backend/libs/three/renderers/webgl/WebGLGeometries.js

import { Uint16BufferAttribute, Uint32BufferAttribute } from '../../core/BufferAttribute.js';
import { arrayMax } from '../../utils.js';

function WebGLGeometries(gl, attributes, info, bindingStates) {
	const geometries = {};
	const wireframeAttributes = new WeakMap();

	function onGeometryDispose(event) {
		const geometry = event.target;

		if (geometry.index !== null) {
			attributes.remove(geometry.index);
		}

		for (const name in geometry.attributes) {
			attributes.remove(geometry.attributes[name]);
		}

		geometry.removeEventListener('dispose', onGeometryDispose);

		delete geometries[geometry.id];

		const attribute = wireframeAttributes.get(geometry);

		if (attribute) {
			attributes.remove(attribute);
			wireframeAttributes.delete(geometry);
		}

		bindingStates.releaseStatesOfGeometry(geometry);

		if (geometry.isInstancedBufferGeometry === true) {
			delete geometry._maxInstanceCount;
		}

		//

		info.memory.geometries--;
	}

	function get(object, geometry) {
		if (geometries[geometry.id] === true) return geometry;

		geometry.addEventListener('dispose', onGeometryDispose);

		geometries[geometry.id] = true;

		info.memory.geometries++;

		return geometry;
	}

	function update(geometry) {
		const geometryAttributes = geometry.attributes;

		// Updating index buffer in VAO now. See WebGLBindingStates.

		for (const name in geometryAttributes) {
			attributes.update(geometryAttributes[name], gl.ARRAY_BUFFER);
		}

		// morph targets

		const morphAttributes = geometry.morphAttributes;

		for (const name in morphAttributes) {
			const array = morphAttributes[name];

			for (let i = 0, l = array.length; i < l; i++) {
				attributes.update(array[i], gl.ARRAY_BUFFER);
			}
		}
	}

	function updateWireframeAttribute(geometry) {
		const indices = [];

		const geometryIndex = geometry.index;
		const geometryPosition = geometry.attributes.position;
		let version = 0;

		if (geometryIndex !== null) {
			const array = geometryIndex.array;
			version = geometryIndex.version;

			for (let i = 0, l = array.length; i < l; i += 3) {
				const a = array[i + 0];
				const b = array[i + 1];
				const c = array[i + 2];

				indices.push(a, b, b, c, c, a);
			}
		} else {
			const array = geometryPosition.array;
			version = geometryPosition.version;

			for (let i = 0, l = array.length / 3 - 1; i < l; i += 3) {
				const a = i + 0;
				const b = i + 1;
				const c = i + 2;

				indices.push(a, b, b, c, c, a);
			}
		}

		const attribute = new (arrayMax(indices) > 65535 ? Uint32BufferAttribute : Uint16BufferAttribute)(indices, 1);
		attribute.version = version;

		// Updating index buffer in VAO now. See WebGLBindingStates

		//

		const previousAttribute = wireframeAttributes.get(geometry);

		if (previousAttribute) attributes.remove(previousAttribute);

		//

		wireframeAttributes.set(geometry, attribute);
	}

	function getWireframeAttribute(geometry) {
		const currentAttribute = wireframeAttributes.get(geometry);

		if (currentAttribute) {
			const geometryIndex = geometry.index;

			if (geometryIndex !== null) {
				// if the attribute is obsolete, create a new one

				if (currentAttribute.version < geometryIndex.version) {
					updateWireframeAttribute(geometry);
				}
			}
		} else {
			updateWireframeAttribute(geometry);
		}

		return wireframeAttributes.get(geometry);
	}

	return {
		get: get,
		update: update,

		getWireframeAttribute: getWireframeAttribute,
	};
}

export { WebGLGeometries };