Creating 3D geometries in webGL and p5.js is a powerful way to create interactive and visually interesting web applications. With the ability to create basic shapes, add textures, lighting, and materials, and transform 3D geometries, we can create a wide range of 3D graphics and animations. By understanding the basics of webGL and p5.js, we can create stunning 3D geometries for their web applications.
The first step is to generate some 3D geometries using webGL and p5.js built-in functions. These shapes can be produced using the library's built-in methods, such as sphere(), box(), and cylinder().
在webGL中，gl.drawArrays()函数可以用来构建基本形状。这个函数有三个输入参数，分别是基本图元类型、起始索引和要显示的索引数。例如，要创建一个球体，我们可以使用gl.TRIANGLES基本图元类型，并传入球体的顶点和索引。
<!DOCTYPE html>
<html>
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/110/three.min.js"></script>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
// Set up the scene
const scene = new THREE.Scene();
// Set up the camera
const camera = new THREE.PerspectiveCamera(
75,
window.innerWidth / window.innerHeight,
0.1,
1000
);
camera.position.z = 5;
// Set up the renderer
const renderer = new THREE.WebGLRenderer({
canvas: document.getElementById("canvas"),
});
renderer.setSize(window.innerWidth, window.innerHeight);
// Create the sphere
const sphereGeometry = new THREE.SphereGeometry(1, 32, 32);
const sphereMaterial = new THREE.MeshBasicMaterial({ color: 0xffff00 });
const sphere = new THREE.Mesh(sphereGeometry, sphereMaterial);
scene.add(sphere);
// Render the scene
renderer.render(scene, camera);
</script>
</body>
</html>
The createShape() function in p5.js can be used to make simple shapes. The CreateShape() function takes a single parameter i.e., “ the type of shape to be created”. To make a sphere, for example, we can use the createShape(SPHERE) method.
<!DOCTYPE html>
<html>
<head>
<title>3D Sphere Example</title>
<script src="https://cdn.jsdelivr.net/npm/p5@1.1.9/lib/p5.min.js"></script>
</head>
<body>
<script>
function setup() {
createCanvas(windowWidth, windowHeight, WEBGL);
}
function draw() {
background(200);
// Create the sphere
push();
fill(255, 0, 0);
sphere(150);
pop();
}
</script>
</body>
</html>
在生成了我们的3D设计之后，我们可以添加纹理来使它们更具吸引力。在webGL和p5.js中，可以分别使用gl.texImage2D()和texture() API将纹理应用于形状。
The gl.texImage2D() function in webGL is used to generate a 2D texture from an image file. This function accepts lots of arguments, including the target, level of detail, internal format, image width and height, and image data format and type.
<html>
<head>
<script src="https://cdn.jsdelivr.net/npm/three@0.115.0/build/three.min.js"></script>
</head>
<body>
<script>
// Set up the scene
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(
75,
window.innerWidth / window.innerHeight,
0.1,
1000
);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
// Create a cube
var geometry = new THREE.BoxGeometry(3, 3, 3);
var texture = new THREE.TextureLoader().load("https://images.pexels.com/photos/1029604/pexels-photo-1029604.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1");
var material = new THREE.MeshBasicMaterial({ map: texture });
var cube = new THREE.Mesh(geometry, material);
scene.add(cube);
// Position the camera
camera.position.z = 5;
// Render the scene
function render() {
requestAnimationFrame(render);
cube.rotation.x += 0.01;
cube.rotation.y += 0.01;
renderer.render(scene, camera);
}
render();
</script>
</body>
</html>
在p5.js中，texture()函数用于将纹理应用到一个对象上。texture()函数接受一个参数：纹理图像文件。
<html>
<head>
<title>p5.js Texture Example</title>
<script src="https://cdn.jsdelivr.net/npm/p5"></script>
<script src="https://cdn.jsdelivr.net/npm/p5/lib/addons/p5.dom.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/p5/lib/addons/p5.sound.min.js"></script>
</head>
<body>
<script>
let img;
function preload() {
img = loadImage("https://images.pexels.com/photos/1029604/pexels-photo-1029604.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1");
}
function setup() {
createCanvas(650, 300, WEBGL);
noStroke();
}
function draw() {
background(200);
texture(img);
rotateX(frameCount * 0.01);
rotateY(frameCount * 0.01);
box(100);
}
</script>
</body>
</html>
We applied WebGL and p5.js to build 3D geometry and applied animation in our web apps. We discussedsome basic concepts of creating 3D geometries in webGL and p5.js, including shapes, textures, lighting, and more.
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