Bug 1924152 - Add multi-frame reftests to wrench. r=gw

Also add a test to exercise the feature as well as the new render-without-present mode in WebRender.

Differential Revision: https://phabricator.services.mozilla.com/D234163

Author: nical

wrench/reftests/image/reftest.list

@@ -25,3 +25,4 @@ fuzzy(1,160000) == image-filter-stretch-tile.yaml green-alpha-ref.yaml
 == snapshot-filters-01.yaml snapshot-filters-01-ref.yaml
 == snapshot-filters-02.yaml snapshot-filters-02-ref.yaml
 fuzzy(3,3000) == snapshot-shadow.yaml snapshot-shadow-ref.yaml
+== snapshot-multiframe.yaml snapshot-multiframe-ref.yaml

wrench/reftests/image/snapshot-multiframe-ref.yaml

@@ -0,0 +1,12 @@
+---
+root:
+  items:
+    - type: stacking-context
+      bounds: [0, 0, 200, 200]
+      items:
+        - type: rect
+          bounds: [ 0, 0, 90, 100 ]
+          color: [0, 150, 0]
+        - type: rect
+          bounds: [ 10, 100, 90, 100 ]
+          color: [150, 0, 0]

wrench/reftests/image/snapshot-multiframe.yaml

@@ -0,0 +1,41 @@
+# This test exercises wrench's multi-frame reftest feature by capturing an
+# out-of-view stacking context snapshot in the first frame and displaying it
+# as an image in the second frame.
+# It also exercises webrender's ability to render a frame without compositing
+# it into the window.
+---
+frames:
+  # First frame
+  - root:
+    # Don't present this frame into the window.
+    present: false
+    items:
+      - type: stacking-context
+        bounds: [0, 0, 100, 100]
+        items:
+        - type: rect
+          bounds: [ 0, 0, 320, 250 ]
+          color: [100, 50, 10]
+        - type: stacking-context
+          # The snapshotted stacking context is far out of the view
+          bounds: [100000, 0, 200, 200]
+          snapshot:
+            name: "snap0"
+            area: [0, 0, 100, 200]
+          items:
+            - type: rect
+              bounds: [ 0, 0, 90, 100 ]
+              color: [0, 150, 0]
+            - type: rect
+              bounds: [ 10, 100, 90, 100 ]
+              color: [150, 0, 0]
+      # This red rectangle that covers the view should not be shown because
+      # it is not part of a snapshot and the frame is not presented.
+      - type: rect
+        bounds: [0, 0, 1000, 1000]
+        color: red
+  # Second frame
+  - root:
+    items:
+      - image: snapshot(snap0)
+        bounds: [0, 0, 100, 200]

wrench/src/wrench.rs

@@ -21,6 +21,19 @@ use webrender::api::units::*;
 use webrender::{DebugFlags, RenderResults, ShaderPrecacheFlags, LayerCompositor};
 use crate::{WindowWrapper, NotifierEvent};
 
+#[derive(Clone)]
+pub struct DisplayList {
+    pub pipeline: PipelineId,
+    pub payload: BuiltDisplayList,
+    /// Whether to request that the transaction is presented to the window.
+    ///
+    /// The transaction will be presented if it contains at least one display list
+    /// with present set to true.
+    pub present: bool,
+    /// If set to true, send the transaction after adding this display list to it.
+    pub send_transaction: bool,
+}
+
 // TODO(gw): This descriptor matches what we currently support for fonts
 //           but is quite a mess. We should at least document and
 //           use better types for things like the style and stretch.
@@ -551,24 +564,36 @@ impl Wrench {
 
     pub fn send_lists(
         &mut self,
-        frame_number: u32,
-        display_lists: Vec<(PipelineId, BuiltDisplayList)>,
+        frame_number: &mut u32,
+        display_lists: Vec<DisplayList>,
         scroll_offsets: &HashMap<ExternalScrollId, Vec<SampledScrollOffset>>,
     ) {
         let mut txn = Transaction::new();
+        let mut present = false;
         for display_list in display_lists {
+            present |= display_list.present;
+
             txn.set_display_list(
-                Epoch(frame_number),
-                display_list,
+                Epoch(*frame_number),
+                (display_list.pipeline, display_list.payload),
             );
-        }
 
-        for (id, offsets) in scroll_offsets {
-            txn.set_scroll_offsets(*id, offsets.clone());
+            if display_list.send_transaction {
+                for (id, offsets) in scroll_offsets {
+                    txn.set_scroll_offsets(*id, offsets.clone());
+                }
+
+                txn.generate_frame(0, present, RenderReasons::TESTING);
+                self.api.send_transaction(self.document_id, txn);
+                txn = Transaction::new();
+
+                present = false;
+                *frame_number += 1;
+            }
         }
 
-        txn.generate_frame(0, true, RenderReasons::TESTING);
-        self.api.send_transaction(self.document_id, txn);
+        // The last display lists should be have send_transaction set to true.
+        assert!(txn.is_empty());
     }
 
     pub fn get_frame_profiles(

wrench/src/yaml_frame_reader.rs

@@ -17,7 +17,7 @@ use webrender::api::*;
 use webrender::render_api::*;
 use webrender::api::units::*;
 use webrender::api::FillRule;
-use crate::wrench::{FontDescriptor, Wrench, WrenchThing};
+use crate::wrench::{FontDescriptor, Wrench, WrenchThing, DisplayList};
 use crate::yaml_helper::{StringEnum, YamlHelper, make_perspective};
 use yaml_rust::{Yaml, YamlLoader};
 use crate::PLATFORM_DEFAULT_FACE_NAME;
@@ -322,7 +322,7 @@ pub struct YamlFrameReader {
     aux_dir: PathBuf,
     frame_count: u32,
 
-    display_lists: Vec<(PipelineId, BuiltDisplayList)>,
+    display_lists: Vec<DisplayList>,
 
     watch_source: bool,
     list_resources: bool,
@@ -447,13 +447,23 @@ impl YamlFrameReader {
 
         if let Some(pipelines) = yaml["pipelines"].as_vec() {
             for pipeline in pipelines {
-                self.build_pipeline(wrench, pipeline["id"].as_pipeline_id().unwrap(), pipeline);
+                let pipeline_id = pipeline["id"].as_pipeline_id().unwrap();
+                let mut builder = DisplayListBuilder::new(pipeline_id);
+                self.build_pipeline(wrench, &mut builder, pipeline_id, false, pipeline);
             }
         }
 
-        let root_stacking_context = &yaml["root"];
-        assert_ne!(*root_stacking_context, Yaml::BadValue);
-        self.build_pipeline(wrench, wrench.root_pipeline_id, root_stacking_context);
+        let mut builder = DisplayListBuilder::new(wrench.root_pipeline_id);
+
+        if let Some(frames) = yaml["frames"].as_vec() {
+            for frame in frames {
+                self.build_pipeline(wrench, &mut builder, wrench.root_pipeline_id, true, frame);
+            }
+        } else {
+            let root_stacking_context = &yaml["root"];
+            assert_ne!(*root_stacking_context, Yaml::BadValue);
+            self.build_pipeline(wrench, &mut builder, wrench.root_pipeline_id, true, root_stacking_context);
+        }
 
         // If replaying the same frame during interactive use, the frame gets rebuilt,
         // but the external image handler has already been consumed by the renderer.
@@ -465,26 +475,37 @@ impl YamlFrameReader {
     fn build_pipeline(
         &mut self,
         wrench: &mut Wrench,
+        builder: &mut DisplayListBuilder,
         pipeline_id: PipelineId,
+        send_transaction: bool,
         yaml: &Yaml
     ) {
+        // By default, present if send_transaction is set to true. Can be overridden
+        // by a field in the pipeline's root.
+        let present = yaml["present"].as_bool().unwrap_or(send_transaction);
+
         // Don't allow referencing clips between pipelines for now.
         self.user_clip_id_map.clear();
         self.user_clipchain_id_map.clear();
         self.user_spatial_id_map.clear();
         self.spatial_id_stack.clear();
         self.spatial_id_stack.push(SpatialId::root_scroll_node(pipeline_id));
 
-        let mut builder = DisplayListBuilder::new(pipeline_id);
         builder.begin();
         let mut info = CommonItemProperties {
             clip_rect: LayoutRect::zero(),
             clip_chain_id: ClipChainId::INVALID,
             spatial_id: SpatialId::new(0, PipelineId::dummy()),
             flags: PrimitiveFlags::default(),
         };
-        self.add_stacking_context_from_yaml(&mut builder, wrench, yaml, IsRoot(true), &mut info);
-        self.display_lists.push(builder.end());
+        self.add_stacking_context_from_yaml(builder, wrench, yaml, IsRoot(true), &mut info);
+        let (pipeline, payload) = builder.end();
+        self.display_lists.push(DisplayList {
+            pipeline,
+            payload,
+            present,
+            send_transaction,
+        });
 
         assert_eq!(self.spatial_id_stack.len(), 1);
     }
@@ -2139,15 +2160,14 @@ impl WrenchThing for YamlFrameReader {
         if should_build_yaml || wrench.should_rebuild_display_lists() {
             wrench.begin_frame();
             wrench.send_lists(
-                self.frame_count,
+                &mut self.frame_count,
                 self.display_lists.clone(),
                 &self.scroll_offsets,
             );
         } else {
             wrench.refresh();
         }
 
-        self.frame_count += 1;
         self.frame_count
     }