move some modules into a new graphics submodule

Force-Push: yes
Change-Id: I5cbdf59870258f099fc6dd47ff2f1566376c1585

1 files changed, 1738 insertions, 0 deletions

diff --git a/src/graphics/window_dressing.rs b/src/graphics/window_dressing.rs
new file mode 100644
index 0000000..dc7f47f
--- /dev/null
+++ b/src/graphics/window_dressing.rs
@@ -0,0 +1,1738 @@
+#![deny(unsafe_code)]
+use crate::error::*;
+use crate::graphics::permanent::{
+  PermanentGraphicsState, GraphicsStateForReinit, QueueFamilyIndices,
+  EnableAnisotropy
+};
+use crate::model_loader::load_model;
+use crate::shader_data::{ Vertex, UniformBlock, VertexPushBlock };
+
+use std::collections::BTreeSet;
+use std::io::Cursor;
+use std::mem::size_of;
+use std::ptr::copy_nonoverlapping;
+
+use png::Decoder;
+use vulkanalia::{ Device, Instance };
+use vulkanalia::vk::{ self, Handle, HasBuilder, InstanceV1_0, DeviceV1_0,
+                      KhrSwapchainExtensionDeviceCommands };
+use winit::window::Window;
+
+
+// TODO: use VK_KHR_swapchain_maintenance1 to put a fence on the presentation
+// operation. doing that will remove the requirement that we have more
+// simultaneous frames than images.
+pub const N_SIMULTANEOUS_FRAMES: usize = 5;
+
+
+//   The WindowDressing collects the Vulkan graphics objects which need to be
+// regenerated or modified when the window changes in certain ways, such as
+// resizing, but are not needed during rendering. The ones which don't need to
+// be regenerated are collected in PermanentGraphicsState. The ones which are
+// needed during rendering are collected in RenderState, below.
+#[derive(Debug)]
+pub struct WindowDressing {
+  pub swapchain: Swapchain,
+
+  color_image: vk::Image,
+  color_image_memory: vk::DeviceMemory,
+  color_image_view: vk::ImageView,
+
+  depth_image: vk::Image,
+  depth_image_memory: vk::DeviceMemory,
+  depth_image_view: vk::ImageView,
+  depth_format: vk::Format,
+
+  primary_command_pool: vk::CommandPool,
+  transient_command_pool: vk::CommandPool,
+
+  texture_image: vk::Image,
+  texture_image_memory: vk::DeviceMemory,
+  texture_image_view: vk::ImageView,
+  mip_count: u32,
+  sampler: vk::Sampler,
+
+  uniform_buffers: Vec<vk::Buffer>,
+  pub uniform_buffer_memory: Vec<vk::DeviceMemory>,
+
+  descriptor_pool: vk::DescriptorPool,
+
+  pub concurrency: Concurrency,
+}
+
+//   The RenderState collects the Vulkan graphics objects which need to be
+// regenerated or modified when the window changes, as with WindowDressing,
+// and which are also used as part of rendering.
+#[derive(Debug)]
+pub struct RenderState {
+  pub render_pass: vk::RenderPass,
+
+  pub pipeline: vk::Pipeline,
+  pub pipeline_layout: vk::PipelineLayout,
+
+  pub vertex_buffer: vk::Buffer,
+  vertex_buffer_memory: vk::DeviceMemory,
+
+  pub index_buffer: vk::Buffer,
+  index_buffer_memory: vk::DeviceMemory,
+  pub index_count: usize,
+
+  pub framebuffers: Vec<vk::Framebuffer>,
+  pub command_buffers: Vec<vk::CommandBuffer>,
+  pub descriptor_sets: Vec<vk::DescriptorSet>,
+}
+
+//   A swapchain is the generalized facility that is used to implement
+// double buffering, triple buffering, rendering passes that feed into each
+// other, and other things of that nature. It's a first-class thing but for
+// now, we use at most one of it. We also support running without one.
+#[derive(Debug)]
+pub struct Swapchain {
+  pub swapchain: vk::SwapchainKHR,
+  images: Vec<vk::Image>,
+  image_views: Vec<vk::ImageView>,
+  format: vk::Format,
+  pub extent: vk::Extent2D,
+}
+
+#[derive(Debug)]
+pub struct Concurrency {
+  pub image_available_semaphores: Vec<vk::Semaphore>,
+  pub rendering_finished_semaphores: Vec<vk::Semaphore>,
+
+  //   Okay, the lifetime management on the fences is really subtle. There is
+  // one fence for each frame, and frame_fences holds the authoritative
+  // reference to it.
+  //
+  //   There is one entry in image_fences for each image. The number of images
+  // is not directly related to the number of frames; it will likely be
+  // larger, but may be smaller or the same. At the start of execution, the
+  // entries are all nulls. Each time an image is acquired from the swapchain,
+  // the corresponding entry in image_fences is overwritten with a duplicate
+  // of the frame fence. This happens during rendering of the frame, so the
+  // frame fence is in the "signaled" state. It will be reset right before
+  // submitting the queue, then signaled again when the submission completes.
+  pub frame_fences: Vec<vk::Fence>,
+  pub image_fences: Vec<vk::Fence>,
+}
+
+
+impl WindowDressing {
+  pub fn new(permanent: &PermanentGraphicsState,
+             for_reinit: &GraphicsStateForReinit,
+             enable_anisotropy: EnableAnisotropy)
+      -> Result<Self>
+  {
+    let window = &permanent.window;
+    let instance = &permanent.instance;
+    let surface = &permanent.surface;
+    let device = &permanent.device;
+    let graphics_queue = &permanent.graphics_queue;
+    let physical_device = &for_reinit.physical_device;
+    let sample_count = for_reinit.sample_count;
+    let indices = &for_reinit.indices;
+
+    let swapchain = init_swapchain(
+            window, instance, surface, &physical_device, device, &indices)?;
+
+    let (color_image, color_image_memory, color_image_view)
+            = init_color(instance, &physical_device, device,
+                         &swapchain.extent, sample_count, swapchain.format)?;
+
+    let (depth_image, depth_image_memory, depth_image_view, depth_format)
+            = init_depth(instance, &physical_device, device,
+                         &swapchain.extent, sample_count)?;
+
+    let (primary_command_pool, transient_command_pool)
+            = init_command_pools(device, indices)?;
+
+    let (texture_image, texture_image_memory, texture_image_view, mip_count)
+            = init_texture(instance, physical_device, device,
+                           graphics_queue, &transient_command_pool)?;
+
+    let sampler = init_sampler(&device, &enable_anisotropy, mip_count)?;
+
+    let (uniform_buffers, uniform_buffer_memory)
+            = init_uniform_buffers(instance, physical_device, device,
+                                   swapchain.images.len())?;
+
+    let descriptor_pool
+            = init_descriptor_pool(device, swapchain.images.len())?;
+
+    let concurrency = init_concurrency(device, &swapchain.images)?;
+
+    Ok(WindowDressing {
+      swapchain,
+      color_image,
+      color_image_memory,
+      color_image_view,
+      depth_image,
+      depth_image_memory,
+      depth_image_view,
+      depth_format,
+      texture_image,
+      texture_image_memory,
+      texture_image_view,
+      mip_count,
+      sampler,
+      uniform_buffers,
+      uniform_buffer_memory,
+      descriptor_pool,
+      primary_command_pool,
+      transient_command_pool,
+      concurrency,
+    })
+  }
+
+
+  #[allow(unsafe_code)]
+  pub fn reinit(&mut self, permanent: &PermanentGraphicsState,
+                for_reinit: &GraphicsStateForReinit)
+      -> Result<()>
+  {
+    let window = &permanent.window;
+    let instance = &permanent.instance;
+    let surface = &permanent.surface;
+    let device = &permanent.device;
+    let physical_device = &for_reinit.physical_device;
+    let sample_count = for_reinit.sample_count;
+    let indices = &for_reinit.indices;
+    let descriptor_set_layout = &for_reinit.descriptor_set_layout;
+
+    unsafe { device.device_wait_idle() }.unwrap();
+
+    self.destroy_replaceable(device);
+
+    let swapchain = init_swapchain(
+            window, instance, surface, &physical_device, device, &indices)?;
+
+    let (color_image, color_image_memory, color_image_view)
+            = init_color(instance, &physical_device, device,
+                         &swapchain.extent, sample_count, swapchain.format)?;
+
+    let (depth_image, depth_image_memory, depth_image_view, depth_format)
+            = init_depth(instance, &physical_device, device,
+                         &swapchain.extent, sample_count)?;
+
+    let (uniform_buffers, uniform_buffer_memory)
+            = init_uniform_buffers(instance, physical_device, device,
+                                   swapchain.images.len())?;
+
+    // Notice that we did NOT reuse the descriptor pool.
+    let descriptor_pool
+            = init_descriptor_pool(device, swapchain.images.len())?;
+
+    self.concurrency.image_fences.resize(swapchain.images.len(),
+                                         vk::Fence::null());
+
+    self.swapchain = swapchain;
+    self.color_image = color_image;
+    self.color_image_memory = color_image_memory;
+    self.color_image_view = color_image_view;
+    self.depth_image = depth_image;
+    self.depth_image_memory = depth_image_memory;
+    self.depth_image_view = depth_image_view;
+    self.depth_format = depth_format;
+    self.uniform_buffers = uniform_buffers;
+    self.uniform_buffer_memory = uniform_buffer_memory;
+    self.descriptor_pool = descriptor_pool;
+
+    Ok(())
+  }
+
+
+  //   This relies on its caller to have already waited for the device to be
+  // idle.
+  #[allow(unsafe_code)]
+  pub fn destroy(mut self, device: &Device) {
+    self.destroy_replaceable(device);
+
+    unsafe { device.destroy_image(self.texture_image, None) };
+    unsafe { device.free_memory(self.texture_image_memory, None) };
+    unsafe { device.destroy_image_view(self.texture_image_view, None) };
+    unsafe { device.destroy_sampler(self.sampler, None) };
+
+    for semaphore in self.concurrency.image_available_semaphores {
+      unsafe { device.destroy_semaphore(semaphore, None) };
+    }
+
+    for semaphore in self.concurrency.rendering_finished_semaphores {
+      unsafe { device.destroy_semaphore(semaphore, None) };
+    }
+
+    for fence in self.concurrency.frame_fences {
+      unsafe { device.destroy_fence(fence, None) };
+    }
+
+    //   Notice that destroy_replaceable() freed the buffers in the pools, but
+    // did not destroy the pools.
+    unsafe { device.destroy_command_pool(self.primary_command_pool, None) };
+    unsafe { device.destroy_command_pool(self.transient_command_pool, None) };
+  }
+
+
+  #[allow(unsafe_code)]
+  fn destroy_replaceable(&mut self, device: &Device) {
+    //   While the descriptor pool is also a pool, it has a preallocated size
+    // which will be different next time. So, we destroy it all the way.
+    unsafe { device.destroy_descriptor_pool(self.descriptor_pool, None) };
+
+    //   Notice that, unlike the vertex and index buffers, we destroy and
+    // re-create these on every reinitialization. That's because the number of
+    // them depends on how many images the swapchain has.
+    for buffer in &self.uniform_buffers {
+      unsafe { device.destroy_buffer(*buffer, None) };
+    }
+    for memory in &self.uniform_buffer_memory {
+      unsafe { device.free_memory(*memory, None) };
+    }
+
+    unsafe { device.destroy_image(self.color_image, None) };
+    unsafe { device.free_memory(self.color_image_memory, None) };
+    unsafe { device.destroy_image_view(self.color_image_view, None) };
+    unsafe { device.destroy_image(self.depth_image, None) };
+    unsafe { device.free_memory(self.depth_image_memory, None) };
+    unsafe { device.destroy_image_view(self.depth_image_view, None) };
+
+    for view in &self.swapchain.image_views {
+      unsafe { device.destroy_image_view(*view, None) };
+    }
+
+    unsafe { device.destroy_swapchain_khr(self.swapchain.swapchain, None) };
+  }
+}
+
+
+impl RenderState {
+  pub fn new(permanent: &PermanentGraphicsState,
+             for_reinit: &GraphicsStateForReinit,
+             window_dressing: &WindowDressing)
+      -> Result<Self>
+  {
+    let device = &permanent.device;
+    let instance = &permanent.instance;
+    let graphics_queue = &permanent.graphics_queue;
+    let physical_device = &for_reinit.physical_device;
+    let sample_count = for_reinit.sample_count;
+    let descriptor_set_layout = &for_reinit.descriptor_set_layout;
+    let primary_command_pool = &window_dressing.primary_command_pool;
+    let transient_command_pool = &window_dressing.transient_command_pool;
+    let swapchain = &window_dressing.swapchain;
+    let depth_format = &window_dressing.depth_format;
+    let color_image_view = &window_dressing.color_image_view;
+    let depth_image_view = &window_dressing.depth_image_view;
+    let texture_image_view = &window_dressing.texture_image_view;
+    let uniform_buffers = &window_dressing.uniform_buffers;
+    let descriptor_pool = &window_dressing.descriptor_pool;
+    let sampler = &window_dressing.sampler;
+
+    let render_pass = init_render_pass(device, sample_count,
+                                       &swapchain.format, &depth_format)?;
+
+    let (pipeline_layout, pipeline)
+            = init_pipeline(device, descriptor_set_layout, &swapchain.extent,
+                            sample_count, &render_pass)?;
+
+    let framebuffers = init_framebuffers(
+            device, &swapchain.extent, &swapchain.image_views,
+            &color_image_view, &depth_image_view, &render_pass)?;
+
+    let (vertices, indices) = load_model()?;
+    let index_count = indices.len();
+
+    let command_buffers = init_command_buffers(device, &framebuffers,
+                                               primary_command_pool)?;
+
+    let (vertex_buffer, vertex_buffer_memory)
+            = init_vertex_buffer(vertices, instance, physical_device, device,
+                                 graphics_queue, &transient_command_pool)?;
+    let (index_buffer, index_buffer_memory)
+            = init_index_buffer(indices, instance, physical_device, device,
+                                graphics_queue, &transient_command_pool)?;
+
+    let descriptor_sets
+            = init_descriptor_sets(device, descriptor_set_layout,
+                                   &uniform_buffers, &descriptor_pool,
+                                   swapchain.images.len(),
+                                   &texture_image_view, &sampler)?;
+
+    Ok(RenderState {
+      render_pass,
+      pipeline,
+      pipeline_layout,
+      vertex_buffer,
+      vertex_buffer_memory,
+      index_buffer,
+      index_buffer_memory,
+      index_count,
+      framebuffers,
+      command_buffers,
+      descriptor_sets,
+    })
+  }
+
+  //   This relies on its caller to have already waited for the device to be
+  // idle.
+  pub fn reinit(&mut self, permanent: &PermanentGraphicsState,
+                for_reinit: &GraphicsStateForReinit,
+                window_dressing: &WindowDressing)
+      -> Result<()>
+  {
+    let device = &permanent.device;
+    let sample_count = for_reinit.sample_count;
+    let descriptor_set_layout = &for_reinit.descriptor_set_layout;
+    let primary_command_pool = &window_dressing.primary_command_pool;
+    let swapchain = &window_dressing.swapchain;
+    let depth_format = &window_dressing.depth_format;
+    let color_image_view = &window_dressing.color_image_view;
+    let depth_image_view = &window_dressing.depth_image_view;
+    let texture_image_view = &window_dressing.texture_image_view;
+    let uniform_buffers = &window_dressing.uniform_buffers;
+    let descriptor_pool = &window_dressing.descriptor_pool;
+    let sampler = &window_dressing.sampler;
+
+    self.destroy_replaceable(device, primary_command_pool);
+
+    let render_pass = init_render_pass(device, sample_count,
+                                       &swapchain.format, &depth_format)?;
+
+    let (pipeline_layout, pipeline)
+            = init_pipeline(device, descriptor_set_layout, &swapchain.extent,
+                            sample_count, &render_pass)?;
+
+    let framebuffers = init_framebuffers(
+            device, &swapchain.extent, &swapchain.image_views,
+            &color_image_view, &depth_image_view, &render_pass)?;
+
+    // Notice that we reused the command pool.
+    let command_buffers = init_command_buffers(device, &framebuffers,
+                                               primary_command_pool)?;
+
+    let descriptor_sets
+            = init_descriptor_sets(device, descriptor_set_layout,
+                                   &uniform_buffers, &descriptor_pool,
+                                   swapchain.images.len(),
+                                   texture_image_view, sampler)?;
+
+    self.render_pass = render_pass;
+    self.pipeline = pipeline;
+    self.pipeline_layout = pipeline_layout;
+    self.framebuffers = framebuffers;
+    self.command_buffers = command_buffers;
+    self.descriptor_sets = descriptor_sets;
+
+    Ok(())
+  }
+
+  //   This relies on its caller to have already waited for the device to be
+  // idle.
+  #[allow(unsafe_code)]
+  pub fn destroy(mut self, device: &Device,
+                 window_dressing: &WindowDressing)
+  {
+    self.destroy_replaceable(device, &window_dressing.primary_command_pool);
+
+    unsafe { device.destroy_buffer(self.vertex_buffer, None) };
+    unsafe { device.free_memory(self.vertex_buffer_memory, None) };
+
+    unsafe { device.destroy_buffer(self.index_buffer, None) };
+    unsafe { device.free_memory(self.index_buffer_memory, None) };
+  }
+
+  #[allow(unsafe_code)]
+  fn destroy_replaceable(&mut self, device: &Device,
+                         primary_command_pool: &vk::CommandPool)
+  {
+    for framebuffer in &self.framebuffers {
+      unsafe { device.destroy_framebuffer(*framebuffer, None) };
+    }
+
+    //   Notice that we free the buffers in the pool, but do not destroy the
+    // pool itself. Notice also that we only do this for the primary command
+    // pool, because that's the only one where we've kept track of the
+    // buffers. We promise ourselves to free buffers in the transient pool
+    // immediately after using them.
+    unsafe {
+      device.free_command_buffers(*primary_command_pool,
+                                  &self.command_buffers)
+    };
+
+    unsafe { device.destroy_pipeline(self.pipeline, None) };
+    unsafe { device.destroy_pipeline_layout(self.pipeline_layout, None) };
+    unsafe { device.destroy_render_pass(self.render_pass, None) };
+  }
+}
+
+
+#[allow(unsafe_code)]
+fn init_swapchain(window: &Window, instance: &Instance,
+                  surface: &vk::SurfaceKHR,
+                  physical_device: &vk::PhysicalDevice, device: &Device,
+                  indices: &QueueFamilyIndices)
+    -> Result<Swapchain>
+{
+  let (capabilities, formats, presentation_modes)
+          = PermanentGraphicsState::find_device_swapchain_features(
+                instance, surface, physical_device)?.require()?;
+
+  let format = pick_surface_format(&formats)?;
+
+  let presentation_mode
+          = pick_presentation_mode(&presentation_modes)?;
+  let extent = pick_image_extent(window, capabilities)?;
+
+  let mut image_count = capabilities.min_image_count + 1;
+  if capabilities.max_image_count != 0 {
+    image_count
+        = image_count.clamp(0, capabilities.max_image_count);
+  }
+
+  let mut unique_queue_family_indices = BTreeSet::new();
+  unique_queue_family_indices.insert(indices.graphics);
+  unique_queue_family_indices.insert(indices.presentation);
+
+  //   If there's only one queue, we use exclusive sharing mode, which
+  // will allow things to work without locks. Otherwise we use concurrent
+  // mode.
+  let (ordered_indices, sharing_mode)
+          = if unique_queue_family_indices.len() < 2
+  {
+    (vec![indices.graphics], vk::SharingMode::EXCLUSIVE)
+  } else {
+    (vec![indices.graphics, indices.presentation],
+     vk::SharingMode::CONCURRENT)
+  };
+
+  let swapchain_info = vk::SwapchainCreateInfoKHR::builder()
+          .surface(*surface)
+          .min_image_count(image_count)
+          .image_format(format.format)
+          .image_color_space(format.color_space)
+          .image_extent(extent)
+          .image_array_layers(1)
+          .image_usage(vk::ImageUsageFlags::COLOR_ATTACHMENT)
+          .image_sharing_mode(sharing_mode)
+          .queue_family_indices(&ordered_indices)
+          .pre_transform(capabilities.current_transform)
+          .composite_alpha(vk::CompositeAlphaFlagsKHR::OPAQUE)
+          .present_mode(presentation_mode)
+          .clipped(true)
+          .old_swapchain(vk::SwapchainKHR::null());
+
+  let swapchain = unsafe {
+    device.create_swapchain_khr(&swapchain_info, None)
+  }?;
+
+  let images = unsafe {
+    device.get_swapchain_images_khr(swapchain)
+  }?;
+
+  let mut image_views = Vec::new();
+  for image in &images {
+    let view = init_image_view(device, image, 1, format.format,
+                               vk::ImageAspectFlags::COLOR)?;
+    image_views.push(view);
+  }
+
+  Ok(Swapchain {
+    swapchain, images, image_views,
+    format: format.format,
+    extent
+  })
+}
+
+
+#[allow(unsafe_code)]
+fn init_color(instance: &Instance, physical_device: &vk::PhysicalDevice,
+              device: &Device, extent: &vk::Extent2D,
+              sample_count: vk::SampleCountFlags, format: vk::Format)
+    -> Result<(vk::Image, vk::DeviceMemory, vk::ImageView)>
+{
+  let (image, image_memory)
+          = allocate_image(instance, physical_device, device,
+                           extent.width, extent.height, 1, sample_count,
+                           format,
+                           vk::ImageTiling::OPTIMAL,
+                           vk::ImageUsageFlags::COLOR_ATTACHMENT
+                           | vk::ImageUsageFlags::TRANSIENT_ATTACHMENT,
+                           vk::MemoryPropertyFlags::DEVICE_LOCAL)?;
+
+  let image_view = init_image_view(device, &image, 1, format,
+                                   vk::ImageAspectFlags::COLOR)?;
+
+  Ok((image, image_memory, image_view))
+}
+
+
+#[allow(unsafe_code)]
+fn init_depth(instance: &Instance, physical_device: &vk::PhysicalDevice,
+              device: &Device, extent: &vk::Extent2D,
+              sample_count: vk::SampleCountFlags)
+    -> Result<(vk::Image, vk::DeviceMemory, vk::ImageView, vk::Format)>
+{
+  let format = pick_depth_format(instance, physical_device)?;
+
+  let (image, image_memory)
+          = allocate_image(instance, physical_device, device,
+                           extent.width, extent.height, 1, sample_count,
+                           format,
+                           vk::ImageTiling::OPTIMAL,
+                           vk::ImageUsageFlags::DEPTH_STENCIL_ATTACHMENT,
+                           vk::MemoryPropertyFlags::DEVICE_LOCAL)?;
+
+  let image_view = init_image_view(device, &image, 1, format,
+                                   vk::ImageAspectFlags::DEPTH)?;
+
+  Ok((image, image_memory, image_view, format))
+}
+
+
+#[allow(unsafe_code)]
+fn init_render_pass(device: &Device, sample_count: vk::SampleCountFlags,
+                    color_format: &vk::Format, depth_format: &vk::Format)
+    -> Result<vk::RenderPass>
+{
+  let color_attachment = vk::AttachmentDescription::builder()
+          .format(*color_format)
+          .samples(sample_count)
+          .load_op(vk::AttachmentLoadOp::CLEAR)
+          .store_op(vk::AttachmentStoreOp::STORE)
+          .stencil_load_op(vk::AttachmentLoadOp::DONT_CARE)
+          .stencil_store_op(vk::AttachmentStoreOp::DONT_CARE)
+          .initial_layout(vk::ImageLayout::UNDEFINED)
+          .final_layout(vk::ImageLayout::COLOR_ATTACHMENT_OPTIMAL);
+
+  let color_attachment_reference = vk::AttachmentReference::builder()
+          .attachment(0)
+          .layout(vk::ImageLayout::COLOR_ATTACHMENT_OPTIMAL);
+
+  let depth_attachment = vk::AttachmentDescription::builder()
+          .format(*depth_format)
+          .samples(sample_count)
+          .load_op(vk::AttachmentLoadOp::CLEAR)
+          .store_op(vk::AttachmentStoreOp::DONT_CARE)
+          .stencil_load_op(vk::AttachmentLoadOp::DONT_CARE)
+          .stencil_store_op(vk::AttachmentStoreOp::DONT_CARE)
+          .initial_layout(vk::ImageLayout::UNDEFINED)
+          .final_layout(vk::ImageLayout::DEPTH_STENCIL_ATTACHMENT_OPTIMAL);
+
+  let depth_attachment_reference = vk::AttachmentReference::builder()
+          .attachment(1)
+          .layout(vk::ImageLayout::DEPTH_STENCIL_ATTACHMENT_OPTIMAL);
+
+  let color_resolve_attachment = vk::AttachmentDescription::builder()
+          .format(*color_format)
+          .samples(vk::SampleCountFlags::_1)
+          .load_op(vk::AttachmentLoadOp::DONT_CARE)
+          .store_op(vk::AttachmentStoreOp::STORE)
+          .stencil_load_op(vk::AttachmentLoadOp::DONT_CARE)
+          .stencil_store_op(vk::AttachmentStoreOp::DONT_CARE)
+          .initial_layout(vk::ImageLayout::UNDEFINED)
+          .final_layout(vk::ImageLayout::PRESENT_SRC_KHR);
+
+  let color_resolve_attachment_reference = vk::AttachmentReference::builder()
+          .attachment(2)
+          .layout(vk::ImageLayout::COLOR_ATTACHMENT_OPTIMAL);
+
+  let color_attachments = [color_attachment_reference];
+  let resolve_attachments = [color_resolve_attachment_reference];
+  let subpass = vk::SubpassDescription::builder()
+          .pipeline_bind_point(vk::PipelineBindPoint::GRAPHICS)
+          .color_attachments(&color_attachments)
+          .depth_stencil_attachment(&depth_attachment_reference)
+          .resolve_attachments(&resolve_attachments);
+
+  let dependency = vk::SubpassDependency::builder()
+          .src_subpass(vk::SUBPASS_EXTERNAL)
+          .src_stage_mask(vk::PipelineStageFlags::COLOR_ATTACHMENT_OUTPUT
+                          | vk::PipelineStageFlags::EARLY_FRAGMENT_TESTS)
+          .src_access_mask(vk::AccessFlags::empty())
+          .dst_subpass(0)
+          .dst_stage_mask(vk::PipelineStageFlags::COLOR_ATTACHMENT_OUTPUT
+                          | vk::PipelineStageFlags::EARLY_FRAGMENT_TESTS)
+          .dst_access_mask(vk::AccessFlags::COLOR_ATTACHMENT_WRITE
+                           | vk::AccessFlags::DEPTH_STENCIL_ATTACHMENT_WRITE);
+
+  let render_attachments = [color_attachment,
+                            depth_attachment,
+                            color_resolve_attachment];
+  let subpasses = [subpass];
+  let dependencies = [dependency];
+  let render_pass_info = vk::RenderPassCreateInfo::builder()
+          .attachments(&render_attachments)
+          .subpasses(&subpasses)
+          .dependencies(&dependencies);
+
+  let render_pass = unsafe {
+    device.create_render_pass(&render_pass_info, None)
+  }?;
+
+  Ok(render_pass)
+}
+
+
+#[allow(unsafe_code)]
+fn init_pipeline(device: &Device,
+                 descriptor_set_layout: &vk::DescriptorSetLayout,
+                 extent: &vk::Extent2D, sample_count: vk::SampleCountFlags,
+                 render_pass: &vk::RenderPass)
+    -> Result<(vk::PipelineLayout, vk::Pipeline)>
+{
+  let vertex_binary = include_bytes!(
+          concat!(env!("OUT_DIR"), "/shader.vert.spv"));
+  let fragment_binary = include_bytes!(
+          concat!(env!("OUT_DIR"), "/shader.frag.spv"));
+
+  let vertex_module = PermanentGraphicsState::load_spirv_shader_module(
+          device, vertex_binary)?;
+  let fragment_module = PermanentGraphicsState::load_spirv_shader_module(
+          device, fragment_binary)?;
+
+  let vertex_stage_info = vk::PipelineShaderStageCreateInfo::builder()
+          .stage(vk::ShaderStageFlags::VERTEX)
+          .module(vertex_module)
+          .name(b"main\0");
+
+  let fragment_stage_info = vk::PipelineShaderStageCreateInfo::builder()
+          .stage(vk::ShaderStageFlags::FRAGMENT)
+          .module(fragment_module)
+          .name(b"main\0");
+
+  let binding_descriptions = [Vertex::<f32>::binding_description()];
+  let attribute_descriptions = Vertex::<f32>::attribute_descriptions();
+  let vertex_input_state_info
+          = vk::PipelineVertexInputStateCreateInfo::builder()
+                .vertex_binding_descriptions(&binding_descriptions)
+                .vertex_attribute_descriptions(&attribute_descriptions);
+
+  let input_assembly_state_info
+          = vk::PipelineInputAssemblyStateCreateInfo::builder()
+                .topology(vk::PrimitiveTopology::TRIANGLE_LIST)
+                .primitive_restart_enable(false);
+
+  let viewport = vk::Viewport::builder()
+          .x(0.0)
+          .y(0.0)
+          .width(extent.width as f32)
+          .height(extent.height as f32)
+          .min_depth(0.0)
+          .max_depth(1.0);
+  let viewports = [viewport];
+
+  let scissor = vk::Rect2D::builder()
+          .offset(vk::Offset2D { x: 0, y: 0 })
+          .extent(*extent);
+  let scissor_list = [scissor];
+
+  let viewport_state_info = vk::PipelineViewportStateCreateInfo::builder()
+          .viewports(&viewports)
+          .scissors(&scissor_list);
+
+  let rasterizer_state_info = vk::PipelineRasterizationStateCreateInfo::builder()
+          .depth_clamp_enable(false)
+          .rasterizer_discard_enable(false)
+          .polygon_mode(vk::PolygonMode::FILL)
+          .line_width(1.0)
+          .cull_mode(vk::CullModeFlags::BACK)
+          .front_face(vk::FrontFace::CLOCKWISE)
+          .depth_bias_enable(false);
+
+  let multisample_state_info
+          = vk::PipelineMultisampleStateCreateInfo::builder()
+                .sample_shading_enable(false)
+                .rasterization_samples(sample_count);
+
+  let depth_state_info = vk::PipelineDepthStencilStateCreateInfo::builder()
+          .depth_test_enable(true)
+          .depth_write_enable(true)
+          .depth_compare_op(vk::CompareOp::LESS)
+          .depth_bounds_test_enable(false)
+          .min_depth_bounds(0.0)
+          .max_depth_bounds(1.0)
+          .stencil_test_enable(false);
+
+  let blend_attachment_info = vk::PipelineColorBlendAttachmentState::builder()
+          .color_write_mask(vk::ColorComponentFlags::all())
+          .blend_enable(false)
+          .src_color_blend_factor(vk::BlendFactor::ONE)
+          .dst_color_blend_factor(vk::BlendFactor::ZERO)
+          .color_blend_op(vk::BlendOp::ADD)
+          .src_alpha_blend_factor(vk::BlendFactor::ONE)
+          .dst_alpha_blend_factor(vk::BlendFactor::ZERO)
+          .alpha_blend_op(vk::BlendOp::ADD);
+  let blend_attachments = [blend_attachment_info];
+
+  let blend_info = vk::PipelineColorBlendStateCreateInfo::builder()
+          .logic_op_enable(false)
+          .logic_op(vk::LogicOp::COPY)
+          .attachments(&blend_attachments)
+          .blend_constants([0.0, 0.0, 0.0, 0.0]);
+
+  let vertex_push_constant_range = vk::PushConstantRange::builder()
+          .stage_flags(vk::ShaderStageFlags::VERTEX)
+          .offset(0)
+          .size(size_of::<VertexPushBlock<f32>>() as u32);
+
+  let layouts = [*descriptor_set_layout];
+  let push_constant_ranges = [vertex_push_constant_range];
+  let pipeline_layout_info = vk::PipelineLayoutCreateInfo::builder()
+                                 .set_layouts(&layouts)
+                                 .push_constant_ranges(&push_constant_ranges);
+
+  let pipeline_layout = unsafe {
+    device.create_pipeline_layout(&pipeline_layout_info, None)
+  }?;
+
+  let stages = [vertex_stage_info, fragment_stage_info];
+  let pipeline_info = vk::GraphicsPipelineCreateInfo::builder()
+          .stages(&stages)
+          .vertex_input_state(&vertex_input_state_info)
+          .input_assembly_state(&input_assembly_state_info)
+          .viewport_state(&viewport_state_info)
+          .rasterization_state(&rasterizer_state_info)
+          .multisample_state(&multisample_state_info)
+          .depth_stencil_state(&depth_state_info)
+          .color_blend_state(&blend_info)
+          .layout(pipeline_layout)
+          .render_pass(*render_pass)
+          .subpass(0);
+
+  let pipeline = unsafe {
+    device.create_graphics_pipelines(vk::PipelineCache::null(),
+                                     &[pipeline_info], None)
+  }?.0[0];
+
+  unsafe {
+    device.destroy_shader_module(vertex_module, None);
+    device.destroy_shader_module(fragment_module, None);
+  };
+
+  Ok((pipeline_layout, pipeline))
+}
+
+
+#[allow(unsafe_code)]
+fn init_framebuffers(device: &Device, extent: &vk::Extent2D,
+                     swapchain_image_views: &Vec<vk::ImageView>,
+                     color_image_view: &vk::ImageView,
+                     depth_image_view: &vk::ImageView,
+                     render_pass: &vk::RenderPass)
+    -> Result<Vec<vk::Framebuffer>>
+{
+  let mut framebuffers = Vec::new();
+
+  for color_resolve_image_view in swapchain_image_views {
+    let attachments = [*color_image_view,
+                       *depth_image_view,
+                       *color_resolve_image_view];
+
+    let framebuffer_info = vk::FramebufferCreateInfo::builder()
+            .render_pass(*render_pass)
+            .attachments(&attachments)
+            .width(extent.width)
+            .height(extent.height)
+            .layers(1);
+
+    let framebuffer = unsafe {
+      device.create_framebuffer(&framebuffer_info, None)
+    }?;
+
+    framebuffers.push(framebuffer);
+  }
+
+  Ok(framebuffers)
+}
+
+
+fn init_vertex_buffer(vertices: Vec<Vertex<f32>>, instance: &Instance,
+                      physical_device: &vk::PhysicalDevice, device: &Device,
+                      queue: &vk::Queue, command_pool: &vk::CommandPool)
+    -> Result<(vk::Buffer, vk::DeviceMemory)>
+{
+  init_buffer(instance, physical_device, device, queue, command_pool,
+              vk::BufferUsageFlags::VERTEX_BUFFER, &vertices)
+}
+
+
+fn init_index_buffer(indices: Vec<u32>, instance: &Instance,
+                     physical_device: &vk::PhysicalDevice, device: &Device,
+                     queue: &vk::Queue, command_pool: &vk::CommandPool)
+    -> Result<(vk::Buffer, vk::DeviceMemory)>
+{
+  init_buffer(instance, physical_device, device, queue, command_pool,
+              vk::BufferUsageFlags::INDEX_BUFFER, &indices)
+}
+
+
+#[allow(unsafe_code)]
+fn init_texture(instance: &Instance,
+                physical_device: &vk::PhysicalDevice, device: &Device,
+                queue: &vk::Queue, command_pool: &vk::CommandPool)
+    -> Result<(vk::Image, vk::DeviceMemory, vk::ImageView, u32)>
+{
+  let png = include_bytes!("../../textures/forest_leaves_04_diff.png");
+
+  let decoder = Decoder::new(Cursor::new(png));
+  let mut reader = decoder.read_info()?;
+
+  let (width, height) = reader.info().size();
+
+  let format_properties = unsafe {
+    instance.get_physical_device_format_properties(*physical_device,
+                                                   vk::Format::R8G8B8A8_SRGB)
+  };
+  let has_linear_filter = format_properties
+          .optimal_tiling_features
+          .contains(vk::FormatFeatureFlags::SAMPLED_IMAGE_FILTER_LINEAR);
+  let mip_count = if has_linear_filter {
+    //   This will generate mips all the way down to 1x1. It is not clear
+    // whether there's a benefit to that.
+    (width.max(height)).ilog2() + 1
+  } else {
+    1
+  };
+
+  let mut pixels = vec![0; reader.info().raw_bytes()];
+  reader.next_frame(&mut pixels)?;
+
+  let (staging_buffer, staging_memory, _byte_size)
+          = stage_in_buffer(instance, physical_device, device, &pixels)?;
+
+  let (image, image_memory)
+          = allocate_image(instance, physical_device, device,
+                           width, height, mip_count, vk::SampleCountFlags::_1,
+                           vk::Format::R8G8B8A8_SRGB,
+                           vk::ImageTiling::OPTIMAL,
+                           vk::ImageUsageFlags::SAMPLED
+                               | vk::ImageUsageFlags::TRANSFER_SRC
+                               | vk::ImageUsageFlags::TRANSFER_DST,
+                           vk::MemoryPropertyFlags::DEVICE_LOCAL)?;
+
+  change_image_layout(device, queue, command_pool, &image, mip_count,
+                      vk::Format::R8G8B8A8_SRGB,
+                      vk::ImageLayout::UNDEFINED,
+                      vk::ImageLayout::TRANSFER_DST_OPTIMAL)?;
+
+  copy_buffer_to_image(device, queue, command_pool, &staging_buffer, &image,
+                       width, height)?;
+
+  // This will also change the layout to SHADER_READ_ONLY_OPTIMAL.
+
+  fill_mip_levels(device, queue, command_pool, &image,
+                  width, height, mip_count)?;
+
+  let view = init_image_view(device, &image, mip_count,
+                             vk::Format::R8G8B8A8_SRGB,
+                             vk::ImageAspectFlags::COLOR)?;
+
+  unsafe { device.destroy_buffer(staging_buffer, None) };
+  unsafe { device.free_memory(staging_memory, None) };
+
+  Ok((image, image_memory, view, mip_count))
+}
+
+
+fn init_uniform_buffers(instance: &Instance,
+                        physical_device: &vk::PhysicalDevice, device: &Device,
+                        count: usize)
+    -> Result<(Vec<vk::Buffer>, Vec<vk::DeviceMemory>)>
+{
+  let mut buffers = Vec::new();
+  let mut all_memory = Vec::new();
+
+  for _ in 0 .. count {
+    let (buffer, memory) = allocate_buffer(
+            instance, physical_device, device,
+            size_of::<UniformBlock<f32>>() as vk::DeviceSize,
+            vk::BufferUsageFlags::UNIFORM_BUFFER,
+            vk::MemoryPropertyFlags::HOST_COHERENT
+            | vk::MemoryPropertyFlags::HOST_VISIBLE)?;
+    buffers.push(buffer);
+    all_memory.push(memory);
+  }
+
+  Ok((buffers, all_memory))
+}
+
+
+#[allow(unsafe_code)]
+fn init_buffer<T>(instance: &Instance,
+                  physical_device: &vk::PhysicalDevice, device: &Device,
+                  queue: &vk::Queue, command_pool: &vk::CommandPool,
+                  usage: vk::BufferUsageFlags, contents: &[T])
+    -> Result<(vk::Buffer, vk::DeviceMemory)>
+{
+  let (staging_buffer, staging_memory, size)
+          = stage_in_buffer(instance, physical_device, device, contents)?;
+
+  let final_usage = vk::BufferUsageFlags::TRANSFER_DST | usage;
+  let final_memory_flags = vk::MemoryPropertyFlags::DEVICE_LOCAL;
+  let (final_buffer, device_memory)
+          = allocate_buffer(instance, physical_device, device,
+                            size as vk::DeviceSize, final_usage,
+                            final_memory_flags)?;
+
+  copy_buffer(device, queue, command_pool, &staging_buffer, &final_buffer,
+              size as vk::DeviceSize)?;
+
+  unsafe { device.destroy_buffer(staging_buffer, None) };
+  unsafe { device.free_memory(staging_memory, None) };
+
+  Ok((final_buffer, device_memory))
+}
+
+
+#[allow(unsafe_code)]
+fn init_sampler(device: &Device, enable_anisotropy: &EnableAnisotropy,
+                mip_count: u32)
+    -> Result<vk::Sampler>
+{
+  let mut sampler_info = vk::SamplerCreateInfo::builder()
+          .mag_filter(vk::Filter::LINEAR)
+          .min_filter(vk::Filter::LINEAR)
+          .address_mode_u(vk::SamplerAddressMode::REPEAT)
+          .address_mode_v(vk::SamplerAddressMode::REPEAT)
+          .address_mode_w(vk::SamplerAddressMode::REPEAT)
+          .border_color(vk::BorderColor::INT_OPAQUE_BLACK)
+          .unnormalized_coordinates(false)
+          .compare_enable(false)
+          .compare_op(vk::CompareOp::ALWAYS)
+          .mipmap_mode(vk::SamplerMipmapMode::LINEAR)
+          .mip_lod_bias(0.0)
+          .min_lod(0.0)
+          .max_lod(mip_count as f32);
+  sampler_info = if enable_anisotropy.0 {
+    sampler_info.anisotropy_enable(true)
+                .max_anisotropy(16.0)
+  } else {
+    sampler_info.anisotropy_enable(false)
+                .max_anisotropy(1.0)
+  };
+
+  let sampler = unsafe { device.create_sampler(&sampler_info, None) }?;
+
+  Ok(sampler)
+}
+
+
+#[allow(unsafe_code)]
+fn init_descriptor_pool(device: &Device, count: usize)
+    -> Result<vk::DescriptorPool>
+{
+  let uniform_block_size = vk::DescriptorPoolSize::builder()
+          .type_(vk::DescriptorType::UNIFORM_BUFFER)
+          .descriptor_count(count as u32);
+
+  let sampler_size = vk::DescriptorPoolSize::builder()
+          .type_(vk::DescriptorType::COMBINED_IMAGE_SAMPLER)
+          .descriptor_count(count as u32);
+
+  let sizes = [uniform_block_size, sampler_size];
+  let pool_info = vk::DescriptorPoolCreateInfo::builder()
+          .pool_sizes(&sizes)
+          .max_sets(count as u32);
+  let pool = unsafe { device.create_descriptor_pool(&pool_info, None) }?;
+
+  Ok(pool)
+}
+
+
+#[allow(unsafe_code)]
+fn init_descriptor_sets(device: &Device, layout: &vk::DescriptorSetLayout,
+                        buffers: &Vec<vk::Buffer>, pool: &vk::DescriptorPool,
+                        count: usize, texture_image_view: &vk::ImageView,
+                        sampler: &vk::Sampler)
+    -> Result<Vec<vk::DescriptorSet>>
+{
+  let layouts = vec![*layout; count];
+  let set_info = vk::DescriptorSetAllocateInfo::builder()
+          .descriptor_pool(*pool)
+          .set_layouts(&layouts);
+  let sets = unsafe { device.allocate_descriptor_sets(&set_info) }?;
+
+  for index in 0 .. count {
+    let buffer_info = vk::DescriptorBufferInfo::builder()
+            .buffer(buffers[index])
+            .offset(0)
+            .range(size_of::<UniformBlock<f32>>() as vk::DeviceSize);
+
+    let buffer_info_list = [buffer_info];
+    let uniform_block_write_info = vk::WriteDescriptorSet::builder()
+            .dst_set(sets[index])
+            .dst_binding(0)
+            .dst_array_element(0)
+            .descriptor_type(vk::DescriptorType::UNIFORM_BUFFER)
+            .buffer_info(&buffer_info_list);
+
+    let image_info = vk::DescriptorImageInfo::builder()
+            .image_layout(vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL)
+            .image_view(*texture_image_view)
+            .sampler(*sampler);
+    let image_info_list = [image_info];
+    let sampler_write_info = vk::WriteDescriptorSet::builder()
+            .dst_set(sets[index])
+            .dst_binding(1)
+            .dst_array_element(0)
+            .descriptor_type(vk::DescriptorType::COMBINED_IMAGE_SAMPLER)
+            .image_info(&image_info_list);
+
+    let write_info_list = [uniform_block_write_info, sampler_write_info];
+    let copy_info_list: [vk::CopyDescriptorSet; 0] = [];
+
+    unsafe {
+      device.update_descriptor_sets(&write_info_list, &copy_info_list)
+    };
+  }
+
+  Ok(sets)
+}
+
+
+#[allow(unsafe_code)]
+fn init_command_pools(device: &Device, indices: &QueueFamilyIndices)
+    -> Result<(vk::CommandPool, vk::CommandPool)>
+{
+  let command_pool_info = vk::CommandPoolCreateInfo::builder()
+          .flags(vk::CommandPoolCreateFlags::TRANSIENT
+                 | vk::CommandPoolCreateFlags::RESET_COMMAND_BUFFER)
+          .queue_family_index(indices.graphics);
+
+  let primary = unsafe {
+    device.create_command_pool(&command_pool_info, None)
+  }?;
+
+  command_pool_info.flags(vk::CommandPoolCreateFlags::TRANSIENT);
+  let transient = unsafe {
+    device.create_command_pool(&command_pool_info, None)
+  }?;
+
+  Ok((primary, transient))
+}
+
+
+#[allow(unsafe_code)]
+fn init_command_buffers(device: &Device,
+                        framebuffers: &Vec<vk::Framebuffer>,
+                        command_pool: &vk::CommandPool)
+    -> Result<Vec<vk::CommandBuffer>>
+{
+  let command_buffer_allocation_info
+          = vk::CommandBufferAllocateInfo::builder()
+                .command_pool(*command_pool)
+                .level(vk::CommandBufferLevel::PRIMARY)
+                .command_buffer_count(framebuffers.len() as u32);
+  let command_buffers = unsafe {
+    device.allocate_command_buffers(&command_buffer_allocation_info)
+  }?;
+
+  Ok(command_buffers)
+}
+
+
+#[allow(unsafe_code)]
+fn init_concurrency(device: &Device,
+                    swapchain_images: &Vec<vk::Image>)
+    -> Result<Concurrency>
+{
+  let semaphore_info = vk::SemaphoreCreateInfo::builder();
+  let fence_info = vk::FenceCreateInfo::builder()
+                       .flags(vk::FenceCreateFlags::SIGNALED);
+
+  let mut image_available_semaphores = Vec::new();
+  let mut rendering_finished_semaphores = Vec::new();
+  let mut frame_fences = Vec::new();
+  for _ in 0 .. N_SIMULTANEOUS_FRAMES {
+    image_available_semaphores.push(unsafe {
+      device.create_semaphore(&semaphore_info, None)
+    }?);
+
+    rendering_finished_semaphores.push(unsafe {
+      device.create_semaphore(&semaphore_info, None)
+    }?);
+
+    frame_fences.push(unsafe {
+      device.create_fence(&fence_info, None)
+    }?);
+  }
+
+  let mut image_fences = Vec::new();
+  for _ in 0 .. swapchain_images.len() {
+    image_fences.push(vk::Fence::null());
+  }
+
+  Ok(Concurrency {
+    image_available_semaphores,
+    rendering_finished_semaphores,
+    frame_fences,
+    image_fences: image_fences,
+  })
+}
+
+
+#[allow(unsafe_code)]
+fn init_image_view(device: &Device, image: &vk::Image, mip_count: u32,
+                   format: vk::Format, aspects: vk::ImageAspectFlags)
+    -> Result<vk::ImageView>
+{
+  //   Component mapping is only for color components (not, for example, depth
+  // or stencil components), so we always just want it like this.
+  let components = vk::ComponentMapping::builder()
+          .r(vk::ComponentSwizzle::IDENTITY)
+          .g(vk::ComponentSwizzle::IDENTITY)
+          .b(vk::ComponentSwizzle::IDENTITY)
+          .a(vk::ComponentSwizzle::IDENTITY);
+
+  let subresource_range = vk::ImageSubresourceRange::builder()
+          .aspect_mask(aspects)
+          .base_mip_level(0)
+          .level_count(mip_count)
+          .base_array_layer(0)
+          .layer_count(1);
+
+  let view_info = vk::ImageViewCreateInfo::builder()
+          .image(*image)
+          .view_type(vk::ImageViewType::_2D)
+          .format(format)
+          .components(components)
+          .subresource_range(subresource_range);
+
+  let view = unsafe {
+    device.create_image_view(&view_info, None)
+  }?;
+
+  Ok(view)
+}
+
+
+fn pick_surface_format(available_formats: &Vec<vk::SurfaceFormatKHR>)
+    -> Result<vk::SurfaceFormatKHR>
+{
+  for format in available_formats {
+    if format.format == vk::Format::B8G8R8A8_SRGB
+       && format.color_space == vk::ColorSpaceKHR::SRGB_NONLINEAR
+    {
+      return Ok(format.clone());
+    }
+  }
+
+  return Ok(available_formats[0].clone());
+}
+
+
+#[allow(unsafe_code)]
+fn pick_depth_format(instance: &Instance,
+                     physical_device: &vk::PhysicalDevice)
+    -> Result<vk::Format>
+{
+  let required_features = vk::FormatFeatureFlags::DEPTH_STENCIL_ATTACHMENT;
+
+  for format in [vk::Format::D32_SFLOAT,
+                 vk::Format::D32_SFLOAT_S8_UINT,
+                 vk::Format::D24_UNORM_S8_UINT]
+  {
+    let properties = unsafe {
+      instance.get_physical_device_format_properties(
+                   *physical_device, format)
+    };
+
+    if properties.optimal_tiling_features.contains(required_features) {
+      return Ok(format);
+    }
+  }
+
+  Err(Error {
+    message: "There is no supported depth-buffer sample format.".to_string()
+  })
+}
+
+
+fn pick_presentation_mode(_available_modes: &Vec<vk::PresentModeKHR>)
+    -> Result<vk::PresentModeKHR>
+{
+  // It's guaranteed to have this one.
+  return Ok(vk::PresentModeKHR::FIFO);
+}
+
+
+fn pick_image_extent(window: &Window,
+                     capabilities: vk::SurfaceCapabilitiesKHR)
+    -> Result<vk::Extent2D>
+{
+  if capabilities.current_extent.width != u32::MAX
+     && capabilities.current_extent.height != u32::MAX
+  {
+    Ok(capabilities.current_extent)
+  } else {
+    let window_size = window.inner_size();
+
+    let width = window_size.width
+                           .clamp(capabilities.min_image_extent.width,
+                                  capabilities.max_image_extent.width);
+    let height = window_size.height
+                            .clamp(capabilities.min_image_extent.height,
+                                   capabilities.max_image_extent.height);
+
+    Ok(vk::Extent2D::builder().width(width).height(height).build())
+  }
+}
+
+
+#[allow(unsafe_code)]
+fn pick_memory_type(instance: &Instance,
+                    physical_device: &vk::PhysicalDevice,
+                    properties: &vk::MemoryPropertyFlags,
+                    requirements: &vk::MemoryRequirements)
+    -> Result<u32>
+{
+  let memory_map = unsafe {
+    instance.get_physical_device_memory_properties(*physical_device)
+  };
+
+  //   So. The memory_type_bits field is a map of which indices are suitable,
+  // based on the buffer our caller passed to
+  // get_buffer_memory_requirements(). Yes, that means there's a hard cap on
+  // how many memory types there can be, based on the size of the bitfield.
+  for index in 0 .. memory_map.memory_type_count {
+    if requirements.memory_type_bits & (1 << index) == 0 {
+      continue;
+    }
+
+    let memory_type = memory_map.memory_types[index as usize];
+
+    if memory_type.property_flags.contains(*properties) {
+      return Ok(index);
+    }
+  }
+
+  Err(Error {
+    message: "The system has no suitable memory for a buffer.".to_string()
+  })
+}
+
+
+#[allow(unsafe_code)]
+fn stage_in_buffer<T>(instance: &Instance,
+                      physical_device: &vk::PhysicalDevice, device: &Device,
+                      contents: &[T])
+    -> Result<(vk::Buffer, vk::DeviceMemory, usize)>
+{
+  let size = size_of::<T>() * contents.len();
+
+  let staging_usage = vk::BufferUsageFlags::TRANSFER_SRC;
+  let staging_memory_flags = vk::MemoryPropertyFlags::HOST_COHERENT
+                             | vk::MemoryPropertyFlags::HOST_VISIBLE;
+  let (staging_buffer, staging_memory)
+          = allocate_buffer(instance, physical_device, device,
+                            size as vk::DeviceSize, staging_usage,
+                            staging_memory_flags)?;
+
+  let host_memory = unsafe {
+    device.map_memory(staging_memory, 0, size as vk::DeviceSize,
+                      vk::MemoryMapFlags::empty())
+  }?;
+
+  unsafe {
+    copy_nonoverlapping(contents.as_ptr(), host_memory.cast(), contents.len())
+  };
+
+  unsafe { device.unmap_memory(staging_memory) };
+
+  Ok((staging_buffer, staging_memory, size))
+}
+
+
+#[allow(unsafe_code)]
+fn allocate_buffer(instance: &Instance,
+                   physical_device: &vk::PhysicalDevice, device: &Device,
+                   size: vk::DeviceSize, usage: vk::BufferUsageFlags,
+                   memory_flags: vk::MemoryPropertyFlags)
+    -> Result<(vk::Buffer, vk::DeviceMemory)>
+{
+  let buffer_info = vk::BufferCreateInfo::builder()
+                        .size(size)
+                        .usage(usage)
+                        .sharing_mode(vk::SharingMode::EXCLUSIVE);
+
+  let buffer = unsafe { device.create_buffer(&buffer_info, None) }?;
+
+  //   The requirements are mostly what you'd think: size and alignment. The
+  // bits field is something special; see pick_memory_type() for the
+  // explanation. Despite the simplicity of this data, Vulkan wants to be the
+  // one to tell us about it, and we let it.
+  let requirements = unsafe { device.get_buffer_memory_requirements(buffer) };
+
+  let type_index = pick_memory_type(instance, physical_device,
+                                    &memory_flags, &requirements)?;
+
+  let memory_info = vk::MemoryAllocateInfo::builder()
+          .allocation_size(requirements.size)
+          .memory_type_index(type_index);
+
+  let device_memory = unsafe { device.allocate_memory(&memory_info, None) }?;
+
+  unsafe { device.bind_buffer_memory(buffer, device_memory, 0) }?;
+
+  Ok((buffer, device_memory))
+}
+
+
+#[allow(unsafe_code)]
+fn copy_buffer(device: &Device, queue: &vk::Queue,
+               command_pool: &vk::CommandPool, source: &vk::Buffer,
+               destination: &vk::Buffer, size: vk::DeviceSize)
+    -> Result<()>
+{
+  let command_buffer = begin_transient_commands(device, command_pool)?;
+
+  let copy_info = vk::BufferCopy::builder().size(size);
+  unsafe {
+    device.cmd_copy_buffer(command_buffer, *source, *destination,
+                           &[copy_info])
+  };
+
+  end_transient_commands(command_buffer, device, queue, command_pool)?;
+
+  Ok(())
+}
+
+
+#[allow(unsafe_code)]
+fn allocate_image(instance: &Instance, physical_device: &vk::PhysicalDevice,
+                  device: &Device, width: u32, height: u32, mip_count: u32,
+                  sample_count: vk::SampleCountFlags, format: vk::Format,
+                  tiling: vk::ImageTiling, usage: vk::ImageUsageFlags,
+                  memory_flags: vk::MemoryPropertyFlags)
+    -> Result<(vk::Image, vk::DeviceMemory)>
+{
+  let image_info = vk::ImageCreateInfo::builder()
+          .image_type(vk::ImageType::_2D)
+          .extent(vk::Extent3D { width, height, depth: 1 })
+          .mip_levels(mip_count)
+          .samples(sample_count)
+          .array_layers(1)
+          .format(format)
+          .tiling(tiling)
+          .initial_layout(vk::ImageLayout::UNDEFINED)
+          .usage(usage)
+          .sharing_mode(vk::SharingMode::EXCLUSIVE)
+          .flags(vk::ImageCreateFlags::empty());
+  let image = unsafe { device.create_image(&image_info, None) }?;
+
+  let requirements = unsafe { device.get_image_memory_requirements(image) };
+
+  let type_index = pick_memory_type(instance, physical_device,
+                                    &memory_flags, &requirements)?;
+
+  let image_memory_info = vk::MemoryAllocateInfo::builder()
+          .allocation_size(requirements.size)
+          .memory_type_index(type_index);
+  let image_memory = unsafe {
+    device.allocate_memory(&image_memory_info, None)
+  }?;
+
+  unsafe { device.bind_image_memory(image, image_memory, 0) }?;
+
+  Ok((image, image_memory))
+}
+
+
+#[allow(unsafe_code)]
+fn copy_buffer_to_image(device: &Device, queue: &vk::Queue,
+                        command_pool: &vk::CommandPool, source: &vk::Buffer,
+                        destination: &vk::Image, width: u32, height: u32)
+    -> Result<()>
+{
+  let command_buffer = begin_transient_commands(device, command_pool)?;
+
+  let subresource_layers = vk::ImageSubresourceLayers::builder()
+          .aspect_mask(vk::ImageAspectFlags::COLOR)
+          .mip_level(0)
+          .base_array_layer(0)
+          .layer_count(1);
+
+  let copy_info = vk::BufferImageCopy::builder()
+          .buffer_offset(0)
+          .buffer_row_length(0)
+          .buffer_image_height(0)
+          .image_subresource(subresource_layers)
+          .image_offset(vk::Offset3D { x: 0, y: 0, z: 0 })
+          .image_extent(vk::Extent3D { width, height, depth: 1 });
+
+  unsafe {
+    device.cmd_copy_buffer_to_image(command_buffer, *source, *destination,
+                                    vk::ImageLayout::TRANSFER_DST_OPTIMAL,
+                                    &[copy_info])
+  };
+
+  end_transient_commands(command_buffer, device, queue, command_pool)?;
+
+  Ok(())
+}
+
+
+#[allow(unsafe_code)]
+fn change_image_layout(device: &Device, queue: &vk::Queue,
+                       command_pool: &vk::CommandPool, image: &vk::Image,
+                       mip_count: u32, format: vk::Format,
+                       old: vk::ImageLayout, new: vk::ImageLayout)
+    -> Result<()>
+{
+  let command_buffer = begin_transient_commands(device, command_pool)?;
+
+  let subresource_range = vk::ImageSubresourceRange::builder()
+          .aspect_mask(vk::ImageAspectFlags::COLOR)
+          .base_mip_level(0)
+          .level_count(mip_count)
+          .base_array_layer(0)
+          .layer_count(1);
+
+  //   Notionally this is a property that our caller is in a better position
+  // to know than we are, but in practice the nature of the transition
+  // strongly implies a particular phase of the image's lifecycle, so we just
+  // compute it here.
+  let (source_access, source_stage, destination_access, destination_stage)
+          = match (old, new)
+  {
+    (vk::ImageLayout::UNDEFINED, vk::ImageLayout::TRANSFER_DST_OPTIMAL)
+        => (vk::AccessFlags::empty(),
+            vk::PipelineStageFlags::TOP_OF_PIPE,
+            vk::AccessFlags::TRANSFER_WRITE,
+            vk::PipelineStageFlags::TRANSFER),
+    (vk::ImageLayout::TRANSFER_DST_OPTIMAL,
+     vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL)
+        => (vk::AccessFlags::TRANSFER_WRITE,
+            vk::PipelineStageFlags::TRANSFER,
+            vk::AccessFlags::SHADER_READ,
+            vk::PipelineStageFlags::FRAGMENT_SHADER),
+    _ => return Err(Error {
+      message:
+          format!("Don't know how to change from image layout {:?} to {:?}",
+                  old, new)
+    })
+  };
+
+  let barrier_info = vk::ImageMemoryBarrier::builder()
+        .image(*image)
+        .subresource_range(subresource_range)
+        .old_layout(old)
+        .new_layout(new)
+        .src_queue_family_index(vk::QUEUE_FAMILY_IGNORED)
+        .dst_queue_family_index(vk::QUEUE_FAMILY_IGNORED)
+        .src_access_mask(source_access)
+        .dst_access_mask(destination_access);
+
+  unsafe {
+    device.cmd_pipeline_barrier(command_buffer,
+                                source_stage, destination_stage,
+                                vk::DependencyFlags::empty(),
+                                &[] as &[vk::MemoryBarrier],
+                                &[] as &[vk::BufferMemoryBarrier],
+                                &[barrier_info])
+  };
+
+  end_transient_commands(command_buffer, device, queue, command_pool)?;
+
+  Ok(())
+}
+
+
+//   An Image can store multiple mip levels within it, as one of several kinds
+// of subresource it has. We deal with this by
+#[allow(unsafe_code)]
+fn fill_mip_levels(device: &Device, queue: &vk::Queue,
+                   command_pool: &vk::CommandPool, image: &vk::Image,
+                   original_width: u32, original_height: u32,
+                   mip_count: u32)
+    -> Result<()>
+{
+  let command_buffer = begin_transient_commands(device, command_pool)?;
+
+  //   We'll be mutating these two builders as we loop through the mip levels,
+  // because we need to construct a lot of similar things. Remember, the
+  // builder methods don't mutate in-place, they return a new builder; to
+  // avoid confusion we always assign that result back to the same variable.
+  let mut barrier_subresource_range = vk::ImageSubresourceRange::builder()
+          .aspect_mask(vk::ImageAspectFlags::COLOR)
+          .level_count(1)
+          .base_array_layer(0)
+          .layer_count(1);
+
+  let mut blit_barrier_info = vk::ImageMemoryBarrier::builder()
+          .image(*image)
+          .src_queue_family_index(vk::QUEUE_FAMILY_IGNORED)
+          .dst_queue_family_index(vk::QUEUE_FAMILY_IGNORED);
+
+  //   Now we loop through the mip levels from largest (low numbers) to
+  // smallest (high numbers). Conceptually, the only thing we're doing is a
+  // blit that copies each mip level from the one immediately before. Recall
+  // though that we don't just want to fill in the pixels, we also care about
+  // pixel format and memory sharing. There are additional operations to deal
+  // with that. These are best done together, as detailed below.
+  //
+  //   This loop has a lot of code in it, so we make the "paragraphs" a little
+  // more dense than usual to make sure the logical grouping is clear.
+  let mut source_width = original_width;
+  let mut source_height = original_height;
+  for destination_mip_level in 1 .. mip_count {
+    let source_mip_level = destination_mip_level - 1;
+    let destination_width = (source_width / 2).max(1);
+    let destination_height = (source_height / 2).max(1);
+
+    //   So. The name pipeline_barrier is a little misleading; it does indeed
+    // mean "barrier" in the concurrency sense, but it isn't just initiating
+    // a wait, it's also performing any needed mutation. We do one of them
+    // here, acting on this iteration's source level, to set it up for
+    // reading.
+    barrier_subresource_range = barrier_subresource_range
+        .base_mip_level(source_mip_level as u32);
+    blit_barrier_info = blit_barrier_info
+        .old_layout(vk::ImageLayout::TRANSFER_DST_OPTIMAL)
+        .new_layout(vk::ImageLayout::TRANSFER_SRC_OPTIMAL)
+        .src_access_mask(vk::AccessFlags::TRANSFER_WRITE)
+        .dst_access_mask(vk::AccessFlags::TRANSFER_READ)
+        .subresource_range(barrier_subresource_range);
+    unsafe {
+      device.cmd_pipeline_barrier(command_buffer,
+                                  vk::PipelineStageFlags::TRANSFER,
+                                  vk::PipelineStageFlags::TRANSFER,
+                                  vk::DependencyFlags::empty(),
+                                  &[] as &[vk::MemoryBarrier],
+                                  &[] as &[vk::BufferMemoryBarrier],
+                                  &[blit_barrier_info])
+    };
+
+    //   Now we do the actual blit. Nice and easy, though specifying the
+    // coordinates is a bit verbose.
+    let blit_source_layer_info = vk::ImageSubresourceLayers::builder()
+            .aspect_mask(vk::ImageAspectFlags::COLOR)
+            .mip_level(source_mip_level as u32)
+            .base_array_layer(0)
+            .layer_count(1);
+    let blit_destination_layer_info = vk::ImageSubresourceLayers::builder()
+            .aspect_mask(vk::ImageAspectFlags::COLOR)
+            .mip_level(destination_mip_level as u32)
+            .base_array_layer(0)
+            .layer_count(1);
+    let blit_info = vk::ImageBlit::builder()
+            .src_offsets([vk::Offset3D { x: 0, y: 0, z: 0 },
+                          vk::Offset3D {
+                            x: source_width as i32,
+                            y: source_height as i32,
+                            z: 1
+                          }])
+            .src_subresource(blit_source_layer_info)
+            .dst_offsets([vk::Offset3D { x: 0, y: 0, z: 0 },
+                          vk::Offset3D {
+                            x: destination_width as i32,
+                            y: destination_height as i32,
+                            z: 1
+                          }])
+            .dst_subresource(blit_destination_layer_info);
+    unsafe {
+      device.cmd_blit_image(command_buffer,
+                            *image, vk::ImageLayout::TRANSFER_SRC_OPTIMAL,
+                            *image, vk::ImageLayout::TRANSFER_DST_OPTIMAL,
+                            &[blit_info],
+                            vk::Filter::LINEAR)
+    };
+
+    //   Now we do another pipeline_barrier. We're still acting on this
+    // iteration's source level, not on the destination. We'll never need to
+    // use it again except from the shader, so we set it appropriately for
+    // that.
+    blit_barrier_info = blit_barrier_info
+        .old_layout(vk::ImageLayout::TRANSFER_SRC_OPTIMAL)
+        .new_layout(vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL)
+        .src_access_mask(vk::AccessFlags::TRANSFER_READ)
+        .dst_access_mask(vk::AccessFlags::SHADER_READ);
+    unsafe {
+      device.cmd_pipeline_barrier(command_buffer,
+                                  vk::PipelineStageFlags::TRANSFER,
+                                  vk::PipelineStageFlags::FRAGMENT_SHADER,
+                                  vk::DependencyFlags::empty(),
+                                  &[] as &[vk::MemoryBarrier],
+                                  &[] as &[vk::BufferMemoryBarrier],
+                                  &[blit_barrier_info])
+    };
+
+    source_width = destination_width;
+    source_height = destination_height;
+  }
+
+  let final_mip_level = mip_count - 1;
+
+  //   We need to do one final pipeline_barrier, because the loop didn't do it
+  // to the smallest (last) mip level. We change it to have the same settings
+  // the loop left the rest of them in. The barrier source properties for this
+  // barrier are different from the others because this level was never useds
+  // as a blit source, only as a blit destination. The barrier destination
+  // properties are the same as the rest, so after this all the subresourcess
+  // will be in their fully-ready state.
+  barrier_subresource_range = barrier_subresource_range
+      .base_mip_level(final_mip_level as u32);
+  blit_barrier_info = blit_barrier_info
+      .old_layout(vk::ImageLayout::TRANSFER_DST_OPTIMAL)
+      .new_layout(vk::ImageLayout::SHADER_READ_ONLY_OPTIMAL)
+      .src_access_mask(vk::AccessFlags::TRANSFER_WRITE)
+      .dst_access_mask(vk::AccessFlags::SHADER_READ)
+      .subresource_range(barrier_subresource_range);
+  unsafe {
+    device.cmd_pipeline_barrier(command_buffer,
+                                vk::PipelineStageFlags::TRANSFER,
+                                vk::PipelineStageFlags::FRAGMENT_SHADER,
+                                vk::DependencyFlags::empty(),
+                                &[] as &[vk::MemoryBarrier],
+                                &[] as &[vk::BufferMemoryBarrier],
+                                &[blit_barrier_info])
+  };
+
+  end_transient_commands(command_buffer, device, queue, command_pool)?;
+
+  Ok(())
+}
+
+
+#[allow(unsafe_code)]
+fn begin_transient_commands(device: &Device, command_pool: &vk::CommandPool)
+    -> Result<vk::CommandBuffer>
+{
+  let command_buffer_allocation_info
+          = vk::CommandBufferAllocateInfo::builder()
+                .command_pool(*command_pool)
+                .level(vk::CommandBufferLevel::PRIMARY)
+                .command_buffer_count(1);
+  let command_buffer = unsafe {
+    device.allocate_command_buffers(&command_buffer_allocation_info)
+  }?[0];
+
+  let command_buffer_begin_info = vk::CommandBufferBeginInfo::builder()
+          .flags(vk::CommandBufferUsageFlags::ONE_TIME_SUBMIT);
+
+  unsafe {
+    device.begin_command_buffer(command_buffer, &command_buffer_begin_info)
+  }?;
+
+  Ok(command_buffer)
+}
+
+
+#[allow(unsafe_code)]
+fn end_transient_commands(command_buffer: vk::CommandBuffer,
+                          device: &Device, queue: &vk::Queue,
+                          command_pool: &vk::CommandPool)
+    -> Result<()>
+{
+  unsafe { device.end_command_buffer(command_buffer) }?;
+
+  let command_buffers = [command_buffer];
+  let submit_info = vk::SubmitInfo::builder()
+          .command_buffers(&command_buffers);
+  unsafe { device.queue_submit(*queue, &[submit_info], vk::Fence::null()) }?;
+
+  unsafe { device.queue_wait_idle(*queue) }?;
+
+  unsafe { device.free_command_buffers(*command_pool, &command_buffers) };
+
+  Ok(())
+}
+