1 files changed, 397 insertions, 0 deletions
diff --git a/stockton-skeleton/src/target.rs b/stockton-skeleton/src/target.rs
new file mode 100644
index 0000000..d0d2380
--- /dev/null
+++ b/stockton-skeleton/src/target.rs
@@ -0,0 +1,397 @@
+//! Resources needed for drawing on the screen, including sync objects
+
+use std::{
+    borrow::Borrow,
+    iter::{empty, once},
+    mem::ManuallyDrop,
+};
+
+use hal::{
+    command::CommandBufferFlags,
+    format::{Aspects, ChannelType, Format, ImageFeature},
+    image::{
+        Access, Extent, FramebufferAttachment, Layout, SubresourceRange, Usage as ImgUsage,
+        ViewCapabilities,
+    },
+    memory::{Barrier, Dependencies},
+    pso::{PipelineStage, Viewport},
+    window::{CompositeAlphaMode, Extent2D, PresentMode, SwapchainConfig},
+};
+
+use super::draw_passes::DrawPass;
+use crate::{error::EnvironmentError, types::*};
+use anyhow::{Context, Result};
+use stockton_types::Session;
+
+#[derive(Debug, Clone)]
+pub struct SwapchainProperties {
+    pub format: Format,
+    pub depth_format: Format,
+    pub present_mode: PresentMode,
+    pub composite_alpha_mode: CompositeAlphaMode,
+    pub viewport: Viewport,
+    pub extent: Extent,
+    pub image_count: u32,
+}
+
+impl SwapchainProperties {
+    pub fn find_best(
+        adapter: &Adapter,
+        surface: &SurfaceT,
+    ) -> Result<SwapchainProperties, EnvironmentError> {
+        let caps = surface.capabilities(&adapter.physical_device);
+        let formats = surface.supported_formats(&adapter.physical_device);
+
+        // Find which settings we'll actually use based on preset preferences
+        let format = match formats {
+            Some(formats) => formats
+                .iter()
+                .find(|format| format.base_format().1 == ChannelType::Srgb)
+                .copied()
+                .ok_or(EnvironmentError::ColorFormat),
+            None => Ok(Format::Rgba8Srgb),
+        }?;
+
+        let depth_format = *[
+            Format::D32SfloatS8Uint,
+            Format::D24UnormS8Uint,
+            Format::D32Sfloat,
+        ]
+        .iter()
+        .find(|format| {
+            format.is_depth()
+                && adapter
+                    .physical_device
+                    .format_properties(Some(**format))
+                    .optimal_tiling
+                    .contains(ImageFeature::DEPTH_STENCIL_ATTACHMENT)
+        })
+        .ok_or(EnvironmentError::DepthFormat)?;
+
+        let present_mode = [
+            PresentMode::MAILBOX,
+            PresentMode::FIFO,
+            PresentMode::RELAXED,
+            PresentMode::IMMEDIATE,
+        ]
+        .iter()
+        .cloned()
+        .find(|pm| caps.present_modes.contains(*pm))
+        .ok_or(EnvironmentError::PresentMode)?;
+
+        let composite_alpha_mode = [
+            CompositeAlphaMode::OPAQUE,
+            CompositeAlphaMode::INHERIT,
+            CompositeAlphaMode::PREMULTIPLIED,
+            CompositeAlphaMode::POSTMULTIPLIED,
+        ]
+        .iter()
+        .cloned()
+        .find(|ca| caps.composite_alpha_modes.contains(*ca))
+        .ok_or(EnvironmentError::CompositeAlphaMode)?;
+
+        let extent = caps.extents.end().to_extent(); // Size
+        let viewport = Viewport {
+            rect: extent.rect(),
+            depth: 0.0..1.0,
+        };
+
+        Ok(SwapchainProperties {
+            format,
+            depth_format,
+            present_mode,
+            composite_alpha_mode,
+            extent,
+            viewport,
+            image_count: if present_mode == PresentMode::MAILBOX {
+                ((*caps.image_count.end()) - 1).min((*caps.image_count.start()).max(3))
+            } else {
+                ((*caps.image_count.end()) - 1).min((*caps.image_count.start()).max(2))
+            },
+        })
+    }
+
+    pub fn framebuffer_attachment(&self) -> FramebufferAttachment {
+        FramebufferAttachment {
+            usage: ImgUsage::COLOR_ATTACHMENT,
+            format: self.format,
+            view_caps: ViewCapabilities::empty(),
+        }
+    }
+}
+
+pub struct TargetChain {
+    /// Surface we're targeting
+    surface: ManuallyDrop<SurfaceT>,
+    properties: SwapchainProperties,
+
+    /// Resources tied to each target frame in the swapchain
+    targets: Box<[TargetResources]>,
+
+    /// Sync objects used in drawing
+    /// These are seperated from the targets because we don't necessarily always match up indexes
+    sync_objects: Box<[SyncObjects]>,
+
+    /// The last set of sync objects used
+    last_syncs: usize,
+
+    /// Last image index of the swapchain drawn to
+    last_image: u32,
+}
+
+impl TargetChain {
+    pub fn new(
+        device: &mut DeviceT,
+        adapter: &Adapter,
+        mut surface: SurfaceT,
+        cmd_pool: &mut CommandPoolT,
+        properties: SwapchainProperties,
+    ) -> Result<TargetChain> {
+        let caps = surface.capabilities(&adapter.physical_device);
+
+        // Number of frames to pre-render
+        let image_count = if properties.present_mode == PresentMode::MAILBOX {
+            ((*caps.image_count.end()) - 1).min((*caps.image_count.start()).max(3))
+        } else {
+            ((*caps.image_count.end()) - 1).min((*caps.image_count.start()).max(2))
+        };
+
+        // Swap config
+        let swap_config = SwapchainConfig {
+            present_mode: properties.present_mode,
+            composite_alpha_mode: properties.composite_alpha_mode,
+            format: properties.format,
+            extent: Extent2D {
+                width: properties.extent.width,
+                height: properties.extent.height,
+            },
+            image_count,
+            image_layers: 1,
+            image_usage: ImgUsage::COLOR_ATTACHMENT,
+        };
+
+        let _fat = swap_config.framebuffer_attachment();
+        let mut targets: Vec<TargetResources> =
+            Vec::with_capacity(swap_config.image_count as usize);
+        let mut sync_objects: Vec<SyncObjects> =
+            Vec::with_capacity(swap_config.image_count as usize);
+
+        for _ in 0..swap_config.image_count {
+            targets.push(
+                TargetResources::new(device, cmd_pool, &properties)
+                    .context("Error creating target resources")?,
+            );
+
+            sync_objects.push(SyncObjects::new(device).context("Error creating sync objects")?);
+        }
+
+        // Configure Swapchain
+        unsafe {
+            surface
+                .configure_swapchain(device, swap_config)
+                .context("Error configuring swapchain")?;
+        }
+
+        Ok(TargetChain {
+            surface: ManuallyDrop::new(surface),
+            targets: targets.into_boxed_slice(),
+            sync_objects: sync_objects.into_boxed_slice(),
+            properties,
+            last_syncs: (image_count - 1) as usize, // This means the next one to be used is index 0
+            last_image: 0,
+        })
+    }
+
+    pub fn deactivate(
+        self,
+        instance: &mut InstanceT,
+        device: &mut DeviceT,
+        cmd_pool: &mut CommandPoolT,
+    ) {
+        let surface = self.deactivate_with_recyling(device, cmd_pool);
+
+        unsafe {
+            instance.destroy_surface(surface);
+        }
+    }
+
+    pub fn deactivate_with_recyling(
+        mut self,
+        device: &mut DeviceT,
+        cmd_pool: &mut CommandPoolT,
+    ) -> SurfaceT {
+        use core::ptr::read;
+        unsafe {
+            for i in 0..self.targets.len() {
+                read(&self.targets[i]).deactivate(device, cmd_pool);
+            }
+
+            for i in 0..self.sync_objects.len() {
+                read(&self.sync_objects[i]).deactivate(device);
+            }
+
+            self.surface.unconfigure_swapchain(device);
+        }
+
+        unsafe { ManuallyDrop::into_inner(read(&self.surface)) }
+    }
+
+    pub fn do_draw_with<'a, DP: DrawPass>(
+        &'a mut self,
+        device: &mut DeviceT,
+        command_queue: &mut QueueT,
+        dp: &mut DP,
+        session: &Session,
+    ) -> Result<()> {
+        self.last_syncs = (self.last_syncs + 1) % self.sync_objects.len();
+        self.last_image = (self.last_image + 1) % self.targets.len() as u32;
+
+        let syncs = &mut self.sync_objects[self.last_syncs];
+        let target = &mut self.targets[self.last_image as usize];
+
+        // Get the image
+        let (img, _) = unsafe {
+            self.surface
+                .acquire_image(core::u64::MAX)
+                .context("Error getting image from swapchain")?
+        };
+
+        // Make sure whatever was last using this has finished
+        unsafe {
+            device
+                .wait_for_fence(&syncs.present_complete, core::u64::MAX)
+                .context("Error waiting for present_complete")?;
+            device
+                .reset_fence(&mut syncs.present_complete)
+                .context("Error resetting present_complete fence")?;
+        };
+
+        // Record commands
+        unsafe {
+            target.cmd_buffer.begin_primary(CommandBufferFlags::empty());
+
+            target.cmd_buffer.pipeline_barrier(
+                PipelineStage::TOP_OF_PIPE..PipelineStage::TOP_OF_PIPE,
+                Dependencies::empty(),
+                once(Barrier::Image {
+                    states: (Access::empty(), Layout::Undefined)
+                        ..(Access::empty(), Layout::ColorAttachmentOptimal),
+                    target: img.borrow(),
+                    range: SubresourceRange {
+                        aspects: Aspects::COLOR,
+                        level_start: 0,
+                        level_count: Some(1),
+                        layer_start: 0,
+                        layer_count: Some(1),
+                    },
+                    families: None,
+                }),
+            );
+
+            dp.queue_draw(session, img.borrow(), &mut target.cmd_buffer)
+                .context("Error in draw pass")?;
+
+            target.cmd_buffer.pipeline_barrier(
+                PipelineStage::BOTTOM_OF_PIPE..PipelineStage::BOTTOM_OF_PIPE,
+                Dependencies::empty(),
+                once(Barrier::Image {
+                    states: (Access::empty(), Layout::ColorAttachmentOptimal)
+                        ..(Access::empty(), Layout::Present),
+                    target: img.borrow(),
+                    range: SubresourceRange {
+                        aspects: Aspects::COLOR,
+                        level_start: 0,
+                        level_count: Some(1),
+                        layer_start: 0,
+                        layer_count: Some(1),
+                    },
+                    families: None,
+                }),
+            );
+
+            target.cmd_buffer.finish();
+        }
+
+        // Submit it
+        unsafe {
+            command_queue.submit(
+                once(&*target.cmd_buffer),
+                empty(),
+                once(&*syncs.render_complete),
+                Some(&mut syncs.present_complete),
+            );
+            command_queue
+                .present(&mut self.surface, img, Some(&mut *syncs.render_complete))
+                .context("Error presenting to surface")?;
+        };
+
+        Ok(())
+    }
+
+    /// Get a reference to the target chain's properties.
+    pub fn properties(&self) -> &SwapchainProperties {
+        &self.properties
+    }
+}
+
+/// Resources for a single target frame, including sync objects
+pub struct TargetResources {
+    /// Command buffer to use when drawing
+    pub cmd_buffer: ManuallyDrop<CommandBufferT>,
+}
+
+impl TargetResources {
+    pub fn new(
+        _device: &mut DeviceT,
+        cmd_pool: &mut CommandPoolT,
+        _properties: &SwapchainProperties,
+    ) -> Result<TargetResources> {
+        // Command Buffer
+        let cmd_buffer = unsafe { cmd_pool.allocate_one(hal::command::Level::Primary) };
+
+        Ok(TargetResources {
+            cmd_buffer: ManuallyDrop::new(cmd_buffer),
+        })
+    }
+
+    pub fn deactivate(self, _device: &mut DeviceT, cmd_pool: &mut CommandPoolT) {
+        use core::ptr::read;
+        unsafe {
+            cmd_pool.free(once(ManuallyDrop::into_inner(read(&self.cmd_buffer))));
+        }
+    }
+}
+
+pub struct SyncObjects {
+    /// Triggered when rendering is done
+    pub render_complete: ManuallyDrop<SemaphoreT>,
+
+    /// Triggered when the image is on screen
+    pub present_complete: ManuallyDrop<FenceT>,
+}
+
+impl SyncObjects {
+    pub fn new(device: &mut DeviceT) -> Result<Self> {
+        // Sync objects
+        let render_complete = device
+            .create_semaphore()
+            .context("Error creating render_complete semaphore")?;
+        let present_complete = device
+            .create_fence(true)
+            .context("Error creating present_complete fence")?;
+
+        Ok(SyncObjects {
+            render_complete: ManuallyDrop::new(render_complete),
+            present_complete: ManuallyDrop::new(present_complete),
+        })
+    }
+
+    pub fn deactivate(self, device: &mut DeviceT) {
+        use core::ptr::read;
+
+        unsafe {
+            device.destroy_semaphore(ManuallyDrop::into_inner(read(&self.render_complete)));
+            device.destroy_fence(ManuallyDrop::into_inner(read(&self.present_complete)));
+        }
+    }
+}