本文实例为大家分享了OpenGL实现不规则区域填充算法，供大家参考，具体内容如下

一、简单递归

利用Dfs实现简单递归填充。
核心代码：

// 简单深度搜索填充 （四连通）void DfsFill(int x, int y){ if (x < 0 || y < 0 || x>23 || y>23) { return; } if (a[x][y] == 0) { a[x][y] = 2; DfsFill(x - 1, y); DfsFill(x + 1, y); DfsFill(x, y - 1); DfsFill(x, y + 1); }}

二、扫描线种子填充算法（四连通）

1. 种子点（x,y）入栈。
2. 栈顶元素（x,y）出栈作为种子点。
3. 从种子点（x,y）开始沿着扫描线向左右两个方向逐个像素进行填充，直到到达边界像素为止。
4. 将上述填充区段的左右端点的横坐标分别记为xleft和xright.
5. 在与当前扫描线相邻的上下两条扫描线的[xleft，xright]范围内进行检查，看看是否全部为边界像素或已填充像素，若存在着非边界且未填充的像素，那么将该区段的最右端像素作为种子点入栈。

void ScanFill(int x, int y){ if (a[x][y]!=0) { return; } Pos first(x, y); s.push(first); while (!s.empty()) { int rightX = 0; int leftX = 0; Pos cur = s.top(); s.pop(); a[cur.x][cur.y] = 2; // 遍历当前行 for (int i = 1; i < 24; i++) { if (cur.x + i < 24) { if (a[cur.x + i][cur.y] == 0) a[cur.x + i][cur.y] = 2; else { rightX = cur.x + i - 1; break; } } if (i==23) { rightX = 23; } } for (int i = 1; i < 24; i++) { if (cur.x - i > -1) { if (a[cur.x - i][cur.y] == 0) a[cur.x - i][cur.y] = 2; else { leftX = cur.x - i + 1; break; } } if (i == 0) { leftX = 0; } } cout << leftX <<","<<rightX << endl; // 判断上行 int upRightX = -1; for (int i = leftX;i<=rightX;i++) { if (a[i][cur.y+1]==0 && cur.y+1<24) { upRightX = i; } } if (upRightX!=-1) { Pos temPos(upRightX,cur.y+1); s.push(temPos); } // 判断下行 int downRightX = -1; for (int i = leftX; i <= rightX; i++) { if (a[i][cur.y - 1] == 0 && cur.y - 1 >=0) { downRightX = i; } } if (downRightX != -1) { Pos temPos(downRightX, cur.y - 1); s.push(temPos); } }}

完整代码：

#include <cmath>#include <stack>#include "gl/glut.h"#include "iostream"using namespace std;#define PI 3.14struct Pos{ int x; int y; Pos(int mx, int my) :x(mx), y(my) {}; Pos() :x(0), y(0) {};};stack<Pos> s;int a[24][24] = { 0 };void init(void){ glClearColor(1.0, 1.0, 1.0, 1.0); glMatrixMode(GL_PROJECTION);//设置投影矩阵 gluOrtho2D(0.0, 600.0, 0.0, 600.0);//二维视景区域 glPointSize(12.0f);}// 画棋子void Drawtri(int x,int y,int color){ double n = 200;//分段数 float R = 10;//半径 int i; if (color == 1) { glColor3f(1.0, 0.0, 0.0); } else if (color == 2) { glColor3f(0.0, 1.0, 0.0); } glBegin(GL_POLYGON); glVertex2f(x, y); for (i = 0; i <= n; i++) glVertex2f(R*cos(2 * PI / n * i)+x, R*sin(2 * PI / n * i)+y); glEnd(); glPopMatrix();}// 绘制格线void playMap(){ glColor3f(0.0, 0.0, 0.0); glBegin(GL_LINES); for (int i = 0; i < 600; i += 25) { glVertex2f(i, 0); glVertex2f(i, 600); } for (int j = 0; j < 600; j += 25) { glVertex2f(0, j); glVertex2f(600, j); } glEnd(); for (int k = 0; k < 24; k++) { for (int l = 0; l < 24; l++) { if (a[k][l] == 1) { Drawtri(k * 25 + 12, l * 25 + 12,1); } else if (a[k][l] == 2) { Drawtri(k * 25 + 12, l * 25 + 12, 2); } } }}// 简单深度搜索填充 （四连通）void DfsFill(int x, int y){ if (x < 0 || y < 0 || x>23 || y>23) { return; } if (a[x][y] == 0) { a[x][y] = 2; DfsFill(x - 1, y); DfsFill(x + 1, y); DfsFill(x, y - 1); DfsFill(x, y + 1); }}// 扫描线种子填充算法（四连通）void ScanFill(int x, int y){ if (a[x][y]!=0) { return; } Pos first(x, y); s.push(first); while (!s.empty()) { int rightX = 0; int leftX = 0; Pos cur = s.top(); s.pop(); a[cur.x][cur.y] = 2; // 遍历当前行 for (int i = 1; i < 24; i++) { if (cur.x + i < 24) { if (a[cur.x + i][cur.y] == 0) a[cur.x + i][cur.y] = 2; else { rightX = cur.x + i - 1; break; } } if (i==23) { rightX = 23; } } for (int i = 1; i < 24; i++) { if (cur.x - i > -1) { if (a[cur.x - i][cur.y] == 0) a[cur.x - i][cur.y] = 2; else { leftX = cur.x - i + 1; break; } } if (i == 0) { leftX = 0; } } cout << leftX <<","<<rightX << endl; // 判断上行 int upRightX = -1; for (int i = leftX;i<=rightX;i++) { if (a[i][cur.y+1]==0 && cur.y+1<24) { upRightX = i; } } if (upRightX!=-1) { Pos temPos(upRightX,cur.y+1); s.push(temPos); } // 判断下行 int downRightX = -1; for (int i = leftX; i <= rightX; i++) { if (a[i][cur.y - 1] == 0 && cur.y - 1 >=0) { downRightX = i; } } if (downRightX != -1) { Pos temPos(downRightX, cur.y - 1); s.push(temPos); } }}void displayFcn(void){ glClear(GL_COLOR_BUFFER_BIT); playMap(); glFlush();}void mouse(GLint button, GLint action, GLint x, GLint y){ int curX, curY; if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN) { curX = x / 25; curY = (600 - y) / 25; a[curX][curY] = 1; glutPostRedisplay();//重绘窗口 } if (button == GLUT_RIGHT_BUTTON && action == GLUT_DOWN) { curX = x / 25; curY = (600 - y) / 25; ScanFill(curX, curY); glutPostRedisplay();//重绘窗口 }}void main(int argc, char** argv){ glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowPosition(300, 100); glutInitWindowSize(600, 600); glutCreateWindow("mouse"); init(); glutDisplayFunc(displayFcn); glutMouseFunc(mouse); glutMainLoop();}

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