three 基础库
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import {
BoxGeometry,
Vector3
} from '../../../build/three.module.js';
const _tempNormal = new Vector3();
function getUv( faceDirVector, normal, uvAxis, projectionAxis, radius, sideLength ) {
const totArcLength = 2 * Math.PI * radius / 4;
// length of the planes between the arcs on each axis
const centerLength = Math.max( sideLength - 2 * radius, 0 );
const halfArc = Math.PI / 4;
// Get the vector projected onto the Y plane
_tempNormal.copy( normal );
_tempNormal[ projectionAxis ] = 0;
_tempNormal.normalize();
// total amount of UV space alloted to a single arc
const arcUvRatio = 0.5 * totArcLength / ( totArcLength + centerLength );
// the distance along one arc the point is at
const arcAngleRatio = 1.0 - ( _tempNormal.angleTo( faceDirVector ) / halfArc );
if ( Math.sign( _tempNormal[ uvAxis ] ) === 1 ) {
return arcAngleRatio * arcUvRatio;
} else {
// total amount of UV space alloted to the plane between the arcs
const lenUv = centerLength / ( totArcLength + centerLength );
return lenUv + arcUvRatio + arcUvRatio * ( 1.0 - arcAngleRatio );
}
}
class RoundedBoxGeometry extends BoxGeometry {
constructor( width = 1, height = 1, depth = 1, segments = 2, radius = 0.1 ) {
// ensure segments is odd so we have a plane connecting the rounded corners
segments = segments * 2 + 1;
// ensure radius isn't bigger than shortest side
radius = Math.min( width / 2, height / 2, depth / 2, radius );
super( 1, 1, 1, segments, segments, segments );
// if we just have one segment we're the same as a regular box
if ( segments === 1 ) return;
const geometry2 = this.toNonIndexed();
this.index = null;
this.attributes.position = geometry2.attributes.position;
this.attributes.normal = geometry2.attributes.normal;
this.attributes.uv = geometry2.attributes.uv;
//
const position = new Vector3();
const normal = new Vector3();
const box = new Vector3( width, height, depth ).divideScalar( 2 ).subScalar( radius );
const positions = this.attributes.position.array;
const normals = this.attributes.normal.array;
const uvs = this.attributes.uv.array;
const faceTris = positions.length / 6;
const faceDirVector = new Vector3();
const halfSegmentSize = 0.5 / segments;
for ( let i = 0, j = 0; i < positions.length; i += 3, j += 2 ) {
position.fromArray( positions, i );
normal.copy( position );
normal.x -= Math.sign( normal.x ) * halfSegmentSize;
normal.y -= Math.sign( normal.y ) * halfSegmentSize;
normal.z -= Math.sign( normal.z ) * halfSegmentSize;
normal.normalize();
positions[ i + 0 ] = box.x * Math.sign( position.x ) + normal.x * radius;
positions[ i + 1 ] = box.y * Math.sign( position.y ) + normal.y * radius;
positions[ i + 2 ] = box.z * Math.sign( position.z ) + normal.z * radius;
normals[ i + 0 ] = normal.x;
normals[ i + 1 ] = normal.y;
normals[ i + 2 ] = normal.z;
const side = Math.floor( i / faceTris );
switch ( side ) {
case 0: // right
// generate UVs along Z then Y
faceDirVector.set( 1, 0, 0 );
uvs[ j + 0 ] = getUv( faceDirVector, normal, 'z', 'y', radius, depth );
uvs[ j + 1 ] = 1.0 - getUv( faceDirVector, normal, 'y', 'z', radius, height );
break;
case 1: // left
// generate UVs along Z then Y
faceDirVector.set( - 1, 0, 0 );
uvs[ j + 0 ] = 1.0 - getUv( faceDirVector, normal, 'z', 'y', radius, depth );
uvs[ j + 1 ] = 1.0 - getUv( faceDirVector, normal, 'y', 'z', radius, height );
break;
case 2: // top
// generate UVs along X then Z
faceDirVector.set( 0, 1, 0 );
uvs[ j + 0 ] = 1.0 - getUv( faceDirVector, normal, 'x', 'z', radius, width );
uvs[ j + 1 ] = getUv( faceDirVector, normal, 'z', 'x', radius, depth );
break;
case 3: // bottom
// generate UVs along X then Z
faceDirVector.set( 0, - 1, 0 );
uvs[ j + 0 ] = 1.0 - getUv( faceDirVector, normal, 'x', 'z', radius, width );
uvs[ j + 1 ] = 1.0 - getUv( faceDirVector, normal, 'z', 'x', radius, depth );
break;
case 4: // front
// generate UVs along X then Y
faceDirVector.set( 0, 0, 1 );
uvs[ j + 0 ] = 1.0 - getUv( faceDirVector, normal, 'x', 'y', radius, width );
uvs[ j + 1 ] = 1.0 - getUv( faceDirVector, normal, 'y', 'x', radius, height );
break;
case 5: // back
// generate UVs along X then Y
faceDirVector.set( 0, 0, - 1 );
uvs[ j + 0 ] = getUv( faceDirVector, normal, 'x', 'y', radius, width );
uvs[ j + 1 ] = 1.0 - getUv( faceDirVector, normal, 'y', 'x', radius, height );
break;
}
}
}
}
export { RoundedBoxGeometry };