Better error message for 16 byte alignment error (#3414)

Co-authored-by: Connor Fitzgerald <connorwadefitzgerald@gmail.com>
Co-authored-by: gilescope <gilescope@gmail.com>
Closes https://github.com/gfx-rs/wgpu/pull/3099
Closes https://github.com/gfx-rs/wgpu/issues/2832

CHANGELOG.md

@@ -38,8 +38,6 @@ Bottom level categories:
 - Hal
 -->
 
-## Unreleased
-
 ### Major Changes
 
 #### Backend selection by features
@@ -186,6 +184,7 @@ let texture = device.create_texture(&wgpu::TextureDescriptor {
 - Add validation in accordance with WebGPU `GPUSamplerDescriptor` valid usage for `lodMinClamp` and `lodMaxClamp`. By @James2022-rgb in [#3353](https://github.com/gfx-rs/wgpu/pull/3353)
 - Remove panics in `Deref` implementations for `QueueWriteBufferView` and `BufferViewMut`. Instead, warnings are logged, since reading from these types is not recommended. By @botahamec in [#3336]
 - Implement `view_formats` in TextureDescriptor to match the WebGPU spec. By @jinleili in [#3237](https://github.com/gfx-rs/wgpu/pull/3237)
+- Show more information in error message for non-aligned buffer bindings in WebGL [#3414](https://github.com/gfx-rs/wgpu/pull/3414)
 - Update `TextureView` validation according to the WebGPU spec. By @teoxoy in [#3410](https://github.com/gfx-rs/wgpu/pull/3410)
 
 #### WebGPU

wgpu-core/src/device/mod.rs

@@ -2997,11 +2997,19 @@ impl<A: HalApi> Device<A> {
             self.require_features(wgt::Features::MULTIVIEW)?;
         }
 
-        for size in shader_binding_sizes.values() {
+        if !self
+            .downlevel
+            .flags
+            .contains(wgt::DownlevelFlags::BUFFER_BINDINGS_NOT_16_BYTE_ALIGNED)
+        {
+            for (binding, size) in shader_binding_sizes.iter() {
                 if size.get() % 16 != 0 {
-                self.require_downlevel_flags(
-                    wgt::DownlevelFlags::BUFFER_BINDINGS_NOT_16_BYTE_ALIGNED,
-                )?;
+                    return Err(pipeline::CreateRenderPipelineError::UnalignedShader {
+                        binding: binding.binding,
+                        group: binding.group,
+                        size: size.get(),
+                    });
+                }
             }
         }
 

wgpu-core/src/pipeline.rs

@@ -373,6 +373,8 @@ pub enum CreateRenderPipelineError {
         stage: wgt::ShaderStages,
         error: String,
     },
+    #[error("In the provided shader, the type given for group {group} binding {binding} has a size of {size}. As the device does not support `DownlevelFlags::BUFFER_BINDINGS_NOT_16_BYTE_ALIGNED`, the type must have a size that is a multiple of 16 bytes.")]
+    UnalignedShader { group: u32, binding: u32, size: u64 },
 }
 
 bitflags::bitflags! {