Threejs BufferGeometry - Render some faces with other Texture

1
votes

i have an output date like this:

geom[0] = {

texturesindexT: new Int16Array([0,1,2,3]),
texturesindexS: new Int16Array([-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,...]),

materialsindexT: new Int16Array([-1,-1,-1,-1]),
materialsindexS: new Int16Array([-1,0,1,2,3,4,5,0,6,2,7,8,-1,0,...]),

startIndicesT: new Uint32Array([0,288,606,897,1380]),
startIndicesS: new Uint32Array([1380,1431,1479,1485,1497,1515,1659,...]),

m_indices: new Uint16Array([0,1,2,3,0,2,4,2,5,4,6,2,7,3,2,8,9,10,...]),

m_vertices: new Float32Array([-81.93996,25.7185,-85.53822,-81.93996,...]),

m_normals: new Float32Array([-0.004215205,0.9999894,-0.001817489,-0.004215205,...]),

m_texCoords: new Float32Array([0,0.04391319,0,0.2671326,0.009521127,0.03514284,...]),

}

var textures = new Array("-1_-1/t0.jpg","-1_-1/t1.jpg","-1_-1/t2.jpg",...);

The Data is in order for an Index, Vertex and Normal-Buffer but sections have to be rendered with other Textures and Maretials.

I have tried to make a THREE.Geometry out of the indices, vertices and texCoords/UVCoords but that didn't work.

Now i am trying use a THREE.BufferGeometry() and this work BUT i need to render index 0 to 287 with Texture "textures[0]" and index 288 to 605 with "textures[1]" and so on.

My first attempt was to make a BufferGeometry for each part with index 288 to 605 , but since the Indices are in order for the hole model, i have to put the complete vertices, normales and UVCoords in the Buffer for just a couple of faces.

Is there a way to render sections of the BufferGeometry with other Textures or to set the Texture Index for each Face?

Or is it possible to create a Material, that renders the first X faces with Texture A and the next with Texture B???

2
javascript3dthree.jsbuffer-geometry

2 Answers

1
votes

If you want to use two different textures with a single BufferGeometry, you can use this pattern, which sets drawcalls:

var geometry1 = new THREE.BufferGeometry();
// ...and set the data...
var geometry2 = geometry1.clone();

// set drawcalls
geometry1.offsets = geometry1.drawcalls = []; // currently required
geometry1.addDrawCall( start1, count1, 0 );

geometry2.offsets = geometry2.drawcalls = []; // currently required
geometry2.addDrawCall( start2, count2, 0 );

var material1 = new THREE.MeshPhongMaterial( { map: map1 } );
var material2 = new THREE.MeshPhongMaterial( { map: map2 } );

var mesh1 = new THREE.Mesh( geometry1, material1 );
var mesh2 = new THREE.Mesh( geometry2, material2 );

three.js r.70

1
votes

You can create two geometries with same vertex buffers and different indexes:

var position = new THREE.BufferAttribute(positionArray, 3);
var normal = new THREE.BufferAttribute(normalArray, 3);
var uv = new THREE.BufferAttribute(uvArray, 2);

var indices1 = new THREE.BufferAttribute(indexArray1, 1);
var geometry1 = new THREE.BufferGeometry();
geometry1.addAttribute('position', position);
geometry1.addAttribute('normal', normal);
geometry1.addAttribute('uv', uv);
geometry1.addAttribute('index', indices1);

var indices2 = new THREE.BufferAttribute(indexArray2, 1);
var geometry2 = new THREE.BufferGeometry();
geometry2.addAttribute('position', position);
geometry2.addAttribute('normal', normal);
geometry2.addAttribute('uv', uv);
geometry2.addAttribute('index', indices2);

and then create 2 meshes with different materials as you normally would. As far as I understand, this will re-use same data in both meshes.