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📄 GroundedSkybox.js

📊 Analysis Summary

Metric	Count
🧱 Classes	1
📦 Imports	4
📊 Variables & Constants	4

📚 Table of Contents

• Imports
• Variables & Constants
• Classes

🛠️ File Location:

📂 examples/jsm/objects/GroundedSkybox.js

📦 Imports

Name	Source
Mesh	three
MeshBasicMaterial	three
SphereGeometry	three
Vector3	three

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Variables & Constants

Name	Type	Kind	Value	Exported
geometry	any	let/var	new SphereGeometry( radius, 2 * resolution, resolution )	✗
tmp	any	let/var	new Vector3()	✗
y1	number	let/var	- height * 3 / 2	✗
f	number	let/var	tmp.y < y1 ? - height / tmp.y : ( 1 - tmp.y * tmp.y / ( 3 * y1 * y1 ) )	✗

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Classes

GroundedSkybox

Class Code

class GroundedSkybox extends Mesh {

    /**
     * Constructs a new ground-projected skybox.
     *
     * @param {Texture} map - The environment map to use.
     * @param {number} height - The height is how far the camera that took the photo was above the ground.
     * A larger value will magnify the downward part of the image.
     * @param {number} radius - The radius of the skybox. Must be large enough to ensure the scene's camera stays inside.
     * @param {number} [resolution=128] - The geometry resolution of the skybox.
     */
    constructor( map, height, radius, resolution = 128 ) {

        if ( height <= 0 || radius <= 0 || resolution <= 0 ) {

            throw new Error( 'GroundedSkybox height, radius, and resolution must be positive.' );

        }

        const geometry = new SphereGeometry( radius, 2 * resolution, resolution );
        geometry.scale( 1, 1, - 1 );

        const pos = geometry.getAttribute( 'position' );
        const tmp = new Vector3();

        for ( let i = 0; i < pos.count; ++ i ) {

            tmp.fromBufferAttribute( pos, i );
            if ( tmp.y < 0 ) {

                // Smooth out the transition from flat floor to sphere:
                const y1 = - height * 3 / 2;
                const f =
                        tmp.y < y1 ? - height / tmp.y : ( 1 - tmp.y * tmp.y / ( 3 * y1 * y1 ) );
                tmp.multiplyScalar( f );
                tmp.toArray( pos.array, 3 * i );

            }

        }

        pos.needsUpdate = true;

        super( geometry, new MeshBasicMaterial( { map, depthWrite: false } ) );

    }

}

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