这是
实验性技术
检查
浏览器兼容性表格
要小心谨慎在生产中使用这之前。
requestPresent()
方法在
VRDisplay
interface starts the
VRDisplay
presenting a scene.
vrDisplayInstance.requestPresent(layers).then(function() {
// Do something after the presentation has begun
});
VRLayerInit
objects representing the scene you want to present. At the moment, this can be a minimum of 0 and a maximum of 1.
A promise that resolves once the presentation has begun. there are a number of rules surrounding the promise's fulfillment or rejection:
VRDisplayCapabilities.canPresent
is false, or if the VRLayer array contains more than
VRDisplayCapabilities.maxLayers
layers, the promise will be rejected.
VRDisplay
is already presenting when
requestPresent()
is called, the
VRDisplay
will update the
VRLayer
array being presented.
requestPresent()
is rejected while the
VRDisplay
is already presenting it will end its presentation.
requestPresent()
is called outside of an engagement gesture the promise will be rejected unless the
VRDisplay
was already presenting. This engagement gesture is also sufficient to allow
requestPointerLock()
calls until presentation has ended.
if(navigator.getVRDisplays) {
console.log('WebVR 1.1 supported');
// Then get the displays attached to the computer
navigator.getVRDisplays().then(function(displays) {
// If a display is available, use it to present the scene
if(displays.length > 0) {
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() {
if(btn.textContent === 'Start VR display') {
vrDisplay.requestPresent([{ source: canvas }]).then(function() {
console.log('Presenting to WebVR display');
// Set the canvas size to the size of the vrDisplay viewport
var leftEye = vrDisplay.getEyeParameters('left');
var rightEye = vrDisplay.getEyeParameters('right');
canvas.width = Math.max(leftEye.renderWidth, rightEye.renderWidth) * 2;
canvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);
// stop the normal presentation, and start the vr presentation
window.cancelAnimationFrame(normalSceneFrame);
drawVRScene();
btn.textContent = 'Exit VR display';
});
} else {
vrDisplay.exitPresent();
console.log('Stopped presenting to WebVR display');
btn.textContent = 'Start VR display';
// Stop the VR presentation, and start the normal presentation
vrDisplay.cancelAnimationFrame(vrSceneFrame);
drawScene();
}
});
}
});
}
注意 : You can see this complete code at raw-webgl-example .
| 规范 | 状态 | 注释 |
|---|---|---|
|
WebVR 1.1
The definition of 'requestPresent()' in that specification. |
草案 | 初始定义 |
| 桌面 | 移动 | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
requestPresent
弃用
|
Chrome No | Edge 15 — 79 |
Firefox
55
|
IE No | Opera ? | Safari No | WebView Android No |
Chrome Android
56 — 80
Disabled
|
Firefox Android 55 | Opera Android ? | Safari iOS ? |
Samsung Internet Android
6.0
|
完整支持
不支持
兼容性未知
实验。期望将来行为有所改变。
弃用。不要用于新网站。
见实现注意事项。
用户必须明确启用此特征。