import TempNode from '../core/TempNode.js';
import { positionWorldDirection } from '../accessors/Position.js';
import { nodeProxy, vec2 } from '../tsl/TSLBase.js';
/** @module EquirectUVNode **/
/**
* Can be used to compute texture coordinates for projecting an
* equirectangular texture onto a mesh for using it as the scene's
* background.
*
* ```js
* scene.backgroundNode = texture( equirectTexture, equirectUV() );
* ```
*
* @augments TempNode
*/
class EquirectUVNode extends TempNode {
static get type() {
return 'EquirectUVNode';
}
/**
* Constructs a new equirect uv node.
*
* @param {Node<vec3>} [dirNode=positionWorldDirection] - A direction vector for sampling which is by default `positionWorldDirection`.
*/
constructor( dirNode = positionWorldDirection ) {
super( 'vec2' );
/**
* A direction vector for sampling why is by default `positionWorldDirection`.
*
* @type {Node<vec3>}
*/
this.dirNode = dirNode;
}
setup() {
const dir = this.dirNode;
const u = dir.z.atan( dir.x ).mul( 1 / ( Math.PI * 2 ) ).add( 0.5 );
const v = dir.y.clamp( - 1.0, 1.0 ).asin().mul( 1 / Math.PI ).add( 0.5 );
return vec2( u, v );
}
}
export default EquirectUVNode;
/**
* TSL function for creating an equirect uv node.
*
* @function
* @param {Node<vec3>} [dirNode=positionWorldDirection] - A direction vector for sampling which is by default `positionWorldDirection`.
* @returns {EquirectUVNode}
*/
export const equirectUV = /*@__PURE__*/ nodeProxy( EquirectUVNode );