9_scanline.c

#include<stdio.h>
#include<stdlib.h>
#include<GL/glut.h>
#include<stdbool.h>
float et[4][4]={{100,250,200,-1},{100,250,200,1},{200,150,300,1},{200,350,300,-1}};
int np=4;
float ae[4][3];
float js;
int iaet=0;
int ymax=0;
void draw_text(float x,float y,char *s)
{
	int i;
	glRasterPos2f(x,y);
	for(i=0;s[i]!='\0';i++)
	glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24,s[i]);
}

void addaet()
{
	int i;
	for(i=0;i<np;i++)
	{
		printf("Scanline = %f & iate=%d \n",js,iaet);
		if(js==et[i][0])
		{
			ae[iaet][0]=et[i][1];
			ae[iaet][1]=et[i][2];
			ae[iaet][2]=et[i][3];
			if(ae[iaet][1]>ymax)
				ymax=ae[iaet][1];
			iaet++;
		}
		glFlush();
	}
}		
void upaet()
{
	int i;
	for(i=0;i<np;i++)
		ae[i][0]=ae[i][0]+ae[i][2];
}
void draw_pixel(float x1,float x2)
{
	float n;
	for(n=x1;n<x2;n++)
	{
		glColor3f(1.0,0.0,0.0);
		glBegin(GL_POINT);
		glVertex2f(n,js);
		glEnd();
		glFlush();
	}
	printf("x1=%f  x2=%f \n",x1,x2);
}
void fill_tri()
{
	float x[3]={0,0,0};
	int i=0;
	bool done=false;
	js= et[0][0];
	do
	{
		i=0;
		addaet();
		printf("1=%f 2=%f %f\n",ae[0][1],ae[1][1],js);
		if(ae[0][1]>js)
		{
			x[i]=ae[0][0];
			i++;
			printf("1=%f ae=%f \n",ae[0][0],x[0]);	
		}
		if(ae[1][1]>js)
		{
			x[i]=ae[1][0];
			i++;
			printf("1=%f 2=%f \n",ae[0][0],x[0]);
		}
		if(ae[2][1]>js)
		{
			x[i]=ae[2][0];
			i++;
			
		}
		if(ae[3][1]>js)
		{
			x[i]=ae[3][0];
			i++;
			
		}
		draw_pixel(x[0],x[1]);
		upaet();
		js++;
	}while(js<=ymax);
}
void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glClearColor(1.0,1.0,1.0,1.0);
	fill_tri();
	draw_text(50,400,"1BI14CS008");
	draw_text(50,420,"Afia Khan");
	glFlush();
}		
	
	
void myinit()
{
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0,499.0,0.0,499.0);
	glMatrixMode(GL_MODELVIEW);
	glFlush();
}

void main(int argc, char **argv)
{
	
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
	glutInitWindowSize(500,500);
	glutCreateWindow("Polygon Filling");
	glutDisplayFunc(display);
	myinit();
	glutMainLoop();
}