쿠탱이의 삽질세상

사용자 삽입 이미지

txt파일로 부터 선과 원의 정보를 읽어 들여 그리는 간단한 프로그램입니다.

GL_line등을 이용하지 않고 브레스넘 알고리즘을 이용해 Point만을 사용했습니다.

브레스넘 알고리즘을 공부하는데 도움이 될겁니다.

txt파일로 읽어 들이는 데이터 형식은

CIRCLE 200 200 30 1.0 0.0 0.0

CIRCLE 200 200 150 0.0 1.0 0.0

CIRCLE 200 200 100 0.0 0.0 1.0

LINE 200 200 400 200 1.0 0.0 0.0 0.0 0.0 1.0

LINE 200 200 400 300 1.0 0.0 0.0 0.0 1.0 1.0

LINE 200 200 300 500 1.0 1.0 0.0 0.0 0.0 1.0

LINE 200 200 400 200 0.0 1.0 1.0 1.0 0.0 1.0

#ifdef __APPLE__
#include "OpenGL/gl.h"
#include "OpenGL/glu.h"
#include "GLUT/glut.h"
#elif defined(_WIN32)
#include <windows.h>
#include "GL/glut.h"
#else
#include <cstdlib>
#include "GL/glut.h"
#endif

#include <stdio.h>
#include <string>
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>

using namespace std;

int main_window = 1;
int position_x = 100;
int position_y = 100;
int width = 512;
int height = 512;
string file_name="";
vector<string> line_input;

void drawCircle(int cx, int cy, int r,GLfloat R, GLfloat G, GLfloat B);
void drawLine(int x1, int y1, int x2, int y2, GLfloat R1, GLfloat G1, GLfloat B1,GLfloat R2, GLfloat G2, GLfloat B2);

//read strings from file
vector<string> read_file(string file_name)
{
	vector<string> line_input;
	string temp;
	ifstream fin(file_name.c_str());
	if(!fin)
	{
		cout<<"Could not open the file!"<<endl;
	        exit(1);
	}
	while (!fin.eof())
	{
		fin>>temp>>ws;
		line_input.push_back(temp);
	}

	return line_input;
}

//convert string to float number
float to_float(string number)
{
	float float_number;
	istringstream iss (number);
	iss>>float_number;
	return float_number;
}

void line_process(vector<string> command)
{
  for(int i=0; i<command.size();i++)
  {
	  if(command[i]=="CIRCLE")
	  {
		  float x=to_float(command[i+1]);
		  float y=to_float(command[i+2]);
		  float rad=to_float(command[i+3]);
		  float R=to_float(command[i+4]);
		  float G=to_float(command[i+5]);
		  float B=to_float(command[i+6]);
		  i+=6;
		  drawCircle(x,y,rad,R,G,B);
	  }
      else if(command[i]=="LINE")
	  {
		  float x1=to_float(command[i+1]);
		  float y1=to_float(command[i+2]);
		  float x2=to_float(command[i+3]);
		  float y2=to_float(command[i+4]);
		  float R1=to_float(command[i+5]);
		  float G1=to_float(command[i+6]);
		  float B1=to_float(command[i+7]);
		  float R2=to_float(command[i+8]);
		  float G2=to_float(command[i+9]);
		  float B2=to_float(command[i+10]);
		  i+=10;
		  drawLine(x1,y1,x2,y2,R1,G1,B1,R2,G2,B2);
	  }
   }
}

void idle(void)
{
	if (glutGetWindow() != main_window)
		glutSetWindow(main_window);

	// just keep redrawing the scene over and over
	glutPostRedisplay();
}


void keyboard(unsigned char key, int x, int y)
{
	switch(key)
	{
		// quit
	case 27: 
	case 'q':
	case 'Q':
		exit(0);
		break;
	}
	glutPostRedisplay();
}

// the window has changed shapes, fix ourselves up
void reshape(GLsizei x, GLsizei y)
{
	width = x;
	height = y;
	printf("%d %d\n", x,y);
	glViewport(0,0,width,height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0,width,0,height,-100,10000);
	glMatrixMode(GL_MODELVIEW);
	glutPostRedisplay();
}

void drawPoint(int x, int y, float r, float g, float b)
{
	//Set color
	glColor3f(r,g,b);

	//Set position
	glVertex3f(x,y,0);
}

void drawCircle(int cx, int cy, int r,GLfloat R, GLfloat G, GLfloat B)
{
	int F, x, y; // f: decision variavle, x,y:points on circle
	x=0;y=r;
	F=3-2*r;
	while(x<=y)
	  {
	    //draw 1/8 circle and reflects
 		drawPoint(cx+x,cy+y,R,G,B);
  		drawPoint(cx+y,cy+x,R,G,B);
		drawPoint(cx-x,cy+y,R,G,B);
		drawPoint(cx-x,cy-y,R,G,B);
		drawPoint(cx+x,cy-y,R,G,B);
		drawPoint(cx-y,cy+x,R,G,B);
		drawPoint(cx-y,cy-x,R,G,B);
		drawPoint(cx+y,cy-x,R,G,B);
 		if(F<0)
		  {
		    F=F+4*x+6;
		  }
		else
		  {
		    F=F+4*(x-y)+10;
		    y--;
		  }
		x++;
	  }
}


void drawLine(int x1, int y1, int x2, int y2, GLfloat R1, GLfloat G1, GLfloat B1,GLfloat R2, GLfloat G2, GLfloat B2)
{
    int F, x, y;	//F: decision variable  x,y: starting point
    GLfloat R,G,B;     //RGB for color change
    GLfloat Rt,Gt,Bt;

    if (x1 > x2)  //compare and swap x,y position to draw up-right direction
	{
        swap(x1, x2);swap(y1, y2);
	Rt=R1;R1=R2;R2=Rt;
	Gt=G1;G1=G2;G2=Gt;
	Bt=B1;B1=B2;B2=Bt;
    }
	
	//draw vertical line
    if (x1 == x2)
    {
        if (y1 > y2) swap(y1, y2);
	Rt=R1;R1=R2;R2=Rt;
	Gt=G1;G1=G2;G2=Gt;
	Bt=B1;B1=B2;B2=Bt;
        x = x1;y = y1;
        while (y <= y2)
        {
	  R=(R1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(R2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	  G=(G1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(G2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	  B=(B1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(B2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	  drawPoint(x,y,R,G,B);
            y++;
        }
        return;
    }

    //draw horizontal line
    else if (y1 == y2)
    {
        x = x1;y = y1;
        while (x <= x2)
        {
	  R=(R1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(R2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	  G=(G1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(G2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	  B=(B1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(B2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	  drawPoint(x,y,R,G,B);
            x++;
        }
        return;
    }
	
    int dy = y2 - y1; 
    int dx = x2 - x1;

    if (dy >= 0) 
    {
		//if m>0
        // nomral E & NE way
        if (dy <= dx)    
        {
            F = 2*dy - dx;
            x = x1; y = y1;
            while (x <= x2)
            {
	      R=(R1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(R2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	      G=(G1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(G2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	      B=(B1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(B2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
              drawPoint(x,y,R,G,B);
              if (F <= 0) F += 2*dy;
              else
                {
                    y++;
                    F += 2*dy-2*dx;
                }
                x++;
            }
        }
	
		//mirror  x=y
        else
        {
            F = 2*dx - dy;
            y = y1; x = x1;
            while (y <= y2)
            {
	      R=(R1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(R2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	      G=(G1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(G2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	      B=(B1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(B2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
                drawPoint(x, y,R,G,B);
                if (F <= 0) F += 2*dx;
				else
                {
                    x++;
                    F -= 2*dy-2*dx;
                }
                y++;
            }
        }
    }
    else    // m < 0
    {
        // mirror x
        if (dx >= -dy)
        {
            F = -2*dy - dx;
            x = x1; y = y1;
            while (x <= x2)
            {
	      R=(R1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(R2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	      G=(G1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(G2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
	      B=(B1*(((GLfloat)x2-(GLfloat)x)/((GLfloat)x2-(GLfloat)x1)))+(B2*(((GLfloat)x-(GLfloat)x1)/((GLfloat)x2-(GLfloat)x1)));
                drawPoint(x, y,R,G,B);
                if (F <= 0) F -= 2*dy;
                else
                {
                    y--;
                    F -= 2*dy+2*dx;
                }
                x++;
            }
        }

		//mirror x and x=y
        else    
        {
            F = 2*dx + dy;
            y = y1; x = x1;
            while (y >= y2)
            {
	      R=(R1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(R2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	      G=(G1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(G2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
	      B=(B1*(((GLfloat)y2-(GLfloat)y)/((GLfloat)y2-(GLfloat)y1)))+(B2*(((GLfloat)y-(GLfloat)y1)/((GLfloat)y2-(GLfloat)y1)));
                drawPoint(x, y,R,G,B);
                if (F <= 0) F += 2*dx;
                else
                {
                    x++;
                    F += 2*dy+2*dx;
                }
                y--;
            }
        }
    }
}


void display( )
{
	//glMatrixMode(GL_MODELVIEW);
	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

	//Clear background to black 
	glClearColor(0.3,0.3,0.3,0.3);
	//glLoadIdentity();

	glBegin(GL_POINTS);
	line_process(line_input);

	glEnd();
	glutSwapBuffers();
}


int main(int argc,	char* argv[])
{
	glutInit(&argc, argv);

	//check command file argument
    if(argc<=1)
    {
		cout<<"Please type command file name with full-path!"<<endl;
		cout<<"ex) ./output test.txt"<<endl;
		return 0;
    }
    file_name=argv[1];

    line_input=read_file(file_name); 
	
	glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE|GLUT_DEPTH);
	glutInitWindowSize(width, height);
	glutInitWindowPosition(100,100);
	main_window = glutCreateWindow("Assignment 2");
	glPointSize(1);

	glutDisplayFunc(display);
	glutKeyboardFunc(keyboard);
	glutReshapeFunc(reshape);
	glutIdleFunc(idle);

	glMatrixMode(GL_PROJECTION);
	glOrtho(0,width,0,height,-100,10000);
	glMatrixMode(GL_MODELVIEW);
	

	glutMainLoop();

	return 0;
}

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Bresenham Line & Circle (브레스넘 알고리즘 )

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