import { Fn, float, uv, Loop, int } from 'three/tsl';
/** @module MotionBlur **/
/**
* Applies a motion blur effect to the given input node.
*
* @function
* @param {Node<vec4>} inputNode - The input node to apply the motion blur for.
* @param {Node<vec2>} velocity - The motion vectors of the beauty pass.
* @param {Node<int>} [numSamples=int(16)] - How many samples the effect should use. A higher value results in better quality but is also more expensive.
* @return {Node<vec4>} The input node with the motion blur effect applied.
*/
export const motionBlur = /*@__PURE__*/ Fn( ( [ inputNode, velocity, numSamples = int( 16 ) ] ) => {
const sampleColor = ( uv ) => inputNode.sample( uv );
const uvs = uv();
const colorResult = sampleColor( uvs ).toVar();
const fSamples = float( numSamples );
Loop( { start: int( 1 ), end: numSamples, type: 'int', condition: '<=' }, ( { i } ) => {
const offset = velocity.mul( float( i ).div( fSamples.sub( 1 ) ).sub( 0.5 ) );
colorResult.addAssign( sampleColor( uvs.add( offset ) ) );
} );
colorResult.divAssign( fSamples );
return colorResult;
} );