import { TextureInfo } from "../textures/TextureInfo";
import { BaseFilter } from "./BaseFilter";
// prettier-ignore
const _GLSL = "float " +
"luA=oCl.a," +
"luN=uL[0].x," +
"luM=luN-1.;" +
"vec3 " +
"luC=clamp(oCl.rgb/max(luA,1e-4),0.,1.);" +
"float " +
"luB=luC.b*luM," +
"luB0=floor(luB)," +
"luB1=min(luB0+1.,luM);" +
"vec2 " +
"luP=vec2((luC.r*luM+.5)/(luN*luN),(luC.g*luM+.5)/luN);" +
"oCl.rgb=mix(" +
"texture(uH,luP+vec2(luB0/luN,0)).rgb," +
"texture(uH,luP+vec2(luB1/luN,0)).rgb," +
"luB-luB0" +
")*luA;";
/**
* <pre>
* Color lookup table filter
* - Remaps colors through a 3D LUT stored as a horizontal strip texture
* - Strip layout: N slices of N x N pixels side by side (N² x N, e.g. 256 x 16 or 1024 x 32),
* red grows to the right inside a slice, green grows along the rows, blue selects the slice
* - The LUT texture must be opaque and keep the TextureInfo defaults
* (LINEAR filtering, CLAMP_TO_EDGE wrapping, no mipmaps)
* - Works on un-premultiplied colors, the alpha is left untouched
* - The intensity is unused, use mix to fade the effect
* </pre>
* @extends {BaseFilter}
*/
export class ColorLUTFilter extends BaseFilter {
/**
* Creates an instance of ColorLUTFilter.
* @constructor
* @param {object} options
* @param {TextureInfo} options.texture - Required <br>
* - LUT strip texture, the shader samples whatever is bound without it
* @param {number} options.lutSize - Default value 16 <br>
* - Size of one LUT slice (N)
*/
constructor(options = {}) {
super(options);
this.texture = options.texture;
this.lutSize = options.lutSize ?? 16;
}
get GLSL() {
return _GLSL;
}
/**
* Set/Get LUT slice size (N)
* @type {number}
*/
get lutSize() {
return this.customData[0];
}
set lutSize(v) {
this.customData[0] = v;
}
}
Extensions