wiki/node_modules/three/examples/jsm/shaders/BrightnessContrastShader.js

/**
 * @module BrightnessContrastShader
 * @three_import import { BrightnessContrastShader } from 'three/addons/shaders/BrightnessContrastShader.js';
 */

/**
 * Brightness and contrast adjustment {@link https://github.com/evanw/glfx.js}.
 * Brightness: -1 to 1 (-1 is solid black, 0 is no change, and 1 is solid white)
 * Contrast: -1 to 1 (-1 is solid gray, 0 is no change, and 1 is maximum contrast)
 *
 * @constant
 * @type {ShaderMaterial~Shader}
 */
const BrightnessContrastShader = {

	name: 'BrightnessContrastShader',

	uniforms: {

		'tDiffuse': { value: null },
		'brightness': { value: 0 },
		'contrast': { value: 0 }

	},

	vertexShader: /* glsl */`

		varying vec2 vUv;

		void main() {

			vUv = uv;

			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

		}`,

	fragmentShader: /* glsl */`

		uniform sampler2D tDiffuse;
		uniform float brightness;
		uniform float contrast;

		varying vec2 vUv;

		void main() {

			gl_FragColor = texture2D( tDiffuse, vUv );

			gl_FragColor.rgb += brightness;

			if (contrast > 0.0) {
				gl_FragColor.rgb = (gl_FragColor.rgb - 0.5) / (1.0 - contrast) + 0.5;
			} else {
				gl_FragColor.rgb = (gl_FragColor.rgb - 0.5) * (1.0 + contrast) + 0.5;
			}

		}`

};

export { BrightnessContrastShader };