quickitemtexture.js Example File

canvas3d/quickitemtexture/qml/quickitemtexture/quickitemtexture.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.
**
** $QT_BEGIN_LICENSE:LGPL3$
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** 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
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** 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.
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** $QT_END_LICENSE$
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****************************************************************************/

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

//
// Draws a cube that has a Qt Quick item as decal texture on each face.
// A simple per vertex lighting equation is used to emulate light landing on the rotating cube.
//

var gl;
var cubeTexture = 0;
var vertexPositionAttribute;
var textureCoordAttribute;
var vertexNormalAttribute;
var mvMatrix = mat4.create();
var pMatrix  = mat4.create();
var nMatrix  = mat4.create();
var pMatrixUniform;
var mvMatrixUniform;
var nUniform;
var width = 0;
var height = 0;
var canvas3d;
var pixelSize;
var canvasTextureProvider = null;
var textureSourceItem = null;

function initializeGL(canvas, textureSource) {
    canvas3d = canvas;
    textureSourceItem = textureSource;

    // Get the OpenGL context object that represents the API we call
    gl = canvas.getContext("canvas3d", {depth:true, antialias:true});

    // Setup the OpenGL state
    gl.enable(gl.DEPTH_TEST);
    gl.depthFunc(gl.LESS);
    gl.enable(gl.CULL_FACE);
    gl.cullFace(gl.BACK);
    gl.clearDepth(1.0);
    gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false);

    // Use fully transparent clear color to allow other QML components to be seen through
    // Canvas3D where not obscured by the rotating cube.
    gl.clearColor(0.0, 0.0, 0.0, 0.0);

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

    // Initialize the shader program
    initShaders();

    // Initialize vertex and color buffers
    initBuffers();

    // Create a texture from the Qt Quick item
    canvasTextureProvider = gl.getExtension("QTCANVAS3D_texture_provider");
    cubeTexture = canvasTextureProvider.createTextureFromSource(textureSourceItem);

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

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

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

function paintGL(canvas) {
    var pixelRatio = canvas.devicePixelRatio;
    var currentWidth = canvas.width * pixelRatio;
    var currentHeight = canvas.height * pixelRatio;
    if (currentWidth !== width || currentHeight !== height ) {
        width = currentWidth;
        height = currentHeight;
        gl.viewport(0, 0, width, height);
        mat4.perspective(pMatrix, degToRad(45), width / height, 0.1, 500.0);
        gl.uniformMatrix4fv(pMatrixUniform, false, pMatrix);
    }

    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    mat4.identity(mvMatrix);
    mat4.translate(mvMatrix, mvMatrix, [(canvas.yRotAnim - 120.0) / 120.0,
                                        (canvas.xRotAnim -  60.0) / 50.0,
                                        -7.0]);
    mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.xRotAnim), [0, 1, 0]);
    mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.yRotAnim), [1, 0, 0]);
    mat4.rotate(mvMatrix, mvMatrix, degToRad(canvas.zRotAnim), [0, 0, 1]);
    gl.uniformMatrix4fv(mvMatrixUniform, false, mvMatrix);

    mat4.invert(nMatrix, mvMatrix);
    mat4.transpose(nMatrix, nMatrix);
    gl.uniformMatrix4fv(nUniform, false, nMatrix);

    gl.drawElements(gl.TRIANGLES, 36, gl.UNSIGNED_SHORT, 0);
}

function initBuffers()
{
    var cubeVertexPositionBuffer = gl.createBuffer();
    cubeVertexPositionBuffer.name = "cubeVertexPositionBuffer";
    gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexPositionBuffer);
    gl.bufferData(
                gl.ARRAY_BUFFER,
                new Float32Array([// 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.STATIC_DRAW);
    gl.vertexAttribPointer(vertexPositionAttribute, 3, gl.FLOAT, false, 0, 0);

    var cubeVertexIndexBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cubeVertexIndexBuffer);
    gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,
                  new Uint16Array([
                                            0,  1,  2,      0,  2,  3,    // front
                                            4,  5,  6,      4,  6,  7,    // back
                                            8,  9,  10,     8,  10, 11,   // top
                                            12, 13, 14,     12, 14, 15,   // bottom
                                            16, 17, 18,     16, 18, 19,   // right
                                            20, 21, 22,     20, 22, 23    // left
                                        ]),
                  gl.STATIC_DRAW);

    var cubeVerticesTextureCoordBuffer = gl.createBuffer();
    cubeVerticesTextureCoordBuffer.name = "cubeVerticesTextureCoordBuffer";
    gl.bindBuffer(gl.ARRAY_BUFFER, cubeVerticesTextureCoordBuffer);
    var textureCoordinates = [
                // Front
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0,
                // Back
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0,
                // Top
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0,
                // Bottom
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0,
                // Right
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0,
                // Left
                1.0,  0.0,
                0.0,  0.0,
                0.0,  1.0,
                1.0,  1.0
            ];
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoordinates),
                  gl.STATIC_DRAW);
    gl.vertexAttribPointer(textureCoordAttribute, 2, gl.FLOAT, false, 0, 0);

    var cubeVerticesNormalBuffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, cubeVerticesNormalBuffer);
    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
                                                              // Front
                                                              0.0,  0.0,  1.0,
                                                              0.0,  0.0,  1.0,
                                                              0.0,  0.0,  1.0,
                                                              0.0,  0.0,  1.0,

                                                              // Back
                                                              0.0,  0.0, -1.0,
                                                              0.0,  0.0, -1.0,
                                                              0.0,  0.0, -1.0,
                                                              0.0,  0.0, -1.0,

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

                                                              // Bottom
                                                              0.0, -1.0,  0.0,
                                                              0.0, -1.0,  0.0,
                                                              0.0, -1.0,  0.0,
                                                              0.0, -1.0,  0.0,

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

                                                              // Left
                                                              -1.0,  0.0,  0.0,
                                                              -1.0,  0.0,  0.0,
                                                              -1.0,  0.0,  0.0,
                                                              -1.0,  0.0,  0.0
                                                          ]), gl.STATIC_DRAW);
    gl.vertexAttribPointer(vertexNormalAttribute, 3, gl.FLOAT, false, 0, 0);
}

function initShaders()
{
    var 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 mediump vec4 vColor;           \
                                  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.VERTEX_SHADER);

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

    // Create the Program3D for shader
    var shaderProgram = gl.createProgram();

    // Attach the shader sources to the shader program
    gl.attachShader(shaderProgram, vertexShader);
    gl.attachShader(shaderProgram, fragmentShader);

    // Link the program
    gl.linkProgram(shaderProgram);

    // Check the linking status
    if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
        console.log("Could not initialize shaders");
        console.log(gl.getProgramInfoLog(shaderProgram));
    }

    // Take the shader program into use
    gl.useProgram(shaderProgram);

    // Look up where the vertex data needs to go
    vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
    gl.enableVertexAttribArray(vertexPositionAttribute);
    textureCoordAttribute = gl.getAttribLocation(shaderProgram, "aTextureCoord");
    gl.enableVertexAttribArray(textureCoordAttribute);
    vertexNormalAttribute = gl.getAttribLocation(shaderProgram, "aVertexNormal");
    gl.enableVertexAttribArray(vertexNormalAttribute);

    // Get the uniform locations
    pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
    mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
    nUniform = gl.getUniformLocation(shaderProgram, "uNormalMatrix");

    // Setup texture sampler uniform
    var textureSamplerUniform = gl.getUniformLocation(shaderProgram, "uSampler")
    gl.activeTexture(gl.TEXTURE0);
    gl.uniform1i(textureSamplerUniform, 0);
    gl.bindTexture(gl.TEXTURE_2D, 0);
}

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;
}

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.