script/dom/webxr/
xrwebgllayer.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::convert::TryInto;
6
7use canvas_traits::webgl::{WebGLCommand, WebGLContextId, WebGLTextureId};
8use dom_struct::dom_struct;
9use euclid::{Rect, Size2D};
10use js::rust::HandleObject;
11use webxr_api::{ContextId as WebXRContextId, LayerId, LayerInit, Viewport};
12
13use crate::canvas_context::CanvasContext;
14use crate::conversions::Convert;
15use crate::dom::bindings::codegen::Bindings::WebGL2RenderingContextBinding::WebGL2RenderingContextConstants as constants;
16use crate::dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextMethods;
17use crate::dom::bindings::codegen::Bindings::XRWebGLLayerBinding::{
18    XRWebGLLayerInit, XRWebGLLayerMethods, XRWebGLRenderingContext,
19};
20use crate::dom::bindings::error::{Error, Fallible};
21use crate::dom::bindings::inheritance::Castable;
22use crate::dom::bindings::num::Finite;
23use crate::dom::bindings::reflector::{DomGlobal, reflect_dom_object_with_proto};
24use crate::dom::bindings::root::{Dom, DomRoot};
25use crate::dom::globalscope::GlobalScope;
26use crate::dom::webgl::webglframebuffer::WebGLFramebuffer;
27use crate::dom::webgl::webglobject::WebGLObject;
28use crate::dom::webgl::webglrenderingcontext::WebGLRenderingContext;
29use crate::dom::webgl::webgltexture::WebGLTexture;
30use crate::dom::window::Window;
31use crate::dom::xrframe::XRFrame;
32use crate::dom::xrlayer::XRLayer;
33use crate::dom::xrsession::XRSession;
34use crate::dom::xrview::XRView;
35use crate::dom::xrviewport::XRViewport;
36use crate::script_runtime::CanGc;
37
38impl Convert<LayerInit> for XRWebGLLayerInit {
39    fn convert(self) -> LayerInit {
40        LayerInit::WebGLLayer {
41            alpha: self.alpha,
42            antialias: self.antialias,
43            depth: self.depth,
44            stencil: self.stencil,
45            framebuffer_scale_factor: *self.framebufferScaleFactor as f32,
46            ignore_depth_values: self.ignoreDepthValues,
47        }
48    }
49}
50
51#[dom_struct]
52pub(crate) struct XRWebGLLayer {
53    xr_layer: XRLayer,
54    antialias: bool,
55    depth: bool,
56    stencil: bool,
57    alpha: bool,
58    ignore_depth_values: bool,
59    /// If none, this is an inline session (the composition disabled flag is true)
60    framebuffer: Option<Dom<WebGLFramebuffer>>,
61}
62
63impl XRWebGLLayer {
64    pub(crate) fn new_inherited(
65        session: &XRSession,
66        context: &WebGLRenderingContext,
67        init: &XRWebGLLayerInit,
68        framebuffer: Option<&WebGLFramebuffer>,
69        layer_id: Option<LayerId>,
70    ) -> XRWebGLLayer {
71        XRWebGLLayer {
72            xr_layer: XRLayer::new_inherited(session, context, layer_id),
73            antialias: init.antialias,
74            depth: init.depth,
75            stencil: init.stencil,
76            alpha: init.alpha,
77            ignore_depth_values: init.ignoreDepthValues,
78            framebuffer: framebuffer.map(Dom::from_ref),
79        }
80    }
81
82    #[allow(clippy::too_many_arguments)]
83    fn new(
84        global: &GlobalScope,
85        proto: Option<HandleObject>,
86        session: &XRSession,
87        context: &WebGLRenderingContext,
88        init: &XRWebGLLayerInit,
89        framebuffer: Option<&WebGLFramebuffer>,
90        layer_id: Option<LayerId>,
91        can_gc: CanGc,
92    ) -> DomRoot<XRWebGLLayer> {
93        reflect_dom_object_with_proto(
94            Box::new(XRWebGLLayer::new_inherited(
95                session,
96                context,
97                init,
98                framebuffer,
99                layer_id,
100            )),
101            global,
102            proto,
103            can_gc,
104        )
105    }
106
107    pub(crate) fn layer_id(&self) -> Option<LayerId> {
108        self.xr_layer.layer_id()
109    }
110
111    pub(crate) fn context_id(&self) -> WebGLContextId {
112        self.xr_layer.context_id()
113    }
114
115    pub(crate) fn session(&self) -> &XRSession {
116        self.xr_layer.session()
117    }
118
119    pub(crate) fn size(&self) -> Size2D<u32, Viewport> {
120        if let Some(framebuffer) = self.framebuffer.as_ref() {
121            let size = framebuffer.size().unwrap_or((0, 0));
122            Size2D::new(
123                size.0.try_into().unwrap_or(0),
124                size.1.try_into().unwrap_or(0),
125            )
126        } else {
127            Size2D::from_untyped(self.context().size())
128        }
129    }
130
131    fn texture_target(&self) -> u32 {
132        if cfg!(target_os = "macos") {
133            glow::TEXTURE_RECTANGLE
134        } else {
135            glow::TEXTURE_2D
136        }
137    }
138
139    pub(crate) fn begin_frame(&self, frame: &XRFrame) -> Option<()> {
140        debug!("XRWebGLLayer begin frame");
141        let framebuffer = self.framebuffer.as_ref()?;
142        let context = framebuffer.upcast::<WebGLObject>().context();
143        let sub_images = frame.get_sub_images(self.layer_id()?)?;
144        let session = self.session();
145        // TODO: Cache this texture
146        let color_texture_id = WebGLTextureId::new(sub_images.sub_image.as_ref()?.color_texture?);
147        let color_texture =
148            WebGLTexture::new_webxr(context, color_texture_id, session, CanGc::note());
149        let target = self.texture_target();
150
151        // Save the current bindings
152        let saved_framebuffer = context.get_draw_framebuffer_slot().get();
153        let saved_framebuffer_target = framebuffer.target();
154        let saved_texture_id = context
155            .textures()
156            .active_texture_slot(target, context.webgl_version())
157            .ok()
158            .and_then(|slot| slot.get().map(|texture| texture.id()));
159
160        // We have to pick a framebuffer target.
161        // If there is a draw framebuffer, we use its target,
162        // otherwise we just use DRAW_FRAMEBUFFER.
163        let framebuffer_target = saved_framebuffer
164            .as_ref()
165            .and_then(|fb| fb.target())
166            .unwrap_or(constants::DRAW_FRAMEBUFFER);
167
168        // Update the attachments
169        context.send_command(WebGLCommand::BindTexture(target, Some(color_texture_id)));
170        framebuffer.bind(framebuffer_target);
171        framebuffer
172            .texture2d_even_if_opaque(
173                constants::COLOR_ATTACHMENT0,
174                self.texture_target(),
175                Some(&color_texture),
176                0,
177            )
178            .ok()?;
179        if let Some(id) = sub_images.sub_image.as_ref()?.depth_stencil_texture {
180            // TODO: Cache this texture
181            let depth_stencil_texture_id = WebGLTextureId::new(id);
182            let depth_stencil_texture =
183                WebGLTexture::new_webxr(context, depth_stencil_texture_id, session, CanGc::note());
184            framebuffer
185                .texture2d_even_if_opaque(
186                    constants::DEPTH_STENCIL_ATTACHMENT,
187                    constants::TEXTURE_2D,
188                    Some(&depth_stencil_texture),
189                    0,
190                )
191                .ok()?;
192        }
193
194        // Restore the old bindings
195        context.send_command(WebGLCommand::BindTexture(target, saved_texture_id));
196        if let Some(framebuffer_target) = saved_framebuffer_target {
197            framebuffer.bind(framebuffer_target);
198        }
199        if let Some(framebuffer) = saved_framebuffer {
200            framebuffer.bind(framebuffer_target);
201        }
202        Some(())
203    }
204
205    pub(crate) fn end_frame(&self, _frame: &XRFrame) -> Option<()> {
206        debug!("XRWebGLLayer end frame");
207        // TODO: invalidate the old texture
208        let framebuffer = self.framebuffer.as_ref()?;
209        // TODO: rebind the current bindings
210        framebuffer.bind(constants::FRAMEBUFFER);
211        framebuffer
212            .texture2d_even_if_opaque(constants::COLOR_ATTACHMENT0, self.texture_target(), None, 0)
213            .ok()?;
214        framebuffer
215            .texture2d_even_if_opaque(
216                constants::DEPTH_STENCIL_ATTACHMENT,
217                constants::DEPTH_STENCIL_ATTACHMENT,
218                None,
219                0,
220            )
221            .ok()?;
222        framebuffer.upcast::<WebGLObject>().context().Flush();
223        Some(())
224    }
225
226    pub(crate) fn context(&self) -> &WebGLRenderingContext {
227        self.xr_layer.context()
228    }
229}
230
231impl XRWebGLLayerMethods<crate::DomTypeHolder> for XRWebGLLayer {
232    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-xrwebgllayer>
233    fn Constructor(
234        global: &Window,
235        proto: Option<HandleObject>,
236        can_gc: CanGc,
237        session: &XRSession,
238        context: XRWebGLRenderingContext,
239        init: &XRWebGLLayerInit,
240    ) -> Fallible<DomRoot<Self>> {
241        let context = match context {
242            XRWebGLRenderingContext::WebGLRenderingContext(ctx) => ctx,
243            XRWebGLRenderingContext::WebGL2RenderingContext(ctx) => ctx.base_context(),
244        };
245
246        // Step 2
247        if session.is_ended() {
248            return Err(Error::InvalidState(None));
249        }
250        // XXXManishearth step 3: throw error if context is lost
251        // XXXManishearth step 4: check XR compat flag for immersive sessions
252
253        let (framebuffer, layer_id) = if session.is_immersive() {
254            // Step 9.2. "Initialize layer’s framebuffer to a new opaque framebuffer created with context."
255            let size = session
256                .with_session(|session| session.recommended_framebuffer_resolution())
257                .ok_or(Error::Operation)?;
258            let framebuffer = WebGLFramebuffer::maybe_new_webxr(session, &context, size, can_gc)
259                .ok_or(Error::Operation)?;
260
261            // Step 9.3. "Allocate and initialize resources compatible with session’s XR device,
262            // including GPU accessible memory buffers, as required to support the compositing of layer."
263            let context_id = WebXRContextId::from(context.context_id());
264            let layer_init: LayerInit = init.convert();
265            let layer_id = session
266                .with_session(|session| session.create_layer(context_id, layer_init))
267                .map_err(|_| Error::Operation)?;
268
269            // Step 9.4: "If layer’s resources were unable to be created for any reason,
270            // throw an OperationError and abort these steps."
271            (Some(framebuffer), Some(layer_id))
272        } else {
273            (None, None)
274        };
275
276        // Ensure that we finish setting up this layer before continuing.
277        context.Finish();
278
279        // Step 10. "Return layer."
280        Ok(XRWebGLLayer::new(
281            &global.global(),
282            proto,
283            session,
284            &context,
285            init,
286            framebuffer.as_deref(),
287            layer_id,
288            can_gc,
289        ))
290    }
291
292    /// <https://www.w3.org/TR/webxr/#dom-xrwebgllayer-getnativeframebufferscalefactor>
293    fn GetNativeFramebufferScaleFactor(_window: &Window, session: &XRSession) -> Finite<f64> {
294        let value: f64 = if session.is_ended() { 0.0 } else { 1.0 };
295        Finite::wrap(value)
296    }
297
298    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-antialias>
299    fn Antialias(&self) -> bool {
300        self.antialias
301    }
302
303    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-ignoredepthvalues>
304    fn IgnoreDepthValues(&self) -> bool {
305        self.ignore_depth_values
306    }
307
308    /// <https://www.w3.org/TR/webxr/#dom-xrwebgllayer-fixedfoveation>
309    fn GetFixedFoveation(&self) -> Option<Finite<f32>> {
310        // Fixed foveation is only available on Quest/Pico headset runtimes
311        None
312    }
313
314    /// <https://www.w3.org/TR/webxr/#dom-xrwebgllayer-fixedfoveation>
315    fn SetFixedFoveation(&self, _value: Option<Finite<f32>>) {
316        // no-op until fixed foveation is supported
317    }
318
319    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-framebuffer>
320    fn GetFramebuffer(&self) -> Option<DomRoot<WebGLFramebuffer>> {
321        self.framebuffer.as_ref().map(|x| DomRoot::from_ref(&**x))
322    }
323
324    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-framebufferwidth>
325    fn FramebufferWidth(&self) -> u32 {
326        self.size().width
327    }
328
329    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-framebufferheight>
330    fn FramebufferHeight(&self) -> u32 {
331        self.size().height
332    }
333
334    /// <https://immersive-web.github.io/webxr/#dom-xrwebgllayer-getviewport>
335    fn GetViewport(&self, view: &XRView) -> Option<DomRoot<XRViewport>> {
336        if self.session() != view.session() {
337            return None;
338        }
339
340        let index = view.viewport_index();
341
342        let viewport = self.session().with_session(|s| {
343            // Inline sessions
344            if s.viewports().is_empty() {
345                Rect::from_size(self.size().to_i32())
346            } else {
347                s.viewports()[index]
348            }
349        });
350
351        // NOTE: According to spec, viewport sizes should be recalculated here if the
352        // requested viewport scale has changed. However, existing browser implementations
353        // don't seem to do this for stereoscopic immersive sessions.
354        // Revisit if Servo gets support for handheld AR/VR via ARCore/ARKit
355
356        Some(XRViewport::new(&self.global(), viewport, CanGc::note()))
357    }
358}
script/dom/webxr/xrwebgllayer.rs

script/dom/webxr/
xrwebgllayer.rs
