const adapter = await navigator.gpu.requestAdapter();
if (!adapter) throw new Error("no WebGPU adapter");
const device = await adapter.requestDevice();

const win = new Deno.BrowserWindow({
  title: "Raw Backend",
  width: 800,
  height: 600,
});

const surface = win.getNativeWindow();
surface.width = 800;
surface.height = 600;

const fmt = navigator.gpu.getPreferredCanvasFormat();
const context = surface.getContext("webgpu") as GPUCanvasContext;
context.configure({ device, format: fmt, alphaMode: "opaque" });

let hue = 0;

setInterval(() => {
  hue = (hue + 0.5) % 360;
  const r = Math.sin(hue * Math.PI / 180) * 0.5 + 0.5;
  const g = Math.sin((hue + 120) * Math.PI / 180) * 0.5 + 0.5;
  const b = Math.sin((hue + 240) * Math.PI / 180) * 0.5 + 0.5;

  const encoder = device.createCommandEncoder();
  const textureView = context.getCurrentTexture().createView();
  const pass = encoder.beginRenderPass({
    colorAttachments: [{
      view: textureView,
      clearValue: { r, g, b, a: 1.0 },
      loadOp: "clear",
      storeOp: "store",
    }],
  });
  pass.end();
  device.queue.submit([encoder.finish()]);
  surface.present();
}, 16);