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- /**
- * Adjusts the saturation of a color.
- *
- * @name czm_saturation
- * @glslFunction
- *
- * @param {vec3} rgb The color.
- * @param {float} adjustment The amount to adjust the saturation of the color.
- *
- * @returns {float} The color with the saturation adjusted.
- *
- * @example
- * vec3 greyScale = czm_saturation(color, 0.0);
- * vec3 doubleSaturation = czm_saturation(color, 2.0);
- */
- vec3 czm_saturation(vec3 rgb, float adjustment)
- {
- // Algorithm from Chapter 16 of OpenGL Shading Language
- const vec3 W = vec3(0.2125, 0.7154, 0.0721);
- vec3 intensity = vec3(dot(rgb, W));
- return mix(intensity, rgb, adjustment);
- }
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