let canvas = document.getElementById("webgl"); let gl = canvas.getContext("webgl"); let VSHADER_SOURCE = 'void main(){'+ 'gl_Position = vec4(0.0,0.0,0.0,1.0);'+// 设置坐标 'gl_PointSize = 10.0;'+// 设置尺寸 '}'; let FSHADER_SOURCE = 'void main(){'+ 'gl_FragColor = vec4(1.0,0.0,0.0,1.0);'+ // 设置颜色 '}'; initShaders(gl, VSHADER_SOURCE, FSHADER_SOURCE); gl.clearColor(0.0,0.0,0.0,1.0); gl.clear(gl.COLOR_BUFFER_BIT); gl.drawArrays(gl.POINTS, 0, 1); //往后的先不研究 // cuon-utils.js (c) 2012 kanda and matsuda /** * Create a program object and make current * @param gl GL context * @param vshader a vertex shader program (string) * @param fshader a fragment shader program (string) * @return true, if the program object was created and successfully made current */ function initShaders(gl, vshader, fshader) { var program = createProgram(gl, vshader, fshader); if (!program) { console.log('Failed to create program'); return false; } gl.useProgram(program); gl.program = program; return true; } /** * Create the linked program object * @param gl GL context * @param vshader a vertex shader program (string) * @param fshader a fragment shader program (string) * @return created program object, or null if the creation has failed */ function createProgram(gl, vshader, fshader) { // Create shader object var vertexShader = loadShader(gl, gl.VERTEX_SHADER, vshader); var fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fshader); if (!vertexShader || !fragmentShader) { return null; } // Create a program object var program = gl.createProgram(); if (!program) { return null; } // Attach the shader objects gl.attachShader(program, vertexShader); gl.attachShader(program, fragmentShader); // Link the program object gl.linkProgram(program); // Check the result of linking var linked = gl.getProgramParameter(program, gl.LINK_STATUS); if (!linked) { var error = gl.getProgramInfoLog(program); console.log('Failed to link program: ' + error); gl.deleteProgram(program); gl.deleteShader(fragmentShader); gl.deleteShader(vertexShader); return null; } return program; } /** * Create a shader object * @param gl GL context * @param type the type of the shader object to be created * @param source shader program (string) * @return created shader object, or null if the creation has failed. */ function loadShader(gl, type, source) { // Create shader object var shader = gl.createShader(type); if (shader == null) { console.log('unable to create shader'); return null; } // Set the shader program gl.shaderSource(shader, source); // Compile the shader gl.compileShader(shader); // Check the result of compilation var compiled = gl.getShaderParameter(shader, gl.COMPILE_STATUS); if (!compiled) { var error = gl.getShaderInfoLog(shader); console.log('Failed to compile shader: ' + error); gl.deleteShader(shader); return null; } return shader; } /** * Initialize and get the rendering for WebGL * @param canvas <cavnas> element * @param opt_debug flag to initialize the context for debugging * @return the rendering context for WebGL */ function getWebGLContext(canvas, opt_debug) { // Get the rendering context for WebGL var gl = WebGLUtils.setupWebGL(canvas); if (!gl) return null; // if opt_debug is explicitly false, create the context for debugging if (arguments.length < 2 || opt_debug) { gl = WebGLDebugUtils.makeDebugContext(gl); } return gl; }
<canvas id="webgl" width="400" height="400"></canvas>