webgl实现canvas粒子风暴爆炸动画效果代码-html代码-BFW代码库

代码语言：html

所属分类：粒子

代码描述：webgl实现canvas粒子风暴爆炸动画效果代码

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<!DOCTYPE html>
<html >
<head>
  <meta charset="UTF-8">

  <style>

body {
    padding: 0;
  margin:0;
}



  </style>
</head>

<body>
  
<canvas id="c"></canvas>

<script id="shader-fs" type="x-shader/x-fragment">
                                #ifdef GL_ES
                                  precision highp float;
                                  #endif
                void main(void) {
                 gl_FragColor = vec4(0.2, 0.3, 0.4, 1.0);
                }
                </script>

  <script id="shader-vs" type="x-shader/x-vertex">
        attribute vec3 vertexPosition;

        uniform mat4 modelViewMatrix;
        uniform mat4 perspectiveMatrix;

        void main(void) {
                gl_Position = perspectiveMatrix * modelViewMatrix * vec4(  vertexPosition, 1.0);
        }
  </script>
  
    <script>
        window.onload = loadScene;

var canvas, gl,
  ratio,
  vertices,
  velocities,
  freqArr,
  cw,
  ch,
  colorLoc,
  thetaArr,
  velThetaArr,
  velRadArr,
  boldRateArr,
  drawType,
  numLines = 40000;
var target = [];
var randomTargetXArr = [], randomTargetYArr = [];
drawType = 2;


/**
 * Initialises WebGL and creates the 3D scene.
 */
function loadScene() {
  //    Get the canvas element
  canvas = document.getElementById("c");
  //    Get the WebGL context
  gl = canvas.getContext("experimental-webgl");
  //    Check whether the WebGL context is available or not
  //    if it's not available exit
  if (!gl) {
    alert("There's no WebGL context available.");
    return;
  }
  //    Set the viewport to the canvas width and height
  cw = window.innerWidth;
  ch = window.innerHeight;
  canvas.width = cw;
  canvas.height = ch;
  gl.viewport(0, 0, canvas.width, canvas.height);

  //    Load the vertex shader that's defined in a separate script
  //    block at the top of this page.
  //    More info about shaders: http://en.wikipedia.org/wiki/Shader_Model
  //    More info about GLSL: http://en.wikipedia.org/wiki/GLSL
  //    More info about vertex shaders: http://en.wikipedia.org/wiki/Vertex_shader

  //    Grab the script element
  var vertexShaderScript = document.getElementById("shader-vs");
  var vertexShader = gl.createShader(gl.VERTEX_SHADER);
  gl.shaderSource(vertexShader, vertexShaderScript.text);
  gl.compileShader(vertexShader);
  if (!gl.getShaderParameter(vertexShader, gl.COMPILE_STATUS)) {
    alert("Couldn't compile the vertex shader");
    gl.deleteShader(vertexShader);
    return;
  }

  //    Load the fragment shader that's defined in a separate script
  //    More info about fragment shaders: http://en.wikipedia.org/wiki/Fragment_shader
  var fragmentShaderScript = document.getElementById("shader-fs");
  var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
  gl.shaderSource(fragmentShader, fragmentShaderScript.text);
  gl.compileShader(fragmentShader);
  if (!gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS)) {
    alert("Couldn't compile the fragment shader");
    gl.deleteShader(fragmentShader);
    return;
  }

  //    Create a shader program.
  gl.program = gl.createProgram();
  gl.attachShader(gl.program, vertexShader);
  gl.attachShader(gl.program, fragmentShader);
  gl.linkProgram(gl.program);
  if (!gl.getProgramParameter(gl.program, gl.LINK_STATUS)) {
    alert("Unable to initialise shaders");
    gl.deleteProgram(gl.program);
    gl.deleteProgram(vertexShader);
    gl.deleteProgram(fragmentShader);
    return;
  }
  //    Install the program as part of the current rendering state
  gl.useProgram(gl.program);
  //    Get the vertexPosition attribute from the linked shader program
  var vertexPosition = gl.getAttribLocation(gl.program, "vertexPosition");
  //    Enable the vertexPosition vertex attribute array. If enabled, the array
  //    will be accessed an used for rendering when calls are made to commands like
  //    gl.drawArrays, gl.drawElements, etc.
  gl.enableVertexAttribArray(vertexPosition);

  //    Clear the color buffer (r, g, b, a) with the specified color
  gl.clearColor(0.0, 0.0, 0.0, 1.0);
  //    Clear the depth buffer. The value specified is clamped to the range [0,1].
  //    More info about depth buffers: http://en.wikipedia.org/wiki/Depth_buffer
  gl.clearDepth(1.0);
  //    Enable depth testing. This is a technique used for hidden surface removal.
  //    It assigns a value (z) to each pixel that represents the distance from this
  //    pixel to the viewer. When another pixel is drawn at the same location the z
  //    values are compared in order to determine which pixel should be drawn.
  //gl.enable(gl.DEPTH_TEST);

  gl.enable(gl.BLEND);
  gl.disable(gl.DEPTH_TEST);
  gl.blendFunc(gl.SRC_ALPHA, gl.ONE);

  //    Specify which function to use for depth buffer comparisons. It compares the
  //    value of the incoming pixel against the one stored in the depth buffer.
  //    Possible values are (from the OpenGL documentation):
  //    GL_NEVER - Never passes.
  //    GL_LESS - Passes if the incoming depth value is less than the stored depth value.
  //    GL_EQUAL - Passes if the incoming depth value is equal to the stored depth value.
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