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, 54 insertions, 1 deletions

diff --git a/intern/ghost/GHOST_Types.h b/intern/ghost/GHOST_Types.h
index 7d819913efc..3a8d0fbfecf 100644
--- a/intern/ghost/GHOST_Types.h
+++ b/intern/ghost/GHOST_Types.h
@@ -634,7 +634,9 @@ typedef enum GHOST_TXrGraphicsBinding {
 
 typedef void (*GHOST_XrErrorHandlerFn)(const struct GHOST_XrError *);
 
+typedef void (*GHOST_XrSessionCreateFn)(void);
 typedef void (*GHOST_XrSessionExitFn)(void *customdata);
+typedef void (*GHOST_XrCustomdataFreeFn)(void *customdata);
 
 typedef void *(*GHOST_XrGraphicsContextBindFn)(void);
 typedef void (*GHOST_XrGraphicsContextUnbindFn)(GHOST_ContextHandle graphics_context);
@@ -665,6 +667,7 @@ typedef struct {
 typedef struct {
   GHOST_XrPose base_pose;
 
+  GHOST_XrSessionCreateFn create_fn;
   GHOST_XrSessionExitFn exit_fn;
   void *exit_customdata;
 } GHOST_XrSessionBeginInfo;
@@ -691,4 +694,54 @@ typedef struct GHOST_XrError {
   void *customdata;
 } GHOST_XrError;
 
-#endif
+typedef struct GHOST_XrActionSetInfo {
+  const char *name;
+
+  GHOST_XrCustomdataFreeFn customdata_free_fn;
+  void *customdata; /* wmXrActionSet */
+} GHOST_XrActionSetInfo;
+
+/** XR action type. Enum values match those in OpenXR's
+ * XrActionType enum for consistency. */
+typedef enum GHOST_XrActionType {
+  GHOST_kXrActionTypeBooleanInput = 1,
+  GHOST_kXrActionTypeFloatInput = 2,
+  GHOST_kXrActionTypeVector2fInput = 3,
+  GHOST_kXrActionTypePoseInput = 4,
+  GHOST_kXrActionTypeVibrationOutput = 100,
+} GHOST_XrActionType;
+
+typedef struct GHOST_XrActionInfo {
+  const char *name;
+  GHOST_XrActionType type;
+  GHOST_TUns32 count_subaction_paths;
+  const char **subaction_paths;
+  /** States for each subaction path. */
+  void *states;
+
+  GHOST_XrCustomdataFreeFn customdata_free_fn;
+  void *customdata; /* wmXrAction */
+} GHOST_XrActionInfo;
+
+typedef struct GHOST_XrActionSpaceInfo {
+  const char *action_name;
+  GHOST_TUns32 count_subaction_paths;
+  const char **subaction_paths;
+  /** Poses for each subaction path. */
+  const GHOST_XrPose *poses;
+} GHOST_XrActionSpaceInfo;
+
+typedef struct GHOST_XrActionBindingInfo {
+  const char *action_name;
+  GHOST_TUns32 count_interaction_paths;
+  /** Interaction path: User (subaction) path + component path. */
+  const char **interaction_paths;
+} GHOST_XrActionBindingInfo;
+
+typedef struct GHOST_XrActionProfileInfo {
+  const char *profile_path;
+  GHOST_TUns32 count_bindings;
+  const GHOST_XrActionBindingInfo *bindings;
+} GHOST_XrActionProfileInfo;
+
+#endif /* WITH_XR_OPENXR */