add AddressMode::ClampToZero

wgpu-core/src/device/mod.rs

@@ -990,6 +990,10 @@ impl<A: HalApi> Device<A> {
             self.require_features(wgt::Features::ADDRESS_MODE_CLAMP_TO_BORDER)?;
         }
 
+        if desc.border_color == Some(wgt::SamplerBorderColor::Zero) {
+            self.require_features(wgt::Features::ADDRESS_MODE_CLAMP_TO_ZERO)?;
+        }
+
         let lod_clamp = if desc.lod_min_clamp > 0.0 || desc.lod_max_clamp < 32.0 {
             Some(desc.lod_min_clamp..desc.lod_max_clamp)
         } else {

wgpu-hal/src/dx12/adapter.rs

@@ -180,6 +180,7 @@ impl super::Adapter {
             | wgt::Features::MULTI_DRAW_INDIRECT
             | wgt::Features::MULTI_DRAW_INDIRECT_COUNT
             | wgt::Features::ADDRESS_MODE_CLAMP_TO_BORDER
+            | wgt::Features::ADDRESS_MODE_CLAMP_TO_ZERO
             | wgt::Features::POLYGON_MODE_LINE
             | wgt::Features::POLYGON_MODE_POINT
             | wgt::Features::VERTEX_WRITABLE_STORAGE

wgpu-hal/src/dx12/conv.rs

@@ -247,7 +247,7 @@ pub fn map_address_mode(mode: wgt::AddressMode) -> d3d12::D3D12_TEXTURE_ADDRESS_
         Am::Repeat => d3d12::D3D12_TEXTURE_ADDRESS_MODE_WRAP,
         Am::MirrorRepeat => d3d12::D3D12_TEXTURE_ADDRESS_MODE_MIRROR,
         Am::ClampToEdge => d3d12::D3D12_TEXTURE_ADDRESS_MODE_CLAMP,
-        Am::ClampToBorder => d3d12::D3D12_TEXTURE_ADDRESS_MODE_BORDER,
+        Am::ClampToBorder | Am::ClampToZero => d3d12::D3D12_TEXTURE_ADDRESS_MODE_BORDER,
         //Am::MirrorClamp => d3d12::D3D12_TEXTURE_ADDRESS_MODE_MIRROR_ONCE,
     }
 }
@@ -276,7 +276,7 @@ pub fn map_comparison(func: wgt::CompareFunction) -> d3d12::D3D12_COMPARISON_FUN
 pub fn map_border_color(border_color: Option<wgt::SamplerBorderColor>) -> [f32; 4] {
     use wgt::SamplerBorderColor as Sbc;
     match border_color {
-        Some(Sbc::TransparentBlack) | None => [0.0; 4],
+        Some(Sbc::TransparentBlack) | Some(Sbc::Zero) | None => [0.0; 4],
         Some(Sbc::OpaqueBlack) => [0.0, 0.0, 0.0, 1.0],
         Some(Sbc::OpaqueWhite) => [1.0; 4],
     }

wgpu-hal/src/dx12/device.rs

@@ -620,6 +620,8 @@ impl crate::Device<super::Api> for super::Device {
                 .anisotropy_clamp
                 .map_or(0, |_| d3d12::D3D12_FILTER_ANISOTROPIC);
 
+        let border_color = conv::map_border_color(desc.border_color);
+
         self.raw.create_sampler(
             handle.raw,
             filter,
@@ -631,7 +633,7 @@ impl crate::Device<super::Api> for super::Device {
             0.0,
             desc.anisotropy_clamp.map_or(0, |aniso| aniso.get() as u32),
             conv::map_comparison(desc.compare.unwrap_or(wgt::CompareFunction::Always)),
-            conv::map_border_color(desc.border_color),
+            border_color,
             desc.lod_clamp.clone().unwrap_or(0.0..16.0),
         );
 

wgpu-hal/src/gles/adapter.rs

@@ -288,7 +288,7 @@ impl super::Adapter {
             | wgt::Features::TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES
             | wgt::Features::CLEAR_TEXTURE;
         features.set(
-            wgt::Features::ADDRESS_MODE_CLAMP_TO_BORDER,
+            wgt::Features::ADDRESS_MODE_CLAMP_TO_BORDER | wgt::Features::ADDRESS_MODE_CLAMP_TO_ZERO,
             extensions.contains("GL_EXT_texture_border_clamp"),
         );
         features.set(

wgpu-hal/src/gles/device.rs

@@ -721,7 +721,7 @@ impl crate::Device<super::Api> for super::Device {
 
         if let Some(border_color) = desc.border_color {
             let border = match border_color {
-                wgt::SamplerBorderColor::TransparentBlack => [0.0; 4],
+                wgt::SamplerBorderColor::TransparentBlack | wgt::SamplerBorderColor::Zero => [0.0; 4],
                 wgt::SamplerBorderColor::OpaqueBlack => [0.0, 0.0, 0.0, 1.0],
                 wgt::SamplerBorderColor::OpaqueWhite => [1.0; 4],
             };

wgpu-hal/src/metal/adapter.rs

@@ -940,10 +940,9 @@ impl super::PrivateCapabilities {
         {
             features.insert(F::STORAGE_RESOURCE_BINDING_ARRAY);
         }
-        features.set(
-            F::ADDRESS_MODE_CLAMP_TO_BORDER,
-            self.sampler_clamp_to_border,
-        );
+
+        features.set(F::ADDRESS_MODE_CLAMP_TO_BORDER, self.sampler_clamp_to_border);
+        features.set(F::ADDRESS_MODE_CLAMP_TO_ZERO, true);
 
         features
     }

wgpu-hal/src/metal/conv.rs

@@ -73,6 +73,7 @@ pub fn map_border_color(border_color: wgt::SamplerBorderColor) -> mtl::MTLSample
         wgt::SamplerBorderColor::TransparentBlack => TransparentBlack,
         wgt::SamplerBorderColor::OpaqueBlack => OpaqueBlack,
         wgt::SamplerBorderColor::OpaqueWhite => OpaqueWhite,
+        wgt::SamplerBorderColor::Zero => unreachable!()
     }
 }
 

wgpu-hal/src/metal/device.rs

@@ -388,15 +388,15 @@ impl crate::Device<super::Api> for super::Device {
             wgt::FilterMode::Linear => mtl::MTLSamplerMipFilter::Linear,
         });
 
-        if let Some(aniso) = desc.anisotropy_clamp {
-            descriptor.set_max_anisotropy(aniso.get() as _);
-        }
-
         let [s, t, r] = desc.address_modes;
         descriptor.set_address_mode_s(conv::map_address_mode(s));
         descriptor.set_address_mode_t(conv::map_address_mode(t));
         descriptor.set_address_mode_r(conv::map_address_mode(r));
 
+        if let Some(aniso) = desc.anisotropy_clamp {
+            descriptor.set_max_anisotropy(aniso.get() as _);
+        }
+
         if let Some(ref range) = desc.lod_clamp {
             descriptor.set_lod_min_clamp(range.start);
             descriptor.set_lod_max_clamp(range.end);
@@ -409,8 +409,23 @@ impl crate::Device<super::Api> for super::Device {
         if let Some(fun) = desc.compare {
             descriptor.set_compare_function(conv::map_compare_function(fun));
         }
+
         if let Some(border_color) = desc.border_color {
-            descriptor.set_border_color(conv::map_border_color(border_color));
+            if let wgt::SamplerBorderColor::Zero = border_color {
+                if s == wgt::AddressMode::ClampToBorder {
+                    descriptor.set_address_mode_s(mtl::MTLSamplerAddressMode::ClampToZero);
+                }
+
+                if t == wgt::AddressMode::ClampToBorder {
+                    descriptor.set_address_mode_t(mtl::MTLSamplerAddressMode::ClampToZero);
+                }
+
+                if r == wgt::AddressMode::ClampToBorder {
+                    descriptor.set_address_mode_r(mtl::MTLSamplerAddressMode::ClampToZero);
+                }
+            } else {
+                descriptor.set_border_color(conv::map_border_color(border_color));
+            }
         }
 
         if let Some(label) = desc.label {

wgpu-hal/src/vulkan/adapter.rs

@@ -329,6 +329,7 @@ impl PhysicalDeviceFeatures {
             | F::MAPPABLE_PRIMARY_BUFFERS
             | F::PUSH_CONSTANTS
             | F::ADDRESS_MODE_CLAMP_TO_BORDER
+            | F::ADDRESS_MODE_CLAMP_TO_ZERO
             | F::TIMESTAMP_QUERY
             | F::PIPELINE_STATISTICS_QUERY
             | F::TEXTURE_ADAPTER_SPECIFIC_FORMAT_FEATURES

wgpu-hal/src/vulkan/conv.rs

@@ -588,14 +588,16 @@ pub fn map_address_mode(mode: wgt::AddressMode) -> vk::SamplerAddressMode {
         wgt::AddressMode::ClampToEdge => vk::SamplerAddressMode::CLAMP_TO_EDGE,
         wgt::AddressMode::Repeat => vk::SamplerAddressMode::REPEAT,
         wgt::AddressMode::MirrorRepeat => vk::SamplerAddressMode::MIRRORED_REPEAT,
-        wgt::AddressMode::ClampToBorder => vk::SamplerAddressMode::CLAMP_TO_BORDER,
-        //wgt::AddressMode::MirrorClamp => vk::SamplerAddressMode::MIRROR_CLAMP_TO_EDGE,
+        wgt::AddressMode::ClampToBorder => vk::SamplerAddressMode::CLAMP_TO_BORDER, 
+        // wgt::AddressMode::MirrorClamp => vk::SamplerAddressMode::MIRROR_CLAMP_TO_EDGE,
     }
 }
 
 pub fn map_border_color(border_color: wgt::SamplerBorderColor) -> vk::BorderColor {
     match border_color {
-        wgt::SamplerBorderColor::TransparentBlack => vk::BorderColor::FLOAT_TRANSPARENT_BLACK,
+        wgt::SamplerBorderColor::TransparentBlack | wgt::SamplerBorderColor::Zero => {
+            vk::BorderColor::FLOAT_TRANSPARENT_BLACK
+        }
         wgt::SamplerBorderColor::OpaqueBlack => vk::BorderColor::FLOAT_OPAQUE_BLACK,
         wgt::SamplerBorderColor::OpaqueWhite => vk::BorderColor::FLOAT_OPAQUE_WHITE,
     }

wgpu-hal/src/vulkan/device.rs

@@ -974,6 +974,7 @@ impl crate::Device<super::Api> for super::Device {
                     .max_anisotropy(aniso.get() as f32);
             }
         }
+
         if let Some(color) = desc.border_color {
             vk_info = vk_info.border_color(conv::map_border_color(color));
         }

wgpu-types/src/lib.rs

@@ -394,7 +394,8 @@ bitflags::bitflags! {
         ///
         /// This is a native only feature.
         const PUSH_CONSTANTS = 1 << 26;
-        /// Allows the use of [`AddressMode::ClampToBorder`].
+        /// Allows the use of [`AddressMode::ClampToBorder`] with a border color
+        /// other than [`SamplerBorderColor::Zero`].
         ///
         /// Supported platforms:
         /// - DX12
@@ -551,6 +552,18 @@ bitflags::bitflags! {
         ///
         /// This is a native only feature.
         const TEXTURE_FORMAT_16BIT_NORM = 1 << 41;
+        /// Allows the use of [`AddressMode::ClampToBorder`] with a border color
+        /// of [`SamplerBorderColor::Zero`].
+        ///
+        /// Supported platforms:
+        /// - DX12
+        /// - Vulkan
+        /// - Metal
+        /// - DX11
+        /// - OpenGL
+        ///
+        /// This is a native only feature.
+        const ADDRESS_MODE_CLAMP_TO_ZERO = 1 << 42;
     }
 }
 
@@ -3532,6 +3545,13 @@ pub enum SamplerBorderColor {
     OpaqueBlack,
     /// [1, 1, 1, 1]
     OpaqueWhite,
+
+    /// On the Metal backend, this is equivalent to `TransparentBlack` for
+    /// textures that have an alpha component, and equivalent to `OpaqueBlack`
+    /// for textures that do not have an alpha component. On other backends,
+    /// this is equivalent to `TransparentBlack`. Requires
+    /// [`Features::ADDRESS_MODE_CLAMP_TO_ZERO`]. Not supported on the web.
+    Zero,
 }
 
 /// Describes how to create a QuerySet.