VRDisplay: getFrameData() method
Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
The getFrameData()
method of the VRDisplay
interface accepts a VRFrameData
object and populates it with the information required to render the current frame.
Note: This method was part of the old WebVR API. It has been superseded by the WebXR Device API.
This includes the VRPose
and view and projection matrices for the current frame.
Syntax
js
getFrameData(frameData)
Parameters
frameData
-
The
VRFrameData
object you want to populate.
Return value
A boolean value — a value of true
is returned if the VRFrameData
object was successfully populated, or false
if it wasn't.
Examples
js
const frameData = new VRFrameData();
let vrDisplay;
navigator.getVRDisplays().then((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", () => {
vrDisplay.requestPresent([{ source: canvas }]).then(() => {
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
const curFramePose = frameData.pose;
const curPos = curFramePose.position;
const 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
const projectionMatrixLocation = gl.getUniformLocation(
shaderProgram,
"projMatrix"
);
const 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
This method was part of the old WebVR API that has been superseded by the WebXR Device API. It is no longer on track to becoming a standard.
Until all browsers have implemented the new WebXR APIs, it is recommended to rely on frameworks, like A-Frame, Babylon.js, or Three.js, or a polyfill, to develop WebXR applications that will work across all browsers [1].
Browser compatibility
BCD tables only load in the browser
See also
- WebVR API homepage
- https://mixedreality.mozilla.org/ — demos, downloads, and other resources from the Mozilla VR team.