Qt 5.11 | Qt Canvas 3D | Interaction Example | interaction.js Example File

Qt 5.11.3 Reference Documentation

# interaction.js Example File

interaction/qml/interaction/interaction.js

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      ** This file is part of the QtCanvas3D module of the Qt Toolkit.
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      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, alpha:false});
              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;
      }