VRPose - Web APIs 编辑

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The VRPose interface of the WebVR API represents the state of a VR sensor at a given timestamp (which includes orientation, position, velocity, and acceleration information.)

This interface is accessible through the VRDisplay.getPose() and VRDisplay.getFrameData() methods. VRDisplay.getPose() is deprecated.

Properties

VRPose.position Read only

Returns the position of the VRDisplay at the current VRPose.timestamp as a 3D vector

VRPose.linearVelocity Read only

Returns the linear velocity of the VRDisplay at the current VRPose.timestamp, in meters per second.

VRPose.linearAcceleration Read only

Returns the linear acceleration of the VRDisplay at the current VRPose.timestamp, in meters per second per second.

VRPose.orientation Read only

Returns the orientation of the sensor at the current VRPose.timestamp, as a quarternion value.

VRPose.angularVelocity Read only

Returns the angular velocity of the VRDisplay at the current VRPose.timestamp, in radians per second.

VRPose.angularAcceleration Read only

Returns the angular acceleration of the VRDisplay at the current VRPose.timestamp, in meters per second per second.

Obsolete properties

VRPose.timeStamp Read only

Returns the current time stamp of the system — a monotonically increasing value useful for determining if position data has been updated, and what order updates have occurred in. This version of timestamp has been removed from the spec — instead, timestamps are now returned when VRDisplay.getFrameData() is called — see VRFrameData.timestamp.

Examples

var frameData = new VRFrameData();
var vrDisplay;

navigator.getVRDisplays().then(function(displays) {
  vrDisplay = displays[0];
  console.log('Display found');
  // Starting the presentation when the button is clicked: It can only be called in response to a user gesture
  btn.addEventListener('click', function() {
    vrDisplay.requestPresent([{ source: canvas }]).then(function() {
      drawVRScene();
    });
  });
});

// WebVR: Draw the scene for the WebVR display.
function drawVRScene() {
  // WebVR: Request the next frame of the animation
  vrSceneFrame = vrDisplay.requestAnimationFrame(drawVRScene);

  // Populate frameData with the data of the next frame to display
  vrDisplay.getFrameData(frameData);

  // You can get the position, orientation, etc. of the display from the current frame's pose
  // curFramePose is a VRPose object
  var curFramePose = frameData.pose;
  var curPos = curFramePose.position;
  var curOrient = curFramePose.orientation;

  // Clear the canvas before we start drawing on it.

  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

  // WebVR: Create the required projection and view matrix locations needed
  // for passing into the uniformMatrix4fv methods below

  var projectionMatrixLocation = gl.getUniformLocation(shaderProgram, "projMatrix");
  var viewMatrixLocation = gl.getUniformLocation(shaderProgram, "viewMatrix");

  // WebVR: Render the left eye’s view to the left half of the canvas
  gl.viewport(0, 0, canvas.width * 0.5, canvas.height);
  gl.uniformMatrix4fv(projectionMatrixLocation, false, frameData.leftProjectionMatrix);
  gl.uniformMatrix4fv(viewMatrixLocation, false, frameData.leftViewMatrix);
  drawGeometry();

  // WebVR: Render the right eye’s view to the right half of the canvas
  gl.viewport(canvas.width * 0.5, 0, canvas.width * 0.5, canvas.height);
  gl.uniformMatrix4fv(projectionMatrixLocation, false, frameData.rightProjectionMatrix);
  gl.uniformMatrix4fv(viewMatrixLocation, false, frameData.rightViewMatrix);
  drawGeometry();

  function drawGeometry() {
    // draw the view for each eye
  }

    ...

  // WebVR: Indicate that we are ready to present the rendered frame to the VR display
  vrDisplay.submitFrame();
}

Note: You can see this complete code at raw-webgl-example.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• WebVR API homepage
• MozVr.com — demos, downloads, and other resources from the Mozilla VR team.