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https://github.com/photonstorm/phaser
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19 lines
869 B
JavaScript
19 lines
869 B
JavaScript
/**
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* Darkens or lightens the colors, depending on the source color value.
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*
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* If the source color is lighter than 0.5, the backdrop is lightened, as if it were dodged;
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* this is useful for adding highlights to a scene.
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*
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* If the source color is darker than 0.5, the backdrop is darkened, as if it were burned in.
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* The degree of lightening or darkening is proportional to the difference between the source color and 0.5;
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* if it is equal to 0.5, the backdrop is unchanged.
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*
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* Painting with pure black or white produces a distinctly darker or lighter area, but does not result in pure black or white.
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* The effect is similar to shining a diffused spotlight on the backdrop.
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*/
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var SoftLight = function (a, b)
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{
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return (b < 128) ? (2 * ((a >> 1) + 64)) * (b / 255) : 255 - (2 * (255 - ((a >> 1) + 64)) * (255 - b) / 255);
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};
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module.exports = SoftLight;
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