mergeVertices colors mapping problem

Alejandro_Insua · July 7, 2019, 10:36am

Hi.

I am using Geometry.mergeVertices method and I have realized that colors are not properly mapped after merging.

In my case I have a IndexedBufferGeometry which I convert into a geometry with:
geometry = new THREE.Geometry().fromBufferGeometry( geometry );

After doing this colors i Geometry are ok.

But after applying mergeVertice they don’t.
geometry.mergeVertices();

It seems that this method doesn’t take in mind colors.

Is there any fix for this?

Best regards

Mugen87 · July 7, 2019, 11:08am

Any chances to demonstrate this issue with a live example? Right now, it’s hard to understand the expected and actual visual result.

Alejandro_Insua · July 8, 2019, 5:27am

Hi.

Today I will try to push a live example.

It’s quite easy to demonstrate with a merged BufferGeometry composed of multiple bufferGeometries with different colors.

Best regards

gkjohnson · July 8, 2019, 4:23pm

mergeVertices in the BufferGeometryUtils example should (if I remember right) account for multiple vertex attributes in a geometry and correctly retain vertex colors:

github.com

mrdoob/three.js/blob/f7efa14bcc8b470c071bec277be7bafbfbeb4735/examples/jsm/utils/BufferGeometryUtils.js#L488


		mem += indices ? indices.count * indices.itemSize * indices.array.BYTES_PER_ELEMENT : 0;
		return mem;


	},


	/**
	 * @param {BufferGeometry} geometry
	 * @param {number} tolerance
	 * @return {BufferGeometry>}
	 */
	mergeVertices: function ( geometry, tolerance = 1e-4 ) {


		tolerance = Math.max( tolerance, Number.EPSILON );


		// Generate an index buffer if the geometry doesn't have one, or optimize it
		// if it's already available.
		var hashToIndex = {};
		var indices = geometry.getIndex();
		var positions = geometry.getAttribute( 'position' );
		var vertexCount = indices ? indices.count : positions.count;

I think in general it’s considered best to not use Geometry if you can avoid it.

Alejandro_Insua · July 22, 2019, 6:13am

Hi

Very sorry for the delay.

I have been on vacations in a place with no internet connection. Really nice.

: )

I will try this option and will keep you informed,

Best regards

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mergeVertices colors mapping problem

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