controller Support Step 1: Internal Abstractions for OpenXR Actions

Adds internal API for creating and managing OpenXR actions at the
GHOST and WM layers. Does not bring about any changes for users since
XR action functionality is not yet exposed in the Python API (will be
added in a subsequent patch).

OpenXR actions are a means to communicate with XR input devices and
can be used to retrieve button/pose states or apply haptic feedback.
Actions are bound to device inputs via a semantic path binding
(https://www.khronos.org/registry/OpenXR/specs/1.0/html/xrspec.html#semantic-path-interaction-profiles),
which serves as an XR version of keymaps.

Main features:

- Abstraction of OpenXR action management functions to GHOST-XR,
  WM-XR APIs.
- New "xr_session_start_pre" callback for creating actions at
  appropriate point in the XR session.
- Creation of name-identifiable action sets/actions.
- Binding of actions to controller inputs.
- Acquisition of controller button states.
- Acquisition of controller poses.
- Application of controller haptic feedback.
- Carefully designed error handling and useful error reporting
  (e.g. action set/action name included in error message).

Reviewed By: Julian Eisel

Differential Revision: http://developer.blender.org/D10942

1 files changed, 104 insertions, 1 deletions

diff --git a/intern/ghost/GHOST_C-api.h b/intern/ghost/GHOST_C-api.h
index c776eb6b44c..2bd9af6df5c 100644
--- a/intern/ghost/GHOST_C-api.h
+++ b/intern/ghost/GHOST_C-api.h
@@ -1059,7 +1059,110 @@ int GHOST_XrSessionNeedsUpsideDownDrawing(const GHOST_XrContextHandle xr_context
  * \returns GHOST_kSuccess if any event was handled, otherwise GHOST_kFailure.
  */
 GHOST_TSuccess GHOST_XrEventsHandle(GHOST_XrContextHandle xr_context);
-#endif
+
+/* actions */
+/**
+ * Create an OpenXR action set for input/output.
+ */
+int GHOST_XrCreateActionSet(GHOST_XrContextHandle xr_context, const GHOST_XrActionSetInfo *info);
+
+/**
+ * Destroy a previously created OpenXR action set.
+ */
+void GHOST_XrDestroyActionSet(GHOST_XrContextHandle xr_context, const char *action_set_name);
+
+/**
+ * Create OpenXR input/output actions.
+ */
+int GHOST_XrCreateActions(GHOST_XrContextHandle xr_context,
+                          const char *action_set_name,
+                          GHOST_TUns32 count,
+                          const GHOST_XrActionInfo *infos);
+
+/**
+ * Destroy previously created OpenXR actions.
+ */
+void GHOST_XrDestroyActions(GHOST_XrContextHandle xr_context,
+                            const char *action_set_name,
+                            GHOST_TUns32 count,
+                            const char *const *action_names);
+
+/**
+ * Create spaces for pose-based OpenXR actions.
+ */
+int GHOST_XrCreateActionSpaces(GHOST_XrContextHandle xr_context,
+                               const char *action_set_name,
+                               GHOST_TUns32 count,
+                               const GHOST_XrActionSpaceInfo *infos);
+
+/**
+ * Destroy previously created spaces for OpenXR actions.
+ */
+void GHOST_XrDestroyActionSpaces(GHOST_XrContextHandle xr_context,
+                                 const char *action_set_name,
+                                 GHOST_TUns32 count,
+                                 const GHOST_XrActionSpaceInfo *infos);
+
+/**
+ * Create input/output path bindings for OpenXR actions.
+ */
+int GHOST_XrCreateActionBindings(GHOST_XrContextHandle xr_context,
+                                 const char *action_set_name,
+                                 GHOST_TUns32 count,
+                                 const GHOST_XrActionProfileInfo *infos);
+
+/**
+ * Destroy previously created bindings for OpenXR actions.
+ */
+void GHOST_XrDestroyActionBindings(GHOST_XrContextHandle xr_context,
+                                   const char *action_set_name,
+                                   GHOST_TUns32 count,
+                                   const GHOST_XrActionProfileInfo *infos);
+
+/**
+ * Attach all created action sets to the current OpenXR session.
+ */
+int GHOST_XrAttachActionSets(GHOST_XrContextHandle xr_context);
+
+/**
+ * Update button/tracking states for OpenXR actions.
+ *
+ * \param action_set_name: The name of the action set to sync. If NULL, all action sets
+ * attached to the session will be synced.
+ */
+int GHOST_XrSyncActions(GHOST_XrContextHandle xr_context, const char *action_set_name);
+
+/**
+ * Apply an OpenXR haptic output action.
+ */
+int GHOST_XrApplyHapticAction(GHOST_XrContextHandle xr_context,
+                              const char *action_set_name,
+                              const char *action_name,
+                              const GHOST_TInt64 *duration,
+                              const float *frequency,
+                              const float *amplitude);
+
+/**
+ * Stop a previously applied OpenXR haptic output action.
+ */
+void GHOST_XrStopHapticAction(GHOST_XrContextHandle xr_context,
+                              const char *action_set_name,
+                              const char *action_name);
+
+/**
+ * Get action set custom data (owned by Blender, not GHOST).
+ */
+void *GHOST_XrGetActionSetCustomdata(GHOST_XrContextHandle xr_context,
+                                     const char *action_set_name);
+
+/**
+ * Get action custom data (owned by Blender, not GHOST).
+ */
+void *GHOST_XrGetActionCustomdata(GHOST_XrContextHandle xr_context,
+                                  const char *action_set_name,
+                                  const char *action_name);
+
+#endif /* WITH_XR_OPENXR */
 
 #ifdef __cplusplus
 }