我试图在WebGL中创建一个三角形平面,我有以下代码。但是,当我在浏览器中渲染它时,它只给我一条与y轴平行的垂直线。
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);
}
}
另外作为一个后续问题,我希望得到一些关于如何用这个平面制作曲面的技巧,类似于山丘。
答案 0 :(得分:2)
original answer中有一个错误。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);
}
}
也固定在original answer。
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>