script/dom/webgl/
vertexarrayobject.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::cell::Cell;
6
7use script_bindings::cell::{DomRefCell, Ref};
8use script_bindings::weakref::WeakRef;
9use servo_canvas_traits::webgl::{
10    ActiveAttribInfo, WebGLCommand, WebGLError, WebGLResult, WebGLVersion, WebGLVertexArrayId,
11};
12
13use crate::dom::bindings::codegen::Bindings::WebGL2RenderingContextBinding::WebGL2RenderingContextConstants as constants2;
14use crate::dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
15use crate::dom::bindings::root::{Dom, MutNullableDom};
16use crate::dom::webgl::webglbuffer::WebGLBuffer;
17use crate::dom::webgl::webglrenderingcontext::{Operation, WebGLRenderingContext};
18
19#[derive(JSTraceable, MallocSizeOf)]
20#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
21pub(crate) struct VertexArrayObject {
22    context: WeakRef<WebGLRenderingContext>,
23    #[no_trace]
24    id: Option<WebGLVertexArrayId>,
25    ever_bound: Cell<bool>,
26    is_deleted: Cell<bool>,
27    vertex_attribs: DomRefCell<Box<[VertexAttribData]>>,
28    element_array_buffer: MutNullableDom<WebGLBuffer>,
29}
30
31impl VertexArrayObject {
32    pub(crate) fn new(context: &WebGLRenderingContext, id: Option<WebGLVertexArrayId>) -> Self {
33        let max_vertex_attribs = context.limits().max_vertex_attribs as usize;
34        Self {
35            context: WeakRef::new(context),
36            id,
37            ever_bound: Default::default(),
38            is_deleted: Default::default(),
39            vertex_attribs: DomRefCell::new(vec![Default::default(); max_vertex_attribs].into()),
40            element_array_buffer: Default::default(),
41        }
42    }
43
44    pub(crate) fn id(&self) -> Option<WebGLVertexArrayId> {
45        self.id
46    }
47
48    pub(crate) fn is_deleted(&self) -> bool {
49        self.is_deleted.get()
50    }
51
52    pub(crate) fn delete(&self, operation_fallibility: Operation) {
53        assert!(self.id.is_some());
54        if self.is_deleted.get() {
55            return;
56        }
57        self.is_deleted.set(true);
58
59        if let Some(context) = self.context.root() {
60            context.send_with_fallibility(
61                WebGLCommand::DeleteVertexArray(self.id.unwrap()),
62                operation_fallibility,
63            );
64        }
65
66        for attrib_data in &**self.vertex_attribs.borrow() {
67            if let Some(buffer) = attrib_data.buffer() {
68                buffer.decrement_attached_counter(operation_fallibility);
69            }
70        }
71        if let Some(buffer) = self.element_array_buffer.get() {
72            buffer.decrement_attached_counter(operation_fallibility);
73        }
74    }
75
76    pub(crate) fn ever_bound(&self) -> bool {
77        self.ever_bound.get()
78    }
79
80    pub(crate) fn set_ever_bound(&self) {
81        self.ever_bound.set(true);
82    }
83
84    pub(crate) fn element_array_buffer(&self) -> &MutNullableDom<WebGLBuffer> {
85        &self.element_array_buffer
86    }
87
88    pub(crate) fn get_vertex_attrib(&self, index: u32) -> Option<Ref<'_, VertexAttribData>> {
89        Ref::filter_map(self.vertex_attribs.borrow(), |attribs| {
90            attribs.get(index as usize)
91        })
92        .ok()
93    }
94
95    pub(crate) fn vertex_attrib_pointer(
96        &self,
97        index: u32,
98        size: i32,
99        type_: u32,
100        stride: i32,
101        offset: i64,
102        kind: VertexAttribPointerKind,
103    ) -> WebGLResult<()> {
104        let mut attribs = self.vertex_attribs.borrow_mut();
105        let data = attribs
106            .get_mut(index as usize)
107            .ok_or(WebGLError::InvalidValue)?;
108
109        if !(1..=4).contains(&size) {
110            return Err(WebGLError::InvalidValue);
111        }
112
113        // https://www.khronos.org/registry/webgl/specs/latest/1.0/#BUFFER_OFFSET_AND_STRIDE
114        // https://www.khronos.org/registry/webgl/specs/latest/1.0/#VERTEX_STRIDE
115        if !(0..=255).contains(&stride) || offset < 0 {
116            return Err(WebGLError::InvalidValue);
117        }
118
119        let Some(context) = self.context.root() else {
120            return Err(WebGLError::ContextLost);
121        };
122
123        let is_webgl2 = matches!(context.webgl_version(), WebGLVersion::WebGL2);
124        let bytes_per_component: i32 = match type_ {
125            constants::BYTE | constants::UNSIGNED_BYTE => 1,
126            constants::SHORT | constants::UNSIGNED_SHORT => 2,
127            constants::FLOAT => 4,
128            constants::INT | constants::UNSIGNED_INT if is_webgl2 => 4,
129            constants2::HALF_FLOAT if is_webgl2 => 2,
130            glow::FIXED if is_webgl2 => 4,
131            constants2::INT_2_10_10_10_REV | constants2::UNSIGNED_INT_2_10_10_10_REV
132                if is_webgl2 && size == 4 =>
133            {
134                4
135            },
136            _ => return Err(WebGLError::InvalidEnum),
137        };
138
139        if offset % bytes_per_component as i64 > 0 || stride % bytes_per_component > 0 {
140            return Err(WebGLError::InvalidOperation);
141        }
142
143        let buffer = context.array_buffer();
144        match buffer {
145            Some(ref buffer) => buffer.increment_attached_counter(),
146            None if offset != 0 => {
147                // https://github.com/KhronosGroup/WebGL/pull/2228
148                return Err(WebGLError::InvalidOperation);
149            },
150            _ => {},
151        }
152        context.send_command(match kind {
153            VertexAttribPointerKind::Float { normalized } => WebGLCommand::VertexAttribPointer(
154                index,
155                size,
156                type_,
157                normalized,
158                stride,
159                offset as u32,
160            ),
161            VertexAttribPointerKind::Integer => {
162                WebGLCommand::VertexAttribIPointer(index, size, type_, stride, offset as u32)
163            },
164        });
165        if let Some(old) = data.buffer() {
166            old.decrement_attached_counter(Operation::Infallible);
167        }
168
169        *data = VertexAttribData {
170            enabled_as_array: data.enabled_as_array,
171            size: size as u8,
172            type_,
173            bytes_per_vertex: size as u8 * bytes_per_component as u8,
174            kind,
175            stride: stride as u8,
176            offset: offset as u32,
177            buffer: buffer.map(|b| Dom::from_ref(&*b)),
178            divisor: data.divisor,
179        };
180
181        Ok(())
182    }
183
184    pub(crate) fn vertex_attrib_divisor(&self, index: u32, value: u32) {
185        self.vertex_attribs.borrow_mut()[index as usize].divisor = value;
186    }
187
188    pub(crate) fn enabled_vertex_attrib_array(&self, index: u32, value: bool) {
189        self.vertex_attribs.borrow_mut()[index as usize].enabled_as_array = value;
190    }
191
192    pub(crate) fn unbind_buffer(&self, buffer: &WebGLBuffer) {
193        for attrib in &mut **self.vertex_attribs.borrow_mut() {
194            if let Some(b) = attrib.buffer() {
195                if b.id() != buffer.id() {
196                    continue;
197                }
198                b.decrement_attached_counter(Operation::Infallible);
199            }
200            attrib.buffer = None;
201        }
202        if self
203            .element_array_buffer
204            .get()
205            .is_some_and(|b| buffer == &*b)
206        {
207            buffer.decrement_attached_counter(Operation::Infallible);
208            self.element_array_buffer.set(None);
209        }
210    }
211
212    pub(crate) fn validate_for_draw(
213        &self,
214        required_len: u32,
215        instance_count: u32,
216        active_attribs: &[ActiveAttribInfo],
217    ) -> WebGLResult<()> {
218        // TODO(nox): Cache limits per VAO.
219        let attribs = self.vertex_attribs.borrow();
220        // https://www.khronos.org/registry/webgl/specs/latest/1.0/#6.2
221        if attribs
222            .iter()
223            .any(|data| data.enabled_as_array && data.buffer.is_none())
224        {
225            return Err(WebGLError::InvalidOperation);
226        }
227        let mut has_active_attrib = false;
228        let mut has_divisor_0 = false;
229        for active_info in active_attribs {
230            let Some(location) = active_info.location else {
231                continue;
232            };
233            has_active_attrib = true;
234            let attrib = &attribs[location as usize];
235            if attrib.divisor == 0 {
236                has_divisor_0 = true;
237            }
238            if !attrib.enabled_as_array {
239                continue;
240            }
241            // https://www.khronos.org/registry/webgl/specs/latest/1.0/#6.6
242            if required_len > 0 && instance_count > 0 {
243                let max_vertices = attrib.max_vertices();
244                if attrib.divisor == 0 {
245                    if max_vertices < required_len {
246                        return Err(WebGLError::InvalidOperation);
247                    }
248                } else if max_vertices
249                    .checked_mul(attrib.divisor)
250                    .is_some_and(|v| v < instance_count)
251                {
252                    return Err(WebGLError::InvalidOperation);
253                }
254            }
255        }
256        if has_active_attrib && !has_divisor_0 {
257            return Err(WebGLError::InvalidOperation);
258        }
259        Ok(())
260    }
261}
262
263impl Drop for VertexArrayObject {
264    fn drop(&mut self) {
265        if self.id.is_some() {
266            self.delete(Operation::Fallible);
267        }
268    }
269}
270
271/// How a `vertexAttrib*Pointer` call delivers attribute values to the shader.
272#[derive(Clone, Copy, JSTraceable, MallocSizeOf)]
273pub(crate) enum VertexAttribPointerKind {
274    /// `vertexAttribPointer`: converted to float.
275    Float { normalized: bool },
276    /// `vertexAttribIPointer`: kept as int/uint.
277    Integer,
278}
279
280impl VertexAttribPointerKind {
281    pub(crate) fn is_normalized(self) -> bool {
282        matches!(self, Self::Float { normalized: true })
283    }
284
285    pub(crate) fn is_integer(self) -> bool {
286        matches!(self, Self::Integer)
287    }
288}
289
290#[derive(Clone, JSTraceable, MallocSizeOf)]
291#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
292pub(crate) struct VertexAttribData {
293    pub(crate) enabled_as_array: bool,
294    pub(crate) size: u8,
295    pub(crate) type_: u32,
296    bytes_per_vertex: u8,
297    pub(crate) kind: VertexAttribPointerKind,
298    pub(crate) stride: u8,
299    pub(crate) offset: u32,
300    pub(crate) buffer: Option<Dom<WebGLBuffer>>,
301    pub(crate) divisor: u32,
302}
303
304impl Default for VertexAttribData {
305    fn default() -> Self {
306        Self {
307            enabled_as_array: false,
308            size: 4,
309            type_: constants::FLOAT,
310            bytes_per_vertex: 16,
311            kind: VertexAttribPointerKind::Float { normalized: false },
312            stride: 0,
313            offset: 0,
314            buffer: None,
315            divisor: 0,
316        }
317    }
318}
319
320impl VertexAttribData {
321    pub(crate) fn buffer(&self) -> Option<&WebGLBuffer> {
322        self.buffer.as_deref()
323    }
324
325    pub(crate) fn max_vertices(&self) -> u32 {
326        let capacity = (self.buffer().unwrap().capacity() as u32).saturating_sub(self.offset);
327        if capacity < self.bytes_per_vertex as u32 {
328            0
329        } else if self.stride == 0 {
330            capacity / self.bytes_per_vertex as u32
331        } else if self.stride < self.bytes_per_vertex {
332            (capacity - (self.bytes_per_vertex - self.stride) as u32) / self.stride as u32
333        } else {
334            let mut max = capacity / self.stride as u32;
335            if capacity % self.stride as u32 >= self.bytes_per_vertex as u32 {
336                max += 1;
337            }
338            max
339        }
340    }
341}
script/dom/webgl/vertexarrayobject.rs

script/dom/webgl/
vertexarrayobject.rs
