From 76cec1b1fd533dda37aa53c40ef7665ed3b406b6 Mon Sep 17 00:00:00 2001
From: David Huculak <davidhuculak5@gmail.com>
Date: Sun, 3 Sep 2023 19:32:38 -0400
Subject: [PATCH 1/2] use @interpolate(flat) attribute as per the WebGPU spec:

User-defined vertex outputs and fragment inputs of scalar or vector integer type must always be specified as @interpolate(flat)

https://www.w3.org/TR/WGSL/#interpolation
---
 wgpu/src/shader/quad.wgsl     | 22 +++++++++++-----------
 wgpu/src/shader/triangle.wgsl | 20 ++++++++++----------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/wgpu/src/shader/quad.wgsl b/wgpu/src/shader/quad.wgsl
index fb402158c7..87055339f8 100644
--- a/wgpu/src/shader/quad.wgsl
+++ b/wgpu/src/shader/quad.wgsl
@@ -147,12 +147,12 @@ fn solid_fs_main(
 
 struct GradientVertexInput {
     @location(0) v_pos: vec2<f32>,
-    @location(1) colors_1: vec4<u32>,
-    @location(2) colors_2: vec4<u32>,
-    @location(3) colors_3: vec4<u32>,
-    @location(4) colors_4: vec4<u32>,
-    @location(5) offsets: vec4<u32>,
-    @location(6) direction: vec4<f32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
+    @location(6) @interpolate(flat) direction: vec4<f32>,
     @location(7) position_and_scale: vec4<f32>,
     @location(8) border_color: vec4<f32>,
     @location(9) border_radius: vec4<f32>,
@@ -161,11 +161,11 @@ struct GradientVertexInput {
 
 struct GradientVertexOutput {
     @builtin(position) position: vec4<f32>,
-    @location(1) colors_1: vec4<u32>,
-    @location(2) colors_2: vec4<u32>,
-    @location(3) colors_3: vec4<u32>,
-    @location(4) colors_4: vec4<u32>,
-    @location(5) offsets: vec4<u32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
     @location(6) direction: vec4<f32>,
     @location(7) position_and_scale: vec4<f32>,
     @location(8) border_color: vec4<f32>,
diff --git a/wgpu/src/shader/triangle.wgsl b/wgpu/src/shader/triangle.wgsl
index 9f512d1489..3a2b984555 100644
--- a/wgpu/src/shader/triangle.wgsl
+++ b/wgpu/src/shader/triangle.wgsl
@@ -38,22 +38,22 @@ fn solid_fs_main(input: SolidVertexOutput) -> @location(0) vec4<f32> {
 
 struct GradientVertexInput {
     @location(0) v_pos: vec2<f32>,
-    @location(1) colors_1: vec4<u32>,
-    @location(2) colors_2: vec4<u32>,
-    @location(3) colors_3: vec4<u32>,
-    @location(4) colors_4: vec4<u32>,
-    @location(5) offsets: vec4<u32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
     @location(6) direction: vec4<f32>,
 }
 
 struct GradientVertexOutput {
     @builtin(position) position: vec4<f32>,
     @location(0) raw_position: vec2<f32>,
-    @location(1) colors_1: vec4<u32>,
-    @location(2) colors_2: vec4<u32>,
-    @location(3) colors_3: vec4<u32>,
-    @location(4) colors_4: vec4<u32>,
-    @location(5) offsets: vec4<u32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
     @location(6) direction: vec4<f32>,
 }
 

From 87800095e27353557adb39ef42ee6f82a0075bc1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?=
 <hector0193@gmail.com>
Date: Thu, 7 Sep 2023 05:43:03 +0200
Subject: [PATCH 2/2] Remove unnecessary `interpolate(flat)` in `quad.wgsl`

---
 wgpu/src/shader/quad.wgsl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/wgpu/src/shader/quad.wgsl b/wgpu/src/shader/quad.wgsl
index 87055339f8..023b5a6d1c 100644
--- a/wgpu/src/shader/quad.wgsl
+++ b/wgpu/src/shader/quad.wgsl
@@ -152,7 +152,7 @@ struct GradientVertexInput {
     @location(3) @interpolate(flat) colors_3: vec4<u32>,
     @location(4) @interpolate(flat) colors_4: vec4<u32>,
     @location(5) @interpolate(flat) offsets: vec4<u32>,
-    @location(6) @interpolate(flat) direction: vec4<f32>,
+    @location(6) direction: vec4<f32>,
     @location(7) position_and_scale: vec4<f32>,
     @location(8) border_color: vec4<f32>,
     @location(9) border_radius: vec4<f32>,