import { modelWorldMatrix } from '../accessors/ModelNode.js';
import { cameraViewMatrix, cameraProjectionMatrix } from '../accessors/Camera.js';
import { positionLocal } from '../accessors/Position.js';
import { Fn, defined } from '../tsl/TSLBase.js';
/** @module SpriteUtils **/
/**
* This can be used to achieve a billboarding behavior for flat meshes. That means they are
* oriented always towards the camera.
*
* ```js
* material.vertexNode = billboarding();
* ```
*
* @method
* @param {Object} config - The configuration object.
* @param {Node<vec3>?} [config.position=null] - Can be used to define the vertex positions in world space.
* @param {Boolean} [config.horizontal=true] - Whether to follow the camera rotation horizontally or not.
* @param {Boolean} [config.vertical=false] - Whether to follow the camera rotation vertically or not.
* @return {Node<vec3>} The updated vertex position in clip space.
*/
export const billboarding = /*@__PURE__*/ Fn( ( { position = null, horizontal = true, vertical = false } ) => {
let worldMatrix;
if ( position !== null ) {
worldMatrix = modelWorldMatrix.toVar();
worldMatrix[ 3 ][ 0 ] = position.x;
worldMatrix[ 3 ][ 1 ] = position.y;
worldMatrix[ 3 ][ 2 ] = position.z;
} else {
worldMatrix = modelWorldMatrix;
}
const modelViewMatrix = cameraViewMatrix.mul( worldMatrix );
if ( defined( horizontal ) ) {
modelViewMatrix[ 0 ][ 0 ] = modelWorldMatrix[ 0 ].length();
modelViewMatrix[ 0 ][ 1 ] = 0;
modelViewMatrix[ 0 ][ 2 ] = 0;
}
if ( defined( vertical ) ) {
modelViewMatrix[ 1 ][ 0 ] = 0;
modelViewMatrix[ 1 ][ 1 ] = modelWorldMatrix[ 1 ].length();
modelViewMatrix[ 1 ][ 2 ] = 0;
}
modelViewMatrix[ 2 ][ 0 ] = 0;
modelViewMatrix[ 2 ][ 1 ] = 0;
modelViewMatrix[ 2 ][ 2 ] = 1;
return cameraProjectionMatrix.mul( modelViewMatrix ).mul( positionLocal );
} );