在WebGL中用三角形制作网格平面

Making a Mesh Plane in WebGL with Triangles

本文关键字：网格 平面 三角形 WebGL      更新时间：2023-09-26

我正在尝试在WebGL中创建一个三角平面，我有以下代码。但是，当我在浏览器中渲染它时，它只是给了我一条平行于 y 轴的垂直线。

var quads = 200;
for (var y = 0; y <= quads; ++y) {
  var v = y / quads * 40;
  for (var x = 0; x <= quads; ++x) {
    var u = x / quads * 40;
    recipient.vertices.push( vec3(u, v, 1))
    recipient.normals.push( vec3(0, 0, 1))
  }
}
var rowSize = (quads + 1);
for (var y = 0; y < quads; ++y) {
  var rowOffset0 = (y + 0) * rowSize;
  var rowOffset1 = (y + 1) * rowSize;
  for (var x = 0; x < quads; ++x) {
    recipient.indices.push(rowOffset0, rowOffset0 + 1, rowOffset1);
    recipient.indices.push(rowOffset1, rowOffset0 + 1, rowOffset1 + 1);
  }
}

同样作为后续问题，我希望获得一些有关如何用这架飞机制作曲面的技巧，类似于山丘。

原始答案中存在错误。应该是这个

var quads = 200;
for (var y = 0; y <= quads; ++y) {
  var v = y / quads;
  for (var x = 0; x <= quads; ++x) {
    var u = x / quads;
    recipient.vertices.push( vec3(u, v, 1))
    recipient.normals.push( vec3(0, 0, 1))
  }
}
var rowSize = (quads + 1);
for (var y = 0; y < quads; ++y) {
  var rowOffset0 = (y + 0) * rowSize;
  var rowOffset1 = (y + 1) * rowSize;
  for (var x = 0; x < quads; ++x) {
    var offset0 = rowOffset0 + x;
    var offset1 = rowOffset1 + x;
    recipient.indices.push(offset0, offset0 + 1, offset1);
    recipient.indices.push(offset1, offset0 + 1, offset1 + 1);
  }
}

在原始答案中也已修复。

function Vec3Array() {
  this.array = [];
  this.push = function(v3) {
    this.array.push.apply(this.array, v3);
  }
}
function vec3(x, y, z) {
  return [x, y, z];
}
  
var recipient = {
  vertices: new Vec3Array(),
  normals: new Vec3Array(),
  indices: [],
};
  
var quads = 200;
for (var y = 0; y <= quads; ++y) {
  var v = y / quads;
  for (var x = 0; x <= quads; ++x) {
    var u = x / quads;
    recipient.vertices.push( vec3(u, v, 1))
    recipient.normals.push( vec3(0, 0, 1))
  }
}
var rowSize = (quads + 1);
for (var y = 0; y < quads; ++y) {
  var rowOffset0 = (y + 0) * rowSize;
  var rowOffset1 = (y + 1) * rowSize;
  for (var x = 0; x < quads; ++x) {
    var offset0 = rowOffset0 + x;
    var offset1 = rowOffset1 + x;
    recipient.indices.push(offset0, offset0 + 1, offset1);
    recipient.indices.push(offset1, offset0 + 1, offset1 + 1);
  }
}
var gl = twgl.getWebGLContext(document.getElementById("c"));
var programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);
var arrays = {
  position: recipient.vertices.array,
  indices: recipient.indices,
};
var bufferInfo = twgl.createBufferInfoFromArrays(gl, arrays);
function render(time) {
  time *= 0.001;
  twgl.resizeCanvasToDisplaySize(gl.canvas);
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
  var scale = 2 + (Math.sin(time) * 0.5 + 0.5) * 16;
  var uniforms = {
    matrix: [
      scale, 0, 0, 0,
      0, scale, 0, 0,
      0, 0, 1, 0,
      -1, -1, 0, 1,
    ],
  };
  gl.useProgram(programInfo.program);
  twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
  twgl.setUniforms(programInfo, uniforms);
  twgl.drawBufferInfo(gl, gl.LINE_STRIP, bufferInfo);
  requestAnimationFrame(render);
}
requestAnimationFrame(render);
html, body {
  width: 100%;
  height: 100%;
  margin: 0;
}
canvas { 
  width: 100%;
  height: 100%;
}
<script src="https://twgljs.org/dist/twgl.min.js"></script>
<script id="vs" type="notjs">
attribute vec4 position;
uniform mat4 matrix;
void main() {
  gl_Position = matrix * position;
}
</script>
<script id="fs" type="notjs">
precision mediump float;
void main() {
  gl_FragColor = vec4(1,0,0,1);
}
  </script>
<canvas id="c"></canvas>

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