first.cpp

计算机图形学的一个project Polyline Editor

#include<glut.h>
static int i = 0;
int k = 0;
int kother = 0;
int delFirstPoint = -1;
int delSecondPoint = -1;

struct GLintPoint{
	GLint x,y;
};
GLintPoint corner[120];
bool selected = false;
bool begin = false;
bool move = false;
bool refresh = false;
bool forK = false;
bool forKother= false ;


void myDisplay(void)

{
	glClear(GL_COLOR_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glColor3f(1.0,0.0,1.0);

	if(selected){
		int j = 0;
		for(;j<i-1;j = j+2)
		{
	      glBegin(GL_LINES);
	      glVertex2i(corner[j].x,corner[j].y);
	      glVertex2i(corner[j+1].x,corner[j+1].y);
		  glEnd();
		}
	}

	if (move)
	{
		glBegin(GL_LINES);
		if ( k%2 ==0  ) 
			glVertex2i(corner[k+1].x,corner[k+1].y);
		else 
			glVertex2i(corner[k-1].x,corner[k-1].y);
		  glVertex2i(corner[k].x,corner[k].y);
		glEnd();

      if(forKother)
		 {
			 glBegin(GL_LINES);
	         if ( kother%2 ==0  ) 
	           glVertex2i(corner[kother+1].x,corner[kother+1].y);
		    else 
			   glVertex2i(corner[kother-1].x,corner[kother-1].y);
		       glVertex2i(corner[kother].x,corner[kother].y);
		    glEnd();
	  }
		 forK = false;
         forKother= false;
	}

	
	if(refresh )
	{
		 glLoadIdentity();

		 glClearColor(1.0,1.0,1.0,0.0);
		 int j = 0;
		 for(;j<i-1;j = j+2)
		 {
			 glBegin(GL_LINES);
	           glVertex2i(corner[j].x,corner[j].y);
	           glVertex2i(corner[j+1].x,corner[j+1].y);
		     glEnd();
		 }
	}
	glutSwapBuffers();
}


void mouse(int button, int state, int x, int y) 
{
	if(begin)
	{
      if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN && i< 120)
	  {
	    corner[i].x = x;
	    corner[i].y = 500 - y;
		i++;
	    selected = true;
	  }
	  glutPostRedisplay();
	}

	  if (move)
	  {
		  if (button == GLUT_LEFT_BUTTON && state == GLUT_UP&& forK)
			   {
				   corner[k].x = x; 
				   corner[k].y = 500 - y;
				   if(forKother)
				   {
				   corner[kother].x = x; 
				   corner[kother].y = 500 - y;
				   }
				
				    forK = false;
					return ;
			   }
		  if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN&& forK == false)
		  { 
			  for(int t = 0;t < i-1;t++)
			   if( corner[t].x - x <= 4 && corner[t].y -(500 - y)<=4&&corner[t].x - x>=-4&&corner[t].y -(500 - y)>=-4)
			   {
				   if(!forK)
				   {
					   k = t;
				       forK = true;
				   }
				   else
				   {
					    kother = t;
						forKother = true;
					    return ;
				   }
			   }
		  }
	  }
}


void myPassiveMotion(int x,int y)
{
	 
	if(move && forK)
	{ 
	
	   corner[k].x = x; 
       corner[k].y =500 - y;

	}
	if (selected)
	{
		corner[i-1].x = x;
        corner[i-1].y =500 - y;
	}
     glutPostRedisplay();

}
void mykey(unsigned char key, int mouseX, int mouseY)
{
   GLint x = mouseX,y = mouseY;
   if (key == 'q') 
	   exit(0);
   if (key == 'b') 
   {
	   begin = true;
	   selected = true;
	   move = false;
	   refresh = false;
	   forK = false;
   }
   if (key == 'm') 
   {
	   begin = false;
	   move = true;
	   refresh = false;
   }
    if (key == 'r') 
	{
	   begin = false;
	   move = false;
	   refresh = true;
	   selected = false;
  }
	
}

void myInit()
{
	glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
	gluOrtho2D(0,500,0,500);
	glMatrixMode(GL_MODELVIEW);
	glClearColor(1.0,1.0,1.0,0.0);
	glViewport(0,0,500,500);
}

int main(int argc,char **argv)
{
	glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(100,150);
    glutCreateWindow("Draw house");  
    

	myInit();
	glutMouseFunc(mouse);
	glutDisplayFunc(myDisplay);
    glutPassiveMotionFunc(myPassiveMotion);
	glutKeyboardFunc(mykey);

	glutMainLoop();

	
}