public void paint(Graphics g)
{
g.drawImage(bufImg,0,0,0);
}

int nodes[][] = {//8/
{20,100},//0
{100,40},//1
{170,80},//2
{150,110},//3
{170,170},//4
{160,150},//5
{110,110},//6
{50,130}//7
};

/*
检查线段x0,y0,x1,y1,与 选段y 的相交情况。
*/
private boolean checkForCut(int y, int y0, int y1)
{
if(y0>=y&&y1<=y){
return true;
}
if(y0<=y&&y1>=y){
return true;
}
return false;
}

//先进后出堆桟
private int heaps[] = null;
//入栈
private void push(int intNum)
{
//增加栈容量
int heapslength;// = heaps.length;
if(heaps != null){
heapslength = heaps.length;
int temp[] = new int[heapslength];
for(int i = 0; i < heapslength; i++){
temp[i] = heaps[i];
}
heaps = new int[heapslength+1];
for(int i = 0; i < heapslength; i++){
heaps[i] =temp[i];
}
}else{
heapslength = 0;
heaps = new int[1];
}

//入栈
heaps[heapslength] = intNum;
System.gc();
}
//出栈
private int pop()
{
if(heaps==null){return -1;}
int heapslength = heaps.length - 1;
int intNum = heaps[heapslength];
if(heapslength == 0){
heaps = null;
}else{
//出栈后缩小栈容量
int temp[] = new int[heapslength];
for(int i = 0; i < heapslength; i++)
{
temp[i] = heaps[i];
}
heaps = new int[heapslength];
for(int i = 0; i < heapslength; i++)
{
heaps[i] = temp[i];
}
System.gc();
}
return intNum;
}

//排序栈（从大到小），算法好坏会对扫描算法有直接影响
private void sortHeaps()
{
if(heaps == null){
return;
}

int heapslength = heaps.length;
//偷懒，偷懒，我就用冒泡排序了^-^&
for(int i = 0; i < heapslength-1; i++){
for(int j = 0; j < heapslength - i - 1; j++){
if(heaps[j]<heaps[j+1]){
int temp = heaps[j];
heaps[j] = heaps[j+1];
heaps[j+1] = temp;
}
}
}
}

private void getCut(int nodes[][],int y)//将交点坐标x入栈
{
int sideNum = nodes.length;
int tx = 0;

for(int i = 0; i < sideNum-1; i++)
{
int x0 = nodes[i][0];
int y0 = nodes[i][1];
int x1 = nodes[i+1][0];
int y1 = nodes[i+1][1];
if(y0 == y1&&y0 == y){
push(x0);
push(x1);
continue;
}
if(checkForCut(y,nodes[i][1],nodes[i+1][1])){
tx = (x1 - x0) * (y - y0) / (y1 - y0) + x0;
push(tx);
}
}
if(nodes[0][1] == nodes[sideNum-1][1]&&nodes[0][1]==y){
push(nodes[0][0]);
push(nodes[sideNum-1][0]);
}else{
if(checkForCut(y,nodes[0][1],nodes[sideNum-1][1])){
tx = (nodes[0][0] - nodes[sideNum-1][0])*(y-nodes[sideNum-1][1])/(nodes[0][1] - nodes[sideNum-1][1])+nodes[sideNum-1][0];
push(tx);
}
}
sortHeaps();
}

private void fillPolygon(int nodes[][])
{
gb.setColor(0x00ff0000);
for(int i = 0; i < nHeight; i++){

getCut(nodes,i);

int bx = 0;
if(heaps == null)
continue;

int j = 0;
while(heaps != null){
if((j%2)==0){
int ex = pop();

bx = ex;
}else{
int ex = pop();

gb.drawLine(bx,i,ex,i);
bx = ex;
}
j++;

}
}
}

private void drawPolygon(int nodes[][])
{
gb.setColor(0x0000ff00);
for(int i = 0; i < nodes.length-1; i++){
gb.drawLine(nodes[i][0],nodes[i][1],nodes[i+1][0],nodes[i+1][1]);
gb.fillArc(nodes[i][0] - 10,nodes[i][1] - 10,20,20,0,360);
}
gb.drawLine(nodes[0][0],nodes[0][1], nodes[nodes.length-1][0], nodes[nodes.length-1][1]);
gb.fillArc(nodes[nodes.length-1][0] - 10,nodes[nodes.length-1][1] - 10,20,20,0,360);
}

public void run()
{
gb.setColor(0x00ffffff);
gb.fillRect(0,0,nWidth,nHeight);
fillPolygon(nodes);
System.out.println("done1");
drawPolygon(nodes);
System.out.println("done2");
repaint();
}

private void pause(long t)
{
try{Thread.sleep(t);}catch(Exception e){}
}

public void keyPressed(int keyCode)
{

}

}

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