From 3c7c9412a4b4b99dc8b8b04d6fd407e2aee91443 Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Wed, 20 Sep 2023 21:02:37 -0400
Subject: [PATCH] wgpu-core: Only produce StageError::InputNotConsumed on
 DX11/DX12 (#4116)

* wgpu-core: Only produce StageError::InputNotConsumed on DX11/DX12

This error only exists due to an issue with naga's HLSL support:
https://github.com/gfx-rs/naga/issues/1945
The WGPU spec itself allows vertex shader outputs that are
not consumed by the fragment shader.

Until the issue is fixed, we can allow unconsumed outputs on
all platforms other than DX11/DX12.

* Add Features::SHADER_UNUSED_VERTEX_OUTPUT to allow disabling check

* Pick an unused feature id
---
 CHANGELOG.md                   | 4 ++++
 deno_webgpu/lib.rs             | 7 +++++++
 wgpu-core/src/validation.rs    | 7 ++++++-
 wgpu-hal/src/gles/adapter.rs   | 1 +
 wgpu-hal/src/metal/adapter.rs  | 1 +
 wgpu-hal/src/vulkan/adapter.rs | 1 +
 wgpu-types/src/lib.rs          | 9 +++++++++
 7 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 15a507c36aa..85bbed9070f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,10 @@ Bottom level categories:
 
 ### Bug Fixes
 
+#### General
+
+- Add `Feature::SHADER_UNUSED_VERTEX_OUTPUT` to allow unused vertex shader outputs. By @Aaron1011 in [#4116](https://github.com/gfx-rs/wgpu/pull/4116).
+
 #### Vulkan
 
 - Fix x11 hang while resizing on vulkan. @Azorlogh in [#4184](https://github.com/gfx-rs/wgpu/pull/4184).
diff --git a/deno_webgpu/lib.rs b/deno_webgpu/lib.rs
index f4757236823..5f671747ccd 100644
--- a/deno_webgpu/lib.rs
+++ b/deno_webgpu/lib.rs
@@ -365,6 +365,9 @@ fn deserialize_features(features: &wgpu_types::Features) -> Vec<&'static str> {
     if features.contains(wgpu_types::Features::SHADER_EARLY_DEPTH_TEST) {
         return_features.push("shader-early-depth-test");
     }
+    if features.contains(wgpu_types::Features::SHADER_UNUSED_VERTEX_OUTPUT) {
+        return_features.push("shader-unused-vertex-output");
+    }
 
     return_features
 }
@@ -624,6 +627,10 @@ impl From<GpuRequiredFeatures> for wgpu_types::Features {
             wgpu_types::Features::SHADER_EARLY_DEPTH_TEST,
             required_features.0.contains("shader-early-depth-test"),
         );
+        features.set(
+            wgpu_types::Features::SHADER_UNUSED_VERTEX_OUTPUT,
+            required_features.0.contains("shader-unused-vertex-output"),
+        );
 
         features
     }
diff --git a/wgpu-core/src/validation.rs b/wgpu-core/src/validation.rs
index 771adba731d..89bc28a4634 100644
--- a/wgpu-core/src/validation.rs
+++ b/wgpu-core/src/validation.rs
@@ -1179,7 +1179,12 @@ impl Interface {
         }
 
         // Check all vertex outputs and make sure the fragment shader consumes them.
-        if shader_stage == naga::ShaderStage::Fragment {
+        // This requirement is removed if the `SHADER_UNUSED_VERTEX_OUTPUT` feature is enabled.
+        if shader_stage == naga::ShaderStage::Fragment
+            && !self
+                .features
+                .contains(wgt::Features::SHADER_UNUSED_VERTEX_OUTPUT)
+        {
             for &index in inputs.keys() {
                 // This is a linear scan, but the count should be low enough
                 // that this should be fine.
diff --git a/wgpu-hal/src/gles/adapter.rs b/wgpu-hal/src/gles/adapter.rs
index 5594dfa237b..074d8f84d7a 100644
--- a/wgpu-hal/src/gles/adapter.rs
+++ b/wgpu-hal/src/gles/adapter.rs
@@ -368,6 +368,7 @@ impl super::Adapter {
             ver >= (3, 2) || extensions.contains("OES_geometry_shader"),
         );
         features.set(wgt::Features::SHADER_EARLY_DEPTH_TEST, ver >= (3, 1));
+        features.set(wgt::Features::SHADER_UNUSED_VERTEX_OUTPUT, true);
         let gles_bcn_exts = [
             "GL_EXT_texture_compression_s3tc_srgb",
             "GL_EXT_texture_compression_rgtc",
diff --git a/wgpu-hal/src/metal/adapter.rs b/wgpu-hal/src/metal/adapter.rs
index c5e6316c195..2d6a33e582e 100644
--- a/wgpu-hal/src/metal/adapter.rs
+++ b/wgpu-hal/src/metal/adapter.rs
@@ -806,6 +806,7 @@ impl super::PrivateCapabilities {
         features.set(F::ADDRESS_MODE_CLAMP_TO_ZERO, true);
 
         features.set(F::RG11B10UFLOAT_RENDERABLE, self.format_rg11b10_all);
+        features.set(F::SHADER_UNUSED_VERTEX_OUTPUT, true);
 
         features
     }
diff --git a/wgpu-hal/src/vulkan/adapter.rs b/wgpu-hal/src/vulkan/adapter.rs
index 1dd3b266e93..b636fb4870d 100644
--- a/wgpu-hal/src/vulkan/adapter.rs
+++ b/wgpu-hal/src/vulkan/adapter.rs
@@ -519,6 +519,7 @@ impl PhysicalDeviceFeatures {
                 | vk::FormatFeatureFlags::COLOR_ATTACHMENT_BLEND,
         );
         features.set(F::RG11B10UFLOAT_RENDERABLE, rg11b10ufloat_renderable);
+        features.set(F::SHADER_UNUSED_VERTEX_OUTPUT, true);
 
         (features, dl_flags)
     }
diff --git a/wgpu-types/src/lib.rs b/wgpu-types/src/lib.rs
index 79bb0f690d3..739748a7082 100644
--- a/wgpu-types/src/lib.rs
+++ b/wgpu-types/src/lib.rs
@@ -730,6 +730,15 @@ bitflags::bitflags! {
         /// This is a native only feature.
         const VERTEX_ATTRIBUTE_64BIT = 1 << 53;
 
+        /// Allows vertex shaders to have outputs which are not consumed
+        /// by the fragment shader.
+        ///
+        /// Supported platforms:
+        /// - Vulkan
+        /// - Metal
+        /// - OpenGL
+        const SHADER_UNUSED_VERTEX_OUTPUT = 1 << 54;
+
         // 54..59 available
 
         // Shader: