import { Mesh, IcosahedronGeometry, ShaderMaterial, DoubleSide } from 'three';
/**
* Ground projected env map adapted from @react-three/drei.
* https://github.com/pmndrs/drei/blob/master/src/core/Environment.tsx
*/
export class GroundProjectedEnv extends Mesh {
constructor( texture, options = {} ) {
const isCubeMap = texture.isCubeTexture;
const defines = [
isCubeMap ? '#define ENVMAP_TYPE_CUBE' : ''
];
const vertexShader = /* glsl */ `
varying vec3 vWorldPosition;
void main()
{
vec4 worldPosition = ( modelMatrix * vec4( position, 1.0 ) );
vWorldPosition = worldPosition.xyz;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}
`;
const fragmentShader = defines.join( '\n' ) + /* glsl */ `
varying vec3 vWorldPosition;
uniform float radius;
uniform float height;
uniform float angle;
#ifdef ENVMAP_TYPE_CUBE
uniform samplerCube map;
#else
uniform sampler2D map;
#endif
// From: https://www.shadertoy.com/view/4tsBD7
float diskIntersectWithBackFaceCulling( vec3 ro, vec3 rd, vec3 c, vec3 n, float r )
{
float d = dot ( rd, n );
if( d > 0.0 ) { return 1e6; }
vec3 o = ro - c;
float t = - dot( n, o ) / d;
vec3 q = o + rd * t;
return ( dot( q, q ) < r * r ) ? t : 1e6;
}
// From: https://www.iquilezles.org/www/articles/intersectors/intersectors.htm
float sphereIntersect( vec3 ro, vec3 rd, vec3 ce, float ra )
{
vec3 oc = ro - ce;
float b = dot( oc, rd );
float c = dot( oc, oc ) - ra * ra;
float h = b * b - c;
if( h < 0.0 ) { return -1.0; }
h = sqrt( h );
return - b + h;
}
vec3 project()
{
vec3 p = normalize( vWorldPosition );
vec3 camPos = cameraPosition;
camPos.y -= height;
float intersection = sphereIntersect( camPos, p, vec3( 0.0 ), radius );
if( intersection > 0.0 ) {
vec3 h = vec3( 0.0, - height, 0.0 );
float intersection2 = diskIntersectWithBackFaceCulling( camPos, p, h, vec3( 0.0, 1.0, 0.0 ), radius );
p = ( camPos + min( intersection, intersection2 ) * p ) / radius;
} else {
p = vec3( 0.0, 1.0, 0.0 );
}
return p;
}
#include <common>
void main()
{
vec3 projectedWorldPosition = project();
#ifdef ENVMAP_TYPE_CUBE
vec3 outcolor = textureCube( map, projectedWorldPosition ).rgb;
#else
vec3 direction = normalize( projectedWorldPosition );
vec2 uv = equirectUv( direction );
vec3 outcolor = texture2D( map, uv ).rgb;
#endif
gl_FragColor = vec4( outcolor, 1.0 );
#include <tonemapping_fragment>
#include <encodings_fragment>
}
`;
const uniforms = {
map: { value: texture },
height: { value: options.height || 15 },
radius: { value: options.radius || 100 },
};
const geometry = new IcosahedronGeometry( 1, 16 );
const material = new ShaderMaterial( {
uniforms,
fragmentShader,
vertexShader,
side: DoubleSide,
} );
super( geometry, material );
this.type = 'GroundProjectedEnv';
}
set radius( radius ) {
this.material.uniforms.radius.value = radius;
}
get radius() {
return this.material.uniforms.radius.value;
}
set height( height ) {
this.material.uniforms.height.value = height;
}
get height() {
return this.material.uniforms.height.value;
}
}