我正在进行材料科学的WEBGL可视化项目。我现在想要完成的是，我有一组原子的三维坐标。它们结合在一起。我想为每个分子创建一个多面体。
我试图通过使用强力方法解决问题：我遍历整个点数组并用三个点的每个组合形成三角形。以下问题是如何检测哪些面被摆脱？因为一些三角形面将穿过外围原子与之结合的中心原子。
我将不胜感激任何建议和想法！ 谢谢！
答案 0 :(得分：2)
图书馆alpha-shape似乎可以做你想要的。
我给了它一组球体点并让它生成三角形。
示例：
//var alphaShape = require('alpha-shape')
var subdivisionsHeight = 12;
var subdivisionsAxis = 16;
var longRange = Math.PI * 2;
var latRange = Math.PI;
var radius = 4;
var points = [];
for (var y = 0; y <= subdivisionsHeight; y++) {
for (var x = 0; x < subdivisionsAxis; x++) {
// Generate a vertex based on its spherical coordinates
var u = x / subdivisionsAxis;
var v = y / subdivisionsHeight;
var theta = longRange * u;
var phi = latRange * v;
var sinTheta = Math.sin(theta);
var cosTheta = Math.cos(theta);
var sinPhi = Math.sin(phi);
var cosPhi = Math.cos(phi);
var ux = cosTheta * sinPhi;
var uy = cosPhi;
var uz = sinTheta * sinPhi;
points.push([radius * ux, radius * uy, radius * uz]);
if (y == 0 || y == subdivisionsHeight) {
break;
}
}
}
// var cells = alphaShape(0.1, points)
// Results from alphaShape
var cells = [ [ 2, 0, 1 ],
[ 0, 2, 3 ],
[ 0, 3, 4 ],
[ 5, 0, 4 ],
[ 5, 6, 0 ],
[ 7, 0, 6 ],
[ 0, 7, 8 ],
[ 0, 16, 1 ],
[ 9, 0, 8 ],
[ 0, 9, 10 ],
[ 0, 10, 11 ],
[ 1, 18, 2 ],
[ 0, 11, 12 ],
[ 18, 3, 2 ],
[ 0, 12, 13 ],
[ 14, 0, 13 ],
[ 3, 20, 4 ],
[ 0, 14, 15 ],
[ 4, 20, 5 ],
[ 15, 16, 0 ],
[ 5, 22, 6 ],
[ 22, 7, 6 ],
[ 18, 1, 17 ],
[ 24, 8, 7 ],
[ 19, 3, 18 ],
[ 9, 8, 24 ],
[ 19, 20, 3 ],
[ 9, 26, 10 ],
[ 20, 21, 5 ],
[ 10, 26, 11 ],
[ 22, 5, 21 ],
[ 1, 16, 32 ],
[ 1, 32, 17 ],
[ 11, 28, 12 ],
[ 22, 23, 7 ],
[ 13, 12, 28 ],
[ 23, 24, 7 ],
[ 14, 13, 30 ],
[ 25, 9, 24 ],
[ 15, 14, 30 ],
[ 25, 26, 9 ],
[ 16, 15, 32 ],
[ 26, 27, 11 ],
[ 28, 11, 27 ],
[ 18, 17, 33 ],
[ 29, 13, 28 ],
[ 13, 29, 30 ],
[ 35, 19, 18 ],
[ 20, 19, 35 ],
[ 15, 30, 31 ],
[ 15, 31, 32 ],
[ 21, 20, 37 ],
[ 37, 22, 21 ],
[ 23, 22, 39 ],
[ 18, 33, 34 ],
[ 23, 39, 24 ],
[ 34, 35, 18 ],
[ 24, 41, 25 ],
[ 20, 35, 36 ],
[ 20, 36, 37 ],
[ 26, 25, 42 ],
[ 27, 26, 43 ],
[ 17, 32, 48 ],
[ 22, 37, 38 ],
[ 17, 48, 33 ],
[ 22, 38, 39 ],
[ 44, 28, 27 ],
[ 29, 28, 44 ],
[ 40, 24, 39 ],
[ 29, 45, 30 ],
[ 24, 40, 41 ],
[ 41, 42, 25 ],
[ 31, 30, 47 ],
[ 32, 31, 47 ],
[ 26, 42, 43 ],
[ 43, 44, 27 ],
[ 50, 34, 33 ],
[ 45, 29, 44 ],
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[ 30, 45, 46 ],
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[ 48, 32, 47 ],
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[ 41, 40, 56 ],
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[ 54, 55, 38 ],
[ 45, 44, 61 ],
[ 56, 40, 55 ],
[ 46, 45, 62 ],
[ 56, 57, 41 ],
[ 62, 47, 46 ],
[ 58, 42, 57 ],
[ 63, 48, 47 ],
[ 58, 59, 43 ],
[ 48, 64, 49 ],
[ 59, 60, 44 ],
[ 60, 61, 44 ],
[ 50, 49, 66 ],
[ 66, 51, 50 ],
[ 45, 61, 62 ],
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[ 53, 52, 68 ],
[ 63, 64, 48 ],
[ 70, 54, 53 ],
[ 70, 55, 54 ],
[ 65, 66, 49 ],
[ 72, 56, 55 ],
[ 51, 66, 67 ],
[ 57, 56, 72 ],
[ 68, 51, 67 ],
[ 74, 58, 57 ],
[ 69, 53, 68 ],
[ 69, 70, 53 ],
[ 59, 58, 75 ],
[ 64, 80, 49 ],
[ 65, 49, 80 ],
[ 59, 76, 60 ],
[ 70, 71, 55 ],
[ 61, 60, 76 ],
[ 71, 72, 55 ],
[ 61, 78, 62 ],
[ 73, 57, 72 ],
[ 73, 74, 57 ],
[ 63, 62, 79 ],
[ 58, 74, 75 ],
[ 80, 64, 63 ],
[ 76, 59, 75 ],
[ 66, 65, 81 ],
[ 77, 61, 76 ],
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[ 78, 61, 77 ],
[ 62, 78, 79 ],
[ 84, 68, 67 ],
[ 80, 63, 79 ],
[ 85, 69, 68 ],
[ 70, 69, 85 ],
[ 65, 80, 81 ],
[ 70, 86, 71 ],
[ 82, 66, 81 ],
[ 87, 72, 71 ],
[ 83, 67, 82 ],
[ 83, 84, 67 ],
[ 72, 89, 73 ],
[ 89, 74, 73 ],
[ 85, 68, 84 ],
[ 74, 90, 75 ],
[ 86, 70, 85 ],
[ 76, 75, 92 ],
[ 86, 87, 71 ],
[ 93, 77, 76 ],
[ 72, 87, 88 ],
[ 77, 93, 78 ],
[ 72, 88, 89 ],
[ 78, 94, 79 ],
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[ 79, 96, 80 ],
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[ 100, 101, 85 ],
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[ 107, 91, 90 ],
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[ 120, 104, 103 ],
[ 114, 115, 99 ],
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[ 105, 104, 121 ],
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function flatten(array) {
return array.reduce(function(a, b) {
return a.concat(b);
}, []);
}
// the cells are triangle (3 points). To draw lines we need 6 A->B, B->C, C->A
function expandToLines(cells) {
return flatten(cells.map(function(cell) {
return [cell[0], cell[1], cell[1], cell[2], cell[2], cell[0]];
}));
}
var vs = `
attribute vec4 position;
uniform mat4 u_matrix;
void main() {
gl_Position = u_matrix * position;
}
`;
var fs = `
precision mediump float;
void main() {
gl_FragColor = vec4(0, 0, 0, 1);
}
`;
var m4 = twgl.m4;
var gl = document.getElementById("c").getContext("webgl");
var programInfo = twgl.createProgramInfo(gl, [vs, fs]);
var arrays = {
position: flatten(points),
indices: expandToLines(cells),
};
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 projection = m4.perspective(
60 * Math.PI / 180, gl.canvas.clientWidth / gl.canvas.clientHeight, 0.5, 20);
var eye = [1, 4, -10];
var target = [0, 0, 0];
var up = [0, 1, 0];
var camera = m4.lookAt(eye, target, up);
var view = m4.inverse(camera);
var viewProjection = m4.multiply(projection, view);
var world = m4.rotateX(m4.rotationY(time), time * 0.7);
var uniforms = {
u_matrix: m4.multiply(viewProjection, world),
};
gl.useProgram(programInfo.program);
twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
twgl.setUniforms(programInfo, uniforms);
twgl.drawBufferInfo(gl, bufferInfo, gl.LINES);
requestAnimationFrame(render);
}
requestAnimationFrame(render);body { margin: 0 }
canvas { width: 100vw; height: 100vh; }<script src="https://twgljs.org/dist/2.x/twgl-full.min.js"></script>
<canvas id="c"></canvas>
请注意，您需要确保不要给出任何重合点。请注意，球体点生成避免了重合点。