4

I have created programmatically a simple mesh:

var CreateSimpleMesh = new function () {
    var xy = [],
        maxX = 7,
        maxY = 10,
        river = [[0, 5], [0, 4], [1, 3], [2, 2], [3, 2], [4, 1], [5, 1], [6, 0]],
        grassGeometry = new THREE.BufferGeometry(),
        grassVertexPositions = []

    this.init = function () {
        for (i = 0; i < maxX; i++) {
            for (j = 0; j < maxY; j++) {
                xy.push([i, j])
            }
        }

        for (var i = 0; i < xy.length; i++) {
            grassVertexPositions.push([xy[i][0], xy[i][1], 0])
            grassVertexPositions.push([xy[i][0] + 1, xy[i][1], 0])
            grassVertexPositions.push([xy[i][0], xy[i][1] + 1, 0])

            grassVertexPositions.push([xy[i][0] + 1, xy[i][1] + 1, 0])
            grassVertexPositions.push([xy[i][0], xy[i][1] + 1, 0])
            grassVertexPositions.push([xy[i][0] + 1, xy[i][1], 0])
        }

        for (var i = 0; i < grassVertexPositions.length; i++) {
            for (var j = 0; j < river.length; j++) {
                if (river[j][0] == grassVertexPositions[i][0] && river[j][1] == grassVertexPositions[i][1]) {
                    grassVertexPositions[i][2] = -0.5
                }
            }
        }

        var grassVertices = new Float32Array(grassVertexPositions.length * 3)

        for (var i = 0; i < grassVertexPositions.length; i++) {
            grassVertices[i * 3 + 0] = grassVertexPositions[i][0];
            grassVertices[i * 3 + 1] = grassVertexPositions[i][1];
            grassVertices[i * 3 + 2] = grassVertexPositions[i][2];
        }

        grassGeometry.addAttribute('position', new THREE.BufferAttribute(grassVertices, 3))

    var grassMaterial = new THREE.MeshLambertMaterial({color: 0x00ff00}),
        grassMesh = new THREE.Mesh(grassGeometry, grassMaterial)

        grassMesh.rotation.x = -Math.PI / 2
        Test.getScene().add(grassMesh);
    }
}

Problem is that this mesh has only vertices. I have tried to add to it faces like in this question using THREE.Shape.Utils.triangulateShape but BufferGeometry is different than normal geometry and it does not work. Is it possible to add faces to BufferGeometry?

EDIT: Working fiddle

4

2 回答 2

3

以下是如何创建具有BufferGeometry. BufferGeometry这是不共享顶点的更简单的“非索引” 。

// non-indexed buffer geometry
var geometry = new THREE.BufferGeometry();

// number of triangles
var NUM_TRIANGLES = 10;

// attributes
var positions = new Float32Array( NUM_TRIANGLES * 3 * 3 );
var normals   = new Float32Array( NUM_TRIANGLES * 3 * 3 );
var colors    = new Float32Array( NUM_TRIANGLES * 3 * 3 );
var uvs       = new Float32Array( NUM_TRIANGLES * 3 * 2 );

var color = new THREE.Color();
var scale = 15;
var size = 5;
var x, y, z;

for ( var i = 0, l = NUM_TRIANGLES * 3; i < l; i ++ ) {

    if ( i % 3 === 0 ) {

        x = ( Math.random() - 0.5 ) * scale;
        y = ( Math.random() - 0.5 ) * scale;
        z = ( Math.random() - 0.5 ) * scale;

    } else {

        x = x + size * ( Math.random() - 0.5 );
        y = y + size * ( Math.random() - 0.5 );
        z = z + size * ( Math.random() - 0.5 );

    }

    var index = 3 * i;

    // positions
    positions[ index     ] = x;
    positions[ index + 1 ] = y;
    positions[ index + 2 ] = z;

    //normals -- we will set normals later

    // colors
    color.setHSL( i / l, 1.0, 0.5 );
    colors[ index     ] = color.r;
    colors[ index + 1 ] = color.g;
    colors[ index + 2 ] = color.b;

    // uvs
    uvs[ index     ] = Math.random(); // just something...
    uvs[ index + 1 ] = Math.random();

}

geometry.addAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
geometry.addAttribute( 'normal', new THREE.BufferAttribute( normals, 3 ) );
geometry.addAttribute( 'color', new THREE.BufferAttribute( colors, 3 ) );
geometry.addAttribute( 'uv', new THREE.BufferAttribute( uvs, 2 ) );

// optional
geometry.computeBoundingBox();
geometry.computeBoundingSphere();

// set the normals
geometry.computeVertexNormals(); // computed vertex normals are orthogonal to the face for non-indexed BufferGeometry

小提琴：http: //jsfiddle.net/5co6c27w/

有关创建BufferGeometry. 还可以查看PlaneBufferGeometry和的源代码SphereBufferGeometry，它们相当容易理解。

三.js r.73

于 2015-12-08T06:16:25.280 回答
1

您可以使用 three.js 内部函数添加面孔 - fromBufferGeometry。在你的情况下，它会是这样的。

var directGeo = new THREE.Geometry();
directGeo.fromBufferGeometry(grassGeometry);

然后用directGeo它来构建你的网格，它会有面。

于 2017-04-20T03:32:23.673 回答