WebGL之三维正射投影(高级)

Posted on 2024年1月30日2024年1月30日 by hackdl

一，前言

1，绘制一个正方体的数据，我们以前，上，右逆时针绘制，对面的用顺时针绘制。

2, 数据准备 cubeModel.js

/**
 * 获得正方体所有顶点位置
 * @param sideLength 边长
 */
window.getCubeVertexesPosition = (sideLength) => {
    //前
    const FRONT = [
        0.0, 0.0, 0.0,
        sideLength, 0.0, 0.0,
        0.0, sideLength, 0.0,
        0.0, sideLength, 0.0,
        sideLength, 0.0, 0.0,
        sideLength, sideLength, 0.0
    ];
    //上
    const TOP = [
        0.0, sideLength, 0.0,
        sideLength, sideLength, 0.0,
        0.0, si服务器托管网deLength, sideLength,
        0.0, sideLength, sideLength,
        sideLength, sideLength, 0.0,
        sideLength, sideLength, sideLength
    ];
    //右
    const RIGHT = [
        sideLength, 0.0, 0.0,
        sideLength, 0.0, sideLength,
        sideLength, sideLength, 0.0,
        sideLength, sideLength, 0.0,
        sideLength, 0.0, sideLength,
        sideLength, sideLength, sideLength
    ];
    //后
    const REAR = [
        0.0, 0.0, sideLength,
        0.0, sideLength, sideLength,
        sideLength, 0.0, sideLength,
        sideLength, 0.0, sideLength,
        0.0, sideLength, sideLength,
        sideLength, sideLength, sideLength
    ];
    //左
    const LEFT = [
        0.0, 0.0, 0.0,
        0.0, sideLength, 0.0,
        0.0, 0.0, sideLength,
        0.0, 0.0, sideLength,
        0.0, sideLength, 0.0,
        0.0, sideLength, sideLength
    ];
    //下
    const BOTTOM = [
        0.0, 0.0, 0.0,
        0.0, 0.0, sideLength,
        sideLength, 0.0, 0.0,
        sideLength, 0.0, 0.0,
        0.0, 0.0, sideLength,
        sideLength, 0.0, sideLength
    ];
    let data = [];
    return data.concat(FRONT, TOP, RIGHT, REAR, BOTTOM, LEFT);
};
/**
 * 获得cube的纹理坐标
 */
window.getCubeTexcoord = () => {
    const TEXCOORD = [
        0.0, 0.0, 0.0,
        1.0, 0.0, 0.0,
        0.0, 1.0, 0.0,
        0.0, 1.0, 0.0,
        1.0, 0.0, 0.0,
        1.0, 1.0, 0.0
    ];
    let data = [];
    return data.concat(TEXCOORD, TEXCOORD, TEXCOORD, TEXCOORD, TEXCOORD, TEXCOORD);//6x6个点的纹理贴图坐标
};
//红橙黄绿蓝靛 (每个面的颜色值) RGBA
window.getCubeColors = () => {
    const FRONT = [1.0, 0.0, 0.0, 0.9];//红
    const TOP = [1.0, 0.55, 0.0, 0.9];//橙
    const RIGHT = [1.0, 1.0, 0.0, 0.9];//黄
    const REAR = [0.0, 1.0, 0.0, 0.9];//绿
    const BOTTOM = [0.0, 0.0, 1.0, 0.9];//蓝
    const LEFT = [0.0, 1.0, 1.0, 0.9];//靛
    let data = [];
    data = data.concat(FRONT, FRONT, FRONT, FRONT, FRONT, FRONT);
    data = data.concat(TOP, TOP, TOP, TOP, TOP, TOP);
    data = data.concat(RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT);
    data = data.concat(REAR, REAR, REAR, REAR, REAR, REAR);
    data = data.concat(BOTTOM, BOTTOM, BOTTOM, BOTTOM, BOTTOM, BOTTOM);
    data = data.concat(LEFT, LEFT, LEFT, LEFT, LEFT, LEFT);
    return data;//6X6个点的颜色值
}

二， index.html


	
	
	
		attribute vec4 a_position;
		attribute vec2 a_texCoord;
		attribute vec4 a_color;
		uniform mat4 u_matrix;//2D变换矩阵
		varying vec2 v_texCoord;
		varying vec4 v_color;//颜色值，每个面用不同的颜色值
		
		void main(){
			v_texCoord = a_texCoord;
			v_color = a_color;
			gl_Position = u_matrix * a_position;
		}

	
		precision mediump float;
		uniform sampler2D u_image;
		varying vec2 v_texCoord;
		varying vec4 v_color;
		void main(){
			gl_FragColor = texture2D(u_image, v_texCoord) * v_color;
		}

三， shaderUtil.js

window.angle2Radian = (angle) => {
    const angleInRadians = angle * Math.PI / 180;
    return angleInRadians;
}

window.radian2Angle = (radian) => {
    const angle = radian * 180 / Math.PI;
    return angle;
}

window.getCS = (radian) => {
    return {
        cos: Math.cos(radian),
        sin: Math.sin(radian)
    };
}

/**
 * 2D变换
 */
window.m3 = {
    projection: (width, height) => {
        // 注意：这个矩阵翻转了 Y 轴，所以 0 在上方
        return [
            2 / width, 0, 0,
            0, -2 / height, 0,
            -1, 1, 1
        ];
    },
    translation: (tx, ty) => {
        return [
            1, 0, 0,
            0, 1, 0,
            tx, ty, 1,
        ];
    },

    rotation: (angle) => {
        const data = getCS(angle2Radian(angle));
        return [
            data.cos, -data.sin, 0,
            data.sin, data.cos, 0,
            0, 0, 1,
        ];
    },

    scaling: (sx, sy) => {
        return [
            sx, 0, 0,
            0, sy, 0,
            0, 0, 1,
        ];
    },

    translate: (m, tx, ty) => {
        return m3.multiply(m, m3.translation(tx, ty));
    },
    rotate: (m, angle) => {
        return m3.multiply(m, m3.rotation(angle));
    },
    scale: (m, sx, sy) => {
        return m3.multiply(m, m3.scaling(sx, sy));
    },

    multiply: (a, b) => {
        const a00 = a[0 * 3 + 0];
        const a01 = a[0 * 3 + 1];
        const a02 = a[0 * 3 + 2];
        const a10 = a[1 * 3 + 0];
        const a11 = a[1 * 3 + 1];
        const a12 = a[1 * 3 + 2];
        const a20 = a[2 * 3 + 0];
        const a21 = a[2 * 3 + 1];
        const a22 = a[2 * 3 + 2];
        const b00 = b[0 * 3 + 0];
        const b01 = b[0 * 3 + 1];
        const b02 = b[0 * 3 + 2];
        const b10 = b[1 * 3 + 0];
        const b11 = b[1 * 3 + 1];
        const b12 = b[1 * 3 + 2];
        const b20 = b[2 * 3 + 0];
        const b21 = b[2 * 3 + 1];
        const b22 = b[2 * 3 + 2];
        return [
            b00 * a00 + b01 * a10 + b02 * a20,
            b00 * a01 + b01 * a11 + b02 * a21,
            b00 * a02 + b01 * a12 + b02 * a22,
            b10 * a00 + b11 * a10 + b12 * a20,
            b10 * a01 + b11 * a11 + b12 * a21,
            b10 * a02 + b11 * a12 + b12 * a22,
            b20 * a00 + b21 * a10 + b22 * a20,
            b20 * a01 + b21 * a11 + b22 * a21,
            b20 * a02 + b21 * a12 + b22 * a22,
        ];
    },
};
/**
 * 3D变换
 */
window.m4 = {
    projection: (width, height, depth) => {
        // 注意：这个矩阵翻转了 Y 轴，所以 0 在上方
        return [
            2 / width, 0, 0, 0,
            0, -2 / height, 0, 0,
            0, 0, 2 / depth, 0,
            -1, 1, 0, 1,
        ];
    },
    translation: (tx, ty, tz) => {
        return [
            1, 0, 0, 0,
            0, 1, 0, 0,
            0, 0, 1, 0,
            tx, ty, tz, 1,

        ];
    },
    xRotation: (angle) => {
        const data = getCS(angle2Radian(angle));
        return [
            1, 0, 0, 0,
            0, data.cos, data.sin, 0,
            0, -data.sin, data.cos, 0,
            0, 0, 0, 1,
        ];
    },

    yRotation: (angle) => {
        const data = getCS(angle2Radian(angle));
        return [
            data.cos, 0, -data.sin, 0,
            0, 1, 0, 0,
            data.sin, 0, data.cos, 0,
            0, 0, 0, 1,
        ];
    },

    zRotation: (angle) => {
        const data = getCS(angle2Radian(angle));
        return [
            data.cos, data.sin, 0, 0,
            -data.sin, data.cos, 0, 0,
            0, 0, 1, 0,
            0, 0, 0, 1,
        ];
    },

    scaling: (sx, sy, sz) => {
        return [
            sx, 0, 0, 0,
            0, sy, 0, 0,
            0, 0, sz, 0,
            0, 0, 0, 1
        ];
    },

    translate: (m, tx, ty, tz) => {
        return m4.multiply(m, m4.translation(tx, ty, tz));
    },
    xRotate: (m, angle) => {
        return m4.multiply(m, m4.xRotation(angle));
    },
    yRotate: (m, angle) => {
        return m4.multiply(m, m4.yRotation(angle));
    },
    zRotate: (m, angle) => {
        return m4.multiply(m, m4.zRotation(angle));
    },
    scale: (m, sx, sy, sz) => {
        return m4.multiply(m, m4.scaling(sx, sy, sz));
    },

    multiply: (a, b) => {
        const a00 = a[0 * 4 + 0];
        const a01 = a[0 * 4 + 1];
        const a02 = a[0 * 4 + 2];
        const a03 = a[0 * 4 + 3];
        const a10 = a[1 * 4 + 0];
        const a11 = a[1 * 4 + 1];
        const a12 = a[1 * 4 + 2];
        const a13 = a[1 * 4 + 3];
        const a20 = a[2 * 4 + 0];
        const a21 = a[2 * 4 + 1];
        const a22 = a[2 * 4 + 2];
        const a23 = a[2 * 4 + 3];
        const a30 = a[3 * 4 + 0];
        const a31 = a[3 * 4 + 1];
        const a32 = a[3 * 4 + 2];
        const a33 = a[3 * 4 + 3];
        const b00 = b[0 * 4 + 0];
        const b01 = b[0 * 4 + 1];
        const b02 = b[0 * 4 + 2];
        const b03 = b[0 * 4 + 3];
        const b10 = b[1 * 4 + 0];
        const b11 = b[1 * 4 + 1];
        const b12 = b[1 * 4 + 2];
        const b13 = b[1 * 4 + 3];
        const b20 = b[2 * 4 + 0];
        const b21 = b[2 * 4 + 1];
        const b22 = b[2 * 4 + 2];
        const b23 = b[2 * 4 + 3];
        const b30 = b[3 * 4 + 0];
        const b31 = b[3 * 4 + 1];
        const b32 = b[3 * 4 + 2];
        const b33 = b[3 * 4 + 3];
        return [
            b00 * a00 + b01 * a10 + b02 * a20 + b03 * a30,
            b00 * a01 + b01 * a11 + b02 * a21 + b03 * a31,
            b00 * a02 + b01 * a12 + b02 * a22 + b03 * a32,
            b00 * a03 + b01 * a13 + b02 * a23 + b03 * a33,
            b10 * a00 + b11 * a10 + b12 * a20 + b13 * a30,
            b10 * a01 + b11 * a11 + b12 * a21 + b13 * a31,
            b10 * a02 + b11 * a12 + b12 * a22 + b13 * a32,
            b10 * a03 + b11 * a13 + b12 * a23 + b13 * a33,
            b20 * a00 + b21 * a10 + b22 * a20 + b23 * a30,
            b20 * a01 + b21 * a11 + b22 * a21 + b23 * a31,
            b20 * a02 + b21 * a12 + b22 * a22 + b23 * a32,
            b20 * a03 + b21 * a13 + b22 * a23 + b23 * a33,
            b30 * a00 + b31 * a10 + b32 * a20 + b33 * a30,
            b30 * a01 + b31 * a11 + b32 * a21 + b33 * a31,
            b30 * a02 + b31 * a12 + b32 * a22 + b33 * a32,
            b30 * a03 + b31 * a13 + b32 * a23 + b33 * a33,
        ];
    },
};

四， shader.js

/**
 * 加载图片
 * @param imageName
 * @param pork
 * @param callback
 */
function loadImage(imageName, pork, callback) {
    const image = new Image();
    image.src = "http://127.0.0.1:" + pork + "/WebGLDemo/textures/" + imageName;
    image.onload = () => {
        callback(image);
    };
}


function setTexture(gl, image) {
    const texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST); //gl.LINEAR
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR); //gl.NEAREST
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
}

function setCube(gl, sideLength) {
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(getCubeVertexesPosition(sideLength)), gl.STATIC_DRAW);
}


/**
 * 获得绘图上下文gl WebGLRenderingContext
 * @param {Object} width
 * @param {Object} height
 */
function getWebGLRenderingContext(width, height) {
    const canvas = document.createElement("canvas");
    document.getElementsByTagName("body")[0].appendChild(canvas);

    canvas.width = width;
    canvas.height = height;

    const gl = canvas.getContext("webgl");
    if (!gl) {
        console.log("%c不支持webgl", "color:#F00");
        return null;
    }
    return gl;
}

function getShaderSource(isVertex) {
    let source;
    if (isVertex) {
        source = document.querySelector("#vertex-shader-2d").text;
    } else {
        source = document.querySelector("#fragment-shader-2d").text;
    }
    return source;
}

/**
 * @param {Object} gl WebGLReanderingContext
 * @param {Object} type gl.VERTEX_SHADER/gl.FRAGMENT_SHADER
 * @param {Object} source source string
 */
function createShader(gl, type, source) {
    const shader = gl.createShader(type); //创建相关类型的shader
    gl.shaderSource(shader, source); //提供shader的资源
    gl.compileShader(shader); //编译shader
    const success = gl.getShaderParameter(shader, gl.COMPILE_STATUS);
    if (success) {
        return shader;
    }
    console.log(gl.getShaderInfoLog(shader));
    gl.deleteShader(shader);
}

/**
 * 链接（link）2个shader，得到着色程序program
 * @param {Object} gl WebGLReanderingContext
 * @param {Object} vertexShader 顶点着色器
 * @param {Object} fragmentShader 片段着色器
 */
function createProgram(gl, vertexShader, fragmentShader) {
    const program = gl.createProgram();
    gl.attachShader(program, vertexShader);
    gl.attachShader(program, fragmentShader);
    gl.linkProgram(program);
    const success = gl.getProgramParameter(program, gl.LINK_STATUS);
    if (success) {
        return program;
    }
    console.log(gl.getProgramInfoLog(program));
    gl.deleteProgram(program);
}

function render(gl, program, image) {
    const positionAttributeLocation = gl.getAttribLocation(program, "a_position");
    const texCoordAttributeLocation = gl.getAttribLocation(program, "a_texCoord");
    const colorAttributeLocation = gl.getAttribLocation(program, "a_color");
    const matrixUniformLocation = gl.getUniformLocation(program, "u_matrix");

    const positionBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
    const MAX_SIDE_LENGTH = Math.max(image.width, image.height);
    setCube(gl, MAX_SIDE_LENGTH); //正方体


    const texCoordBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(getCubeTexcoord()), gl.STATIC_DRAW);

    const colorBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, colorBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(getCubeColors()), gl.STATIC_DRAW);

    //开始渲染
    gl.viewport(0, 0, gl.canvas.clientWidth, gl.canvas.clientHeight);
    gl.clearColor(0, 0, 0, 0);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    gl.enable(gl.CULL_FACE);//剔除背面
    gl.enable(gl.DEPTH_TEST);//服务器托管网开启深度测试
    gl.useProgram(program);


    gl.enableVertexAttribArray(positionAttributeLocation);
    gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
    const size = 3; //每次迭代运行提取3个单位数据
    const type = gl.FLOAT; //每个单位数据是32位的浮点数
    const normaliza = false; //不需要归一化数据
    const stride = 0; //0 = 移动单位数量 * 每个单位占用的内存（sizeof(type)）
    const offset = 0; //每次迭代运行运动多少内存到下一个数据开始点,从缓冲起始位置开始读取
    gl.vertexAttribPointer(positionAttributeLocation, size, type, normaliza, stride, offset);

    gl.enableVertexAttribArray(texCoordAttributeLocation);
    gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
    gl.vertexAttribPointer(texCoordAttributeLocation, 3, gl.FLOAT, false, 0, 0);

    gl.enableVertexAttribArray(colorAttributeLocation);
    gl.bindBuffer(gl.ARRAY_BUFFER, colorBuffer);
    gl.vertexAttribPointer(colorAttributeLocation, 4, gl.FLOAT, false, 0, 0);//RGBA 4个数据


    setTexture(gl, image); //设置贴图


    const primitiveType = gl.TRIANGLES; //绘制三角形
    const pOffset = 0; //从第一个点开始绘制
    const count = 6 * 6; //一个面绘制6次,总共有6个面 36个点
    let matrix;
    let scale = 0.7;
    let angle = 0;
    let isScaleAdd = true;
    setInterval(() => {
        matrix = m4.projection(gl.canvas.clientWidth, gl.canvas.clientHeight, 400);
        matrix = m4.translate(matrix, 150, 200, 0);
        angle += 1;
        if (angle >= 360) {
            angle = 360 - angle;
        }
        matrix = m4.yRotate(matrix, angle);
        matrix = m4.zRotate(matrix, angle);
        if (isScaleAdd) {
            scale += 0.01;
            if (scale >= 1.4) {
                isScaleAdd = false;
            }
        } else {
            scale -= 0.01;
            if (scale  {
        render(gl, program, image);
    });
}

main();

五，效果

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