基于BufferGeometry Three.js网未出现 [英] Three.js mesh based on BufferGeometry not appearing

问题描述

我正在使用Three.js＆放一个WebGL的游戏;我决定改用从我的（工作）规则几何形状解决方案BufferGeometry实现。我搞乱的东西了，因为网不画。我已经给了我下面的code中的相关部分。如果我切换到正规的几何形状，一切工作正常。

I'm working on a WebGL game using Three.js & I've decided to switch to a BufferGeometry implementation from my (working) regular geometry solution. I'm messing something up, because the mesh does not draw. I've given the relevant parts of my code below. If I switch to a regular geometry, everything works fine.

这是一个基于体素的比赛，我已经pre-创建的每个立方体作为常规THREE.Geometry的每一面。所述positionVertices函数采用顶点和面从每个面的几何形状，其定位使得它们对应于体素，并生成缓冲器数据为BufferGeometry。没有任何错误或警告，最终目就是不出现。我怀疑我的问题有少做Three.js多的3D图形编程我有限的了解。我最好的猜测现在的问题是，它有什么做的指标不是正确的。如果删除了索引，对象出现，但半三角形的有其法线在相反的方向

It's a voxel based game, and I've pre-created each face of each cube as a regular THREE.Geometry. The positionVertices function takes the vertices and faces from each face geometry, positions them so that they correspond to the voxel, and generates the buffer data for the BufferGeometry. There are no errors or warnings, the final mesh just doesn't appear. I suspect my problem has less to do with Three.js and more with my limited understanding of 3D graphics programming. My best guess right now is that it has something to do with the indexes not being correct. If I remove the indexes, the object appears, but half of the triangles have their normals in the opposite direction.

Chunk.prototype.positionVertices = function( position, vertices, faces, vertexBuffer, indexBuffer, normalBuffer, colorBuffer ) {
    var vertexOffset = vertexBuffer.length / 3;
    for( var i = 0; i < faces.length; ++i ) {
        indexBuffer.push( faces[i].a + vertexOffset );
        indexBuffer.push( faces[i].b + vertexOffset );
        indexBuffer.push( faces[i].c + vertexOffset );

        normalBuffer.push( faces[i].vertexNormals[0].x );
        normalBuffer.push( faces[i].vertexNormals[0].y );
        normalBuffer.push( faces[i].vertexNormals[0].z );

        normalBuffer.push( faces[i].vertexNormals[1].x );
        normalBuffer.push( faces[i].vertexNormals[1].y );
        normalBuffer.push( faces[i].vertexNormals[1].z );

        normalBuffer.push( faces[i].vertexNormals[2].x );
        normalBuffer.push( faces[i].vertexNormals[2].y );
        normalBuffer.push( faces[i].vertexNormals[2].z );
    }

    var color = new THREE.Color();
    color.setRGB( 0, 0, 1 );
    for( var i = 0; i < vertices.length; ++i ) {
        vertexBuffer.push( vertices[i].x + position.x );
        vertexBuffer.push( vertices[i].y + position.y );
        vertexBuffer.push( vertices[i].z + position.z );

        colorBuffer.push( color.r );
        colorBuffer.push( color.g );
        colorBuffer.push( color.b );
    }
};

// This will need to change when more than one type of block exists.
Chunk.prototype.buildMesh = function() {

    var cube = new THREE.Mesh();
    var vertexBuffer = []; // [0] = v.x, [1] = v.y, etc
    var faceBuffer = [];
    var normalBuffer = [];
    var colorBuffer = [];
    for( var k = 0; k < this.size; ++k )
    for( var j = 0; j < this.size; ++j )
    for( var i = 0; i < this.size; ++i ) {
        // Iterates over all of the voxels in this chunk and calls
        // positionVertices( position, vertices, faces, vertexBuffer, indexBuffer, normalBuffer, colorBuffer ) for each face in the chunk
    }

    var bGeo = new THREE.BufferGeometry();

    bGeo.attributes = {

        index: {
            itemSize: 1,
            array: new Uint16Array( faceBuffer ),
            numItems: faceBuffer.length
        },
        position: {
            itemSize: 3,
            array: new Float32Array( vertexBuffer ),
            numItems: vertexBuffer.length
        },
        normal: {
            itemSize: 3,
            array: new Float32Array( normalBuffer ),
            numItems: normalBuffer.length
        },
        color: {
            itemSize: 3,
            array: new Float32Array( colorBuffer ),
            numItems: colorBuffer.length
        }
    }


    var mesh = new THREE.Mesh( bGeo, VOXEL_MATERIALS["ROCK"]);

    return mesh;
}

感谢您的帮助！

Thanks for the help!

推荐答案

我需要设置一个单一的几何偏差。

I needed to set a single offset on the geometry.

    bGeo.offsets = [
        {
            start: 0,
            index: 0,
            count: faceBuffer.length
        }
    ];

固定它。三角形仍显示错了，所以我想坏了脸，但我可以明白这一点很轻松了。

Fixed it. The triangles are still displaying wrong, so I guess the faces are messed up, but I can figure that out easily enough.

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