1 files changed, 134 insertions, 0 deletions
diff --git a/stockton-skeleton/src/buffers/dedicated_image.rs b/stockton-skeleton/src/buffers/dedicated_image.rs
new file mode 100644
index 0000000..bf49a38
--- /dev/null
+++ b/stockton-skeleton/src/buffers/dedicated_image.rs
@@ -0,0 +1,134 @@
+//! A dedicated image. Used for depth buffers.
+
+use crate::texture::PIXEL_SIZE;
+use crate::types::*;
+
+use std::mem::ManuallyDrop;
+
+use anyhow::{Context, Result};
+use hal::{
+    format::{Format, Swizzle},
+    image::{SubresourceRange, Usage, Usage as ImgUsage, ViewKind},
+    memory,
+    memory::Properties,
+    MemoryTypeId,
+};
+use thiserror::Error;
+
+/// Holds an image that's loaded into GPU memory dedicated only to that image, bypassing the memory allocator.
+pub struct DedicatedLoadedImage {
+    /// The GPU Image handle
+    image: ManuallyDrop<ImageT>,
+
+    /// The full view of the image
+    pub image_view: ManuallyDrop<ImageViewT>,
+
+    /// The memory backing the image
+    memory: ManuallyDrop<MemoryT>,
+}
+
+#[derive(Debug, Error)]
+pub enum ImageLoadError {
+    #[error("No suitable memory type for image memory")]
+    NoMemoryTypes,
+}
+
+impl DedicatedLoadedImage {
+    pub fn new(
+        device: &mut DeviceT,
+        adapter: &Adapter,
+        format: Format,
+        usage: Usage,
+        resources: SubresourceRange,
+        width: usize,
+        height: usize,
+    ) -> Result<DedicatedLoadedImage> {
+        let (memory, image_ref) = {
+            // Round up the size to align properly
+            let initial_row_size = PIXEL_SIZE * width;
+            let limits = adapter.physical_device.properties().limits;
+            let row_alignment_mask = limits.optimal_buffer_copy_pitch_alignment as u32 - 1;
+
+            let row_size =
+                ((initial_row_size as u32 + row_alignment_mask) & !row_alignment_mask) as usize;
+            debug_assert!(row_size as usize >= initial_row_size);
+
+            // Make the image
+            let mut image_ref = unsafe {
+                use hal::image::{Kind, Tiling, ViewCapabilities};
+
+                device.create_image(
+                    Kind::D2(width as u32, height as u32, 1, 1),
+                    1,
+                    format,
+                    Tiling::Optimal,
+                    usage,
+                    memory::SparseFlags::empty(),
+                    ViewCapabilities::empty(),
+                )
+            }
+            .context("Error creating image")?;
+
+            // Allocate memory
+            let memory = unsafe {
+                let requirements = device.get_image_requirements(&image_ref);
+
+                let memory_type_id = adapter
+                    .physical_device
+                    .memory_properties()
+                    .memory_types
+                    .iter()
+                    .enumerate()
+                    .find(|&(id, memory_type)| {
+                        requirements.type_mask & (1 << id) != 0
+                            && memory_type.properties.contains(Properties::DEVICE_LOCAL)
+                    })
+                    .map(|(id, _)| MemoryTypeId(id))
+                    .ok_or(ImageLoadError::NoMemoryTypes)?;
+
+                let memory = device
+                    .allocate_memory(memory_type_id, requirements.size)
+                    .context("Error allocating memory for image")?;
+
+                device
+                    .bind_image_memory(&memory, 0, &mut image_ref)
+                    .context("Error binding memory to image")?;
+
+                memory
+            };
+
+            (memory, image_ref)
+        };
+
+        // Create ImageView and sampler
+        let image_view = unsafe {
+            device.create_image_view(
+                &image_ref,
+                ViewKind::D2,
+                format,
+                Swizzle::NO,
+                ImgUsage::DEPTH_STENCIL_ATTACHMENT,
+                resources,
+            )
+        }
+        .context("Error creating image view")?;
+
+        Ok(DedicatedLoadedImage {
+            image: ManuallyDrop::new(image_ref),
+            image_view: ManuallyDrop::new(image_view),
+            memory: ManuallyDrop::new(memory),
+        })
+    }
+
+    /// Properly frees/destroys all the objects in this struct
+    /// Dropping without doing this is a bad idea
+    pub fn deactivate(self, device: &mut DeviceT) {
+        unsafe {
+            use core::ptr::read;
+
+            device.destroy_image_view(ManuallyDrop::into_inner(read(&self.image_view)));
+            device.destroy_image(ManuallyDrop::into_inner(read(&self.image)));
+            device.free_memory(ManuallyDrop::into_inner(read(&self.memory)));
+        }
+    }
+}