VR: Initial Virtual Reality support - Milestone 1, Scene Inspection

NOTE: While most of the milestone 1 goals are there, a few smaller features and
improvements are still to be done.

Big picture of this milestone: Initial, OpenXR-based virtual reality support
for users and foundation for advanced use cases.
Maniphest Task: https://developer.blender.org/T71347
The tasks contains more information about this milestone.

To be clear: This is not a feature rich VR implementation, it's focused on the
initial scene inspection use case. We intentionally focused on that, further
features like controller support are part of the next milestone.

- How to use?
Instructions on how to use this are here:
https://wiki.blender.org/wiki/User:Severin/GSoC-2019/How_to_Test
These will be updated and moved to a more official place (likely the manual) soon.

Currently Windows Mixed Reality and Oculus devices are usable. Valve/HTC
headsets don't support the OpenXR standard yet and hence, do not work with this
implementation.

---------------

This is the C-side implementation of the features added for initial VR
support as per milestone 1. A "VR Scene Inspection" Add-on will be
committed separately, to expose the VR functionality in the UI. It also
adds some further features for milestone 1, namely a landmarking system
(stored view locations in the VR space)

Main additions/features:
* Support for rendering viewports to an HMD, with good performance.
* Option to sync the VR view perspective with a fully interactive,
  regular 3D View (VR-Mirror).
* Option to disable positional tracking. Keeps the current position (calculated
  based on the VR eye center pose) when enabled while a VR session is running.
* Some regular viewport settings for the VR view
* RNA/Python-API to query and set VR session state information.
* WM-XR: Layer tying Ghost-XR to the Blender specific APIs/data
* wmSurface API: drawable, non-window container (manages Ghost-OpenGL and GPU
  context)
* DNA/RNA for management of VR session settings
* `--debug-xr` and `--debug-xr-time` commandline options
* Utility batch & config file for using the Oculus runtime on Windows.
* Most VR data is runtime only. The exception is user settings which are saved
  to files (`XrSessionSettings`).
* VR support can be disabled through the `WITH_XR_OPENXR` compiler flag.

For architecture and code documentation, see
https://wiki.blender.org/wiki/Source/Interface/XR.

---------------

A few thank you's:
* A huge shoutout to Ray Molenkamp for his help during the project - it would
  have not been that successful without him!
* Sebastian Koenig and Simeon Conzendorf for testing and feedback!
* The reviewers, especially Brecht Van Lommel!
* Dalai Felinto for pushing and managing me to get this done ;)
* The OpenXR working group for providing an open standard. I think we're the
  first bigger application to adopt OpenXR. Congratulations to them and
  ourselves :)

This project started as a Google Summer of Code 2019 project - "Core Support of
Virtual Reality Headsets through OpenXR" (see
https://wiki.blender.org/wiki/User:Severin/GSoC-2019/).
Some further information, including ideas for further improvements can be found
in the final GSoC report:
https://wiki.blender.org/wiki/User:Severin/GSoC-2019/Final_Report

Differential Revisions: D6193, D7098

Reviewed by: Brecht Van Lommel, Jeroen Bakker

1 files changed, 77 insertions, 53 deletions

diff --git a/source/blender/editors/space_view3d/view3d_edit.c b/source/blender/editors/space_view3d/view3d_edit.c
index a7136cc580c..68d5765e43d 100644
--- a/source/blender/editors/space_view3d/view3d_edit.c
+++ b/source/blender/editors/space_view3d/view3d_edit.c
@@ -85,6 +85,52 @@ enum {
   HAS_ROTATE = (1 << 0),
 };
 
+/* test for unlocked camera view in quad view */
+static bool view3d_camera_user_poll(bContext *C)
+{
+  View3D *v3d;
+  ARegion *region;
+
+  if (ED_view3d_context_user_region(C, &v3d, &region)) {
+    RegionView3D *rv3d = region->regiondata;
+    if ((rv3d->persp == RV3D_CAMOB) && !(RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ANY_TRANSFORM)) {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+static bool view3d_lock_poll(bContext *C)
+{
+  View3D *v3d = CTX_wm_view3d(C);
+  if (v3d) {
+    RegionView3D *rv3d = CTX_wm_region_view3d(C);
+    if (rv3d) {
+      return ED_view3d_offset_lock_check(v3d, rv3d);
+    }
+  }
+  return false;
+}
+
+static bool view3d_pan_poll(bContext *C)
+{
+  if (ED_operator_region_view3d_active(C)) {
+    const RegionView3D *rv3d = CTX_wm_region_view3d(C);
+    return !(RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_LOCATION);
+  }
+  return false;
+}
+
+static bool view3d_zoom_or_dolly_poll(bContext *C)
+{
+  if (ED_operator_region_view3d_active(C)) {
+    const RegionView3D *rv3d = CTX_wm_region_view3d(C);
+    return !(RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ZOOM_AND_DOLLY);
+  }
+  return false;
+}
+
 /* -------------------------------------------------------------------- */
 /** \name Generic View Operator Properties
  * \{ */
@@ -935,7 +981,7 @@ static int viewrotate_invoke(bContext *C, wmOperator *op, const wmEvent *event)
   vod = op->customdata;
 
   /* poll should check but in some cases fails, see poll func for details */
-  if (vod->rv3d->viewlock & RV3D_LOCKED) {
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_LOCK_ROTATION) {
     viewops_data_free(C, op);
     return OPERATOR_PASS_THROUGH;
   }
@@ -983,34 +1029,6 @@ static int viewrotate_invoke(bContext *C, wmOperator *op, const wmEvent *event)
   }
 }
 
-/* test for unlocked camera view in quad view */
-static bool view3d_camera_user_poll(bContext *C)
-{
-  View3D *v3d;
-  ARegion *region;
-
-  if (ED_view3d_context_user_region(C, &v3d, &region)) {
-    RegionView3D *rv3d = region->regiondata;
-    if (rv3d->persp == RV3D_CAMOB) {
-      return 1;
-    }
-  }
-
-  return 0;
-}
-
-static bool view3d_lock_poll(bContext *C)
-{
-  View3D *v3d = CTX_wm_view3d(C);
-  if (v3d) {
-    RegionView3D *rv3d = CTX_wm_region_view3d(C);
-    if (rv3d) {
-      return ED_view3d_offset_lock_check(v3d, rv3d);
-    }
-  }
-  return false;
-}
-
 static void viewrotate_cancel(bContext *C, wmOperator *op)
 {
   viewops_data_free(C, op);
@@ -1051,7 +1069,7 @@ static bool ndof_has_translate(const wmNDOFMotionData *ndof,
 
 static bool ndof_has_rotate(const wmNDOFMotionData *ndof, const RegionView3D *rv3d)
 {
-  return !is_zero_v3(ndof->rvec) && ((rv3d->viewlock & RV3D_LOCKED) == 0);
+  return !is_zero_v3(ndof->rvec) && ((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION) == 0);
 }
 
 /**
@@ -1159,7 +1177,7 @@ static void view3d_ndof_pan_zoom(const struct wmNDOFMotionData *ndof,
     /* move center of view opposite of hand motion (this is camera mode, not object mode) */
     sub_v3_v3(rv3d->ofs, pan_vec);
 
-    if (rv3d->viewlock & RV3D_BOXVIEW) {
+    if (RV3D_LOCK_FLAGS(rv3d) & RV3D_BOXVIEW) {
       view3d_boxview_sync(sa, region);
     }
   }
@@ -1176,7 +1194,7 @@ static void view3d_ndof_orbit(const struct wmNDOFMotionData *ndof,
 
   float view_inv[4];
 
-  BLI_assert((rv3d->viewlock & RV3D_LOCKED) == 0);
+  BLI_assert((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION) == 0);
 
   ED_view3d_persp_ensure(vod->depsgraph, v3d, region);
 
@@ -1400,7 +1418,7 @@ static int ndof_orbit_invoke(bContext *C, wmOperator *op, const wmEvent *event)
     const bool has_rotation = ndof_has_rotate(ndof, rv3d);
     /* if we can't rotate, fallback to translate (locked axis views) */
     const bool has_translate = ndof_has_translate(ndof, v3d, rv3d) &&
-                               (rv3d->viewlock & RV3D_LOCKED);
+                               (RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION);
     const bool has_zoom = (ndof->tvec[2] != 0.0f) && !rv3d->is_persp;
 
     if (has_translate || has_zoom) {
@@ -1732,7 +1750,7 @@ static void viewmove_apply(ViewOpsData *vod, int x, int y)
 
     add_v3_v3(vod->rv3d->ofs, dvec);
 
-    if (vod->rv3d->viewlock & RV3D_BOXVIEW) {
+    if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_BOXVIEW) {
       view3d_boxview_sync(vod->sa, vod->region);
     }
   }
@@ -1807,12 +1825,17 @@ static int viewmove_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 
   /* makes op->customdata */
   viewops_data_alloc(C, op);
+  vod = op->customdata;
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_LOCK_LOCATION) {
+    viewops_data_free(C, op);
+    return OPERATOR_PASS_THROUGH;
+  }
+
   viewops_data_create(C,
                       op,
                       event,
                       (viewops_flag_from_prefs() & ~VIEWOPS_FLAG_ORBIT_SELECT) |
                           (use_cursor_init ? VIEWOPS_FLAG_USE_MOUSE_INIT : 0));
-  vod = op->customdata;
 
   ED_view3d_smooth_view_force_finish(C, vod->v3d, vod->region);
 
@@ -2165,7 +2188,7 @@ static void viewzoom_apply_3d(ViewOpsData *vod,
   /* these limits were in old code too */
   CLAMP(vod->rv3d->dist, dist_range[0], dist_range[1]);
 
-  if (vod->rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(vod->sa, vod->region);
   }
 
@@ -2318,7 +2341,7 @@ static int viewzoom_exec(bContext *C, wmOperator *op)
     }
   }
 
-  if (rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(sa, region);
   }
 
@@ -2416,7 +2439,7 @@ void VIEW3D_OT_zoom(wmOperatorType *ot)
   ot->invoke = viewzoom_invoke;
   ot->exec = viewzoom_exec;
   ot->modal = viewzoom_modal;
-  ot->poll = ED_operator_region_view3d_active;
+  ot->poll = view3d_zoom_or_dolly_poll;
   ot->cancel = viewzoom_cancel;
 
   /* flags */
@@ -2514,7 +2537,7 @@ static void viewdolly_apply(ViewOpsData *vod, const int xy[2], const short zoom_
     view_dolly_to_vector_3d(vod->region, vod->init.ofs, vod->init.mousevec, zfac);
   }
 
-  if (vod->rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(vod->sa, vod->region);
   }
 
@@ -2612,7 +2635,7 @@ static int viewdolly_exec(bContext *C, wmOperator *op)
 
   view_dolly_to_vector_3d(region, rv3d->ofs, mousevec, delta < 0 ? 0.2f : 1.8f);
 
-  if (rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(sa, region);
   }
 
@@ -2641,7 +2664,7 @@ static int viewdolly_invoke(bContext *C, wmOperator *op, const wmEvent *event)
   vod = op->customdata;
 
   /* poll should check but in some cases fails, see poll func for details */
-  if (vod->rv3d->viewlock & RV3D_LOCKED) {
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_LOCK_ROTATION) {
     viewops_data_free(C, op);
     return OPERATOR_PASS_THROUGH;
   }
@@ -3121,7 +3144,7 @@ void VIEW3D_OT_view_selected(wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = viewselected_exec;
-  ot->poll = ED_operator_region_view3d_active;
+  ot->poll = view3d_zoom_or_dolly_poll;
 
   /* flags */
   ot->flag = 0;
@@ -3265,7 +3288,7 @@ void VIEW3D_OT_view_center_cursor(wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = viewcenter_cursor_exec;
-  ot->poll = ED_operator_view3d_active;
+  ot->poll = view3d_pan_poll;
 
   /* flags */
   ot->flag = 0;
@@ -3317,7 +3340,7 @@ void VIEW3D_OT_view_center_pick(wmOperatorType *ot)
 
   /* api callbacks */
   ot->invoke = viewcenter_pick_invoke;
-  ot->poll = ED_operator_view3d_active;
+  ot->poll = view3d_pan_poll;
 
   /* flags */
   ot->flag = 0;
@@ -3701,7 +3724,7 @@ static int view3d_zoom_border_exec(bContext *C, wmOperator *op)
                             .dist = &new_dist,
                         });
 
-  if (rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(CTX_wm_area(C), region);
   }
 
@@ -3721,7 +3744,7 @@ void VIEW3D_OT_zoom_border(wmOperatorType *ot)
   ot->modal = WM_gesture_box_modal;
   ot->cancel = WM_gesture_box_cancel;
 
-  ot->poll = ED_operator_region_view3d_active;
+  ot->poll = view3d_zoom_or_dolly_poll;
 
   /* flags */
   ot->flag = 0;
@@ -3834,7 +3857,7 @@ static void axis_set_view(bContext *C,
     rv3d->view_axis_roll = view_axis_roll;
   }
 
-  if (rv3d->viewlock & RV3D_LOCKED) {
+  if (RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION) {
     ED_region_tag_redraw(region);
     return;
   }
@@ -4058,7 +4081,7 @@ static int view_camera_exec(bContext *C, wmOperator *op)
 
   ED_view3d_smooth_view_force_finish(C, v3d, region);
 
-  if ((rv3d->viewlock & RV3D_LOCKED) == 0) {
+  if ((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ANY_TRANSFORM) == 0) {
     /* lastview -  */
 
     ViewLayer *view_layer = CTX_data_view_layer(C);
@@ -4207,7 +4230,7 @@ static int vieworbit_exec(bContext *C, wmOperator *op)
                                                   RV3D_VIEW_USER;
   orbitdir = RNA_enum_get(op->ptr, "type");
 
-  if ((rv3d->viewlock & RV3D_LOCKED) && (view_opposite == RV3D_VIEW_USER)) {
+  if ((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION) && (view_opposite == RV3D_VIEW_USER)) {
     /* no NULL check is needed, poll checks */
     ED_view3d_context_user_region(C, &v3d, &region);
     rv3d = region->regiondata;
@@ -4215,7 +4238,7 @@ static int vieworbit_exec(bContext *C, wmOperator *op)
 
   ED_view3d_smooth_view_force_finish(C, v3d, region);
 
-  if ((rv3d->viewlock & RV3D_LOCKED) == 0 || (view_opposite != RV3D_VIEW_USER)) {
+  if ((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ROTATION) == 0 || (view_opposite != RV3D_VIEW_USER)) {
     if ((rv3d->persp != RV3D_CAMOB) || ED_view3d_camera_lock_check(v3d, rv3d)) {
       int smooth_viewtx = WM_operator_smooth_viewtx_get(op);
       float quat_mul[4];
@@ -4352,7 +4375,7 @@ static void viewroll_apply(ViewOpsData *vod, int x, int UNUSED(y))
         vod->rv3d->ofs, vod->init.ofs, vod->init.quat, vod->rv3d->viewquat, vod->dyn_ofs);
   }
 
-  if (vod->rv3d->viewlock & RV3D_BOXVIEW) {
+  if (RV3D_LOCK_FLAGS(vod->rv3d) & RV3D_BOXVIEW) {
     view3d_boxview_sync(vod->sa, vod->region);
   }
 
@@ -4621,7 +4644,7 @@ void VIEW3D_OT_view_pan(wmOperatorType *ot)
 
   /* api callbacks */
   ot->invoke = viewpan_invoke;
-  ot->poll = ED_operator_region_view3d_active;
+  ot->poll = view3d_pan_poll;
 
   /* flags */
   ot->flag = 0;
@@ -4647,7 +4670,8 @@ static int viewpersportho_exec(bContext *C, wmOperator *UNUSED(op))
   ED_view3d_context_user_region(C, &v3d_dummy, &region);
   rv3d = region->regiondata;
 
-  if ((rv3d->viewlock & RV3D_LOCKED) == 0) {
+  /* Could add a separate lock flag for locking persp. */
+  if ((RV3D_LOCK_FLAGS(rv3d) & RV3D_LOCK_ANY_TRANSFORM) == 0) {
     if (rv3d->persp != RV3D_ORTHO) {
       rv3d->persp = RV3D_ORTHO;
     }