Extract texture <-> buffer copy logic to wgpu-types (#7553)

Author: cwfitzgerald

wgpu-core/src/command/transfer.rs

@@ -235,96 +235,88 @@ pub(crate) fn validate_linear_texture_data(
     copy_size: &Extent3d,
     need_copy_aligned_rows: bool,
 ) -> Result<(BufferAddress, BufferAddress), TransferError> {
-    // Convert all inputs to BufferAddress (u64) to avoid some of the overflow issues
-    // Note: u64 is not always enough to prevent overflow, especially when multiplying
-    // something with a potentially large depth value, so it is preferable to validate
-    // the copy size before calling this function (for example via `validate_texture_copy_range`).
-    let copy_width = copy_size.width as BufferAddress;
-    let copy_height = copy_size.height as BufferAddress;
-    let depth_or_array_layers = copy_size.depth_or_array_layers as BufferAddress;
-
-    let offset = layout.offset;
-
-    let block_size = format.block_copy_size(Some(aspect)).unwrap() as BufferAddress;
-    let (block_width, block_height) = format.block_dimensions();
-    let block_width = block_width as BufferAddress;
-    let block_height = block_height as BufferAddress;
-
-    if copy_width % block_width != 0 {
+    let wgt::BufferTextureCopyInfo {
+        copy_width,
+        copy_height,
+        depth_or_array_layers,
+
+        offset,
+
+        block_size_bytes,
+        block_width_texels,
+        block_height_texels,
+
+        width_blocks: _,
+        height_blocks,
+
+        row_bytes_dense,
+        row_stride_bytes,
+
+        image_stride_rows: _,
+        image_stride_bytes,
+
+        image_rows_dense: _,
+        image_bytes_dense: _,
+
+        bytes_in_copy,
+    } = layout.get_buffer_texture_copy_info(format, aspect, copy_size);
+
+    if copy_width % block_width_texels != 0 {
         return Err(TransferError::UnalignedCopyWidth);
     }
-    if copy_height % block_height != 0 {
+    if copy_height % block_height_texels != 0 {
         return Err(TransferError::UnalignedCopyHeight);
     }
 
-    let width_in_blocks = copy_width / block_width;
-    let height_in_blocks = copy_height / block_height;
-
-    let bytes_in_last_row = width_in_blocks * block_size;
+    let requires_multiple_rows = depth_or_array_layers > 1 || height_blocks > 1;
+    let requires_multiple_images = depth_or_array_layers > 1;
 
-    let bytes_per_row = if let Some(bytes_per_row) = layout.bytes_per_row {
-        let bytes_per_row = bytes_per_row as BufferAddress;
-        if bytes_per_row < bytes_in_last_row {
+    if let Some(raw_bytes_per_row) = layout.bytes_per_row {
+        let raw_bytes_per_row = raw_bytes_per_row as BufferAddress;
+        if raw_bytes_per_row < row_bytes_dense {
             return Err(TransferError::InvalidBytesPerRow);
         }
-        bytes_per_row
-    } else {
-        if depth_or_array_layers > 1 || height_in_blocks > 1 {
-            return Err(TransferError::UnspecifiedBytesPerRow);
-        }
-        0
-    };
-    let rows_per_image = if let Some(rows_per_image) = layout.rows_per_image {
-        let rows_per_image = rows_per_image as BufferAddress;
-        if rows_per_image < height_in_blocks {
+    } else if requires_multiple_rows {
+        return Err(TransferError::UnspecifiedBytesPerRow);
+    }
+
+    if let Some(raw_rows_per_image) = layout.rows_per_image {
+        let raw_rows_per_image = raw_rows_per_image as BufferAddress;
+        if raw_rows_per_image < height_blocks {
             return Err(TransferError::InvalidRowsPerImage);
         }
-        rows_per_image
-    } else {
-        if depth_or_array_layers > 1 {
-            return Err(TransferError::UnspecifiedRowsPerImage);
-        }
-        0
+    } else if requires_multiple_images {
+        return Err(TransferError::UnspecifiedRowsPerImage);
     };
 
     if need_copy_aligned_rows {
         let bytes_per_row_alignment = wgt::COPY_BYTES_PER_ROW_ALIGNMENT as BufferAddress;
 
-        let mut offset_alignment = block_size;
+        let mut offset_alignment = block_size_bytes;
         if format.is_depth_stencil_format() {
             offset_alignment = 4
         }
         if offset % offset_alignment != 0 {
             return Err(TransferError::UnalignedBufferOffset(offset));
         }
 
-        if bytes_per_row % bytes_per_row_alignment != 0 {
+        // The alignment of row_stride_bytes is only required if there are
+        // multiple rows
+        if requires_multiple_rows && row_stride_bytes % bytes_per_row_alignment != 0 {
             return Err(TransferError::UnalignedBytesPerRow);
         }
     }
 
-    let bytes_per_image = bytes_per_row * rows_per_image;
-
-    let required_bytes_in_copy = if depth_or_array_layers == 0 {
-        0
-    } else {
-        let mut required_bytes_in_copy = bytes_per_image * (depth_or_array_layers - 1);
-        if height_in_blocks > 0 {
-            required_bytes_in_copy += bytes_per_row * (height_in_blocks - 1) + bytes_in_last_row;
-        }
-        required_bytes_in_copy
-    };
-
-    if offset + required_bytes_in_copy > buffer_size {
+    if offset + bytes_in_copy > buffer_size {
         return Err(TransferError::BufferOverrun {
             start_offset: offset,
-            end_offset: offset + required_bytes_in_copy,
+            end_offset: offset + bytes_in_copy,
             buffer_size,
             side: buffer_side,
         });
     }
 
-    Ok((required_bytes_in_copy, bytes_per_image))
+    Ok((bytes_in_copy, image_stride_bytes))
 }
 
 /// WebGPU's [validating texture copy range][vtcr] algorithm.

wgpu-types/src/lib.rs

@@ -39,10 +39,12 @@ mod env;
 mod features;
 pub mod instance;
 pub mod math;
+mod transfers;
 
 pub use counters::*;
 pub use features::*;
 pub use instance::*;
+pub use transfers::*;
 
 /// Integral type used for [`Buffer`] offsets and sizes.
 ///