Android WebVR implementation, Cardboard 0.5.5 SDK

content/browser/vr/android/cardboard/cardboard_vr_device.cc

+// 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.
+
+#include "content/browser/vr/android/cardboard/cardboard_vr_device.h"
+
+#include <math.h>
+#include <algorithm>
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_array.h"
+#include "base/android/jni_string.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/time/time.h"
+#include "jni/CardboardVRDevice_jni.h"
+
+using base::android::AttachCurrentThread;
+
+namespace content {
+
+namespace {
+
+// Source:
+// http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/
+VRVector4Ptr MatrixToOrientationQuat(const float m[16]) {

[jochen (gone - plz use gerrit), 2015/07/22 09:38:56]

can we add a unit test for this?

+  VRVector4Ptr out = VRVector4::New();
+  float trace = m[0] + m[5] + m[10];
+  float root;
+  if (trace > 0.0f) {
+    root = sqrtf(1.0f + trace) * 2.0f;
+    out->x = (m[9] - m[6]) / root;
+    out->y = (m[2] - m[8]) / root;
+    out->z = (m[4] - m[1]) / root;
+    out->w = 0.25f * root;
+  } else if ((m[0] > m[5]) && (m[0] > m[10])) {
+    root = sqrtf(1.0f + m[0] - m[5] - m[10]) * 2.0f;
+    out->x = 0.25f * root;
+    out->y = (m[1] + m[4]) / root;
+    out->z = (m[2] + m[8]) / root;
+    out->w = (m[9] - m[6]) / root;
+  } else if (m[5] > m[10]) {
+    root = sqrtf(1.0f + m[5] - m[0] - m[10]) * 2.0f;
+    out->x = (m[1] + m[4]) / root;
+    out->y = 0.25f * root;
+    out->z = (m[6] + m[9]) / root;
+    out->w = (m[2] - m[8]) / root;
+  } else {
+    root = sqrtf(1.0f + m[10] - m[0] - m[5]) * 2.0f;
+    out->x = (m[2] + m[8]) / root;
+    out->y = (m[6] + m[9]) / root;
+    out->z = 0.25f * root;
+    out->w = (m[4] - m[1]) / root;
+  }
+
+  return out.Pass();
+}
+
+}  // namespace
+
+bool CardboardVRDevice::RegisterCardboardVRDevice(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+CardboardVRDevice::CardboardVRDevice(VRDeviceProvider* provider)
+    : VRDevice(provider), frame_index_(0) {
+  JNIEnv* env = AttachCurrentThread();
+  j_cardboard_device_.Reset(Java_CardboardVRDevice_create(
+      env, base::android::GetApplicationContext()));
+  j_head_matrix_.Reset(env, env->NewFloatArray(16));
+}
+
+CardboardVRDevice::~CardboardVRDevice() {
+  Java_CardboardVRDevice_stopTracking(AttachCurrentThread(),
+                                      j_cardboard_device_.obj());
+}
+
+VRDeviceInfoPtr CardboardVRDevice::GetVRDevice() {
+  VRDeviceInfoPtr device = VRDeviceInfo::New();
+
+  JNIEnv* env = AttachCurrentThread();
+
+  ScopedJavaLocalRef<jstring> j_device_name =
+      Java_CardboardVRDevice_getDeviceName(env, j_cardboard_device_.obj());
+  device->deviceName =
+      base::android::ConvertJavaStringToUTF8(env, j_device_name.obj());
+
+  ScopedJavaLocalRef<jfloatArray> j_fov(env, env->NewFloatArray(4));
+  Java_CardboardVRDevice_getFieldOfView(env, j_cardboard_device_.obj(),
+                                        j_fov.obj());
+
+  std::vector<float> fov;
+  base::android::JavaFloatArrayToFloatVector(env, j_fov.obj(), &fov);
+
+  device->hmdInfo = VRHMDInfo::New();
+  VRHMDInfoPtr& hmdInfo = device->hmdInfo;
+
+  hmdInfo->leftEye = VREyeParameters::New();
+  hmdInfo->rightEye = VREyeParameters::New();
+  VREyeParametersPtr& left_eye = hmdInfo->leftEye;
+  VREyeParametersPtr& right_eye = hmdInfo->rightEye;
+
+  left_eye->recommendedFieldOfView = VRFieldOfView::New();
+  left_eye->recommendedFieldOfView->upDegrees = fov[0];
+  left_eye->recommendedFieldOfView->downDegrees = fov[1];
+  left_eye->recommendedFieldOfView->leftDegrees = fov[2];
+  left_eye->recommendedFieldOfView->rightDegrees = fov[3];
+
+  // Cardboard devices always assume a mirrored FOV, so this is just the left
+  // eye FOV with the left and right degrees swapped.
+  right_eye->recommendedFieldOfView = VRFieldOfView::New();
+  right_eye->recommendedFieldOfView->upDegrees = fov[0];
+  right_eye->recommendedFieldOfView->downDegrees = fov[1];
+  right_eye->recommendedFieldOfView->leftDegrees = fov[3];
+  right_eye->recommendedFieldOfView->rightDegrees = fov[2];
+
+  // Cardboard does not support configurable FOV.
+  left_eye->maximumFieldOfView = left_eye->recommendedFieldOfView.Clone();
+  right_eye->maximumFieldOfView = right_eye->recommendedFieldOfView.Clone();
+  left_eye->minimumFieldOfView = left_eye->recommendedFieldOfView.Clone();
+  right_eye->minimumFieldOfView = right_eye->recommendedFieldOfView.Clone();
+
+  float ipd = Java_CardboardVRDevice_getIpd(env, j_cardboard_device_.obj());
+
+  left_eye->eyeTranslation = VRVector3::New();
+  left_eye->eyeTranslation->x = ipd * -0.5f;
+  left_eye->eyeTranslation->y = 0.0f;
+  left_eye->eyeTranslation->z = 0.0f;
+
+  right_eye->eyeTranslation = VRVector3::New();
+  right_eye->eyeTranslation->x = ipd * 0.5f;
+  right_eye->eyeTranslation->y = 0.0f;
+  right_eye->eyeTranslation->z = 0.0f;
+
+  ScopedJavaLocalRef<jintArray> j_screen_size(env, env->NewIntArray(2));
+  Java_CardboardVRDevice_getScreenSize(env, j_cardboard_device_.obj(),
+                                       j_screen_size.obj());
+
+  std::vector<int> screen_size;
+  base::android::JavaIntArrayToIntVector(env, j_screen_size.obj(),
+                                         &screen_size);
+
+  left_eye->renderRect = VRRect::New();
+  left_eye->renderRect->x = 0;
+  left_eye->renderRect->y = 0;
+  left_eye->renderRect->width = screen_size[0] / 2.0;
+  left_eye->renderRect->height = screen_size[1];
+
+  right_eye->renderRect = VRRect::New();
+  right_eye->renderRect->x = screen_size[0] / 2.0;
+  right_eye->renderRect->y = 0;
+  right_eye->renderRect->width = screen_size[0] / 2.0;
+  right_eye->renderRect->height = screen_size[1];
+
+  return device.Pass();
+}
+
+VRSensorStatePtr CardboardVRDevice::GetSensorState() {
+  VRSensorStatePtr state = VRSensorState::New();
+
+  state->timestamp = base::Time::Now().ToJsTime();
+  state->frameIndex = frame_index_++;
+
+  JNIEnv* env = AttachCurrentThread();
+  Java_CardboardVRDevice_getSensorState(env, j_cardboard_device_.obj(),
+                                        j_head_matrix_.obj());
+
+  std::vector<float> head_matrix;
+  base::android::JavaFloatArrayToFloatVector(env, j_head_matrix_.obj(),
+                                             &head_matrix);
+
+  state->orientation = MatrixToOrientationQuat(&head_matrix[0]);
+
+  state->position = VRVector3::New();
+  state->position->x = -head_matrix[12];
+  state->position->y = head_matrix[13];
+  state->position->z = head_matrix[14];
+
+  return state.Pass();
+}
+
+void CardboardVRDevice::ResetSensor() {
+  Java_CardboardVRDevice_resetSensor(AttachCurrentThread(),
+                                     j_cardboard_device_.obj());
+}
+
+}  // namespace content