import TempNode from '../core/TempNode.js';
import { transformedNormalView } from '../accessors/Normal.js';
import { positionViewDirection } from '../accessors/Position.js';
import { nodeImmutable, vec2, vec3 } from '../tsl/TSLBase.js';
/** @module MatcapUVNode **/
/**
* Can be used to compute texture coordinates for projecting a
* matcap onto a mesh. Used by {@link MeshMatcapNodeMaterial}.
*
* @augments TempNode
*/
class MatcapUVNode extends TempNode {
static get type() {
return 'MatcapUVNode';
}
/**
* Constructs a new matcap uv node.
*/
constructor() {
super( 'vec2' );
}
setup() {
const x = vec3( positionViewDirection.z, 0, positionViewDirection.x.negate() ).normalize();
const y = positionViewDirection.cross( x );
return vec2( x.dot( transformedNormalView ), y.dot( transformedNormalView ) ).mul( 0.495 ).add( 0.5 ); // 0.495 to remove artifacts caused by undersized matcap disks
}
}
export default MatcapUVNode;
/**
* TSL function for creating a matcap uv node.
*
* @function
* @returns {MatcapUVNode}
*/
export const matcapUV = /*@__PURE__*/ nodeImmutable( MatcapUVNode );