Use zero buffer as transform buffer.

Vecvec · Feb 6, 2025 · 44f7fd7 · 44f7fd7
1 parent 0585918
commit 44f7fd7
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Showing 4 changed files with 40 additions and 4 deletions.
diff --git a/wgpu-core/src/device/ray_tracing.rs b/wgpu-core/src/device/ray_tracing.rs
@@ -57,14 +57,27 @@ impl Device {
                             self.features.allowed_vertex_formats_for_blas(),
                         ));
                     }
+
+                    let mut transform = None;
+
+                    if blas_desc
+                        .flags
+                        .contains(wgt::AccelerationStructureFlags::USE_TRANSFORM)
+                    {
+                        transform = Some(wgpu_hal::AccelerationStructureTriangleTransform {
+                            buffer: self.zero_buffer.as_ref(),
+                            offset: 0,
+                        })
+                    }
+
                     entries.push(hal::AccelerationStructureTriangles::<dyn hal::DynBuffer> {
                         vertex_buffer: None,
                         vertex_format: desc.vertex_format,
                         first_vertex: 0,
                         vertex_count: desc.vertex_count,
                         vertex_stride: 0,
                         indices,
-                        transform: None,
+                        transform,
                         flags: desc.flags,
                     });
                 }

diff --git a/wgpu-core/src/device/resource.rs b/wgpu-core/src/device/resource.rs
@@ -208,7 +208,9 @@ impl Device {
             raw_device.create_buffer(&hal::BufferDescriptor {
                 label: hal_label(Some("(wgpu internal) zero init buffer"), instance_flags),
                 size: ZERO_BUFFER_SIZE,
-                usage: wgt::BufferUses::COPY_SRC | wgt::BufferUses::COPY_DST,
+                usage: wgt::BufferUses::COPY_SRC
+                    | wgt::BufferUses::COPY_DST
+                    | wgt::BufferUses::TOP_LEVEL_ACCELERATION_STRUCTURE_INPUT,
                 memory_flags: hal::MemoryFlags::empty(),
             })
         }

diff --git a/wgpu-hal/src/dx12/device.rs b/wgpu-hal/src/dx12/device.rs
@@ -2151,7 +2151,15 @@ impl crate::Device for super::Device {
                             .flags
                             .contains(wgt::AccelerationStructureFlags::USE_TRANSFORM)
                         {
-                            1
+                            unsafe {
+                                triangle
+                                    .transform
+                                    .as_ref()
+                                    .unwrap()
+                                    .buffer
+                                    .resource
+                                    .GetGPUVirtualAddress()
+                            }
                         } else {
                             0
                         },

diff --git a/wgpu-hal/src/vulkan/device.rs b/wgpu-hal/src/vulkan/device.rs
@@ -2379,7 +2379,20 @@ impl crate::Device for super::Device {
                                     .flags
                                     .contains(wgt::AccelerationStructureFlags::USE_TRANSFORM)
                                 {
-                                    1
+                                    unsafe {
+                                        ray_tracing_functions
+                                            .buffer_device_address
+                                            .get_buffer_device_address(
+                                                &vk::BufferDeviceAddressInfo::default().buffer(
+                                                    triangles
+                                                        .transform
+                                                        .as_ref()
+                                                        .unwrap()
+                                                        .buffer
+                                                        .raw,
+                                                ),
+                                            )
+                                    }
                                 } else {
                                     0
                                 },