boolean isCollisionPolygon(int[] xPoints, int[] yPoints, int posx, int posy) {
int i, j;
int y;
int miny, maxy;
int x1, y1;
int x2, y2;
int ind1, ind2;
int ints;
int[] polyInts;
int nPoints = xPoints.length;
if (nPoints < 3) {
return false;
}
polyInts = new int[nPoints];
miny = yPoints[0];
maxy = yPoints[0];
for (i = 1; i < nPoints; i++) {
if (yPoints[i] < miny) {
miny = yPoints[i];
}
else if (yPoints[i] > maxy) {
maxy = yPoints[i];
}
}
for (y = miny; y <= maxy; y++) {
ints = 0;
for (i = 0; i < nPoints; i++) {
if (i == 0) {
ind1 = nPoints - 1;
ind2 = 0;
}
else {
ind1 = i - 1;
ind2 = i;
}
y1 = yPoints[ind1];
y2 = yPoints[ind2];
if (y1 < y2) {
x1 = xPoints[ind1];
x2 = xPoints[ind2];
}
else if (y1 > y2) {
y2 = yPoints[ind1];
y1 = yPoints[ind2];
x2 = xPoints[ind1];
x1 = xPoints[ind2];
}
else {
continue;
}
if ( (y >= y1) && (y < y2)) {
polyInts[ints++] = (y - y1) * (x2 - x1) / (y2 - y1) + x1;
}
else if ( (y == maxy) && (y > y1) && (y <= y2)) {
polyInts[ints++] = (y - y1) * (x2 - x1) / (y2 - y1) + x1;
}
}
for (i = polyInts.length; --i >= 0; ) {
for (j = 0; j < i; j++) {
if (polyInts[j] > polyInts[j + 1]) {
int T = polyInts[j];
polyInts[j] = polyInts[j + 1];
polyInts[j + 1] = T;
}
}
}
for (i = 0; i < ints; i += 2) {
if (posy == y) {
if (posx >= polyInts[i] && posx <= polyInts[i + 1]) {
return true;
}
}
}
}
return false;
}
boolean isCollisionPolygon(int[] xPoints, int[] yPoints, int posx, int posy)
使用方法.
xPoints,是多边形的X坐标,yPoints是Y坐标
posx,posy是那个要检测点的坐标
