Add basic vertex and fragment shader

assets/shaders/shader.wgsl

@@ -0,0 +1,19 @@
+struct VertexOutput {
+    @builtin(position) clip_position: vec4<f32>,
+};
+
+@vertex
+fn vertex(
+    @builtin(vertex_index) in_vertex_index: u32,
+) -> VertexOutput {
+    var out: VertexOutput;
+    let x = f32(1 - i32(in_vertex_index)) * 0.5;
+    let y = f32(i32(in_vertex_index & 1u) * 2 - 1) * 0.5;
+    out.clip_position = vec4<f32>(x, y, 0.0, 1.0);
+    return out;
+}
+
+@fragment
+fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
+    return vec4<f32>(0.3, 0.2, 0.1, 1.0);
+}