Improve error message: "Format Bgra8UnormSrgb can't be multisampled"

wgpu-core/src/device/resource.rs

@@ -662,6 +662,14 @@ impl<A: HalApi> Device<A> {
                 return Err(CreateTextureError::InvalidSampleCount(
                     desc.sample_count,
                     desc.format,
+                    desc.format
+                        .guaranteed_format_features(self.features)
+                        .flags
+                        .supported_sample_counts(),
+                    adapter
+                        .get_texture_format_features(desc.format)
+                        .flags
+                        .supported_sample_counts(),
                 ));
             };
         }
@@ -2815,7 +2823,18 @@ impl<A: HalApi> Device<A> {
                             .flags
                             .sample_count_supported(desc.multisample.count)
                     {
-                        break Some(pipeline::ColorStateError::FormatNotMultisampled(cs.format));
+                        break Some(pipeline::ColorStateError::InvalidSampleCount(
+                            desc.multisample.count,
+                            cs.format,
+                            cs.format
+                                .guaranteed_format_features(self.features)
+                                .flags
+                                .supported_sample_counts(),
+                            adapter
+                                .get_texture_format_features(cs.format)
+                                .flags
+                                .supported_sample_counts(),
+                        ));
                     }
                     if let Some(blend_mode) = cs.blend {
                         for factor in [
@@ -2870,8 +2889,17 @@ impl<A: HalApi> Device<A> {
                         .flags
                         .sample_count_supported(desc.multisample.count)
                 {
-                    break Some(pipeline::DepthStencilStateError::FormatNotMultisampled(
+                    break Some(pipeline::DepthStencilStateError::InvalidSampleCount(
+                        desc.multisample.count,
                         ds.format,
+                        ds.format
+                            .guaranteed_format_features(self.features)
+                            .flags
+                            .supported_sample_counts(),
+                        adapter
+                            .get_texture_format_features(ds.format)
+                            .flags
+                            .supported_sample_counts(),
                     ));
                 }
 

wgpu-core/src/pipeline.rs

@@ -299,8 +299,8 @@ pub enum ColorStateError {
     FormatNotBlendable(wgt::TextureFormat),
     #[error("Format {0:?} does not have a color aspect")]
     FormatNotColor(wgt::TextureFormat),
-    #[error("Format {0:?} can't be multisampled")]
-    FormatNotMultisampled(wgt::TextureFormat),
+    #[error("Sample count {0} is not supported by format {1:?} on this device. The WebGPU spec guarentees {2:?} samples are supported by this format. With the TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES feature your device supports {3:?}.")]
+    InvalidSampleCount(u32, wgt::TextureFormat, Vec<u32>, Vec<u32>),
     #[error("Output format {pipeline} is incompatible with the shader {shader}")]
     IncompatibleFormat {
         pipeline: validation::NumericType,
@@ -321,8 +321,8 @@ pub enum DepthStencilStateError {
     FormatNotDepth(wgt::TextureFormat),
     #[error("Format {0:?} does not have a stencil aspect, but stencil test/write is enabled")]
     FormatNotStencil(wgt::TextureFormat),
-    #[error("Format {0:?} can't be multisampled")]
-    FormatNotMultisampled(wgt::TextureFormat),
+    #[error("Sample count {0} is not supported by format {1:?} on this device. The WebGPU spec guarentees {2:?} samples are supported by this format. With the TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES feature your device supports {3:?}.")]
+    InvalidSampleCount(u32, wgt::TextureFormat, Vec<u32>, Vec<u32>),
 }
 
 #[derive(Clone, Debug, Error)]

wgpu-core/src/resource.rs

@@ -579,8 +579,8 @@ pub enum CreateTextureError {
     InvalidMultisampledStorageBinding,
     #[error("Format {0:?} does not support multisampling")]
     InvalidMultisampledFormat(wgt::TextureFormat),
-    #[error("Sample count {0} is not supported by format {1:?} on this device. It may be supported by your adapter through the TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES feature.")]
-    InvalidSampleCount(u32, wgt::TextureFormat),
+    #[error("Sample count {0} is not supported by format {1:?} on this device. The WebGPU spec guarentees {2:?} samples are supported by this format. With the TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES feature your device supports {3:?}.")]
+    InvalidSampleCount(u32, wgt::TextureFormat, Vec<u32>, Vec<u32>),
     #[error("Multisampled textures must have RENDER_ATTACHMENT usage")]
     MultisampledNotRenderAttachment,
     #[error("Texture format {0:?} can't be used due to missing features")]

wgpu-types/src/lib.rs

@@ -2097,6 +2097,15 @@ impl TextureFormatFeatureFlags {
             _ => false,
         }
     }
+
+    /// A `Vec` of supported sample counts.
+    pub fn supported_sample_counts(&self) -> Vec<u32> {
+        let all_possible_sample_counts: [u32; 5] = [1, 2, 4, 8, 16];
+        all_possible_sample_counts
+            .into_iter()
+            .filter(|&sc| self.sample_count_supported(sc))
+            .collect()
+    }
 }
 
 impl_bitflags!(TextureFormatFeatureFlags);