如何使用three.js所两种颜色之间吐温？ [英] How to tween between two colours using three.js?

问题描述

我有一个three.js所对象，它是一个给定的颜色。我想要顺利动画到另一个颜色。在动画，它应该只显示的开始和结束之间的直接灰度。即，它不应该在RGB颜色空间线性执行补间。我甚至相信HSV空间内的线性补看起来不太妙。

I have an three.js object which is a given colour. I want to animate it smoothly to another colour. During the animation, it should only show a direct gradation between the start and end. That is, it should not perform the tween linearly in RGB colour space. I'm not even sure that a linear tween within HSV space would look good either.

我怎样才能得到这种颜色调整的three.js所对象？

How can I get this kind of colour tween on a three.js object?

推荐答案

我有一个版本的这一点，使得HSV空间补间。它并不是完美的，因为许多不同的色调可以前进的道路上出现。

I have a version of this that makes a tween in HSV space. It's not perfect, as many different hues can appear along the way.

three.js所不包括从 THREE.Color 获取HSV值的方法。因此，添加一个：

Three.js doesn't include a method for getting the HSV values from a THREE.Color. So, add one:

THREE.Color.prototype.getHSV = function()
{
    var rr, gg, bb,
        h, s,
        r = this.r,
        g = this.g,
        b = this.b,
        v = Math.max(r, g, b),
        diff = v - Math.min(r, g, b),
        diffc = function(c)
        {
            return (v - c) / 6 / diff + 1 / 2;
        };

    if (diff == 0) {
        h = s = 0;
    } else {
        s = diff / v;
        rr = diffc(r);
        gg = diffc(g);
        bb = diffc(b);

        if (r === v) {
            h = bb - gg;
        } else if (g === v) {
            h = (1 / 3) + rr - bb;
        } else if (b === v) {
            h = (2 / 3) + gg - rr;
        }
        if (h < 0) {
            h += 1;
        } else if (h > 1) {
            h -= 1;
        }
    }
    return {
        h: h,
        s: s,
        v: v
    };
};

然后，吐温是相对比较简单：

Then, the tween is relatively straightforward:

new TWEEN.Tween(mesh.material.color.getHSV())
    .to({h: h, s: s, v: v}, 200)
    .easing(TWEEN.Easing.Quartic.In)
    .onUpdate(
        function()
        {
            mesh.material.color.setHSV(this.h, this.s, this.v);
        }
    )
    .start();

我很想听到更多的感知自然过渡。

I'd be interested to hear of a more perceptually natural transition.

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