Construct the program that uses appropriate OpeuGL commands

Construct the program that uses appropriate OpeuGL commands to generate the output with all the geometric primitives in different colors as shown below.

Solution

Answer:

#include <GL/gl.h>
#include <GL/glut.h>

#define drawOneLine(x1,y1,x2,y2) glBegin(GL_LINES); \\
glVertex2f ((x1),(y1)); glVertex2f ((x2),(y2)); glEnd();

void init(void)
{
glClearColor (0.0, 0.0, 0.0, 0.0);
glShadeModel (GL_FLAT);
}

void display(void)
{
int i;

glClear (GL_COLOR_BUFFER_BIT);
/* select white for all lines */
glColor3f (1.0, 1.0, 1.0);

/* in 1st row, 3 lines, each with a different stipple */
glEnable (GL_LINE_STIPPLE);

glLineStipple (1, 0x0101); /* dotted */
drawOneLine (50.0, 125.0, 150.0, 125.0);
glLineStipple (1, 0x00FF); /* dashed */
drawOneLine (150.0, 125.0, 250.0, 125.0);
glLineStipple (1, 0x1C47); /* dash/dot/dash */
drawOneLine (250.0, 125.0, 350.0, 125.0);
/* in 2nd row, 3 wide lines, each with different stipple */
glLineWidth (5.0);
glLineStipple (1, 0x0101); /* dotted */
drawOneLine (50.0, 100.0, 150.0, 100.0);
glLineStipple (1, 0x00FF); /* dashed */
drawOneLine (150.0, 100.0, 250.0, 100.0);
glLineStipple (1, 0x1C47); /* dash/dot/dash */
drawOneLine (250.0, 100.0, 350.0, 100.0);
glLineWidth (1.0);

/* in 3rd row, 6 lines, with dash/dot/dash stipple */
/* as part of a single connected line strip */
glLineStipple (1, 0x1C47); /* dash/dot/dash */
glBegin (GL_LINE_STRIP);
for (i = 0; i < 7; i++)
glVertex2f (50.0 + ((GLfloat) i * 50.0), 75.0);
glEnd ();

/* in 4th row, 6 independent lines with same stipple */
for (i = 0; i < 6; i++) {
drawOneLine (50.0 + ((GLfloat) i * 50.0), 50.0,
50.0 + ((GLfloat)(i+1) * 50.0), 50.0);
}

/* in 5th row, 1 line, with dash/dot/dash stipple */
/* and a stipple repeat factor of 5 */
glLineStipple (5, 0x1C47); /* dash/dot/dash */
drawOneLine (50.0, 25.0, 350.0, 25.0);

glDisable (GL_LINE_STIPPLE);
glFlush ();
}

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);
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (400, 150);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
init ();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
return 0;
}