aurora: Use staging buffer for mapping

aurora/lib/aurora.cpp

@@ -293,6 +293,7 @@ void app_run(std::unique_ptr<AppDelegate> app, Icon icon, int argc, char** argv)
         .label = "Redraw encoder",
     };
     auto encoder = g_device.CreateCommandEncoder(&encoderDescriptor);
+    gfx::end_frame(encoder);
     {
       const std::array attachments{
           wgpu::RenderPassColorAttachment{
@@ -324,7 +325,7 @@ void app_run(std::unique_ptr<AppDelegate> app, Icon icon, int argc, char** argv)
           .depthStencilAttachment = &depthStencilAttachment,
       };
       auto pass = encoder.BeginRenderPass(&renderPassDescriptor);
-      gfx::end_frame(pass);
+      gfx::render(pass);
       pass.End();
     }
     {

aurora/lib/gfx/common.cpp

@@ -24,6 +24,8 @@ constexpr uint64_t VertexBufferSize = 5242880;    // 5mb
 constexpr uint64_t IndexBufferSize = 2097152;     // 2mb
 constexpr uint64_t StorageBufferSize = 134217728; // 128mb
 
+constexpr uint64_t StagingBufferSize = UniformBufferSize + VertexBufferSize + IndexBufferSize + StorageBufferSize;
+
 struct ShaderState {
   movie_player::State moviePlayer;
   colored_quad::State coloredQuad;
@@ -209,6 +211,7 @@ wgpu::Buffer g_uniformBuffer;
 wgpu::Buffer g_indexBuffer;
 wgpu::Buffer g_storageBuffer;
 size_t g_staticStorageLastSize = 0;
+static wgpu::Buffer g_stagingBuffer;
 
 static ShaderState g_state;
 static PipelineRef g_currentPipeline;
@@ -389,15 +392,21 @@ void initialize() {
   const auto createBuffer = [](wgpu::Buffer& out, wgpu::BufferUsage usage, uint64_t size, const char* label) {
     const wgpu::BufferDescriptor descriptor{
         .label = label,
-        .usage = usage | wgpu::BufferUsage::CopyDst | wgpu::BufferUsage::MapWrite,
+        .usage = usage,
         .size = size,
     };
     out = g_device.CreateBuffer(&descriptor);
   };
-  createBuffer(g_uniformBuffer, wgpu::BufferUsage::Uniform, UniformBufferSize, "Shared Uniform Buffer");
+  createBuffer(g_uniformBuffer, wgpu::BufferUsage::Uniform | wgpu::BufferUsage::CopyDst, UniformBufferSize,
-  createBuffer(g_vertexBuffer, wgpu::BufferUsage::Vertex, VertexBufferSize, "Shared Vertex Buffer");
+               "Shared Uniform Buffer");
-  createBuffer(g_indexBuffer, wgpu::BufferUsage::Index, IndexBufferSize, "Shared Index Buffer");
+  createBuffer(g_vertexBuffer, wgpu::BufferUsage::Vertex | wgpu::BufferUsage::CopyDst, VertexBufferSize,
-  createBuffer(g_storageBuffer, wgpu::BufferUsage::Storage, StorageBufferSize, "Shared Storage Buffer");
+               "Shared Vertex Buffer");
+  createBuffer(g_indexBuffer, wgpu::BufferUsage::Index | wgpu::BufferUsage::CopyDst, IndexBufferSize,
+               "Shared Index Buffer");
+  createBuffer(g_storageBuffer, wgpu::BufferUsage::Storage | wgpu::BufferUsage::CopyDst, StorageBufferSize,
+               "Shared Storage Buffer");
+  createBuffer(g_stagingBuffer, wgpu::BufferUsage::MapWrite | wgpu::BufferUsage::CopySrc, StagingBufferSize,
+               "Staging Buffer");
 
   g_state.moviePlayer = movie_player::construct_state();
   g_state.coloredQuad = colored_quad::construct_state();
@@ -420,61 +429,55 @@ void shutdown() {
   g_uniformBuffer = {};
   g_indexBuffer = {};
   g_storageBuffer = {};
+  g_stagingBuffer = {};
 
   g_state = {};
 }
 
 void begin_frame() {
-  int mappedBuffers = 0, totalBuffers = 0;
+  bool bufferMapped = false;
-  const auto mapBuffer = [&](ByteBuffer& buf, wgpu::Buffer& out, uint64_t size) {
+  size_t bufferOffset = 0;
-    struct MapCallbackData {
+  const auto mapBuffer = [&](ByteBuffer& buf, uint64_t size) {
-      ByteBuffer& buf;
+    buf = ByteBuffer{static_cast<u8*>(g_stagingBuffer.GetMappedRange(bufferOffset, size)), size};
-      wgpu::Buffer& out;
+    bufferOffset += size;
-      uint64_t size;
-      int& mappedBuffers;
   };
-    auto* data = new MapCallbackData{
+  g_stagingBuffer.MapAsync(
-        .buf = buf,
+      wgpu::MapMode::Write, 0, StagingBufferSize,
-        .out = out,
-        .size = size,
-        .mappedBuffers = mappedBuffers,
-    };
-    out.MapAsync(
-        wgpu::MapMode::Write, 0, size,
       [](WGPUBufferMapAsyncStatus status, void* userdata) {
         if (status != WGPUBufferMapAsyncStatus_Success) {
           Log.report(logvisor::Fatal, FMT_STRING("Buffer mapping failed: {}"), status);
           unreachable();
         }
-          auto* data = static_cast<MapCallbackData*>(userdata);
+        *static_cast<bool*>(userdata) = true;
-          data->buf = ByteBuffer{static_cast<uint8_t*>(data->out.GetMappedRange(0, data->size)), data->size};
-          ++data->mappedBuffers;
-          delete data;
       },
-        data);
+      &bufferMapped);
-    ++totalBuffers;
+  while (!bufferMapped) {
-  };
-  mapBuffer(g_verts, g_vertexBuffer, VertexBufferSize);
-  mapBuffer(g_uniforms, g_uniformBuffer, UniformBufferSize);
-  mapBuffer(g_indices, g_indexBuffer, IndexBufferSize);
-  mapBuffer(g_storage, g_storageBuffer, StorageBufferSize);
-  while (mappedBuffers < totalBuffers) {
     g_device.Tick();
   }
+  mapBuffer(g_verts, VertexBufferSize);
+  mapBuffer(g_uniforms, UniformBufferSize);
+  mapBuffer(g_indices, IndexBufferSize);
+  mapBuffer(g_storage, StorageBufferSize);
 }
 
-void end_frame(const wgpu::RenderPassEncoder& pass) {
+void end_frame(const wgpu::CommandEncoder& cmd) {
-  const auto writeBuffer = [](ByteBuffer& buf, wgpu::Buffer& out, std::string_view label) {
+  uint64_t bufferOffset = 0;
-    const auto size = buf.size();
+  const auto writeBuffer = [&](ByteBuffer& buf, wgpu::Buffer& out, uint64_t size, std::string_view label) {
-    // Log.report(logvisor::Info, FMT_STRING("{} buffer usage: {}"), label, size);
+    const auto writeSize = buf.size(); // Only need to copy this many bytes
+    if (writeSize > 0) {
+      cmd.CopyBufferToBuffer(g_stagingBuffer, bufferOffset, out, 0, writeSize);
       buf.clear();
-    out.Unmap();
+    }
+    bufferOffset += size;
   };
-  writeBuffer(g_verts, g_vertexBuffer, "Vertex");
+  g_stagingBuffer.Unmap();
-  writeBuffer(g_uniforms, g_uniformBuffer, "Uniform");
+  writeBuffer(g_verts, g_vertexBuffer, VertexBufferSize, "Vertex");
-  writeBuffer(g_indices, g_indexBuffer, "Index");
+  writeBuffer(g_uniforms, g_uniformBuffer, UniformBufferSize, "Uniform");
-  writeBuffer(g_storage, g_storageBuffer, "Storage");
+  writeBuffer(g_indices, g_indexBuffer, IndexBufferSize, "Index");
+  writeBuffer(g_storage, g_storageBuffer, StorageBufferSize, "Storage");
+}
 
+void render(const wgpu::RenderPassEncoder& pass) {
   g_currentPipeline = UINT64_MAX;
 
   for (const auto& cmd : g_commands) {

aurora/lib/gfx/common.hpp

@@ -172,7 +172,8 @@ void initialize();
 void shutdown();
 
 void begin_frame();
-void end_frame(const wgpu::RenderPassEncoder& pass);
+void end_frame(const wgpu::CommandEncoder& cmd);
+void render(const wgpu::RenderPassEncoder& pass);
 
 Range push_verts(const uint8_t* data, size_t length);
 template <typename T>