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, 68 insertions, 0 deletions

diff --git a/source/blender/windowmanager/xr/intern/wm_xr_intern.h b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
index 25e3da3ffb4..9bf63be61dd 100644
--- a/source/blender/windowmanager/xr/intern/wm_xr_intern.h
+++ b/source/blender/windowmanager/xr/intern/wm_xr_intern.h
@@ -24,6 +24,21 @@
 
 #include "wm_xr.h"
 
+struct wmXrActionSet;
+
+typedef struct wmXrControllerData {
+  /** OpenXR path identifier. Length is dependent on OpenXR's XR_MAX_PATH_LENGTH (256).
+  This subaction path will later be combined with a component path, and that combined path should
+  also have a max of XR_MAX_PATH_LENGTH (e.g. subaction_path = /user/hand/left, component_path =
+  /input/trigger/value, interaction_path = /user/hand/left/input/trigger/value).
+  */
+  char subaction_path[64];
+  /** Last known controller pose (in world space) stored for queries. */
+  GHOST_XrPose pose;
+  /** The last known controller matrix, calculated from above's controller pose. */
+  float mat[4][4];
+} wmXrControllerData;
+
 typedef struct wmXrSessionState {
   bool is_started;
 
@@ -39,11 +54,23 @@ typedef struct wmXrSessionState {
   Object *prev_base_pose_object;
   /** Copy of XrSessionSettings.flag created on the last draw call, stored to detect changes. */
   int prev_settings_flag;
+  /** Copy of wmXrDrawData.base_pose. */
+  GHOST_XrPose prev_base_pose;
+  /** Copy of GHOST_XrDrawViewInfo.local_pose. */
+  GHOST_XrPose prev_local_pose;
   /** Copy of wmXrDrawData.eye_position_ofs. */
   float prev_eye_position_ofs[3];
 
   bool force_reset_to_base_pose;
   bool is_view_data_set;
+
+  /** Last known controller data. */
+  wmXrControllerData controllers[2];
+
+  /** The currently active action set that will be updated on calls to
+   * wm_xr_session_actions_update(). If NULL, all action sets will be treated as active and
+   * updated. */
+  struct wmXrActionSet *active_action_set;
 } wmXrSessionState;
 
 typedef struct wmXrRuntimeData {
@@ -79,6 +106,40 @@ typedef struct wmXrDrawData {
   float eye_position_ofs[3]; /* Local/view space. */
 } wmXrDrawData;
 
+typedef struct wmXrAction {
+  char *name;
+  eXrActionType type;
+  unsigned int count_subaction_paths;
+  char **subaction_paths;
+  /** States for each subaction path. */
+  void *states;
+  /** Previous states, stored to determine XR events. */
+  void *states_prev;
+
+  /** Input threshold for float/vector2f actions. */
+  float float_threshold;
+
+  /** The currently active subaction path (if any) for modal actions. */
+  char **active_modal_path;
+
+  /** Operator to be called on XR events. */
+  struct wmOperatorType *ot;
+  IDProperty *op_properties;
+  eXrOpFlag op_flag;
+} wmXrAction;
+
+typedef struct wmXrActionSet {
+  char *name;
+
+  /** The XR pose action that determines the controller
+   * transforms. This is usually identified by the OpenXR path "/grip/pose" or "/aim/pose",
+   * although it could differ depending on the specification and hardware. */
+  wmXrAction *controller_pose_action;
+
+  /** The currently active modal action (if any). */
+  wmXrAction *active_modal_action;
+} wmXrActionSet;
+
 wmXrRuntimeData *wm_xr_runtime_data_create(void);
 void wm_xr_runtime_data_free(wmXrRuntimeData **runtime);
 
@@ -95,5 +156,12 @@ bool wm_xr_session_surface_offscreen_ensure(wmXrSurfaceData *surface_data,
 void *wm_xr_session_gpu_binding_context_create(void);
 void wm_xr_session_gpu_binding_context_destroy(GHOST_ContextHandle context);
 
+void wm_xr_session_actions_init(wmXrData *xr);
+void wm_xr_session_actions_update(wmXrData *xr);
+void wm_xr_session_controller_data_populate(const wmXrAction *controller_pose_action,
+                                            wmXrData *xr);
+void wm_xr_session_controller_data_clear(wmXrSessionState *state);
+
 void wm_xr_pose_to_viewmat(const GHOST_XrPose *pose, float r_viewmat[4][4]);
+void wm_xr_controller_pose_to_mat(const GHOST_XrPose *pose, float r_mat[4][4]);
 void wm_xr_draw_view(const GHOST_XrDrawViewInfo *draw_view, void *customdata);