Fix Metal Mipmap Behvior

CHANGELOG.md

@@ -84,14 +84,14 @@ By @teoxoy in [#3534](https://github.com/gfx-rs/wgpu/pull/3534)
 
 #### Anisotropic Filtering
 
-Anisotropic filtering has been brought in line with the spec. The anisotropic clamp is now a f32 which must be between 1.0 and 16.0 inclusive.
+Anisotropic filtering has been brought in line with the spec. The anisotropic clamp is now a u16 (was a `Option<u8>`) which must be at least 1.
 
-If the anisotropy clamp is not 1.0, all the filters in a sampler must be `Linear`.
+If the anisotropy clamp is not 1, all the filters in a sampler must be `Linear`.
 
 ```diff
 SamplerDescriptor {
 -    anisotropic_clamp: None,
-+    anisotropic_clamp: 1.0,
++    anisotropic_clamp: 1,
 }
 ```
 

deno_webgpu/sampler.rs

@@ -40,7 +40,7 @@ pub struct CreateSamplerArgs {
     lod_min_clamp: f32,
     lod_max_clamp: f32,
     compare: Option<wgpu_types::CompareFunction>,
-    max_anisotropy: f32,
+    max_anisotropy: u16,
 }
 
 #[op]

wgpu-core/src/device/mod.rs

@@ -1322,13 +1322,13 @@ impl<A: HalApi> Device<A> {
             });
         }
 
-        if !(1.0..=16.0).contains(&desc.anisotropy_clamp) {
+        if desc.anisotropy_clamp < 1 {
             return Err(resource::CreateSamplerError::InvalidAnisotropy(
                 desc.anisotropy_clamp,
             ));
         }
 
-        if desc.anisotropy_clamp != 1.0 {
+        if desc.anisotropy_clamp != 1 {
             if !matches!(desc.min_filter, wgt::FilterMode::Linear) {
                 return Err(
                     resource::CreateSamplerError::InvalidFilterModeWithAnisotropy {
@@ -1358,6 +1358,18 @@ impl<A: HalApi> Device<A> {
             }
         }
 
+        let anisotropy_clamp = if self
+            .downlevel
+            .flags
+            .contains(wgt::DownlevelFlags::ANISOTROPIC_FILTERING)
+        {
+            // Clamp anisotropy clamp to [1, 16] per the wgpu-hal interface
+            desc.anisotropy_clamp.min(16)
+        } else {
+            // If it isn't supported, set this unconditionally to 1
+            1
+        };
+
         //TODO: check for wgt::DownlevelFlags::COMPARISON_SAMPLERS
 
         let hal_desc = hal::SamplerDescriptor {
@@ -1368,7 +1380,7 @@ impl<A: HalApi> Device<A> {
             mipmap_filter: desc.mipmap_filter,
             lod_clamp: desc.lod_min_clamp..desc.lod_max_clamp,
             compare: desc.compare,
-            anisotropy_clamp: desc.anisotropy_clamp,
+            anisotropy_clamp,
             border_color: desc.border_color,
         };
 

wgpu-core/src/resource.rs

@@ -689,30 +689,13 @@ pub struct SamplerDescriptor<'a> {
     pub lod_max_clamp: f32,
     /// If this is enabled, this is a comparison sampler using the given comparison function.
     pub compare: Option<wgt::CompareFunction>,
-    /// Valid values between 1 and 16 inclusive. If this is not 1.0, all filter modes must be linear.
-    pub anisotropy_clamp: f32,
+    /// Must be at least 1. If this is not 1, all filter modes must be linear.
+    pub anisotropy_clamp: u16,
     /// Border color to use when address_mode is
     /// [`AddressMode::ClampToBorder`](wgt::AddressMode::ClampToBorder)
     pub border_color: Option<wgt::SamplerBorderColor>,
 }
 
-impl Default for SamplerDescriptor<'_> {
-    fn default() -> Self {
-        Self {
-            label: None,
-            address_modes: Default::default(),
-            mag_filter: Default::default(),
-            min_filter: Default::default(),
-            mipmap_filter: Default::default(),
-            lod_min_clamp: 0.0,
-            lod_max_clamp: std::f32::MAX,
-            compare: None,
-            anisotropy_clamp: 1.0,
-            border_color: None,
-        }
-    }
-}
-
 #[derive(Debug)]
 pub struct Sampler<A: hal::Api> {
     pub(crate) raw: A::Sampler,
@@ -752,13 +735,13 @@ pub enum CreateSamplerError {
         lod_min_clamp: f32,
         lod_max_clamp: f32,
     },
-    #[error("Invalid anisotropic clamp: {0}. Must be in the range 1 to 16 inclusive.")]
-    InvalidAnisotropy(f32),
+    #[error("Invalid anisotropic clamp: {0}. Must be at least 1.")]
+    InvalidAnisotropy(u16),
     #[error("Invalid filter mode for {filter_type:?}: {filter_mode:?}. When anistropic clamp is not 1.0 (it is {anisotropic_clamp}), all filter modes must be linear.")]
     InvalidFilterModeWithAnisotropy {
         filter_type: SamplerFilterErrorType,
         filter_mode: wgt::FilterMode,
-        anisotropic_clamp: f32,
+        anisotropic_clamp: u16,
     },
     #[error("Cannot create any more samplers")]
     TooManyObjects,

wgpu-hal/examples/halmark/main.rs

@@ -357,7 +357,7 @@ impl<A: hal::Api> Example<A> {
             mipmap_filter: wgt::FilterMode::Nearest,
             lod_clamp: 0.0..32.0,
             compare: None,
-            anisotropy_clamp: 1.0,
+            anisotropy_clamp: 1,
             border_color: None,
         };
         let sampler = unsafe { device.create_sampler(&sampler_desc).unwrap() };

wgpu-hal/src/dx12/device.rs

@@ -588,7 +588,7 @@ impl crate::Device<super::Api> for super::Device {
             | conv::map_filter_mode(desc.mipmap_filter) << d3d12_ty::D3D12_MIP_FILTER_SHIFT
             | reduction << d3d12_ty::D3D12_FILTER_REDUCTION_TYPE_SHIFT;
 
-        if desc.anisotropy_clamp != 1.0 {
+        if desc.anisotropy_clamp != 1 {
             filter |= d3d12_ty::D3D12_FILTER_ANISOTROPIC;
         };
 

wgpu-hal/src/gles/adapter.rs

@@ -315,10 +315,11 @@ impl super::Adapter {
                 && (vertex_shader_storage_blocks != 0 || vertex_ssbo_false_zero),
         );
         downlevel_flags.set(wgt::DownlevelFlags::FRAGMENT_STORAGE, supports_storage);
-        downlevel_flags.set(
-            wgt::DownlevelFlags::ANISOTROPIC_FILTERING,
-            extensions.contains("EXT_texture_filter_anisotropic"),
-        );
+        if extensions.contains("EXT_texture_filter_anisotropic") {
+            let max_aniso =
+                unsafe { gl.get_parameter_i32(glow::MAX_TEXTURE_MAX_ANISOTROPY_EXT) } as u32;
+            downlevel_flags.set(wgt::DownlevelFlags::ANISOTROPIC_FILTERING, max_aniso >= 16);
+        }
         downlevel_flags.set(
             wgt::DownlevelFlags::BUFFER_BINDINGS_NOT_16_BYTE_ALIGNED,
             !(cfg!(target_arch = "wasm32") || is_angle),

wgpu-hal/src/gles/device.rs

@@ -867,9 +867,16 @@ impl crate::Device<super::Api> for super::Device {
         unsafe { gl.sampler_parameter_f32(raw, glow::TEXTURE_MIN_LOD, desc.lod_clamp.start) };
         unsafe { gl.sampler_parameter_f32(raw, glow::TEXTURE_MAX_LOD, desc.lod_clamp.end) };
 
-        unsafe {
-            gl.sampler_parameter_f32(raw, glow::TEXTURE_MAX_ANISOTROPY, desc.anisotropy_clamp)
-        };
+        // If clamp is not 1, we know anisotropy is supported up to 16x
+        if desc.anisotropy_clamp != 1 {
+            unsafe {
+                gl.sampler_parameter_i32(
+                    raw,
+                    glow::TEXTURE_MAX_ANISOTROPY,
+                    desc.anisotropy_clamp as i32,
+                )
+            };
+        }
 
         //set_param_float(glow::TEXTURE_LOD_BIAS, info.lod_bias.0);
 

wgpu-hal/src/lib.rs

@@ -921,8 +921,10 @@ pub struct SamplerDescriptor<'a> {
     pub mipmap_filter: wgt::FilterMode,
     pub lod_clamp: Range<f32>,
     pub compare: Option<wgt::CompareFunction>,
-    // Must be in the range 1.0 to 16.0 inclusive. Anisotropic filtering must be supported if this is not 1.0.
-    pub anisotropy_clamp: f32,
+    // Must in the range [1, 16].
+    //
+    // Anisotropic filtering must be supported if this is not 1.
+    pub anisotropy_clamp: u16,
     pub border_color: Option<wgt::SamplerBorderColor>,
 }
 

wgpu-hal/src/metal/device.rs

@@ -427,6 +427,7 @@ impl crate::Device<super::Api> for super::Device {
             descriptor.set_address_mode_t(conv::map_address_mode(t));
             descriptor.set_address_mode_r(conv::map_address_mode(r));
 
+            // Anisotropy is always supported on mac up to 16x
             descriptor.set_max_anisotropy(desc.anisotropy_clamp as _);
 
             descriptor.set_lod_min_clamp(desc.lod_clamp.start);

wgpu-hal/src/vulkan/adapter.rs

@@ -345,7 +345,10 @@ impl PhysicalDeviceFeatures {
             caps.supports_extension(vk::KhrSwapchainMutableFormatFn::name()),
         );
         dl_flags.set(Df::CUBE_ARRAY_TEXTURES, self.core.image_cube_array != 0);
-        dl_flags.set(Df::ANISOTROPIC_FILTERING, self.core.sampler_anisotropy != 0);
+        dl_flags.set(
+            Df::ANISOTROPIC_FILTERING,
+            self.core.sampler_anisotropy >= 16,
+        );
         dl_flags.set(
             Df::FRAGMENT_WRITABLE_STORAGE,
             self.core.fragment_stores_and_atomics != 0,
@@ -1320,7 +1323,6 @@ impl super::Adapter {
             },
             vendor_id: self.phd_capabilities.properties.vendor_id,
             timestamp_period: self.phd_capabilities.properties.limits.timestamp_period,
-            downlevel_flags: self.downlevel_flags,
             private_caps: self.private_caps.clone(),
             workarounds: self.workarounds,
             render_passes: Mutex::new(Default::default()),

wgpu-hal/src/vulkan/device.rs

@@ -1120,14 +1120,12 @@ impl crate::Device<super::Api> for super::Device {
                 .compare_op(conv::map_comparison(fun));
         }
 
-        if self
-            .shared
-            .downlevel_flags
-            .contains(wgt::DownlevelFlags::ANISOTROPIC_FILTERING)
-        {
+        if desc.anisotropy_clamp != 1 {
+            // We only enable the downlevel flag if supports 16x anisotropy,
+            // and wgpu-hal interface guarentees the clamp is in the range [1, 16]
             vk_info = vk_info
                 .anisotropy_enable(true)
-                .max_anisotropy(desc.anisotropy_clamp);
+                .max_anisotropy(desc.anisotropy_clamp as f32);
         }
 
         if let Some(color) = desc.border_color {

wgpu-hal/src/vulkan/mod.rs

@@ -249,7 +249,6 @@ struct DeviceShared {
     extension_fns: DeviceExtensionFunctions,
     vendor_id: u32,
     timestamp_period: f32,
-    downlevel_flags: wgt::DownlevelFlags,
     private_caps: PrivateCapabilities,
     workarounds: Workarounds,
     render_passes: Mutex<rustc_hash::FxHashMap<RenderPassKey, vk::RenderPass>>,

wgpu/src/lib.rs

@@ -1008,8 +1008,8 @@ pub struct SamplerDescriptor<'a> {
     pub lod_max_clamp: f32,
     /// If this is enabled, this is a comparison sampler using the given comparison function.
     pub compare: Option<CompareFunction>,
-    /// Valid values between 1 and 16 inclusive. If this is not 1.0, all filter modes must be linear.
-    pub anisotropy_clamp: f32,
+    /// Must be at least 1. If this is not 1, all filter modes must be linear.
+    pub anisotropy_clamp: u16,
     /// Border color to use when address_mode is [`AddressMode::ClampToBorder`]
     pub border_color: Option<SamplerBorderColor>,
 }
@@ -1026,9 +1026,9 @@ impl Default for SamplerDescriptor<'_> {
             min_filter: Default::default(),
             mipmap_filter: Default::default(),
             lod_min_clamp: 0.0,
-            lod_max_clamp: std::f32::MAX,
+            lod_max_clamp: 32.0,
             compare: None,
-            anisotropy_clamp: 1.0,
+            anisotropy_clamp: 1,
             border_color: None,
         }
     }