Below is the simple OpenGL Computer Graphics Program to draw Line. This is very basic OpenGL program, You can compare this with C "Hello World" program.
void glutInitWindowPosition(int x, int y);
voidglClearColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha);
// It specifies value to clear color buffer.
voidglMatrixMode(GLenum mode);
// Initialize current matrix
void gluOrtho2D(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top);
// Used to define orthographic projection of 2D matrix
voidglClear(GLbitfield mask);
// clear preset values of buffer
voidglColor3f(colR,colG,colB);
//set colour
void glBegin(GLenum mode);
// delimit the vertices of a primitive or a group of like primitives
void glBegin(GLenum mode);
// delimit the vertices of a primitive or a group of like primitives
void glEnd( void);
// delimit the vertices of a primitive or a group of like primitives
voidglutInitDisplayMode(unsigned int mode);
// Used to set initial display mode.
voidglutInitWindowSize(int width, int height);
//it sets the size of window and position of window.
void glutInitWindowPosition(int x, int y);
//initalize window size
voidglutDisplayFunc(void (*func)(void));
// it sets display callback for current window
OpenGL C Program to draw Line:
Title#include
void initialize2D( float r, float g, float b)
{
glClearColor(r,g,b,0.0);
glMatrixMode (GL_PROJECTION);
gluOrtho2D (0.0, 205.0, 0.0, 155.0);
}
void displayLine(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 0.0, 0.0);
glBegin(GL_POINTS);
for(int j = 0; j {
glVertex2i(10+5*j,110);
}
glEnd();
glBegin(GL_LINES);
glVertex2i(10,10);
glVertex2i(100,100);
glEnd();
glFlush();
}
void main(int iargc,char *iargv[])
{
glutInit(&iargc,iargv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // initialize Display Mode
glutInitWindowSize (500, 500); // initialize window size
glutInitWindowPosition (100, 100); // initialize window position
glutCreateWindow ("points and lines");
initialize2D(0.0,0.0,0.0);
glutDisplayFunc(displayLine); // call displayLine() function
glutMainLoop();
}
void initialize2D( float r, float g, float b)
{
glClearColor(r,g,b,0.0);
glMatrixMode (GL_PROJECTION);
gluOrtho2D (0.0, 205.0, 0.0, 155.0);
}
void displayLine(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 0.0, 0.0);
glBegin(GL_POINTS);
for(int j = 0; j {
glVertex2i(10+5*j,110);
}
glEnd();
glBegin(GL_LINES);
glVertex2i(10,10);
glVertex2i(100,100);
glEnd();
glFlush();
}
void main(int iargc,char *iargv[])
{
glutInit(&iargc,iargv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); // initialize Display Mode
glutInitWindowSize (500, 500); // initialize window size
glutInitWindowPosition (100, 100); // initialize window position
glutCreateWindow ("points and lines");
initialize2D(0.0,0.0,0.0);
glutDisplayFunc(displayLine); // call displayLine() function
glutMainLoop();
}
