734 lines
20 KiB
JavaScript
734 lines
20 KiB
JavaScript
/*
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* Copyright 2015-2020 MDN Contributors
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* Copyright 2024 Mark Callow
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* SPDX-License-Identifier: CC0-1.0
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*/
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/*
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This code originated from sample 7 in the MDN WebGL examples
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at https://github.com/mdn/webgl-examples which is licensed
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under Creative Commons Zero v1.0 Universal. Modifications
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made here are also licensed under CC0v1.
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*/
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var cubeRotation = 0.0;
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var gl;
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var texture;
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var astcSupported = false;
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var etcSupported = false;
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var dxtSupported = false;
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var pvrtcSupported = false;
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//
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// Start here
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//
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const canvas = document.querySelector('#glcanvas');
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gl = canvas.getContext('webgl2');
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// If we don't have a GL context, give up now
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if (!gl) {
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alert('Unable to initialize WebGL. Your browser or machine may not support it.');
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} else {
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createKtxReadModule({preinitializedWebGLContext: gl}).then(instance => {
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window.ktx = instance;
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// Make existing WebGL context current for Emscripten OpenGL.
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ktx.GL.makeContextCurrent(
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ktx.GL.createContext(document.getElementById("glcanvas"),
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{ majorVersion: 2.0 })
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);
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main()
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});
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}
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function main() {
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texture = loadTexture(gl, 'ktx_app_basis.ktx2');
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astcSupported = !!gl.getExtension('WEBGL_compressed_texture_astc');
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etcSupported = !!gl.getExtension('WEBGL_compressed_texture_etc1');
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dxtSupported = !!gl.getExtension('WEBGL_compressed_texture_s3tc');
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pvrtcSupported = !!(gl.getExtension('WEBGL_compressed_texture_pvrtc')) || !!(gl.getExtension('WEBKIT_WEBGL_compressed_texture_pvrtc'));
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// Vertex shader program
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const vsSource = `
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attribute vec4 aVertexPosition;
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attribute vec3 aVertexNormal;
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attribute vec3 aTextureCoord;
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uniform mat4 uNormalMatrix;
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uniform mat4 uModelViewMatrix;
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uniform mat4 uProjectionMatrix;
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uniform mat3 uUVMatrix;
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varying highp vec2 vTextureCoord;
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varying highp vec3 vLighting;
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void main(void) {
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gl_Position = uProjectionMatrix * uModelViewMatrix * aVertexPosition;
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//vTextureCoord.x = aTextureCoord.x;
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// Invert Y coordinate to account for PNG top-left origin.
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//vTextureCoord.y = aTextureCoord.y * -1.0 + 1.0;
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vTextureCoord = vec2(uUVMatrix * aTextureCoord);
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// Apply lighting effect
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highp vec3 ambientLight = vec3(0.3, 0.3, 0.3);
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highp vec3 directionalLightColor = vec3(1, 1, 1);
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highp vec3 directionalVector = normalize(vec3(0.85, 0.8, 0.75));
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highp vec4 transformedNormal = uNormalMatrix * vec4(aVertexNormal, 1.0);
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highp float directional = max(dot(transformedNormal.xyz, directionalVector), 0.0);
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vLighting = ambientLight + (directionalLightColor * directional);
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}
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`;
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// Fragment shader program
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const fsSource = `
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varying highp vec2 vTextureCoord;
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varying highp vec3 vLighting;
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uniform sampler2D uSampler;
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highp vec3 srgb_encode(highp vec3 color) {
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highp float r = color.r < 0.0031308 ? 12.92 * color.r : 1.055 * pow(color.r, 1.0/2.4) - 0.055;
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highp float g = color.g < 0.0031308 ? 12.92 * color.g : 1.055 * pow(color.g, 1.0/2.4) - 0.055;
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highp float b = color.b < 0.0031308 ? 12.92 * color.b : 1.055 * pow(color.b, 1.0/2.4) - 0.055;
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return vec3(r, g, b);
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}
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void main(void) {
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highp vec3 vertexColor = vec3(0.9, 0.9, 0.9);
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highp vec4 texelColor = texture2D(uSampler, vTextureCoord);
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highp vec4 fragcolor;
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// DECAL
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fragcolor.rgb = vertexColor.rgb * (1.0 - texelColor.a) + texelColor.rgb * texelColor.a;
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fragcolor.a = texelColor.a;
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fragcolor.rgb *= vLighting;
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fragcolor.rgb = srgb_encode(fragcolor.rgb);
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gl_FragColor = fragcolor;
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}
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`;
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// Initialize a shader program; this is where all the lighting
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// for the vertices and so forth is established.
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const shaderProgram = initShaderProgram(gl, vsSource, fsSource);
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// Collect all the info needed to use the shader program.
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// Look up which attributes our shader program is using
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// for aVertexPosition, aVertexNormal, aTextureCoord,
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// and look up uniform locations.
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const programInfo = {
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program: shaderProgram,
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attribLocations: {
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vertexPosition: gl.getAttribLocation(shaderProgram, 'aVertexPosition'),
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vertexNormal: gl.getAttribLocation(shaderProgram, 'aVertexNormal'),
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textureCoord: gl.getAttribLocation(shaderProgram, 'aTextureCoord'),
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},
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uniformLocations: {
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projectionMatrix: gl.getUniformLocation(shaderProgram, 'uProjectionMatrix'),
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modelViewMatrix: gl.getUniformLocation(shaderProgram, 'uModelViewMatrix'),
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normalMatrix: gl.getUniformLocation(shaderProgram, 'uNormalMatrix'),
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uvMatrix: gl.getUniformLocation(shaderProgram, 'uUVMatrix'),
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uSampler: gl.getUniformLocation(shaderProgram, 'uSampler'),
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},
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};
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// Here's where we call the routine that builds all the
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// objects we'll be drawing.
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const buffers = initBuffers(gl);
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var then = 0;
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// Draw the scene repeatedly
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function render(now) {
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now *= 0.001; // convert to seconds
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const deltaTime = now - then;
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then = now;
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drawScene(gl, programInfo, buffers, texture, deltaTime);
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requestAnimationFrame(render);
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}
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requestAnimationFrame(render);
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}
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//
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// initBuffers
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//
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// Initialize the buffers we'll need. For this demo, we just
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// have one object -- a simple three-dimensional cube.
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//
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function initBuffers(gl) {
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// Create a buffer for the cube's vertex positions.
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const positionBuffer = gl.createBuffer();
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// Select the positionBuffer as the one to apply buffer
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// operations to from here out.
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gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
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// Now create an array of positions for the cube.
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const positions = [
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// Front face
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-1.0, -1.0, 1.0,
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1.0, -1.0, 1.0,
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1.0, 1.0, 1.0,
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-1.0, 1.0, 1.0,
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// Back face
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-1.0, -1.0, -1.0,
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-1.0, 1.0, -1.0,
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1.0, 1.0, -1.0,
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1.0, -1.0, -1.0,
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// Top face
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-1.0, 1.0, -1.0,
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-1.0, 1.0, 1.0,
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1.0, 1.0, 1.0,
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1.0, 1.0, -1.0,
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// Bottom face
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-1.0, -1.0, -1.0,
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1.0, -1.0, -1.0,
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1.0, -1.0, 1.0,
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-1.0, -1.0, 1.0,
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// Right face
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1.0, -1.0, -1.0,
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1.0, 1.0, -1.0,
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1.0, 1.0, 1.0,
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1.0, -1.0, 1.0,
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// Left face
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-1.0, -1.0, -1.0,
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-1.0, -1.0, 1.0,
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-1.0, 1.0, 1.0,
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-1.0, 1.0, -1.0,
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];
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// Now pass the list of positions into WebGL to build the
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// shape. We do this by creating a Float32Array from the
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// JavaScript array, then use it to fill the current buffer.
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gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);
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// Set up the normals for the vertices, so that we can compute lighting.
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const normalBuffer = gl.createBuffer();
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gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
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const vertexNormals = [
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// Front
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0.0, 0.0, 1.0,
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0.0, 0.0, 1.0,
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0.0, 0.0, 1.0,
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0.0, 0.0, 1.0,
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// Back
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0.0, 0.0, -1.0,
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0.0, 0.0, -1.0,
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0.0, 0.0, -1.0,
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0.0, 0.0, -1.0,
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// Top
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0.0, 1.0, 0.0,
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0.0, 1.0, 0.0,
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0.0, 1.0, 0.0,
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0.0, 1.0, 0.0,
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// Bottom
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0.0, -1.0, 0.0,
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0.0, -1.0, 0.0,
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0.0, -1.0, 0.0,
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0.0, -1.0, 0.0,
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// Right
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1.0, 0.0, 0.0,
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1.0, 0.0, 0.0,
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1.0, 0.0, 0.0,
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1.0, 0.0, 0.0,
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// Left
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-1.0, 0.0, 0.0,
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-1.0, 0.0, 0.0,
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-1.0, 0.0, 0.0,
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-1.0, 0.0, 0.0
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];
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gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertexNormals),
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gl.STATIC_DRAW);
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// Now set up the texture coordinates for the faces.
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const textureCoordBuffer = gl.createBuffer();
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gl.bindBuffer(gl.ARRAY_BUFFER, textureCoordBuffer);
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const textureCoordinates = [
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// Front
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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// Back
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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// Top
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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// Bottom
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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// Right
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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// Left
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0.0, 0.0,
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1.0, 0.0,
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1.0, 1.0,
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0.0, 1.0,
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];
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gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoordinates),
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gl.STATIC_DRAW);
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// Build the element array buffer; this specifies the indices
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// into the vertex arrays for each face's vertices.
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const indexBuffer = gl.createBuffer();
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gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
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// This array defines each face as two triangles, using the
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// indices into the vertex array to specify each triangle's
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// position.
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const indices = [
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0, 1, 2, 0, 2, 3, // front
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4, 5, 6, 4, 6, 7, // back
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8, 9, 10, 8, 10, 11, // top
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12, 13, 14, 12, 14, 15, // bottom
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16, 17, 18, 16, 18, 19, // right
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20, 21, 22, 20, 22, 23, // left
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];
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// Now send the element array to GL
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gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,
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new Uint16Array(indices), gl.STATIC_DRAW);
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return {
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position: positionBuffer,
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normal: normalBuffer,
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textureCoord: textureCoordBuffer,
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indices: indexBuffer,
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};
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}
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function elem(id) {
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return document.getElementById(id);
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}
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// Upload content of a ktxTexture to WebGL.
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//
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// Returns the created WebGL texture object and matching texture target.
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//
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// needs Emscripten's OpenGL ES emulation.
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function uploadTextureToGl(gl, ktexture) {
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const { transcode_fmt } = ktx;
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var formatString;
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if (ktexture.needsTranscoding) {
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var format;
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if (astcSupported) {
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formatString = 'ASTC';
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format = transcode_fmt.ASTC_4x4_RGBA;
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} else if (dxtSupported) {
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formatString = ktexture.numComponents == 4 ? 'BC3' : 'BC1';
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format = transcode_fmt.BC1_OR_3;
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} else if (pvrtcSupported) {
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formatString = 'PVRTC1';
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format = transcode_fmt.PVRTC1_4_RGBA;
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} else if (etcSupported) {
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formatString = 'ETC';
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format = transcode_fmt.ETC;
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} else {
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formatString = 'RGBA4444';
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format = transcode_fmt.RGBA4444;
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}
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if (ktexture.transcodeBasis(format, 0) != ktx.error_code.SUCCESS) {
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alert('Texture transcode failed. See console for details.');
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return undefined;
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}
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}
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const result = ktexture.glUpload();
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if (result.error != gl.NO_ERROR) {
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alert('WebGL error when uploading texture, code = '
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+ result.error.toString(16));
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return undefined;
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}
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if (result.object === undefined) {
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alert('Texture upload failed. See console for details.');
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return undefined;
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}
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if (result.target != gl.TEXTURE_2D) {
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alert('Loaded texture is not a TEXTURE2D.');
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return undefined;
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}
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return {
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target: result.target,
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object: result.object,
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format: formatString,
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uvMatrix: null
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}
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}
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function createPlaceholderTexture(gl, color)
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{
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// // Must create texture via Emscripten so it knows of it.
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// var texName;
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// ktx.GL._glGenTextures(1, texName);
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// texture = ktx.GL.textures[texName];
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// Since it doesn't seem possible to get the above to work
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// use a placeholder WebGLTexture object for a temporary
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// image.
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const placeholder = gl.createTexture();
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gl.bindTexture(gl.TEXTURE_2D, placeholder);
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const level = 0;
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const internalFormat = gl.RGBA;
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const width = 1;
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const height = 1;
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const border = 0;
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const srcFormat = gl.RGBA;
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const srcType = gl.UNSIGNED_BYTE;
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const pixel = new Uint8Array(color);
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gl.texImage2D(gl.TEXTURE_2D, level, internalFormat,
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width, height, border, srcFormat, srcType,
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pixel);
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return {
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target: gl.TEXTURE_2D,
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object: placeholder,
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format: "",
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uvMatrix: mat3.create()
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};
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}
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//
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// Sets the uvMatrix for a texture.
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//
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// The WebGL texture object is expected to have been created from the
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// content of the ktxTexture object. The matrix is adjusted according
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// to the orientation in the ktxTexture object.
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//
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function setUVMatrix(texture, inMatrix, ktexture) {
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texture.uvMatrix = inMatrix;
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if (ktexture.orientation.x == ktx.OrientationX.LEFT) {
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mat3.translate(texture.uvMatrix, texture.uvMatrix, [1.0, 0.0]);
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mat3.scale(texture.uvMatrix, texture.uvMatrix, [-1.0, 1.0]);
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}
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if (ktexture.orientation.y == ktx.OrientationY.DOWN) {
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mat3.translate(texture.uvMatrix, texture.uvMatrix, [0.0, 1.0]);
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mat3.scale(texture.uvMatrix, texture.uvMatrix, [1.0, -1.0]);
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}
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}
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//
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// Binds a texture and sets suitable texture parameters.
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//
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// The WebGL texture object is expected to have been created from the
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// content of the ktxTexture object.
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//
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function setTexParameters(texture, ktexture) {
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gl.bindTexture(texture.target, texture.object);
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if (ktexture.numLevels > 1 || ktexture.generateMipmaps) {
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// Enable bilinear mipmapping.
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gl.texParameteri(texture.target,
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gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
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} else {
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gl.texParameteri(texture.target, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
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}
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gl.texParameteri(texture.target, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
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gl.bindTexture(texture.target, null);
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}
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function loadTexture(gl, url)
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{
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// Because images have to be downloaded over the internet
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// they might take a moment until they are ready. Until
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// then temporarily fill the texture with a single pixel image
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// so we can use it immediately. When the image has finished
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// downloading we'll update texture to the new contents
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const placeholder = createPlaceholderTexture(gl, [0, 0, 255, 255]);
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gl.bindTexture(placeholder.target, placeholder.object);
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var xhr = new XMLHttpRequest();
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xhr.open('GET', url);
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xhr.responseType = "arraybuffer";
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xhr.onload = function(){
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var ktxdata = new Uint8Array(this.response);
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ktexture = new ktx.texture(ktxdata);
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const tex = uploadTextureToGl(gl, ktexture);
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setUVMatrix(tex, mat3.create(), ktexture);
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setTexParameters(tex, ktexture);
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gl.bindTexture(tex.target, tex.object);
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gl.deleteTexture(texture.object);
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texture = tex;
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elem('format').innerText = tex.format;
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ktexture.delete();
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};
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//xhr.onprogress = runProgress;
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//xhr.onloadstart = openProgress;
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xhr.send();
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return placeholder;
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}
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function isPowerOf2(value) {
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return (value & (value - 1)) == 0;
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}
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//
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// Draw the scene.
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//
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function drawScene(gl, programInfo, buffers, texture, deltaTime) {
|
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gl.enable(gl.CULL_FACE);
|
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gl.enable(gl.DEPTH_TEST);
|
|
gl.enable(gl.DEPTH_TEST); // Enable depth testing
|
|
gl.depthFunc(gl.LEQUAL); // Near things obscure far things
|
|
|
|
// In case the source image has translucent parts ...
|
|
gl.enable(gl.BLEND);
|
|
gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
|
|
|
|
gl.clearColor(0.0, 0.0, 0.0, 1.0); // Clear to black, fully opaque
|
|
gl.clearDepth(1.0); // Clear everything
|
|
|
|
// Clear the canvas before we start drawing on it.
|
|
|
|
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
|
|
|
|
// Create a perspective matrix, a special matrix that is
|
|
// used to simulate the distortion of perspective in a camera.
|
|
// Our field of view is 45 degrees, with a width/height
|
|
// ratio that matches the display size of the canvas
|
|
// and we only want to see objects between 0.1 units
|
|
// and 100 units away from the camera.
|
|
|
|
const fieldOfView = 45 * Math.PI / 180; // in radians
|
|
const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
|
|
const zNear = 0.1;
|
|
const zFar = 100.0;
|
|
const projectionMatrix = mat4.create();
|
|
|
|
// note: glmatrix.js always has the first argument
|
|
// as the destination to receive the result.
|
|
mat4.perspective(projectionMatrix,
|
|
fieldOfView,
|
|
aspect,
|
|
zNear,
|
|
zFar);
|
|
|
|
// Set the drawing position to the "identity" point, which is
|
|
// the center of the scene.
|
|
const modelViewMatrix = mat4.create();
|
|
|
|
// Now move the drawing position a bit to where we want to
|
|
// start drawing the square.
|
|
|
|
mat4.translate(modelViewMatrix, // destination matrix
|
|
modelViewMatrix, // matrix to translate
|
|
[-0.0, 0.0, -6.0]); // amount to translate
|
|
mat4.rotate(modelViewMatrix, // destination matrix
|
|
modelViewMatrix, // matrix to rotate
|
|
cubeRotation, // amount to rotate in radians
|
|
[0, 0, 1]); // axis to rotate around (Z)
|
|
mat4.rotate(modelViewMatrix, // destination matrix
|
|
modelViewMatrix, // matrix to rotate
|
|
cubeRotation * .7,// amount to rotate in radians
|
|
[0, 1, 0]); // axis to rotate around (X)
|
|
|
|
const normalMatrix = mat4.create();
|
|
mat4.invert(normalMatrix, modelViewMatrix);
|
|
mat4.transpose(normalMatrix, normalMatrix);
|
|
|
|
// Tell WebGL how to pull out the positions from the position
|
|
// buffer into the vertexPosition attribute
|
|
{
|
|
const numComponents = 3;
|
|
const type = gl.FLOAT;
|
|
const normalize = false;
|
|
const stride = 0;
|
|
const offset = 0;
|
|
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.position);
|
|
gl.vertexAttribPointer(
|
|
programInfo.attribLocations.vertexPosition,
|
|
numComponents,
|
|
type,
|
|
normalize,
|
|
stride,
|
|
offset);
|
|
gl.enableVertexAttribArray(
|
|
programInfo.attribLocations.vertexPosition);
|
|
}
|
|
|
|
// Tell WebGL how to pull out the texture coordinates from
|
|
// the texture coordinate buffer into the textureCoord attribute.
|
|
{
|
|
const numComponents = 2;
|
|
const type = gl.FLOAT;
|
|
const normalize = false;
|
|
const stride = 0;
|
|
const offset = 0;
|
|
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.textureCoord);
|
|
gl.vertexAttribPointer(
|
|
programInfo.attribLocations.textureCoord,
|
|
numComponents,
|
|
type,
|
|
normalize,
|
|
stride,
|
|
offset);
|
|
gl.enableVertexAttribArray(
|
|
programInfo.attribLocations.textureCoord);
|
|
}
|
|
|
|
// Tell WebGL how to pull out the normals from
|
|
// the normal buffer into the vertexNormal attribute.
|
|
{
|
|
const numComponents = 3;
|
|
const type = gl.FLOAT;
|
|
const normalize = false;
|
|
const stride = 0;
|
|
const offset = 0;
|
|
gl.bindBuffer(gl.ARRAY_BUFFER, buffers.normal);
|
|
gl.vertexAttribPointer(
|
|
programInfo.attribLocations.vertexNormal,
|
|
numComponents,
|
|
type,
|
|
normalize,
|
|
stride,
|
|
offset);
|
|
gl.enableVertexAttribArray(
|
|
programInfo.attribLocations.vertexNormal);
|
|
}
|
|
|
|
// Tell WebGL which indices to use to index the vertices
|
|
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffers.indices);
|
|
|
|
// Tell WebGL to use our program when drawing
|
|
|
|
gl.useProgram(programInfo.program);
|
|
|
|
// Set the shader uniforms
|
|
|
|
gl.uniformMatrix4fv(
|
|
programInfo.uniformLocations.projectionMatrix,
|
|
false,
|
|
projectionMatrix);
|
|
gl.uniformMatrix4fv(
|
|
programInfo.uniformLocations.modelViewMatrix,
|
|
false,
|
|
modelViewMatrix);
|
|
gl.uniformMatrix4fv(
|
|
programInfo.uniformLocations.normalMatrix,
|
|
false,
|
|
normalMatrix);
|
|
gl.uniformMatrix3fv(
|
|
programInfo.uniformLocations.uvMatrix,
|
|
false,
|
|
texture.uvMatrix);
|
|
|
|
// Specify the texture to map onto the faces.
|
|
|
|
// Tell WebGL we want to affect texture unit 0
|
|
gl.activeTexture(gl.TEXTURE0);
|
|
|
|
// Bind the texture to texture unit 0
|
|
gl.bindTexture(texture.target, texture.object);
|
|
|
|
// Tell the shader we bound the texture to texture unit 0
|
|
gl.uniform1i(programInfo.uniformLocations.uSampler, 0);
|
|
|
|
{
|
|
const vertexCount = 36;
|
|
const type = gl.UNSIGNED_SHORT;
|
|
const offset = 0;
|
|
gl.drawElements(gl.TRIANGLES, vertexCount, type, offset);
|
|
}
|
|
|
|
// Update the rotation for the next draw
|
|
|
|
cubeRotation += deltaTime;
|
|
}
|
|
|
|
//
|
|
// Initialize a shader program, so WebGL knows how to draw our data
|
|
//
|
|
function initShaderProgram(gl, vsSource, fsSource) {
|
|
const vertexShader = loadShader(gl, gl.VERTEX_SHADER, vsSource);
|
|
const fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fsSource);
|
|
|
|
// Create the shader program
|
|
|
|
const shaderProgram = gl.createProgram();
|
|
gl.attachShader(shaderProgram, vertexShader);
|
|
gl.attachShader(shaderProgram, fragmentShader);
|
|
gl.linkProgram(shaderProgram);
|
|
|
|
// If creating the shader program failed, alert
|
|
|
|
if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
|
|
alert('Unable to initialize the shader program: ' + gl.getProgramInfoLog(shaderProgram));
|
|
return null;
|
|
}
|
|
|
|
return shaderProgram;
|
|
}
|
|
|
|
//
|
|
// creates a shader of the given type, uploads the source and
|
|
// compiles it.
|
|
//
|
|
function loadShader(gl, type, source) {
|
|
const shader = gl.createShader(type);
|
|
|
|
// Send the source to the shader object
|
|
|
|
gl.shaderSource(shader, source);
|
|
|
|
// Compile the shader program
|
|
|
|
gl.compileShader(shader);
|
|
|
|
// See if it compiled successfully
|
|
|
|
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
|
|
alert('An error occurred compiling the shaders: ' + gl.getShaderInfoLog(shader));
|
|
gl.deleteShader(shader);
|
|
return null;
|
|
}
|
|
|
|
return shader;
|
|
}
|
|
|