fantasy-console/graphics.ts

import {
	DwmWindow,
	gl
} from "./deps.ts";

function loadShader(type: number, src: string) {
	const shader = gl.CreateShader(type);
	gl.ShaderSource(
		shader,
		1,
		new Uint8Array(
			new BigUint64Array([
				BigInt(
					Deno.UnsafePointer.value(
						Deno.UnsafePointer.of(new TextEncoder().encode(src)),
					),
				),
			]).buffer,
		),
		new Int32Array([src.length]),
	);
	gl.CompileShader(shader);
	const status = new Int32Array(1);
	gl.GetShaderiv(shader, gl.COMPILE_STATUS, status);
	if (status[0] === gl.FALSE) {
		const logLength = new Int32Array(1);
		gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, logLength);
		const log = new Uint8Array(logLength[0]);
		gl.GetShaderInfoLog(shader, logLength[0], logLength, log);
		console.log(new TextDecoder().decode(log));
		gl.DeleteShader(shader);
		return 0;
	}
	return shader;
}

const vShaderSrc = `
  attribute vec4 vPosition;
  void main() {
	gl_Position = vPosition;
  }
  `;

const fShaderSrc = `
  void main() {
	gl_FragColor = vec4(1.0, 1.0, 0.0, 1.0);
  }
  `;

const vShader = loadShader(gl.VERTEX_SHADER, vShaderSrc);
const fShader = loadShader(gl.FRAGMENT_SHADER, fShaderSrc);

const program = gl.CreateProgram();
gl.AttachShader(program, vShader);
gl.AttachShader(program, fShader);

gl.BindAttribLocation(program, 0, new TextEncoder().encode("vPosition\0"));

gl.LinkProgram(program);

const status = new Int32Array(1);
gl.GetProgramiv(program, gl.LINK_STATUS, status);
if (status[0] === gl.FALSE) {
	const logLength = new Int32Array(1);
	gl.GetProgramiv(program, gl.INFO_LOG_LENGTH, logLength);
	const log = new Uint8Array(logLength[0]);
	gl.GetProgramInfoLog(program, logLength[0], logLength, log);
	console.log(new TextDecoder().decode(log));
	gl.DeleteProgram(program);
	Deno.exit(1);
}

gl.ClearColor(0.0, 0.0, 0.0, 1.0);

addEventListener("resize", (event) => {
	gl.Viewport(0, 0, event.width, event.height);
});

export const makeFrameFunc = (swapBuffers: DwmWindow["swapBuffers"]) => {
	return () => {
		gl.Clear(gl.COLOR_BUFFER_BIT);
		gl.UseProgram(program);
		// deno-fmt-ignore
		gl.VertexAttribPointer(0, 3, gl.FLOAT, gl.FALSE, 0, new Float32Array([
			0.0, 0.5, 0.0,  
			-0.5, 0.0, 0.0,
			0.5, 0.0, 0.0,
		]));
		gl.EnableVertexAttribArray(0);
		gl.DrawArrays(gl.TRIANGLES, 0, 3);
		swapBuffers();
	}
}