0

我制作了一个使用凸多边形的游戏。我的计划是让这些多边形根据它们的质量和速度发生碰撞和反弹。但首先我需要确保它们没有重叠。此代码检查多边形 A 的每条边，以查看多边形 B 的任何顶点是否在垂直于边的轴上重叠。整个方法返回修复多边形 A 所需的结果向量：

    /**Calculates adjustment vector for EntityPolygon A*/
public Vector calculateCollision(EntityPolygon A, EntityPolygon B) {

    //this is a large number so the first comparison of overlap is true
    double overlap = 10000;

            //this is the angle of the axis to apply the overlap vector
    double angle = 0;

            //I ran a for loop for every edge of the polygon
    for(int x = 0; x <= A.numPoint - 1; x++) {

                    //create variables
        Vector edge;
        Vector axis;
        double centerA;
        double centerB;
        double maxA;
        double maxB;
        double minA;
        double minB;

                    //this if statement finds this point and the next point
                    //to make a Vector of the edge
        if(x != A.numPoint - 1) {
            edge = new Vector(A.point[x], A.point[x + 1]);
        } else {
            edge = new Vector(A.point[x], A.point[0]);
        }

                    //this finds the axis perpendicular axis of the edge
        axis = edge.getRightNormal();

        //finds the location of both polygon's centers when projected onto
                    //the velocity(projectionOnVelocity() projects the point on the                                                           
                    //new axis)
        centerA = A.getLocation().getProjectionOnVelocity(axis);
        centerB = B.getLocation().getProjectionOnVelocity(axis);

                    //finds the location of polygons A and B on the axis by
                    //setting the min and max of their highest and lowest points
        maxA = findMax(A, axis);
        maxB = findMax(B, axis);
        minA = findMin(A, axis);
        minB = findMin(B,axis);

        //final comparison to find overlapping vector.
        if(centerA > centerB) {//if A is above B on the axis
            if(maxB > minA) {//if the max point on B is above min on A
                double m = maxB - minA;
                if(m < overlap) {
                    overlap = m;
                    angle = axis.angle;
                }
            } else {
                                    //(0,0) vector
                return Vector.getDefault();
            }
        } else if(centerB > centerA) {//if B is above A on axis
            if(maxA > minB) {//if the max point on A is above min on B
                double m = maxA - minB;
                if(m < overlap) {
                    overlap = m;
                    angle = axis.angle + Math.PI;
                }
            } else {
                                    //(0,0) vector
                return Vector.getDefault();
            }
        }
    }
            //if the overlap value has been set by the edges of Polygon A
    if(overlap != 10000) {
                    //returns the adjustment vector along overlap edge axis
        return new Vector(angle, overlap, true);
    } else {
                    (0,0) vector
        return Vector.getDefault();
    }
}

这段代码有一个错误，在一个非常平坦的部分高于方形部分的情况下会导致问题，平坦的部分认为它比实际下降得更远。结果，扁平件和方形件发生碰撞，将它们推到下图中的当前位置

这是预赛阶段实际比赛的照片。右边的蓝色方块在他们接触之前就已经被顶部的障碍物移动了。这发生在程序开始时，此时方块位于屏幕的最左侧。

4

1 回答 1

0

我同意 Beta，你的算法看起来不正确（主要是因为我很确定多边形相交不会那么容易。只是为了检查 2 个形状的相交（没有任何智能），你必须检查是否有任何边缘相交与其他形状的任何边缘，但即使是适度简单的形状也很慢。

矩形相交很容易做到，三角形相交应该不会太难，如果你可以将你的形状分成其中一个（或者实际上任何一组具有相当简单公式的形状），它会让事情变得更容易。

你也可以看看这个问题。

多边形相交是一个经过充分研究的问题，只要谷歌一下，你应该会得到很多选择。

于 2012-11-23T18:32:14.843 回答