54 lines
2.3 KiB
JavaScript
54 lines
2.3 KiB
JavaScript
import { float, Fn, vec2, uv, sin, rand, degrees, cos, Loop, vec4, premultiplyAlpha, unpremultiplyAlpha, convertToTexture, nodeObject } from 'three/tsl';
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/**
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* Applies a hash blur effect to the given texture node.
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*
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* The approach of this blur is different compared to Gaussian and box blur since
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* it does not rely on a kernel to apply a convolution. Instead, it reads the base
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* texture multiple times in a random pattern and then averages the samples. A
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* typical artifact of this technique is a slightly noisy appearance of the blur which
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* can be mitigated by increasing the number of iterations (see `repeats` parameter).
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* Compared to Gaussian blur, hash blur requires just a single pass.
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*
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* Reference: {@link https://www.shadertoy.com/view/4lXXWn}.
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*
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* @function
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* @param {Node<vec4>} textureNode - The texture node that should be blurred.
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* @param {Node<float>} [bluramount=float(0.1)] - This node determines the amount of blur.
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* @param {Object} [options={}] - Additional options for the hash blur effect.
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* @param {Node<float>} [options.repeats=float(45)] - The number of iterations for the blur effect.
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* @param {boolean} [options.premultipliedAlpha=false] - Whether to use premultiplied alpha for the blur effect.
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* @return {Node<vec4>} The blurred texture node.
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*/
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export const hashBlur = /*#__PURE__*/ Fn( ( [ textureNode, bluramount = float( 0.1 ), options = {} ] ) => {
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textureNode = convertToTexture( textureNode );
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const repeats = nodeObject( options.repeats ) || float( 45 );
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const premultipliedAlpha = options.premultipliedAlpha || false;
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const tap = ( uv ) => {
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const sample = textureNode.sample( uv );
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return premultipliedAlpha ? premultiplyAlpha( sample ) : sample;
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};
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const targetUV = textureNode.uvNode || uv();
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const blurred_image = vec4( 0. );
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Loop( { start: 0., end: repeats, type: 'float' }, ( { i } ) => {
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const q = vec2( vec2( cos( degrees( i.div( repeats ).mul( 360. ) ) ), sin( degrees( i.div( repeats ).mul( 360. ) ) ) ).mul( rand( vec2( i, targetUV.x.add( targetUV.y ) ) ).add( bluramount ) ) );
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const uv2 = vec2( targetUV.add( q.mul( bluramount ) ) );
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blurred_image.addAssign( tap( uv2 ) );
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} );
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blurred_image.divAssign( repeats );
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return premultipliedAlpha ? unpremultiplyAlpha( blurred_image ) : blurred_image;
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} );
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