Internal change

ink/rendering/webgpu/BUILD.bazel

@@ -0,0 +1,19 @@
+package(
+    default_applicable_licenses = ["//ink:license"],
+    default_visibility = ["//ink:__subpackages__"],
+)
+
+genrule(
+    name = "stroke_shader_metal",
+    srcs = ["StrokeShader.wgsl"],
+    outs = [
+        "StrokeShader_vs.metal",
+        "StrokeShader_fs.metal",
+    ],
+    cmd = (
+        "$(location //third_party/dawn:tint) $< --format msl --ep vertexMain -o $(location StrokeShader_vs.metal) && " +
+        "$(location //third_party/dawn:tint) $< --format msl --ep fragmentMain -o $(location StrokeShader_fs.metal)"
+    ),
+    tools = ["//third_party/dawn:tint"],
+    visibility = ["//ink/ios/rendering/metal:__pkg__"],
+)

ink/rendering/webgpu/StrokeShader.wgsl

@@ -0,0 +1,31 @@
+struct VertexOut {
+  @builtin(position) position: vec4<f32>,
+  @location(0) color: vec4<f32>,
+}
+
+struct Uniforms {
+  modelTransform: mat4x4<f32>,
+  viewTransform: mat4x4<f32>,
+  projectionTransform: mat4x4<f32>,
+  color: vec4<f32>,
+  vertexStride: u32,
+}
+
+@group(0) @binding(0) var<uniform> uniforms: Uniforms;
+@group(0) @binding(1) var<storage, read> vertices: array<f32>;
+
+@vertex
+fn vertexMain(@builtin(vertex_index) vertexID: u32) -> VertexOut {
+  var out: VertexOut;
+  let floatOffset = (vertexID * uniforms.vertexStride) / 4u;
+  let pos = vec2<f32>(vertices[floatOffset], vertices[floatOffset + 1u]);
+
+  out.position = uniforms.projectionTransform * uniforms.viewTransform * uniforms.modelTransform * vec4<f32>(pos, 0.0, 1.0);
+  out.color = uniforms.color;
+  return out;
+}
+
+@fragment
+fn fragmentMain(in: VertexOut) -> @location(0) vec4<f32> {
+  return in.color;
+}