openGL_tri.c

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/*
 * Testing openGL with drawing a simple triangle with shades
 */
#include <GL/glut.h>
#include <math.h>
#include <stdio.h>
 
#define pi 3.142857
 
void display() {
    // setting every pixel in frame buffer to a clear color
    glClear(GL_COLOR_BUFFER_BIT);
 
    // being drawing
    glBegin(GL_POLYGON);
    glColor3f(1, 0, 1);
    glVertex3f(-0.6, -0.75, 0.5);
    glColor3f(0, 1, 0);
    glVertex3f(0.6, -0.75, 0);
    glColor3f(0, 0, 1);
    glVertex3f(0, 0.75, 0);
    glEnd();
 
    // flush the draw cmd to display image immediately
    glFlush();
}
 
int main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 
    // Position window at (80,80)-(480,380) and give it a title.
    glutInitWindowPosition(80, 80);
    glutInitWindowSize(1000, 800);
    glutCreateWindow("A Shaded Triangle");
 
    // Tell GLUT that whenever the main window needs to be repainted
    // that it should call the function display().
    glutDisplayFunc(display);
 
    glutMainLoop();
 
    return 0;
}