device/vr/vr_service.mojom

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module device.mojom;

import "mojo/common/time.mojom";
import "gpu/ipc/common/mailbox_holder.mojom";
import "gpu/ipc/common/sync_token.mojom";
import "ui/gfx/geometry/mojo/geometry.mojom";

// A field of view, given by 4 degrees describing the view from a center point.
struct VRFieldOfView {
  float upDegrees;
  float downDegrees;
  float leftDegrees;
  float rightDegrees;
};

// A display's position, orientation, velocity, and acceleration state at the
// given timestamp.
struct VRPose {
  array<float, 4>? orientation;
  array<float, 3>? position;
  array<float, 3>? angularVelocity;
  array<float, 3>? linearVelocity;
  array<float, 3>? angularAcceleration;
  array<float, 3>? linearAcceleration;
};

struct VRDisplayCapabilities {
  bool hasPosition;
  bool hasExternalDisplay;
  bool canPresent;
};

// Information about the optical properties for an eye in a VRDisplay.
struct VREyeParameters {
  VRFieldOfView fieldOfView;
  array<float, 3> offset;
  uint32 renderWidth;
  uint32 renderHeight;
};

struct VRStageParameters {
  array<float, 16> standingTransform;
  float sizeX;
  float sizeZ;
};

struct VRDisplayInfo {
  uint32 index;
  string displayName;
  VRDisplayCapabilities capabilities;
  VRStageParameters? stageParameters;
  VREyeParameters leftEye;
  VREyeParameters rightEye;
};

enum VRDisplayEventReason {
  NONE = 0,
  NAVIGATION = 1,
  MOUNTED = 2,
  UNMOUNTED = 3
};

// TODO(shaobo.yan@intel.com) : Add comments to describe these interfaces about
// how to use and where they live.
interface VRService {
  // TODO(shaobo.yan@intel.com, crbug/701027): Use a factory function which
  // takes a VRServiceClient so we will never have a half-initialized VRService.
  SetClient(VRServiceClient client) => (uint32 number_of_connected_devices);
  // Inform the service that the page is listening for vrdisplayactivate events.
  SetListeningForActivate(bool listening);
};

interface VRServiceClient {
  OnDisplayConnected(VRDisplay display, VRDisplayClient& request,
                     VRDisplayInfo display_info);
};

interface VRSubmitFrameClient {
  OnSubmitFrameTransferred();
  OnSubmitFrameRendered();
};

// Represents a physical VR device that can be used to present WebVR content, or get orientation
// data (VRPose) when not presenting (aka magic window).
interface VRDisplay {
  RequestPresent(bool secure_origin, VRSubmitFrameClient client,
                 VRPresentationProvider& request) => (bool success);
  ExitPresent();
  GetNextMagicWindowPose() => (VRPose? pose);
};

// Provides the necessary functionality for a presenting WebVR page to draw frames for a VrDisplay.
interface VRPresentationProvider {
  enum VSyncStatus { SUCCESS, CLOSING };

  // The frameId maps a VSync to a frame arriving from the compositor. IDs will
  // be reused after the frame arrives from the compositor. Negative IDs imply
  // no mapping.
  GetVSync() => (VRPose? pose, mojo.common.mojom.TimeDelta time, int16 frame_id,
                 VSyncStatus status);
  SubmitFrame(int16 frame_id, gpu.mojom.MailboxHolder mailbox_holder);
  UpdateLayerBounds(int16 frame_id, gfx.mojom.RectF left_bounds,
                    gfx.mojom.RectF right_bounds, gfx.mojom.Size source_size);
};

interface VRDisplayClient {
  OnChanged(VRDisplayInfo display);
  OnExitPresent();
  OnBlur();
  OnFocus();
  OnActivate(VRDisplayEventReason reason) => (bool will_not_present);
  OnDeactivate(VRDisplayEventReason reason);
};