OpenGL 学习之简单的图形用户界面和交互输入

最简单的电脑与用户之间的交互就是使用鼠标

//#include <gl/glut.h>//#include <stdlib.h>//#include <stdio.h>//////GLsizei winWidth = 500,winHeight = 500;////void init()//{//glClearColor(0.0,0.0,0.0,0.0);//glMatrixMode(GL_PROJECTION);//gluOrtho2D(0.0,200.0,0.0,200.0);//}////void display()//{//glClear(GL_COLOR_BUFFER_BIT);//glColor3f(1.0,0.0,0.0);//glPointSize(5);//}////void reshape(int w,int h)//{//glViewport(0,0,(GLsizei)w,(GLsizei)h);//glMatrixMode(GL_PROJECTION);//glLoadIdentity();//gluOrtho2D(0.0,(GLdouble)w,0.0,(GLdouble)h);//winHeight = w;//winHeight = h;//}////void plotPoint(GLint x,GLint y)//{////glBegin(GL_POINTS);//glVertex2i(x,y);//glEnd();//}////////void mousefun(GLint button,GLint action,GLint xMouse,GLint yMouse)//{////GLint temp[2];////int ch;//FILE *fp;////if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN)//{//plotPoint(xMouse,winHeight-yMouse);//printf("the x is %d\nthe y is %d\n",xMouse,winHeight-yMouse);////temp[0] = xMouse;////temp[1] = yMouse;////}//fp = fopen("D:\\1.txt","w+");//if (fp==NULL)//{//printf("cannot open this file!\n");//}//else//{////fprintf(fp,"%d\n",xMouse);//fprintf(fp,"%d\n",winHeight-yMouse);////printf("OK!");////}//fclose(fp);//glFlush();////return temp;//}//////void ////void show_number(GLint xMouse,GLint yMouse)////{////if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN)////{////////}////}//int main(int argc,char **argv)//{//glutInit(&argc,argv);//glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);//glutInitWindowPosition(200,200);//glutInitWindowSize(winWidth,winHeight);//glutCreateWindow("hello");//init();////show_number()//glutDisplayFunc(display);//glutReshapeFunc(reshape);////glutMouseFunc(mousefun);////glutMainLoop();//return 0;//}#include <gl/glut.h>#include <stdio.h>#include <stdlib.h>GLsizei winwidth = 500;GLsizei winHeight = 500;GLint endPtctr = 0;class scrPt{public:GLint x,y;};void init(){glClearColor(0.0,0.0,0.0,1.0);glMatrixMode(GL_PROJECTION);gluOrtho2D(0.0,300.0,0.0,300.0);}void display(){glClear(GL_COLOR_BUFFER_BIT);}void reshape(int w,int h){glViewport(0,0,(GLsizei)w,(GLsizei)h);glMatrixMode(GL_PROJECTION);glLoadIdentity();gluOrtho2D(0.0,(GLdouble)w,0.0,(GLdouble)h);winwidth = w;winHeight = h;}void plotpoint(GLint x,GLint y){glPointSize(5);glBegin(GL_POINTS);glVertex2i(x,y);//glVertex2i(endpt2.x,endpt2.y);glEnd();}void draw_line(scrPt endpt1,scrPt endpt2){//glFlush();glLineWidth(5);glColor3f(1.0,0.0,0.0);glBegin(GL_LINES);glVertex2i(endpt1.x,endpt1.y);glVertex2i(endpt2.x,endpt2.y);glEnd();}void polyline(GLint button,GLint action,GLint xMouse, GLint yMouse){static scrPt endpt1,endPt2;if(endPtctr == 0){if (button == GLUT_LEFT_BUTTON && action ==GLUT_DOWN){endpt1.x = xMouse;endpt1.y = winHeight - yMouse;plotpoint(xMouse,winHeight-yMouse);endPtctr = 1;}else{if (button == GLUT_RIGHT_BUTTON)//quit the program{exit(0);}}}else{if (button == GLUT_LEFT_BUTTON && action == GLUT_DOWN){endPt2.x = xMouse;endPt2.y = winHeight - yMouse;draw_line(endpt1,endPt2);endpt1 = endPt2;} else{if (button == GLUT_RIGHT_BUTTON){exit(0);}}}glFlush();}int main(int argc,char **argv){glutInit(&argc,argv);glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);glutInitWindowSize(winwidth,winHeight);glutInitWindowPosition(200,200);glutCreateWindow("hello");init();glutDisplayFunc(display);glutReshapeFunc(reshape);glutMouseFunc(polyline);glutMainLoop();return 0;}

分成两个程序，第一个就是简单那的在屏幕上画点，第二个程序将画的点进行描绘成直线段，程序非常的简单。