rt: abstract away the buffer backing of acceleration structures

blade-graphics/src/lib.rs

@@ -46,7 +46,6 @@ pub mod limits {
     pub const PLAIN_DATA_SIZE: u32 = 256;
     pub const RESOURCES_IN_GROUP: u32 = 8;
     pub const STORAGE_BUFFER_ALIGNMENT: u64 = 256;
-    pub const ACCELERATION_STRUCTURE_BUFFER_ALIGNMENT: u64 = 256;
     pub const ACCELERATION_STRUCTURE_SCRATCH_ALIGNMENT: u64 = 256;
 }
 
@@ -349,10 +348,6 @@ pub enum AccelerationStructureType {
 pub struct AccelerationStructureDesc<'a> {
     pub name: &'a str,
     pub ty: AccelerationStructureType,
-    pub buffer: Buffer,
-    /// Offset into the buffer where AS is placed.
-    /// Must be a multiple of `limits::ACCELERATION_STRUCTURE_BUFFER_ALIGNMENT`.
-    pub offset: u64,
     pub size: u64,
 }
 

blade-graphics/src/vulkan/mod.rs

@@ -151,6 +151,8 @@ pub struct Sampler {
 #[derive(Clone, Copy, Debug, Hash, PartialEq)]
 pub struct AccelerationStructure {
     raw: vk::AccelerationStructureKHR,
+    buffer: vk::Buffer,
+    memory_handle: usize,
 }
 
 #[derive(Debug, Default)]

blade-graphics/src/vulkan/resource.rs

@@ -176,6 +176,22 @@ impl super::Context {
         &self,
         desc: crate::AccelerationStructureDesc,
     ) -> super::AccelerationStructure {
+        let buffer_info = vk::BufferCreateInfo::builder()
+            .size(desc.size)
+            .usage(vk::BufferUsageFlags::ACCELERATION_STRUCTURE_STORAGE_KHR)
+            .sharing_mode(vk::SharingMode::EXCLUSIVE);
+
+        let buffer = unsafe { self.device.core.create_buffer(&buffer_info, None).unwrap() };
+        let requirements = unsafe { self.device.core.get_buffer_memory_requirements(buffer) };
+        let allocation = self.allocate_memory(requirements, crate::Memory::Device);
+
+        unsafe {
+            self.device
+                .core
+                .bind_buffer_memory(buffer, allocation.memory, allocation.offset)
+                .unwrap()
+        };
+
         let raw_ty = match desc.ty {
             crate::AccelerationStructureType::TopLevel => {
                 vk::AccelerationStructureTypeKHR::TOP_LEVEL
@@ -186,8 +202,7 @@ impl super::Context {
         };
         let vk_info = vk::AccelerationStructureCreateInfoKHR::builder()
             .ty(raw_ty)
-            .buffer(desc.buffer.raw)
-            .offset(desc.offset)
+            .buffer(buffer)
             .size(desc.size);
 
         let rt = self.device.ray_tracing.as_ref().unwrap();
@@ -196,7 +211,16 @@ impl super::Context {
                 .create_acceleration_structure(&vk_info, None)
                 .unwrap()
         };
-        super::AccelerationStructure { raw }
+
+        if !desc.name.is_empty() {
+            self.set_object_name(vk::ObjectType::BUFFER, buffer, desc.name);
+            self.set_object_name(vk::ObjectType::ACCELERATION_STRUCTURE_KHR, raw, desc.name);
+        }
+        super::AccelerationStructure {
+            raw,
+            buffer,
+            memory_handle: allocation.handle,
+        }
     }
 
     pub fn destroy_acceleration_structure(
@@ -207,7 +231,11 @@ impl super::Context {
         unsafe {
             rt.acceleration_structure
                 .destroy_acceleration_structure(acceleration_structure.raw, None);
+            self.device
+                .core
+                .destroy_buffer(acceleration_structure.buffer, None);
         }
+        self.free_memory(acceleration_structure.memory_handle);
     }
 }
 
@@ -232,9 +260,8 @@ impl crate::traits::ResourceDevice for super::Context {
             )
             .sharing_mode(vk::SharingMode::EXCLUSIVE);
         if self.device.ray_tracing.is_some() {
-            vk_info.usage |= Buf::SHADER_DEVICE_ADDRESS
-                | Buf::ACCELERATION_STRUCTURE_STORAGE_KHR
-                | Buf::ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_KHR;
+            vk_info.usage |=
+                Buf::SHADER_DEVICE_ADDRESS | Buf::ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_KHR;
         }
 
         let raw = unsafe { self.device.core.create_buffer(&vk_info, None).unwrap() };

examples/ray-trace/main.rs

@@ -24,9 +24,7 @@ struct ShaderData {
 struct Example {
     start_time: time::Instant,
     blas: blade::AccelerationStructure,
-    blas_buffer: blade::Buffer,
     tlas: blade::AccelerationStructure,
-    tlas_buffer: blade::Buffer,
     pipeline: blade::RenderPipeline,
     command_encoder: blade::CommandEncoder,
     prev_sync_point: Option<blade::SyncPoint>,
@@ -122,16 +120,9 @@ impl Example {
             is_opaque: true,
         }];
         let blas_sizes = context.get_bottom_level_acceleration_structure_sizes(&meshes);
-        let blas_buffer = context.create_buffer(blade::BufferDesc {
-            name: "BLAS",
-            size: blas_sizes.data,
-            memory: blade::Memory::Device,
-        });
         let blas = context.create_acceleration_structure(blade::AccelerationStructureDesc {
             name: "triangle",
             ty: blade::AccelerationStructureType::BottomLevel,
-            buffer: blas_buffer,
-            offset: 0,
             size: blas_sizes.data,
         });
 
@@ -162,16 +153,9 @@ impl Example {
         ];
         let tlas_sizes = context.get_top_level_acceleration_structure_sizes(instances.len() as u32);
         let instance_buffer = context.create_acceleration_structure_instance_buffer(&instances);
-        let tlas_buffer = context.create_buffer(blade::BufferDesc {
-            name: "TLAS",
-            size: tlas_sizes.data,
-            memory: blade::Memory::Device,
-        });
         let tlas = context.create_acceleration_structure(blade::AccelerationStructureDesc {
             name: "TLAS",
             ty: blade::AccelerationStructureType::TopLevel,
-            buffer: tlas_buffer,
-            offset: 0,
             size: tlas_sizes.data,
         });
         let tlas_scratch_offset = (blas_sizes.scratch
@@ -211,9 +195,7 @@ impl Example {
         Self {
             start_time: time::Instant::now(),
             blas,
-            blas_buffer,
             tlas,
-            tlas_buffer,
             pipeline,
             command_encoder,
             prev_sync_point: None,
@@ -227,8 +209,7 @@ impl Example {
             self.context.wait_for(&sp, !0);
         }
         self.context.destroy_acceleration_structure(self.blas);
-        self.context.destroy_buffer(self.blas_buffer);
-        self.context.destroy_buffer(self.tlas_buffer);
+        self.context.destroy_acceleration_structure(self.tlas);
     }
 
     fn render(&mut self) {