- Qt 5.5
- Qt Canvas 3D
- Interaction Example
- interaction.js Example File
- Qt 5.5.1 Reference Documentation

# interaction.js Example File

canvas3d/interaction/qml/interaction/interaction.js

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the QtCanvas3D module of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:LGPL3$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
    ** accordance with the commercial license agreement provided with the
    ** Software or, alternatively, in accordance with the terms contained in
    ** a written agreement between you and The Qt Company. For licensing terms
    ** and conditions see http://www.qt.io/terms-conditions. For further
    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 3 as published by the Free Software
    ** Foundation and appearing in the file LICENSE.LGPLv3 included in the
    ** packaging of this file. Please review the following information to
    ** ensure the GNU Lesser General Public License version 3 requirements
    ** will be met: https://www.gnu.org/licenses/lgpl.html.
    **
    ** GNU General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU
    ** General Public License version 2.0 or later as published by the Free
    ** Software Foundation and appearing in the file LICENSE.GPL included in
    ** the packaging of this file. Please review the following information to
    ** ensure the GNU General Public License version 2.0 requirements will be
    ** met: http://www.gnu.org/licenses/gpl-2.0.html.
    **
    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    Qt.include("gl-matrix.js")
    Qt.include("ThreeJSLoader.js")

    var gl;

    var texturedShaderProgram = 0;
    var vertexShader = 0;
    var fragmentShader = 0;

    var vertexPositionAttribute;
    var textureCoordAttribute;
    var vertexNormalAttribute;

    var pMatrixUniform;
    var mvMatrixUniform;
    var nMatrixUniform;
    var textureSamplerUniform;

    var barrelTexture = 0;

    var mvMatrix = mat4.create();
    var pMatrix  = mat4.create();
    var nMatrix  = mat4.create();
    var startTime;

    var canvas3d;
    var isLogEnabled = false;

    function log(message) {
        if (isLogEnabled)
            console.log(message)
    }

    function Model() {
        this.verticesVBO = 0;
        this.normalsVBO  = 0;
        this.texCoordVBO = 0;
        this.indexVBO    = 0;
        this.count       = 0;
    }

    var theModel = new Model();

    function initializeGL(canvas) {
        canvas3d = canvas
        log("*******************************************************************************************")
        log("initializeGL ENTER...")
        try {
            startTime = Date.now();

            // Get the OpenGL context jsonObj that represents the API we call
            log("Getting Context");
            gl = canvas.getContext("canvas3d", {depth:true, antialias:true});
            log("Context received "+gl);

            var contextConfig = gl.getContextAttributes();
            log("Depth: "+contextConfig.alpha);
            log("Stencil: "+contextConfig.stencil);
            log("Antialiasing: "+contextConfig.antialias);
            log("Premultiplied alpha: "+contextConfig.premultipliedAlpha);
            log("Preserve drawingbuffer: "+contextConfig.preserveDrawingBuffer);
            log("Prefer Low Power To High Performance: "+contextConfig.preferLowPowerToHighPerformance);
            log("Fail If Major Performance Caveat: "+contextConfig.failIfMajorPerformanceCaveat);

            // Setup the OpenGL state
            gl.enable(gl.DEPTH_TEST);
            gl.enable(gl.CULL_FACE);

            gl.frontFace(gl.CCW);
            gl.cullFace(gl.BACK);

            gl.disable(gl.BLEND);

            gl.clearColor(0.98, 0.98, 0.98, 1.0);
            gl.clearDepth(1.0);

            // Set viewport
            gl.viewport(0, 0,
                        canvas.width * canvas.devicePixelRatio,
                        canvas.height * canvas.devicePixelRatio);

            // Initialize the shader program
            initShaders();

            // Initialize buffers
            theModel.verticesVBO = gl.createBuffer();
            theModel.verticesVBO.name = "BarrelModel.verticesVBO";
            theModel.normalsVBO = gl.createBuffer();
            theModel.normalsVBO.name = "BarrelModel.normalsVBO";
            theModel.texCoordVBO = gl.createBuffer();
            theModel.texCoordVBO.name = "BarrelModel.texCoordVBO";
            theModel.indexVBO = gl.createBuffer();
            theModel.indexVBO.name = "BarrelModel.indexVBO";

            // Load the barrel texture
            gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
            // Load the Qt logo as texture
            var barrelImage = TextureImageFactory.newTexImage();
            barrelImage.imageLoaded.connect(function() {
                barrelTexture = gl.createTexture();
                barrelTexture.name = "barrelTexture"
                gl.bindTexture(gl.TEXTURE_2D, barrelTexture);
                gl.texImage2D(gl.TEXTURE_2D,    // target
                              0,                // level
                              gl.RGBA,          // internalformat
                              gl.RGBA,          // format
                              gl.UNSIGNED_BYTE, // type
                              barrelImage);     // pixels

                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);
            });
            barrelImage.imageLoadingFailed.connect(function() {
                console.log("Texture load FAILED, "+barrelImage.errorString);
            });
            // Aliasing doesn't work correctly with QtQuick compiler for some reason,
            // so use full names for barrel.jpg and barrel.json
            barrelImage.src = "qrc:/qml/interaction/barrel.jpg";

            // Load the model
            log("    Create XMLHttpRequest")
            var request = new XMLHttpRequest();
            log("    XMLHttpRequest.open")
            request.open("GET", "qrc:/qml/interaction/barrel.json");
            log("    XMLHttpRequest.onreadystatechange")
            request.onreadystatechange = function () {
                if (request.readyState === XMLHttpRequest.DONE) {
                    handleLoadedModel(JSON.parse(request.responseText));
                }
            }
            log("    XMLHttpRequest.send")
            request.send();

            log("...initializeGL EXIT");
        } catch(e) {
            console.log("...initializeGL FAILURE!");
            console.log(""+e);
            console.log(""+e.message);
        }
        log("*******************************************************************************************");
    }

    function resizeGL(canvas)
    {
        var pixelRatio = canvas.devicePixelRatio;
        canvas.pixelSize = Qt.size(canvas.width * pixelRatio,
                                   canvas.height * pixelRatio);
        if (gl)
            gl.viewport(0, 0,
                        canvas.width * canvas.devicePixelRatio,
                        canvas.height * canvas.devicePixelRatio);
    }

    function paintGL(canvas) {
        // draw
        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        // draw only when we have the mesh and texture
        if (theModel.count <= 0 || barrelTexture == 0) return;

        gl.useProgram(texturedShaderProgram);

        // Calculate the perspective projection
        mat4.perspective(pMatrix, degToRad(45), canvas.width / canvas.height, 0.1, 10000.0);
        gl.uniformMatrix4fv(pMatrixUniform, false, pMatrix);

        // Bind the correct buffers
        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.verticesVBO);
        gl.enableVertexAttribArray(vertexPositionAttribute);
        gl.vertexAttribPointer(vertexPositionAttribute, 3, gl.FLOAT, false, 0, 0);

        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.normalsVBO);
        gl.enableVertexAttribArray(vertexNormalAttribute);
        gl.vertexAttribPointer(vertexNormalAttribute, 3, gl.FLOAT, false, 0, 0);

        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.texCoordVBO);
        gl.enableVertexAttribArray(textureCoordAttribute);
        gl.vertexAttribPointer(textureCoordAttribute, 2, gl.FLOAT, false, 0, 0);

        gl.activeTexture(gl.TEXTURE0);
        gl.bindTexture(gl.TEXTURE_2D, barrelTexture);
        gl.uniform1i(textureSamplerUniform, 0);

        // Calculate and apply the modelview matrix
        mvMatrix = mat4.identity(mvMatrix);
        mvMatrix = mat4.translate(mvMatrix, mvMatrix, [0, -40, -700]);
        mvMatrix = mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.xRotSlider), [1, 0, 0]);
        mvMatrix = mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.yRotSlider), [0, 1, 0]);
        mvMatrix = mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.zRotSlider), [0, 0, 1]);
        gl.uniformMatrix4fv(mvMatrixUniform, false, mvMatrix);

        // Calculate normal matrix
        nMatrix = mat4.invert(nMatrix, mvMatrix);
        nMatrix = mat4.transpose(nMatrix, nMatrix);
        gl.uniformMatrix4fv(nMatrixUniform, false, nMatrix);

        // Draw the barrel
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, theModel.indexVBO);
        gl.drawElements(gl.TRIANGLES, theModel.count, gl.UNSIGNED_SHORT, 0);

        // Calculate and apply the modelview matrix
        mvMatrix = mat4.identity(mvMatrix);
        mvMatrix = mat4.translate(mvMatrix, mvMatrix, [-250, -50, -700]);
        mvMatrix = mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.xRotSlider), [0, 1, 0]);
        gl.uniformMatrix4fv(mvMatrixUniform, false, mvMatrix);

        // Calculate normal matrix
        nMatrix = mat4.invert(nMatrix, mvMatrix);
        nMatrix = mat4.transpose(nMatrix, nMatrix);
        gl.uniformMatrix4fv(nMatrixUniform, false, nMatrix);

        // Draw the barrel
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, theModel.indexVBO);
        gl.drawElements(gl.POINTS, theModel.count, gl.UNSIGNED_SHORT, 0);

        // Calculate and apply the modelview matrix
        mvMatrix = mat4.identity(mvMatrix);
        mvMatrix = mat4.translate(mvMatrix, mvMatrix, [250, -50, -700]);
        mvMatrix = mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.zRotSlider), [0, 1, 0]);
        gl.uniformMatrix4fv(mvMatrixUniform, false, mvMatrix);

        // Calculate normal matrix
        nMatrix = mat4.invert(nMatrix, mvMatrix);
        nMatrix = mat4.transpose(nMatrix, nMatrix);
        gl.uniformMatrix4fv(nMatrixUniform, false, nMatrix);

        // Draw the barrel
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, theModel.indexVBO);
        gl.drawElements(gl.LINES, theModel.count, gl.UNSIGNED_SHORT, 0);
    }

    function handleLoadedModel(jsonObj) {
        log("*******************************************************************************************");
        log("handleLoadedModel ENTER...")
        var modelData = parseJSON3DModel(jsonObj, "");

        log("    "+theModel.verticesVBO);
        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.verticesVBO);
        gl.bufferData(gl.ARRAY_BUFFER,
                      new Float32Array(modelData.vertices),
                      gl.STATIC_DRAW);

        log("    "+theModel.normalsVBO);
        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.normalsVBO);
        gl.bufferData(gl.ARRAY_BUFFER,
                      new Float32Array(modelData.normals),
                      gl.STATIC_DRAW);

        log("    "+theModel.texCoordVBO);
        gl.bindBuffer(gl.ARRAY_BUFFER, theModel.texCoordVBO);
        gl.bufferData(gl.ARRAY_BUFFER,
                      new Float32Array(modelData.texCoords[0]),
                      gl.STATIC_DRAW);

        log("    "+theModel.indexVBO);
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, theModel.indexVBO);
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,
                      new Uint16Array(modelData.indices),
                      gl.STATIC_DRAW);

        theModel.count = modelData.indices.length;
        log("...handleLoadedModel EXIT");
        log("*******************************************************************************************");
    }

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

    function initShaders()
    {
        log("    initShaders ENTER...")

        vertexShader = getShader(gl,
                                 "attribute highp vec3 aVertexNormal;       \
                                  attribute highp vec3 aVertexPosition;     \
                                  attribute highp vec2 aTextureCoord;       \
                                                                            \
                                  uniform highp mat4 uNormalMatrix;         \
                                  uniform mat4 uMVMatrix;                   \
                                  uniform mat4 uPMatrix;                    \
                                                                            \
                                  varying highp vec2 vTextureCoord;         \
                                  varying highp vec3 vLighting;             \
                                                                            \
                                  void main(void) {                         \
                                     gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0); \
                                     vTextureCoord = aTextureCoord;                                   \
                                     highp vec3 ambientLight = vec3(0.5, 0.5, 0.5);                   \
                                     highp vec3 directionalLightColor = vec3(0.75, 0.75, 0.75);       \
                                     highp vec3 directionalVector = vec3(0.85, 0.8, 0.75);            \
                                     highp vec4 transformedNormal = uNormalMatrix * vec4(aVertexNormal, 1.0); \
                                                                                                              \
                                     highp float directional = max(dot(transformedNormal.xyz, directionalVector), 0.0); \
                                     vLighting = ambientLight + (directionalLightColor * directional);                  \
                                     gl_PointSize = 1.0; \
                                 }", gl.VERTEX_SHADER);

        fragmentShader = getShader(gl,
                                   "varying highp vec2 vTextureCoord;             \
                                    varying highp vec3 vLighting;                 \
                                                                                  \
                                    uniform sampler2D uSampler;                   \
                                                                                  \
                                    void main(void) {                             \
                                        mediump vec4 texelColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));  \
                                        gl_FragColor = vec4(texelColor.rgb * vLighting, 1.0);                                   \
                                    }", gl.FRAGMENT_SHADER);

        texturedShaderProgram = gl.createProgram();
        texturedShaderProgram.name = "TexturedShaderProgram";
        gl.attachShader(texturedShaderProgram, vertexShader);
        gl.attachShader(texturedShaderProgram, fragmentShader);
        gl.linkProgram(texturedShaderProgram);

        if (!gl.getProgramParameter(texturedShaderProgram, gl.LINK_STATUS)) {
            console.log("Could not initialize shaders");
            console.log(gl.getProgramInfoLog(texturedShaderProgram));
        }

        gl.useProgram(texturedShaderProgram);

        // look up where the vertex data needs to go.
        vertexPositionAttribute = gl.getAttribLocation(texturedShaderProgram, "aVertexPosition");
        vertexPositionAttribute.name = "aVertexPosition_AttribLocation";
        gl.enableVertexAttribArray(vertexPositionAttribute);
        vertexNormalAttribute = gl.getAttribLocation(texturedShaderProgram, "aVertexNormal");
        vertexPositionAttribute.name = "aVertexNormal_AttribLocation";
        gl.enableVertexAttribArray(vertexNormalAttribute);
        textureCoordAttribute = gl.getAttribLocation(texturedShaderProgram, "aTextureCoord");
        vertexPositionAttribute.name = "aTextureCoord_AttribLocation";
        gl.enableVertexAttribArray(textureCoordAttribute);

        pMatrixUniform  = gl.getUniformLocation(texturedShaderProgram, "uPMatrix");
        pMatrixUniform.name = "uPMatrix_UniformLocation";
        mvMatrixUniform = gl.getUniformLocation(texturedShaderProgram, "uMVMatrix");
        mvMatrixUniform.name = "uMVMatrix_UniformLocation";
        textureSamplerUniform = gl.getUniformLocation(texturedShaderProgram, "uSampler")
        textureSamplerUniform.name = "uSampler_UniformLocation";
        nMatrixUniform = gl.getUniformLocation(texturedShaderProgram, "uNormalMatrix");
        nMatrixUniform.name = "uNormalMatrix_UniformLocation";
        log("    ... initShaders EXIT");
    }

    function getShader(gl, str, type) {
        var shader = gl.createShader(type);
        gl.shaderSource(shader, str);
        gl.compileShader(shader);

        if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
            console.log("JS:Shader compile failed");
            console.log(gl.getShaderInfoLog(shader));
            return null;
        }

        return shader;
    }