JSFiddle - React, Tailwind, and code Playground
by Simon060694
HTML
<canvas id = "canvas" width=300 height=300></canvas>
<script id="2d-vertex-shader" type="x-shader/x-vertex">
attribute vec2 a_position;
uniform vec2 u_resolution;
void main() {
// convert the rectangle from pixels to 0.0 to 1.0
vec2 zeroToOne = a_position / u_resolution;
// convert from 0->1 to 0->2
vec2 zeroToTwo = zeroToOne * 2.0;
// convert from 0->2 to -1->+1 (clipspace)
vec2 clipSpace = zeroToTwo - 1.0;
gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);
}
</script>
<script id="2d-fragment-shader" type="x-shader/x-fragment">
precision mediump float;
uniform vec4 u_color;
void main() {
gl_FragColor = u_color; // green
}
</script>
JavaScript
function compileShader(gl, shaderSource, shaderType) {
// Create the shader object
var shader = gl.createShader(shaderType);
// Set the shader source code.
gl.shaderSource(shader, shaderSource);
// Compile the shader
gl.compileShader(shader);
// Check if it compiled
var success = gl.getShaderParameter(shader, gl.COMPILE_STATUS);
if (!success) {
// Something went wrong during compilation; get the error
throw "could not compile shader:" + gl.getShaderInfoLog(shader);
}
return shader;
}
function createProgram(gl, vertexShader, fragmentShader) {
// create a program.
var program = gl.createProgram();
// attach the shaders.
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
// link the program.
gl.linkProgram(program);
// Check if it linked.
var success = gl.getProgramParameter(program, gl.LINK_STATUS);
if (!success) {
// something went wrong with the link
throw ("program filed to link:" + gl.getProgramInfoLog (program));
}
return program;
};
function createShaderFromScript(gl, scriptId, opt_shaderType) {
// look up the script tag by id.
var shaderScript = document.getElementById(scriptId);
if (!shaderScript) {
throw("*** Error: unknown script element" + scriptId);
}
// extract the contents of the script tag.
var shaderSource = shaderScript.text;
// If we didn't pass in a type, use the 'type' from
// the script tag.
if (!opt_shaderType) {
if (shaderScript.type == "x-shader/x-vertex") {
opt_shaderType = gl.VERTEX_SHADER;
} else if (shaderScript.type == "x-shader/x-fragment") {
opt_shaderType = gl.FRAGMENT_SHADER;
} else if (!opt_shaderType) {
throw("*** Error: shader type not set");
}
}
return compileShader(gl, shaderSource, opt_shaderType);
};
// Get A WebGL context
var canvas = document.getElementById("canvas");
var gl = canvas.getContext("experimental-webgl");
// setup a GLSL program
var...