node_modules/three/src/renderers/shaders/ShaderLib/equirect.glsl.js

export const vertex = /* glsl */`
varying vec3 vWorldDirection;

#include <common>

void main() {

	vWorldDirection = transformDirection( position, modelMatrix );

	#include <begin_vertex>
	#include <project_vertex>

}
`;

export const fragment = /* glsl */`
uniform sampler2D tEquirect;

varying vec3 vWorldDirection;

#include <common>

void main() {

	vec3 direction = normalize( vWorldDirection );

	vec2 sampleUV = equirectUv( direction );

	gl_FragColor = texture2D( tEquirect, sampleUV );

	#include <tonemapping_fragment>
	#include <colorspace_fragment>

}
`;