From c1b448433a3f1b2b9a11c440dfd1b324c8be2648 Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Wed, 12 Apr 2023 13:48:07 -0400
Subject: [PATCH] Use staging buffer with the vertex buffer

---
 justfile        | 13 ++++++++++
 src/app/data.rs | 67 +++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 73 insertions(+), 7 deletions(-)

diff --git a/justfile b/justfile
index 9d33e13..b28f4cc 100644
--- a/justfile
+++ b/justfile
@@ -6,3 +6,16 @@ default:
 compile-shaders:
     glslc shaders/shader.vert -o shaders/vert.spv
     glslc shaders/shader.frag -o shaders/frag.spv
+
+# Cargo fmt
+fmt:
+    cargo fmt
+
+# Checks
+check:
+    cargo check
+    cargo clippy
+
+# Cargo fix
+fix:
+    cargo fix
diff --git a/src/app/data.rs b/src/app/data.rs
index 52ee848..63ff77e 100644
--- a/src/app/data.rs
+++ b/src/app/data.rs
@@ -542,7 +542,7 @@ impl AppData {
     // Buffers
     //================================================
 
-    pub(super) unsafe fn create_buffer(
+    unsafe fn create_buffer(
         &self,
         instance: &Instance,
         device: &Device,
@@ -570,28 +570,81 @@ impl AppData {
         Ok((buffer, buffer_memory))
     }
 
+    unsafe fn copy_buffer(
+        &self,
+        device: &Device,
+        source: vk::Buffer,
+        destination: vk::Buffer,
+        size: vk::DeviceSize,
+    ) -> Result<()> {
+        // Create the command buffer
+        let info = vk::CommandBufferAllocateInfo::builder()
+            .level(vk::CommandBufferLevel::PRIMARY)
+            .command_pool(self.command_pool)
+            .command_buffer_count(1);
+
+        let command_buffer = device.allocate_command_buffers(&info)?[0];
+
+        let info = vk::CommandBufferBeginInfo::builder()
+            .flags(vk::CommandBufferUsageFlags::ONE_TIME_SUBMIT);
+
+        device.begin_command_buffer(command_buffer, &info)?;
+
+        let regions = vk::BufferCopy::builder().size(size);
+        device.cmd_copy_buffer(command_buffer, source, destination, &[regions]);
+
+        device.end_command_buffer(command_buffer)?;
+
+        // Execute command buffer
+        let command_buffers = &[command_buffer];
+        let info = vk::SubmitInfo::builder().command_buffers(command_buffers);
+
+        device.queue_submit(self.graphics_queue, &[info], vk::Fence::null())?;
+        device.queue_wait_idle(self.graphics_queue)?;
+
+        device.free_command_buffers(self.command_pool, &[command_buffer]);
+
+        Ok(())
+    }
+
     pub(super) unsafe fn create_vertex_buffer(
         &mut self,
         instance: &Instance,
         device: &Device,
     ) -> Result<()> {
+        // Create staging buffer
         let size = (size_of::<Vertex>() * VERTICES.len()) as u64;
+        let (staging_buffer, staging_buffer_memory) = self.create_buffer(
+            instance,
+            device,
+            size,
+            vk::BufferUsageFlags::TRANSFER_SRC,
+            vk::MemoryPropertyFlags::HOST_COHERENT | vk::MemoryPropertyFlags::HOST_VISIBLE,
+        )?;
+
+        let memory =
+            device.map_memory(staging_buffer_memory, 0, size, vk::MemoryMapFlags::empty())?;
+        memcpy(VERTICES.as_ptr(), memory.cast(), VERTICES.len());
+        device.unmap_memory(staging_buffer_memory);
+
+        // Create vertex buffer
         let (vertex_buffer, vertex_buffer_memory) = self.create_buffer(
             instance,
             device,
             size,
-            vk::BufferUsageFlags::VERTEX_BUFFER,
-            vk::MemoryPropertyFlags::HOST_COHERENT | vk::MemoryPropertyFlags::HOST_VISIBLE,
+            vk::BufferUsageFlags::TRANSFER_DST | vk::BufferUsageFlags::VERTEX_BUFFER,
+            vk::MemoryPropertyFlags::DEVICE_LOCAL,
         )?;
 
         self.vertex_buffer = vertex_buffer;
         self.vertex_buffer_memory = vertex_buffer_memory;
 
-        let memory =
-            device.map_memory(vertex_buffer_memory, 0, size, vk::MemoryMapFlags::empty())?;
+        // Copy to the vertex buffer
+        self.copy_buffer(device, staging_buffer, vertex_buffer, size)?;
 
-        memcpy(VERTICES.as_ptr(), memory.cast(), VERTICES.len());
-        device.unmap_memory(vertex_buffer_memory);
+        // cleanup
+        device.destroy_buffer(staging_buffer, None);
+        device.free_memory(staging_buffer_memory, None);
 
         Ok(())
     }