This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.
The leftProjectionMatrix
read-only property of the VRFrameData
interface returns a Float32Array
representing a 4x4 matrix that describes the projection to be used for the left eye’s rendering.
This value may be passed directly to WebGL’s uniformMatrix4fv
function.
Important: It is highly recommended that applications use this matrix without modification. Failure to use this projection matrix when rendering may cause the presented frame to be distorted or badly aligned, resulting in varying degrees of user discomfort.
Syntax
var myLPM = vrFrameDataInstance.leftProjectionMatrix;
Value
A Float32Array
object.
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
Specification | Status | Comment |
WebVR 1.1The definition of 'leftProjectionMatrix' in that specification. | Draft | Initial definition |
Browser compatibility
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
No support No |
Edge
No support 15 — 79 |
Firefox Full support 55 Full support 55 Notes' Windows support was enabled in Firefox 55. Full support 64 Notes' macOS support was enabled in Firefox 64. |
IE
No support No |
Opera
? |
Safari
No support No |
WebView Android
No support No |
Chrome Android No support 56 — 80 No support 56 — 80 Notes' Only works in an experimental version of Chrome. (Other builds won't return any devices when |
Firefox Android
Full support 55 |
Opera Android
? |
Safari iOS
? |
Samsung Internet Android Full support 6.0 Full support 6.0 Notes' Google Cardboard supported in Samsung Internet 7.0. |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.'
- Experimental. Expect behavior to change in the future.
- Deprecated. Not for use in new websites.'
- Deprecated. Not for use in new websites.
- See implementation notes.'
- See implementation notes.
- User must explicitly enable this feature.'
- User must explicitly enable this feature.
See also
- WebVR API homepage
- MozVr.com — demos, downloads, and other resources from the Mozilla VR team.
VRFrameData.leftProjectionMatrix by Mozilla Contributors is licensed under CC-BY-SA 2.5.