// cc -Wall triangle.c -o tiangle -lGL -lGLU -lglut -lm -lX11 -L /usr/X11R6/lib; ./triangle
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>

GLfloat t_angle;

void display( );

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glLoadIdentity( );
    glRotatef(t_angle, 1.0f, 1.0f, 1.0f);
    glBegin(GL_TRIANGLES);
        glColor3f(0.0f, 0.0f, 1.0f);
        glVertex3f(0.0f, 0.0f, 0.0f);

        glColor3f(0.0f, 1.0f, 0.0f);
        glVertex3f(1.0f, 0.0f, 0.0f);

        glColor3f(1.0f, 0.0f, 0.0f);
        glVertex3f(1.0f, 1.0f, 0.0f);
    glEnd( );

    glPushMatrix( );
    glTranslatef(-0.5f, 0.0f, -0.5f);
    glRotatef(t_angle, 1.0f, 0.0f, 0.0f);
    glBegin(GL_POLYGON);
        glColor3f(1.0f, 0.0f, 1.0f);
        glVertex3f(0.0f, 0.0f, 0.0f);

        glColor3f(0.0f, 1.0f, 1.0f);
        glVertex3f(1.0f, 0.0f, 0.0f);

        glColor3f(1.0f, 1.0f, 0.0f);
        glVertex3f(1.0f, 1.0f, 0.0f);

        glColor3f(0.0f, 0.0f, 0.0f);
        glVertex3f(0.0f, 1.0f, 0.0f);
    glEnd( );
    glPopMatrix( );

    glutSwapBuffers( );
    glutPostRedisplay( );
/*    t_angle += 0.02;*/
}

void init(void)
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glMatrixMode(GL_FLAT);
    glLoadIdentity( );
    glTranslatef(0.0f, 0.0f, 0.0f);
    glOrtho(-2.0, 2.0, -2.0, 2.0, -2.0, 2.0);
    t_angle = 0.1;
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(250,250);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Hello");
    init( );
    glutDisplayFunc(display);
/*    glutIdleFunc(display);*/
    glutMainLoop( );
    return 0;
}