"use strict";
let canvas = document.getElementById("canvas");
let gl = canvas.getContext("webgl");
gl.canvas.width = 3;
gl.canvas.height = 3;
gl.canvas.style.width="90px";
let vertex = `
attribute vec2 a_position;
attribute vec2 a_texCoord;
uniform vec2 u_resolution;
varying vec2 v_texCoord;
void main() {
vec2 zeroToOne = a_position / u_resolution;
vec2 zeroToTwo = zeroToOne * 2.0;
vec2 clipSpace = zeroToTwo - 1.0;
gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);
v_texCoord = a_texCoord;
}
`;
let fragment = `
precision mediump float;
uniform sampler2D u_image;
varying vec2 v_texCoord;
void main() {
gl_FragColor = texture2D(u_image, v_texCoord);
gl_FragColor.rgb *= gl_FragColor.a;
}
`;