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sample-webgl-buffer.js / js



  /*
   Introductory SceneJS scene which demonstrates using the frameBuf node for render-to-texture
  
   Lindsay S. Kay,
   lindsay.kay@xeolabs.com
  
   github.com/xeolabs/scenejs/wiki/frameBuf
  
   */
  SceneJS.createScene({
  
    type: "scene",
  
    /* ID that we'll access the scene by when we want to render it
     */
    id: "theScene",
  
    /* Bind scene to a WebGL canvas:
     */
    canvasId: "theCanvas",
  
    /* You can optionally write logging to a DIV - scene will log to the console as well.
     */
    loggingElementId: "theLoggingDiv",
  
    nodes: [
  
      /*-------------------------------------------------------------------------------------------
       * First subgraph renders our rotating teapot, with light blue backdrop, to a texture.
       *
       * The subgraph is wrapped in an frameBuf node, which captures each frame the subgraph
       * renders and makes it available by ID as an image source for the texture node defined in the
       * second subgraph, defined further down in this example.
       *
       * The frameBuf captures the frames to a hidden frame buffer, so they will not render by
       * themselves and will only be visible via the texture.
       *
       * This example assumes that you know what the various other node types are - see the
       * other examples first if you're not sure.
       *------------------------------------------------------------------------------------------*/
  
      {
        type: "frameBuf",
        id: "teapot-frameBuf",
  
        nodes: [
  
          {
            type: "lookAt",
            eye : { x: 0.0, y: 10.0, z: -15 },
            look : { y:1.0 },
            up : { y: 1.0 },
  
            nodes: [
              {
                type: "camera",
                optics: {
                  type: "perspective",
                  fovy : 25.0,
                  aspect : 1,
                  near : 0.10,
                  far : 300.0
                },
  
                nodes: [
                  {
                    type: "light",
                    mode:          "dir",
                    color:         { r: 1.0, g: 1.0, b: 1.0 },
                    diffuse:        true,
                    specular:        true,
                    dir:          { x: 0.0, y: 0.0, z: 1.0 }
                  },
  
                  /* Light blue backdrop slab
                   */
                  {
                    type: "material",
                    emit: 20,
                    baseColor:   { r: 0.0, g: 1, b:1 },
                    specularColor: { r: 0., g: 0., b: 1. },
                    specular:    0.9,
                    shine:     100.0,
  
                    nodes: [
                      {
                        type:"translate",
                        z:15,
                        nodes: [
                          {
                            type:"scale",
                            x:20,
                            y:20,
                            nodes:[
                              {
                                type : "cube"
                              }
                            ]
                          }
                        ]
                      }
                    ]
                  },
  
                  /* Teapot, oriented with a couple of rotations
                   */
                  {
                    type: "rotate",
                    id: "teapot-pitch",
                    angle: 180.0,
                    x : 1.0,
  
                    nodes: [
                      {
                        type: "rotate",
                        id: "teapot-yaw",
                        angle: 0.0,
                        y : 1.0,
  
                        nodes: [
  
                          {
                            type: "material",
                            emit: 0,
                            baseColor:   { r: 0.5, g: 0.5, b: 0.9 },
                            specularColor: { r: 0.9, g: 0.9, b: 0.9 },
                            specular:    0.9,
                            shine:     100.0,
  
                            nodes: [
                              {
                                type : "teapot"
                              }
                            ]
                          }
                        ]
                      }
                    ]
                  }
                ]
              }
            ]
          }
        ]
      },
  
      /*-------------------------------------------------------------------------------------------
       * The second subgraph renders a cube with a texture that is dynamically sourced from
       * the frameBuf defined in the subgraph above.
       *------------------------------------------------------------------------------------------*/
  
      {
        type: "lookAt",
        eye : { x: 0.0, y: 0.0, z: -10},
        look : { x : 0.0, y : 0.0, z : 0 },
        up : { x: 0.0, y: 1.0, z: 0.0 },
  
        nodes: [
          {
            type: "camera",
            optics: {
              type: "perspective",
              fovy : 25.0,
              aspect : 1.47,
              near : 0.10,
              far : 300.0
            },
  
            nodes: [
              {
                type:     "light",
                mode:     "dir",
                color:     { r: 1.0, g: 1.0, b: 1.0 },
                diffuse:    true,
                specular:   false,
                dir:      { x: 1.0, y: 1.0, z: -1.0 }
              },
              {
                type:     "light",
                mode:     "dir",
                color:     { r: 1.0, g: 1.0, b: 1.0 },
                diffuse:    true,
                specular:   false,
                dir:      { x: 0.0, y: 1.0, z: 1.0 }
              },
              {
                type: "material",
                baseColor:   { r: 0.5, g: 0.5, b: 0.5 },
                specularColor: { r: 1.0, g: 1.0, b: 1.0 },
                specular:    0.2,
                shine:     6.0,
  
                nodes: [
                  {
                    type: "texture",
                    id: "theTexture",
  
                    /* Recall that textures can have multiple layers. Our texture has just
                     * one, which sources it's image from the frameBuf we defined earlier.
                     */
                    layers: [
                      {
                        frameBuf: "teapot-frameBuf",
                        blendMode: "multiply"
                      }
                    ],
  
                    nodes: [
                      {
                        type: "rotate",
                        id: "cube-pitch",
                        angle: 0.0,
                        x : 1.0,
  
                        nodes: [
                          {
                            type: "rotate",
                            id: "cube-yaw",
                            angle: 0.0,
                            y : 1.0,
  
                            nodes: [
                              {
                                type: "cube"
                              }
                            ]
                          }
                        ]
                      }
                    ]
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  });
  
  /*----------------------------------------------------------------------
   * Scene rendering loop and mouse handler stuff follows
   *---------------------------------------------------------------------*/
  
  var scene = SceneJS.scene("theScene");
  
  var teapotPitch = scene.findNode("teapot-pitch");
  var teapotYaw = scene.findNode("teapot-yaw");
  
  var cubePitch = scene.findNode("cube-pitch");
  var cubeYaw = scene.findNode("cube-yaw");
  
  var yaw = 0;
  var pitch = 0;
  var lastX;
  var lastY;
  var dragging = false;
  
  var canvas = document.getElementById("theCanvas");
  
  function mouseDown(event) {
    lastX = event.clientX;
    lastY = event.clientY;
    dragging = true;
  }
  
  function touchStart(event) {
    lastX = event.targetTouches[0].clientX;
    lastY = event.targetTouches[0].clientY;
    dragging = true;
  }
  
  function mouseUp() {
    dragging = false;
  }
  
  function touchEnd() {
    dragging = false;
  }
  
  function mouseMove(event) {
    var posX = event.clientX;
    var posY = event.clientY;
    actionMove(posX,posY);
  }
  
  function touchMove(event) {
    var posX = event.targetTouches[0].clientX;
    var posY = event.targetTouches[0].clientY;
    actionMove(posX,posY);
  }
  
  /* On a mouse/touch drag, we'll re-render the scene, passing in
   * incremented angles in each time.
   */
  function actionMove(posX, posY) {
    if (dragging) {
      yaw += (posX - lastX) * 0.5;
      pitch += (posY - lastY) * -0.5;
  
      cubeYaw.set("angle", yaw);
      cubePitch.set("angle", pitch);
  
      lastX = posX;
      lastY = posY;
    }
  }
  
  canvas.addEventListener('mousedown', mouseDown, true);
  canvas.addEventListener('mousemove', mouseMove, true);
  canvas.addEventListener('mouseup', mouseUp, true);
  canvas.addEventListener('touchstart', touchStart, true);
  canvas.addEventListener('touchmove', touchMove, true);
  canvas.addEventListener('touchend', touchEnd, true);
  
  scene.start({
    idleFunc: function() {
      teapotYaw.inc("angle", 1);
      teapotPitch.inc("angle", .3);
  
      cubeYaw.inc("angle", .1);
      cubePitch.inc("angle", .2);
    }
  });
  
  


(C) Æliens 04/09/2009

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