Простейшая 3D программа — различия между версиями

// Куб на чистом WebGL
// Версия 4.0 от 24.08.2014

function Main_WebGL_example() {
    var gl;

    function initGL(canvas) {
        try {
            gl = canvas.getContext("experimental-webgl");
            gl.viewportWidth = canvas.width;
            gl.viewportHeight = canvas.height;
        } catch (e) {
        }
        if (!gl) {
            alert("Could not initialise WebGL, sorry :-(");
        }
    }

    function getShader(gl, id) {
        var shaderScript = document.getElementById(id);
        if (!shaderScript) {
            return null;
        }

        var str = "";
        var k = shaderScript.firstChild;
        while (k) {
            if (k.nodeType == 3) {
                str += k.textContent;
            }
            k = k.nextSibling;
        }

        var shader;
        if (shaderScript.type == "x-shader/x-fragment") {
            shader = gl.createShader(gl.FRAGMENT_SHADER);
        } else if (shaderScript.type == "x-shader/x-vertex") {
            shader = gl.createShader(gl.VERTEX_SHADER);
        } else {
            return null;
        }

        gl.shaderSource(shader, str);
        gl.compileShader(shader);

        if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
            alert(gl.getShaderInfoLog(shader));
            return null;
        }

        return shader;
    }


    var shaderProgram;

    function initShaders() {
        var fragmentShader = getShader(gl, "shader-fs");
        var vertexShader = getShader(gl, "shader-vs");

        shaderProgram = gl.createProgram();
        gl.attachShader(shaderProgram, vertexShader);
        gl.attachShader(shaderProgram, fragmentShader);
        gl.linkProgram(shaderProgram);

        if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
            alert("Could not initialise shaders");
        }

        gl.useProgram(shaderProgram);

        shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
        gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);

        shaderProgram.textureCoordAttribute = gl.getAttribLocation(shaderProgram, "aTextureCoord");
        gl.enableVertexAttribArray(shaderProgram.textureCoordAttribute);

        shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
        shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
        shaderProgram.samplerUniform = gl.getUniformLocation(shaderProgram, "uSampler");
    }


    function handleLoadedTexture(textures) {
        gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);

        gl.bindTexture(gl.TEXTURE_2D, textures[0]);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, textures[0].image);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

        gl.bindTexture(gl.TEXTURE_2D, textures[1]);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, textures[1].image);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);

        gl.bindTexture(gl.TEXTURE_2D, textures[2]);
        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, textures[2].image);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_NEAREST);
        gl.generateMipmap(gl.TEXTURE_2D);

        gl.bindTexture(gl.TEXTURE_2D, null);
    }


    var crateTextures = Array();

    function initTexture() {
        var crateImage = new Image();

        for (var i=0; i < 3; i++) {
            var texture = gl.createTexture();
            texture.image = crateImage;
            crateTextures.push(texture);
        }

        crateImage.onload = function () {
            handleLoadedTexture(crateTextures)
        }
        crateImage.src = "teormeh.png";
    }


    var mvMatrix = mat4.create();
    var mvMatrixStack = [];
    var pMatrix = mat4.create();

    //function mvPushMatrix() {
    //    var copy = mat4.create();
    //    mat4.set(mvMatrix, copy);
    //    mvMatrixStack.push(copy);
    //}
    //
    //function mvPopMatrix() {
    //    if (mvMatrixStack.length == 0) {
    //        throw "Invalid popMatrix!";
    //    }
    //    mvMatrix = mvMatrixStack.pop();
    //}


    function setMatrixUniforms() {
        gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, pMatrix);
        gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mvMatrix);
    }


    function degToRad(degrees) {
        return degrees * Math.PI / 180;
    }


    var xRot = 0;
    var xSpeed = 0;

    var yRot = 0;
    var ySpeed = 0;

    var z = -4.0;

    var filter = 1;


    var currentlyPressedKeys = {};

    function handleKeyDown(event) {
        currentlyPressedKeys[event.keyCode] = true;

        if (String.fromCharCode(event.keyCode) == "F") {
            filter += 1;
            if (filter == 3) {
                filter = 0;
            }
        }
        if (event.keyCode == "36") {                            // TODO удалить
            mat4.identity(rotate_buf);
        }
    }


    function handleKeyUp(event) {
        currentlyPressedKeys[event.keyCode] = false;
    }


    function handleKeys() {
        if (currentlyPressedKeys[33]) {z += 0.05;}          // Page Up
        if (currentlyPressedKeys[34]) {z -= 0.05;}          // Page Down
        if (currentlyPressedKeys[37]) {ySpeed -= 2;}    // Влево
        if (currentlyPressedKeys[39]) {ySpeed += 2;}    // Вправо
        if (currentlyPressedKeys[38]) {xSpeed -= 2;}    // Вверх
        if (currentlyPressedKeys[40]) {xSpeed += 2;}    // Вниз
    }


    var cubeVertexPositionBuffer;
    var cubeVertexTextureCoordBuffer;
    var cubeVertexIndexBuffer;
    function initBuffers() {
        cubeVertexPositionBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexPositionBuffer);
        vertices = [
            // Front face
            -1.0, -1.0,  1.0,
            1.0, -1.0,  1.0,
            1.0,  1.0,  1.0,
            -1.0,  1.0,  1.0,

            // Back face
            -1.0, -1.0, -1.0,
            -1.0,  1.0, -1.0,
            1.0,  1.0, -1.0,
            1.0, -1.0, -1.0,

            // Top face
            -1.0,  1.0, -1.0,
            -1.0,  1.0,  1.0,
            1.0,  1.0,  1.0,
            1.0,  1.0, -1.0,

            // Bottom face
            -1.0, -1.0, -1.0,
            1.0, -1.0, -1.0,
            1.0, -1.0,  1.0,
            -1.0, -1.0,  1.0,

            // Right face
            1.0, -1.0, -1.0,
            1.0,  1.0, -1.0,
            1.0,  1.0,  1.0,
            1.0, -1.0,  1.0,

            // Left face
            -1.0, -1.0, -1.0,
            -1.0, -1.0,  1.0,
            -1.0,  1.0,  1.0,
            -1.0,  1.0, -1.0,
        ];
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
        cubeVertexPositionBuffer.itemSize = 3;
        cubeVertexPositionBuffer.numItems = 24;

        cubeVertexTextureCoordBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexTextureCoordBuffer);
        var textureCoords = [
            // Front face
            0.0, 0.0,
            1.0, 0.0,
            1.0, 1.0,
            0.0, 1.0,

            // Back face
            1.0, 0.0,
            1.0, 1.0,
            0.0, 1.0,
            0.0, 0.0,

            // Top face
            0.0, 1.0,
            0.0, 0.0,
            1.0, 0.0,
            1.0, 1.0,

            // Bottom face
            1.0, 1.0,
            0.0, 1.0,
            0.0, 0.0,
            1.0, 0.0,

            // Right face
            1.0, 0.0,
            1.0, 1.0,
            0.0, 1.0,
            0.0, 0.0,

            // Left face
            0.0, 0.0,
            1.0, 0.0,
            1.0, 1.0,
            0.0, 1.0,
        ];
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoords), gl.STATIC_DRAW);
        cubeVertexTextureCoordBuffer.itemSize = 2;
        cubeVertexTextureCoordBuffer.numItems = 24;

        cubeVertexIndexBuffer = gl.createBuffer();
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cubeVertexIndexBuffer);
        var cubeVertexIndices = [
            0, 1, 2,      0, 2, 3,    // Front face
            4, 5, 6,      4, 6, 7,    // Back face
            8, 9, 10,     8, 10, 11,  // Top face
            12, 13, 14,   12, 14, 15, // Bottom face
            16, 17, 18,   16, 18, 19, // Right face
            20, 21, 22,   20, 22, 23  // Left face
        ]
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(cubeVertexIndices), gl.STATIC_DRAW);
        cubeVertexIndexBuffer.itemSize = 1;
        cubeVertexIndexBuffer.numItems = 36;
    }

    var rotate_buf = mat4.create();
    function drawScene() {
        gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        mat4.perspective(pMatrix, 45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0);

        mat4.identity(mvMatrix);


        mat4.translate(mvMatrix, mvMatrix, [0, 0, z]);

        var new_rotate = mat4.create();

        mat4.rotateX(new_rotate, new_rotate, degToRad(xRot));
        mat4.rotateY(new_rotate, new_rotate, degToRad(yRot));


        mat4.multiply(rotate_buf, new_rotate, rotate_buf);
        mat4.multiply(mvMatrix, mvMatrix, rotate_buf);


        gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexPositionBuffer);
        gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, cubeVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);

        gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexTextureCoordBuffer);
        gl.vertexAttribPointer(shaderProgram.textureCoordAttribute, cubeVertexTextureCoordBuffer.itemSize, gl.FLOAT, false, 0, 0);


        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, crateTextures[filter]);
        gl.uniform1i(shaderProgram.samplerUniform, 0);

        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cubeVertexIndexBuffer);
        setMatrixUniforms();
        gl.drawElements(gl.TRIANGLES, cubeVertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0);
    }

    function animate() {
        xRot = xSpeed;
        yRot = ySpeed;
        xSpeed = ySpeed = 0;
    }

    function tick() {
        requestAnimFrame(tick);
        handleKeys();
        drawScene();
        animate();
    }

    function webGLStart() {
        var canvas = document.getElementById("WebGL_canvas");
        initGL(canvas);
        initShaders();
        initBuffers();
        initTexture();

        gl.clearColor(0.95, 0.95, 1.0, 1.0);
        gl.enable(gl.DEPTH_TEST);

        document.onkeydown = handleKeyDown;
        document.onkeyup = handleKeyUp;

        tick();
    }

    // Запуск программы
    webGLStart();
}

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>WebGL Example</title>

    <!--<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>-->
    <script type="text/javascript" src="gl-matrix.js"></script>
    <script type="text/javascript" src="webgl-utils.js"></script>
    <script id="shader-fs" type="x-shader/x-fragment">
        precision mediump float;

        varying vec2 vTextureCoord;

        uniform sampler2D uSampler;

        void main(void) {
        gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
        }
    </script>
    <script id="shader-vs" type="x-shader/x-vertex">
        attribute vec3 aVertexPosition;
        attribute vec2 aTextureCoord;

        uniform mat4 uMVMatrix;
        uniform mat4 uPMatrix;

        varying vec2 vTextureCoord;


        void main(void) {
        gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
        vTextureCoord = aTextureCoord;
        }
    </script>
    <script src="WebGL_Example_v4.js"></script>
</head>

<body onload="Main_WebGL_example();">
<canvas id="WebGL_canvas" style="border: none;" width="500" height="500"></canvas>

<ul>
    <li>Стрелочки - поворот куба
    <li><code>[Home]</code> - вернуть куб в исходное положение
    <li><code>[Page Up]</code>/<code>[Page Down]</code> - приближение/отдаление
</ul>
</body>

</html>