From a51b4f92325699a4b7c1920ca86c8f71eb5a2db4 Mon Sep 17 00:00:00 2001
From: Andreas Reich <r_andreas2@web.de>
Date: Tue, 19 Jan 2021 22:59:34 +0100
Subject: [PATCH] buffer zero initialization prior to use in submit

---
 wgpu-core/src/command/mod.rs  | 30 ++++++++++++++++++++++++++++++
 wgpu-core/src/device/queue.rs |  8 +++++++-
 wgpu-core/src/resource.rs     |  7 ++++++-
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/wgpu-core/src/command/mod.rs b/wgpu-core/src/command/mod.rs
index b98ce39598..03999fad5d 100644
--- a/wgpu-core/src/command/mod.rs
+++ b/wgpu-core/src/command/mod.rs
@@ -78,6 +78,36 @@ impl<B: GfxBackend> CommandBuffer<B> {
         }
     }
 
+    pub(crate) fn insert_zero_initializations(
+        raw: &mut B::CommandBuffer,
+        head: &TrackerSet,
+        buffer_guard: &mut Storage<Buffer<B>, id::BufferId>,
+        // TODO: Textures also need initialization!
+        _texture_guard: &mut Storage<Texture<B>, id::TextureId>,
+    ) {
+        // Make sure all used buffers are fully initialized.
+        // TODO This is not optimal since buffer usage may be target of a copy operation.
+        for id in head.buffers.used() {
+            let buffer = &mut buffer_guard[id];
+            let uninitialized_ranges: Vec<std::ops::Range<wgt::BufferAddress>> =
+                buffer.uninitialized_ranges().collect();
+            for uninitialized_range in uninitialized_ranges {
+                // TODO this itself needs resource barriers. How can we make this work?
+                unsafe {
+                    raw.fill_buffer(
+                        &buffer.raw.as_ref().unwrap().0,
+                        hal::buffer::SubRange {
+                            offset: uninitialized_range.start,
+                            size: Some(uninitialized_range.end - uninitialized_range.start),
+                        },
+                        0,
+                    );
+                }
+                buffer.mark_initialized(uninitialized_range);
+            }
+        }
+    }
+
     pub(crate) fn insert_barriers(
         raw: &mut B::CommandBuffer,
         base: &mut TrackerSet,
diff --git a/wgpu-core/src/device/queue.rs b/wgpu-core/src/device/queue.rs
index fa09be5cfc..86b9a21bc6 100644
--- a/wgpu-core/src/device/queue.rs
+++ b/wgpu-core/src/device/queue.rs
@@ -505,7 +505,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                     let (compute_pipe_guard, mut token) = hub.compute_pipelines.read(&mut token);
                     let (render_pipe_guard, mut token) = hub.render_pipelines.read(&mut token);
                     let (mut buffer_guard, mut token) = hub.buffers.write(&mut token);
-                    let (texture_guard, mut token) = hub.textures.read(&mut token);
+                    let (mut texture_guard, mut token) = hub.textures.write(&mut token);
                     let (texture_view_guard, mut token) = hub.texture_views.read(&mut token);
                     let (sampler_guard, _) = hub.samplers.read(&mut token);
 
@@ -613,6 +613,12 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                                 .begin_primary(hal::command::CommandBufferFlags::ONE_TIME_SUBMIT);
                         }
                         tracing::trace!("Stitching command buffer {:?} before submission", cmb_id);
+                        CommandBuffer::insert_zero_initializations(
+                            &mut transit,
+                            &cmdbuf.trackers,
+                            &mut *buffer_guard,
+                            &mut *texture_guard,
+                        );
                         CommandBuffer::insert_barriers(
                             &mut transit,
                             &mut *trackers,
diff --git a/wgpu-core/src/resource.rs b/wgpu-core/src/resource.rs
index 0510a3d776..ec21f9d736 100644
--- a/wgpu-core/src/resource.rs
+++ b/wgpu-core/src/resource.rs
@@ -169,7 +169,6 @@ pub struct Buffer<B: hal::Backend> {
 
 impl<B: hal::Backend> Buffer<B> {
     pub(crate) fn uninitialized_ranges_in_range<
-        'a,
         R: std::iter::FromIterator<Range<wgt::BufferAddress>>,
     >(
         &self,
@@ -190,6 +189,12 @@ impl<B: hal::Backend> Buffer<B> {
             .collect::<R>()
     }
 
+    pub(crate) fn uninitialized_ranges<'a>(
+        &'a self,
+    ) -> impl 'a + Iterator<Item = Range<wgt::BufferAddress>> {
+        self.uninitialized_ranges.allocated_ranges()
+    }
+
     // Range must be continuous previously uninitialized section.
     pub(crate) fn mark_initialized(&mut self, range: Range<wgt::BufferAddress>) {
         self.uninitialized_ranges.free_range(range);