1 files changed, 103 insertions, 0 deletions
diff --git a/stockton-skeleton/src/buffers/staging.rs b/stockton-skeleton/src/buffers/staging.rs
new file mode 100644
index 0000000..5c80f51
--- /dev/null
+++ b/stockton-skeleton/src/buffers/staging.rs
@@ -0,0 +1,103 @@
+//! A buffer that can be written to by the CPU
+
+use crate::{
+    context::RenderingContext,
+    error::LockPoisoned,
+    mem::{Block, MappableBlock, MemoryPool},
+    types::*,
+};
+
+use std::{mem::ManuallyDrop, ops::Range};
+
+use anyhow::{Context, Result};
+use hal::{buffer::Usage, memory::SparseFlags};
+
+/// A buffer that can be written to by the CPU. Usage will be `Usage::TRANSFER_SRC`.
+pub struct StagingBuffer<P: MemoryPool> {
+    buf: ManuallyDrop<BufferT>,
+    mem: ManuallyDrop<P::Block>,
+}
+
+impl<P> StagingBuffer<P>
+where
+    P: MemoryPool,
+    P::Block: MappableBlock,
+{
+    /// Create a new staging buffer from the given RenderingContext. `size` is in bytes.
+    pub fn from_context(context: &mut RenderingContext, size: u64) -> Result<Self> {
+        context.ensure_memory_pool::<P>()?;
+
+        let mut device = context.device().write().map_err(|_| LockPoisoned::Device)?;
+        let mut mempool = context
+            .existing_memory_pool()
+            .unwrap()
+            .write()
+            .map_err(|_| LockPoisoned::MemoryPool)?;
+
+        Self::from_device_pool(&mut device, &mut mempool, size)
+    }
+
+    /// Create a new staging buffer from the given device and memory pool. `size` is in bytes.
+    pub fn from_device_pool(device: &mut DeviceT, mempool: &mut P, size: u64) -> Result<Self> {
+        let mut buffer =
+            unsafe { device.create_buffer(size, Usage::TRANSFER_SRC, SparseFlags::empty()) }
+                .context("Error creating buffer")?;
+
+        let requirements = unsafe { device.get_buffer_requirements(&buffer) };
+
+        let (memory, _) = mempool
+            .alloc(device, requirements.size, requirements.alignment)
+            .context("Error allocating staging memory")?;
+
+        unsafe { device.bind_buffer_memory(memory.memory(), memory.range().start, &mut buffer) }
+            .context("Error binding staging memory to buffer")?;
+
+        Ok(StagingBuffer {
+            buf: ManuallyDrop::new(buffer),
+            mem: ManuallyDrop::new(memory),
+        })
+    }
+
+    /// Map the given range to CPU-visible memory, returning a pointer to the start of that range.
+    /// inner_range is local to this block of memory, not to the container as a whole.
+    pub fn map(&mut self, device: &mut DeviceT, inner_range: Range<u64>) -> Result<*mut u8> {
+        Ok(<<P as MemoryPool>::Block>::map(
+            &mut *self.mem,
+            device,
+            inner_range,
+        )?)
+    }
+
+    /// Remove any mappings present for this staging buffer.
+    pub unsafe fn unmap(&mut self, device: &mut DeviceT) -> Result<()> {
+        self.mem.unmap(device)
+    }
+
+    pub fn deactivate_context(self, context: &mut RenderingContext) {
+        let mut device = context.device().write().unwrap();
+        let mut mempool = context.existing_memory_pool().unwrap().write().unwrap();
+
+        self.deactivate_device_pool(&mut device, &mut mempool)
+    }
+
+    /// Destroy all vulkan objects. This should be called before dropping
+    pub fn deactivate_device_pool(self, device: &mut DeviceT, mempool: &mut P) {
+        unsafe {
+            use std::ptr::read;
+            // Destroy buffer
+            device.destroy_buffer(read(&*self.buf));
+            // Free memory
+            mempool.free(device, read(&*self.mem));
+        }
+    }
+
+    /// Get a reference to the staging buffer's memory.
+    pub fn mem(&self) -> &P::Block {
+        &self.mem
+    }
+
+    /// Get a reference to the staging buffer.
+    pub fn buf(&self) -> &ManuallyDrop<BufferT> {
+        &self.buf
+    }
+}