opengl画网格，画横线11条，画竖线11条，再画对角线与网格交点打白点。
opengl画网格代码：
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#include <windows.h> #include <GL/glut.h> void init(void); void reshape(int w, int h); void display(void); void init(void) { } void reshape(int w, int h) { glViewport(0, 0, w, h); } void display(void) { int i; glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(-1.0, 11.0, -1.0, 11.0); //窗口坐标范围 glMatrixMode(GL_MODELVIEW); glLoadIdentity(); //画10*10网格 glColor3f(0.0f, 1.0f, 0.0f); //绿色 for (i = 0; i <= 10; i++) //11条水平线 { glBegin(GL_LINES); glVertex2d(0.0, i * 1.0); glVertex2d(10.0, i * 1.0); glEnd(); } glBegin(GL_LINES); //11条竖线 for (i = 0; i <= 10; i++) { glVertex2d(i * 1.0, 0.0); glVertex2d(i * 1.0, 10.0); } glEnd(); //在对角线画点 glColor3f(1.0f, 1.0f, 1.0f); //白色 glPointSize(10.0f); //点大小 glBegin(GL_POINTS); for (i = 0; i <= 10; i++) glVertex2d(i * 1.0, i * 1.0); glEnd(); for (i = 0; i <= 10; i++) { glBegin(GL_POINTS); glVertex2d(i * 1.0, 10.0 - i * 1.0); glEnd(); } glFlush(); } int main(int argc,char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500, 500); glutInitWindowPosition(0, 0); glutCreateWindow("GL_0_2d"); init(); glutDisplayFunc(display); glutReshapeFunc(reshape); glutMainLoop(); return 0; } |
opengl画网格测试结果：
