Add some initial code draft

DESIGN.md

@@ -130,3 +130,7 @@ Pipelines, however, would still be created manually.
 ## Memory views
 
 **To do**
+
+## Context loss
+
+**To do**

src/command_buffer.rs

@@ -0,0 +1,97 @@
+
+/// Represents a prototype of a command buffer.
+///
+/// # Usage
+///
+/// ```norun
+/// let commands_buffer =
+///     CommandBufferBuilder::new(&device)
+///         .copy_memory(..., ...)
+///         .draw(...)
+///         .build();
+/// 
+/// ```
+///
+/// # Implementation
+///
+/// Builds a command buffer and starts writing into it. Each function call directly adds a command
+/// into the buffer.
+///
+/// Resources that are used are held in the `CommandBufferBuilder` and the `CommandBuffer`,
+/// ensuring that they don't get destroyed as long as the command buffer is alive.
+///
+pub struct CommandBufferBuilder {
+    device: Arc<Device>,
+    cmd: Option<ffi::GR_CMD_BUFFER>,
+    memory_refs: Vec<ffi::GR_MEMORY_REF>,
+    buffers: Vec<Arc<Buffer>>,
+    images: Vec<Arc<Image>>,
+    pipelines: Vec<Arc<Pipeline>>,
+}
+
+impl CommandBufferBuilder {
+    /// Builds a new prototype of a command buffer.
+    pub fn new(device: &Arc<Device>) -> CommandBufferBuilder {
+        let infos = ffi::GR_CMD_BUFFER_CREATE_INFO {
+            queueType: ffi::GR_QUEUE_UNIVERSAL,
+            flags: 0,
+        };
+
+        let cmd_buffer = unsafe {
+            let mut cmd = mem::uninitialized();
+            error::check_result(ffi::grCreateCommandBuffer(*device.get_id(),
+                                                           &infos, &mut cmd)).unwrap();
+            cmd
+        };
+
+        error::check_result(unsafe { ffi::grBeginCommandBuffer(cmd_buffer, 0) }).unwrap();
+
+        CommandBufferBuilder {
+            device: device.clone(),
+            cmd: Some(cmd_buffer),
+            memory_refs: Vec::new(),
+        }
+    }
+
+    /// Builds the command buffer containing all the commands.
+    pub fn build(mut self) -> Arc<CommandBuffer> {
+        let cmd_buffer = self.cmd.take().unwrap();
+        error::check_result(unsafe { ffi::grEndCommandBuffer(cmd_buffer) }).unwrap();
+
+        Arc::new(CommandBuffer {
+            device: self.device.clone(),
+            cmd: cmd_buffer,
+            memory_refs: mem::replace(&mut self.memory_refs, Vec::with_capacity(0)),
+            buffers: mem::replace(&mut self.buffers, Vec::with_capacity(0)),
+            images: mem::replace(&mut self.images, Vec::with_capacity(0)),
+            pipelines: mem::replace(&mut self.pipelines, Vec::with_capacity(0)),
+        })
+    }
+}
+
+impl Drop for CommandBufferBuilder {
+    fn drop(&mut self) {
+        if let Some(cmd) = self.cmd {
+            error::check_result(unsafe { ffi::grEndCommandBuffer(cmd) }).unwrap();
+            error::check_result(unsafe { ffi::grDestroyObject(cmd) }).unwrap();
+        }
+    }
+}
+
+/// Represents a command buffer.
+///
+/// Can be submitted to a queue.
+pub struct CommandBuffer {
+    device: Arc<Device>,
+    cmd: ffi::GR_CMD_BUFFER,
+    memory_refs: Vec<ffi::GR_MEMORY_REF>,
+    buffers: Vec<Arc<Buffer>>,
+    images: Vec<Arc<Image>>,
+    pipelines: Vec<Arc<Pipeline>>,
+}
+
+impl Drop for CommandBuffer {
+    fn drop(&mut self) {
+        error::check_result(unsafe { ffi::grDestroyObject(cmd) }).unwrap();
+    }
+}

src/device/mod.rs

@@ -0,0 +1,28 @@
+
+/// Represents a Vulkan context.
+pub struct Device {
+    device: ffi::GR_DEVICE,
+    queue: ffi::GR_QUEUE,
+}
+
+impl Device {
+    /// Builds a new Vulkan context for the given GPU.
+    pub fn new(gpu: &GpuId) -> Arc<Device> {
+        unimplemented!();
+    }
+
+    /// Enumerates the list of universal queues. These queues can do anything.
+    pub fn universal_queues(&self) -> UniversalQueuesIter {
+        unimplemented!();
+    }
+
+    /// Enumerates the list of compute queues.
+    pub fn compute_queues(&self) -> ComputeQueuesIter {
+        unimplemented!();
+    }
+
+    /// Enumerates the list of DMA queues. DMA queues can only transfer data.
+    pub fn dma_queues(&self) -> DmaQueueIter {
+        unimplemented!();
+    }
+}

src/lib.rs

@@ -0,0 +1,8 @@
+
+mod buffer;
+mod command_buffer;
+mod device;
+mod image;
+
+pub use self::command_buffer::CommandBufferBuilder;
+pub use self::command_buffer::CommandBuffer;