From 55c22a0d9ab2a88ff53db041e059feec64e27996 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <dmalyshau@mozilla.com>
Date: Thu, 24 Jan 2019 06:32:12 -0800
Subject: [PATCH] Implement basic set_buffer_data

---
 wgpu-native/src/device.rs     | 66 +++++++++++++++++++++++++++++++++++
 wgpu-native/src/swap_chain.rs | 17 ++++-----
 wgpu-native/src/track.rs      | 11 ++++++
 wgpu-rs/src/lib.rs            |  6 ++++
 4 files changed, 89 insertions(+), 11 deletions(-)

diff --git a/wgpu-native/src/device.rs b/wgpu-native/src/device.rs
index 4afc25ab3e..9565af3e5e 100644
--- a/wgpu-native/src/device.rs
+++ b/wgpu-native/src/device.rs
@@ -17,6 +17,7 @@ use hal::{self,
     Device as _Device,
     Surface as _Surface,
 };
+use log::trace;
 //use rendy_memory::{allocator, Config, Heaps};
 use parking_lot::{Mutex};
 
@@ -1198,3 +1199,68 @@ pub extern "C" fn wgpu_device_create_swap_chain(
 
     swap_chain_id
 }
+
+
+
+#[no_mangle]
+pub extern "C" fn wgpu_buffer_set_sub_data(
+    buffer_id: BufferId,
+    start: u32, count: u32, data: *const u8,
+) {
+    let buffer_guard = HUB.buffers.read();
+    let buffer = buffer_guard.get(buffer_id);
+    let mut device_guard = HUB.devices.write();
+    let device = device_guard.get_mut(buffer.device_id.value);
+
+    //Note: this is just doing `update_buffer`, which is limited to 64KB
+
+    trace!("transit {:?} to transfer dst", buffer_id);
+    let barrier = device.buffer_tracker
+        .lock()
+        .transit(
+            buffer_id,
+            &buffer.life_guard.ref_count,
+            resource::BufferUsageFlags::TRANSFER_DST,
+            TrackPermit::REPLACE,
+        )
+        .unwrap()
+        .into_source()
+        .map(|old| hal::memory::Barrier::Buffer {
+            states: conv::map_buffer_state(old) ..
+                hal::buffer::State::TRANSFER_WRITE,
+            target: &buffer.raw,
+            families: None,
+            range: None .. None, //TODO: could be partial
+        });
+
+    let mut comb = device.com_allocator.allocate(buffer.device_id.clone(), &device.raw);
+    unsafe {
+        let raw = comb.raw.last_mut().unwrap();
+        raw.begin(
+            hal::command::CommandBufferFlags::ONE_TIME_SUBMIT,
+            hal::command::CommandBufferInheritanceInfo::default(),
+        );
+        raw.pipeline_barrier(
+            hal::pso::PipelineStage::TOP_OF_PIPE .. hal::pso::PipelineStage::TRANSFER,
+            hal::memory::Dependencies::empty(),
+            barrier,
+        );
+        raw.update_buffer(
+            &buffer.raw,
+            start as hal::buffer::Offset,
+            slice::from_raw_parts(data, count as usize),
+        );
+        raw.finish();
+
+        let submission = hal::queue::Submission {
+            command_buffers: iter::once(&*raw),
+            wait_semaphores: None,
+            signal_semaphores: None,
+        };
+        device.queue_group.queues[0]
+            .as_raw_mut()
+            .submit::<_, _, <back::Backend as hal::Backend>::Semaphore, _, _>(submission, None);
+    }
+
+    device.com_allocator.after_submit(comb);
+}
diff --git a/wgpu-native/src/swap_chain.rs b/wgpu-native/src/swap_chain.rs
index f822083d9d..bb692cbc9b 100644
--- a/wgpu-native/src/swap_chain.rs
+++ b/wgpu-native/src/swap_chain.rs
@@ -3,7 +3,7 @@ use crate::{Stored, WeaklyStored,
 };
 use crate::{conv, resource};
 use crate::registry::{HUB, Items};
-use crate::track::{Tracktion, TrackPermit};
+use crate::track::{TrackPermit};
 
 use hal;
 use hal::{Device as _Device, Swapchain as _Swapchain};
@@ -116,7 +116,7 @@ pub extern "C" fn wgpu_swap_chain_present(
     }
 
     trace!("transit {:?} to present", frame.texture_id.value);
-    let tracktion = device.texture_tracker
+    let barrier = device.texture_tracker
         .lock()
         .transit(
             frame.texture_id.value,
@@ -124,20 +124,15 @@ pub extern "C" fn wgpu_swap_chain_present(
             resource::TextureUsageFlags::PRESENT,
             TrackPermit::REPLACE,
         )
-        .unwrap();
-
-    let barrier = match tracktion {
-        Tracktion::Keep => None,
-        Tracktion::Replace { old } => Some(hal::memory::Barrier::Image {
+        .unwrap()
+        .into_source()
+        .map(|old| hal::memory::Barrier::Image {
             states: conv::map_texture_state(old, hal::format::Aspects::COLOR) ..
                 (hal::image::Access::empty(), hal::image::Layout::Present),
             target: &texture.raw,
             families: None,
             range: texture.full_range.clone(),
-        }),
-        Tracktion::Init |
-        Tracktion::Extend {..} => unreachable!(),
-    };
+        });
 
     unsafe {
         frame.comb.begin(false);
diff --git a/wgpu-native/src/track.rs b/wgpu-native/src/track.rs
index 0f2e38de69..6b9cdace5f 100644
--- a/wgpu-native/src/track.rs
+++ b/wgpu-native/src/track.rs
@@ -20,6 +20,17 @@ pub enum Tracktion<T> {
     Replace { old: T },
 }
 
+impl<T> Tracktion<T> {
+    pub fn into_source(self) -> Option<T> {
+        match self {
+            Tracktion::Init |
+            Tracktion::Keep => None,
+            Tracktion::Extend { old } |
+            Tracktion::Replace { old } => Some(old),
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub struct Query<T> {
     pub usage: T,
diff --git a/wgpu-rs/src/lib.rs b/wgpu-rs/src/lib.rs
index 8fa586f301..09defc2ebf 100644
--- a/wgpu-rs/src/lib.rs
+++ b/wgpu-rs/src/lib.rs
@@ -352,6 +352,12 @@ impl Device {
     }
 }
 
+impl Buffer {
+    pub fn set_sub_data(&self, offset: u32, data: &[u8]) {
+        wgn::wgpu_buffer_set_sub_data(self.id, offset, data.len() as u32, data.as_ptr());
+    }
+}
+
 impl Texture {
     pub fn create_texture_view(&self, desc: &TextureViewDescriptor) -> TextureView {
         TextureView {