8. COMPUTER GRAPHICS LAB | READ NOW

VTU COMPUTER GRAPHICS LAB

Program 8:- Develop a menu driven program to animate a flag using Bezier Curve algorithm

STEPS TO RUN CG PROGRAM

1. Copy the below copy
2. Past it in any code compiler ex- Code Blocks, DEV C++, VS Code
3. Save the file with .cpp extension
4. Compile and Run the code
5. Program Execution Successful

Note:- if you use Dev C++, right click on project>project options>parameter>linker paste the below code in Linker – as shown in image.

-lopengl32
-lfreeglut
-lglu32

Program Code [lab8.cpp]

#include<GL/glut.h>
#include<math.h>
#include<stdio.h>

void bezierCoefficients(int n,int *c)
{
	int k,i;
	for(k=0;k<=n;k++)
	{
		c[k]=1;
		for(i=n;i>=k+1;i--)
			c[k]*=i;
		for(i=n-k;i>=2;i--)
			c[k]/=i;
	}
}

void display()
{
	int cp[4][2]={{10,10},{100,200},{200,50},{300,300}};
	int c[4],k,n=3;
	float x,y,u,blend;
	bezierCoefficients(n,c);
	glClear(GL_COLOR_BUFFER_BIT);
		glColor3f(1.0,0.0,0.0);
		glLineWidth(5.0);
	glBegin(GL_LINE_STRIP);
		for(u=0;u<1.0;u+=0.01)
		{
			x=0;y=0;
			for(k=0;k<4;k++)
			{
				blend=c[k]*pow(u,k)*pow(1-u,n-k);
				x+=cp[k][0]*blend;
				y+=cp[k][1]*blend;
			}
		glVertex2f(x,y);
		}
	glEnd();
	glFlush();
}

void myinit()
{
	glClearColor(1.0,1.0,1.0,1.0);
	glColor3f(1.0,0.0,0.0);
	glPointSize(5.0);
	gluOrtho2D(0.0,600,0.0,600.0);
}

int main(int argc, char ** argv)
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
	glutInitWindowSize(600,600);
	glutCreateWindow("Bezier Curve");
	glutDisplayFunc(display);
	myinit();
	glutMainLoop();
	return 0;
}

COMPUTER GRAPHICS LAB OUTPUT

Alternative Method [lab8.cpp]

#include<GL/glut.h>
#include<math.h>
#include<stdio.h>

void bezierCoefficients(int n,int *c)
{
	int k,i;
	for(k=0;k<=n;k++)
	{
		c[k]=1;
		for(i=n;i>=k+1;i--)
			c[k]*=i;
		for(i=n-k;i>=2;i--)
			c[k]/=i;
	}
}

void display()
{
	int cp[4][2]={{10,10},{100,200},{200,50},{300,300}};
	int c[4],k,n=3;
	float x,y,u,blend;
	bezierCoefficients(n,c);
	glClear(GL_COLOR_BUFFER_BIT);
		glColor3f(1.0,0.0,0.0);
		glLineWidth(5.0);
	glBegin(GL_LINE_STRIP);
		for(u=0;u<1.0;u+=0.01)
		{
			x=0;y=0;
			for(k=0;k<4;k++)
			{
				blend=c[k]*pow(u,k)*pow(1-u,n-k);
				x+=cp[k][0]*blend;
				y+=cp[k][1]*blend;
			}
		glVertex2f(x,y);
		}
	glEnd();
	glFlush();
}

void myinit()
{
	glClearColor(1.0,1.0,1.0,1.0);
	glColor3f(1.0,0.0,0.0);
	glPointSize(5.0);
	gluOrtho2D(0.0,600,0.0,600.0);
}

int main(int argc, char ** argv)
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
	glutInitWindowSize(600,600);
	glutCreateWindow("Bezier Curve");
	glutDisplayFunc(display);
	myinit();
	glutMainLoop();
	return 0;
}

COMPUTER GRAPHICS Alternative Method Output