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我正在尝试通过使用 3d 点填充查找表来优化 3d 演示（矢量 3D http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/geom/Vector3D.html），我稍后将访问。

这些 3D 点将在 3D 空间中定义一条随机且可循环的路径。

有谁知道实现这一目标的方法？

我正在考虑修改 Greensock Bezier 补间以在 3d 空间中创建一个贝塞尔，然后以某种方式获取生成的补间的 xyz 值。

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好的，你需要做两件事：

  1. 从多个片段创建一个循环的 3D 三次贝塞尔曲线

  2. 创建一个自定义补间函数，它将您的对象作为目标，将贝塞尔循环作为路径和总循环时间。

三次贝塞尔曲线的一个片段总是需要 4 个顶点，一个完整的循环必须包含至少 2 个线段，因此您需要随机创建至少 7 个顶点。顶点的数量始终是3 * NumberOfSegments + 1，但我们将存储3 * NumberOfSegments第一个顶点等于最后一个顶点

最简单的情况（2段，6个顶点）：

...
private function generateRandomPoints():Vector<Vector3D>
{
    var resultingVector:Vector<Vector3D> = new Vector<Vector3D>();
    for(var i:int = 0; i < 6; i++)
    {
        var x:Number = Math.random() * 10;
        var y:Number = Math.random() * 10;
        var z:Number = Math.random() * 10;
        var currentPoint3D:Vector3D = new Vector3D(x, y, z);
        resultingVector.push(currentPoint3D);
    }
    return resultingVector;
}
...

现在，当我们有了路径时，我们可以解析它以获得这种补间效果。您可以在每次需要新坐标时调用此函数（但您需要将初始时间存储在某处），或者创建一个 tweener 对象来为您处理所有事情。我将展示最基本的示例 - 自治功能：

public static function getNextCoordinates(loopStartTime:int, totalLoopTime:int, path:Vector.<Vector3D>):Vector3D
    {
        var resultingPoint:Vector3D = new Vector3D();
        var passedTime:int = getTimer() - loopStartTime;

        //Total passed ratio
        var passedRatio:Number = passedTime / totalLoopTime;
        var totalSegments:int = path.length / 3;

        var totalTimePerSegment:Number = totalLoopTime / totalSegments;

        //So it can loop forever
        while (passedRatio > 1)
        {
            passedRatio -= 1;
        }
        //Let's find our current bezier curve segment number
        var currentSegment:int = Math.floor( passedRatio * totalSegments);
        var currentSegmentRatio:Number = (passedTime - currentSegment * totalTimePerSegment) / totalTimePerSegment;
        //It can be optimized here
        while (currentSegmentRatio > 1)
        {
            currentSegmentRatio -= 1;
        }

        var startingIndex:int = currentSegment * 3;
        //our four path vertices
        var point0:Vector3D = path[startingIndex];
        var point1:Vector3D = path[startingIndex + 1];
        var point2:Vector3D = path[startingIndex + 2];

        //if it's a last segment, we need to "connect" to the first vertex
        if (startingIndex + 3 >= path.length)
        {
            var point3:Vector3D = path[0];
        }
        else
        {
            point3 = path[startingIndex + 3];
        }
        //At last, we find our coordinates
        var tempRatio:Number = 1 - currentSegmentRatio;
        resultingPoint.x = tempRatio * tempRatio * tempRatio * point0.x + 3 * tempRatio * tempRatio * currentSegmentRatio * point1.x + 3 * tempRatio * currentSegmentRatio * currentSegmentRatio * point2.x + currentSegmentRatio * currentSegmentRatio * currentSegmentRatio * point3.x;
        resultingPoint.y = tempRatio * tempRatio * tempRatio * point0.y + 3 * tempRatio * tempRatio * currentSegmentRatio * point1.y + 3 * tempRatio * currentSegmentRatio * currentSegmentRatio * point2.y + currentSegmentRatio * currentSegmentRatio * currentSegmentRatio * point3.y;
        resultingPoint.z = tempRatio * tempRatio * tempRatio * point0.z + 3 * tempRatio * tempRatio * currentSegmentRatio * point1.z + 3 * tempRatio * currentSegmentRatio * currentSegmentRatio * point2.z + currentSegmentRatio * currentSegmentRatio * currentSegmentRatio * point3.z;

        return resultingPoint;
    }

您可以将此函数扩展为补间对象的一部分。我已经在 2D 空间中对其进行了测试，它完美地将精灵的运动沿着随机的多段贝塞尔曲线循环

干杯!

于 2013-09-30T16:28:49.283 回答