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- <h1>[name]</h1>
- <p class="desc">
- 一个包含 [page:BufferGeometry BufferGeometry] 实例的实用方法的类。
- </p>
- <h2>导入</h2>
- <p>
- [name] 是一个附加组件,必须显式导入。
- See [link:#manual/introduction/Installation Installation / Addons].
- </p>
- <code>
- import * as BufferGeometryUtils from 'three/addons/utils/BufferGeometryUtils.js';
- </code>
- <h2>方法</h2>
- <h3>[method:Object computeMikkTSpaceTangents]( [param:BufferGeometry geometry], [param:Object MikkTSpace], [param:Boolean negateSign] = true )</h3>
- <ul>
- <li>geometry -- Instance of [page:BufferGeometry].</li>
- <li>MikkTSpace -- Instance of <i>examples/jsm/libs/mikktspace.module.js</i>, or <i>mikktspace</i> npm package. Await <i>MikkTSpace.ready</i> before use.
- <li>negateSign -- Whether to negate the sign component (.w) of each tangent. Required for normal map conventions in some formats, including glTF.</li>
- </ul>
- <p>
- Computes vertex tangents using the [link:http://www.mikktspace.com/ MikkTSpace] algorithm.
- MikkTSpace generates the same tangents consistently, and is used in most modelling tools and
- normal map bakers. Use MikkTSpace for materials with normal maps, because inconsistent
- tangents may lead to subtle visual issues in the normal map, particularly around mirrored
- UV seams.
- </p>
- <p>
- In comparison to this method, [page:BufferGeometry.computeTangents] (a
- custom algorithm) generates tangents that probably will not match the tangents
- in other software. The custom algorithm is sufficient for general use with a
- [page:ShaderMaterial], and may be faster than MikkTSpace.
- </p>
- <p>
- Returns the original [page:BufferGeometry]. Indexed geometries will be de-indexed.
- Requires position, normal, and uv attributes.
- </p>
- <h3>[method:Object computeMorphedAttributes]( [param:Mesh | Line | Points object] )</h3>
- <p>
- object -- Instance of [page:Mesh Mesh] | [page:Line Line] | [page:Points Points].<br /><br />
- Returns the current attributes (Position and Normal) of a morphed/skinned [page:Object3D Object3D] whose geometry is a
- [page:BufferGeometry BufferGeometry], together with the original ones: An Object with 4 properties:
- `positionAttribute`, `normalAttribute`, `morphedPositionAttribute` and `morphedNormalAttribute`.
- Helpful for Raytracing or Decals (i.e. a [page:DecalGeometry DecalGeometry] applied to a morphed Object
- with a [page:BufferGeometry BufferGeometry] will use the original BufferGeometry, not the morphed/skinned one,
- generating an incorrect result.
- Using this function to create a shadow Object3D the DecalGeometry can be correctly generated).
- </p>
- <h3>[method:Number estimateBytesUsed]( [param:BufferGeometry geometry] )</h3>
- <p>
- geometry -- 通过 [page:BufferGeometry BufferGeometry] 的实例来估计内存使用情况。<br /><br />
- 返回所有用于表示几何体的属性所占用的字节数。
- </p>
- <h3>[method:InterleavedBufferAttribute interleaveAttributes]( [param:Array attributes] )</h3>
- <p>
- attributes -- 由 [page:BufferAttribute BufferAttribute] 实例组成的数组。<br /><br />
- 交叉存储一组属性并返回一个新的对应属性数组,这些属性共享一个 InterleavedBuffer 实例。所有属性都必须兼容的该类型。如果合并不成功,则该方法返回 null 。
- </p>
- <h3>[method:BufferAttribute mergeAttributes]( [param:Array attributes] )</h3>
- <p>
- attributes -- 由 [page:BufferAttribute BufferAttribute] 实例组成的数组。<br /><br />
- 将一组属性合并为一个单一的实例。所有几何体都必须兼容该属性,不支持 [page:InterleavedBufferAttribute InterleavedBufferAttributes] 。
- 如果合并不成功,则该方法返回 null 。
- </p>
- <h3>[method:BufferGeometry mergeGeometries]( [param:Array geometries], [param:Boolean useGroups] )</h3>
- <p>
- geometries -- 由 [page:BufferGeometry BufferGeometry] 实例的数组。<br />
- useGroups -- 是否要为了合并几何体而产生组。<br /><br />
- 将一组几何体合并到一个实例中。所有几何体都必须兼容该属性。
- 如果合并不成功,则该方法返回 null。
- </p>
- <h3>[method:BufferGeometry mergeGroups]( [param:BufferGeometry geometry] )</h3>
- <p>
- geometry -- Instance of [page:BufferGeometry BufferGeometry] to merge the groups of.<br /><br />
- Merges the [page:BufferGeometry.groups groups] for the given geometry.
- </p>
- <h3>[method:BufferGeometry mergeVertices]( [param:BufferGeometry geometry], [param:Number tolerance] )</h3>
- <p>
- geometry -- 用于合并顶点的 [page:BufferGeometry BufferGeometry] 实例。<br />
- tolerance -- 要合并的顶点属性之间允许的最大差异。 默认为 1e-4。<br /><br />
- 返回一个新的 [page:BufferGeometry BufferGeometry] ,其中包含将所有(在容差范围内的)具有相似属性的顶点合并而成的顶点。
- </p>
- <h3>[method:BufferGeometry toCreasedNormals]( [param:BufferGeometry geometry], [param:Number creaseAngle] )</h3>
- <ul>
- <li>geometry -- The input geometry.</li>
- <li>creaseAngle -- The crease angle in radians.</li>
- </ul>
- <p>
- Modifies the supplied geometry if it is non-indexed, otherwise creates a new,
- non-indexed geometry.
- </p>
- <p>
- Returns the geometry with smooth normals everywhere except faces
- that meet at an angle greater than the crease angle.
- </p>
- <h3>[method:BufferGeometry toTrianglesDrawMode]( [param:BufferGeometry geometry], [param:TrianglesDrawMode drawMode] )</h3>
- <p>
- geometry -- Instance of [page:BufferGeometry BufferGeometry].<br />
- drawMode -- The draw mode of the given geometry. Valid inputs are `THREE.TriangleStripDrawMode` and `THREE.TriangleFanDrawMode`.<br /><br />
- Returns a new indexed geometry based on `THREE.TrianglesDrawMode` draw mode. This mode corresponds to the `gl.TRIANGLES` WebGL primitive.
- </p>
- <h2>源代码</h2>
- <p>
- [link:https://github.com/mrdoob/three.js/blob/master/examples/jsm/utils/BufferGeometryUtils.js examples/jsm/utils/BufferGeometryUtils.js]
- </p>
- </body>
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