70 lines
1.9 KiB
JavaScript
70 lines
1.9 KiB
JavaScript
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import { Mesh, MeshBasicMaterial, SphereGeometry, Vector3 } from 'three';
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/**
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* A ground-projected skybox.
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*
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* By default the object is centered at the camera, so it is often helpful to set
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* `skybox.position.y = height` to put the ground at the origin.
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*
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* ```js
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* const height = 15, radius = 100;
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*
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* const skybox = new GroundedSkybox( envMap, height, radius );
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* skybox.position.y = height;
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* scene.add( skybox );
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* ```
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*
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* @augments Mesh
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* @three_import import { GroundedSkybox } from 'three/addons/objects/GroundedSkybox.js';
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*/
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class GroundedSkybox extends Mesh {
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/**
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* Constructs a new ground-projected skybox.
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*
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* @param {Texture} map - The environment map to use.
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* @param {number} height - The height is how far the camera that took the photo was above the ground.
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* A larger value will magnify the downward part of the image.
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* @param {number} radius - The radius of the skybox. Must be large enough to ensure the scene's camera stays inside.
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* @param {number} [resolution=128] - The geometry resolution of the skybox.
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*/
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constructor( map, height, radius, resolution = 128 ) {
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if ( height <= 0 || radius <= 0 || resolution <= 0 ) {
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throw new Error( 'GroundedSkybox height, radius, and resolution must be positive.' );
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}
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const geometry = new SphereGeometry( radius, 2 * resolution, resolution );
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geometry.scale( 1, 1, - 1 );
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const pos = geometry.getAttribute( 'position' );
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const tmp = new Vector3();
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for ( let i = 0; i < pos.count; ++ i ) {
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tmp.fromBufferAttribute( pos, i );
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if ( tmp.y < 0 ) {
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// Smooth out the transition from flat floor to sphere:
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const y1 = - height * 3 / 2;
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const f =
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tmp.y < y1 ? - height / tmp.y : ( 1 - tmp.y * tmp.y / ( 3 * y1 * y1 ) );
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tmp.multiplyScalar( f );
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tmp.toArray( pos.array, 3 * i );
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}
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}
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pos.needsUpdate = true;
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super( geometry, new MeshBasicMaterial( { map, depthWrite: false } ) );
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}
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}
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export { GroundedSkybox };
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