/* Demo of the color interpolation. This shows that the order of vertices
   of a triangle does *not* matter, since these triangles look the same.

Implemented Fall 2003
Scott D. Anderson
*/

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

GLfloat A[3] = {0,0,0};
GLfloat B[3] = {1,0,0};
GLfloat C[3] = {0,1,0};

GLfloat Red[3]   = {1,0,0};
GLfloat Green[3] = {0,1,0};
GLfloat Blue[3]  = {0,0,1};

void drawABC() {
    glBegin(GL_TRIANGLES);
    {
        glColor3fv(Red);        glVertex3fv(A);
        glColor3fv(Green);        glVertex3fv(B);
        glColor3fv(Blue);        glVertex3fv(C);
    }
    glEnd();
}

void drawCAB() {
    glBegin(GL_TRIANGLES);
    {
        glColor3fv(Blue);        glVertex3fv(C);
        glColor3fv(Red);        glVertex3fv(A);
        glColor3fv(Green);        glVertex3fv(B);
    }
    glEnd();
}
void display(void) {
    twDisplayInit();
    twCamera();

    glShadeModel(GL_SMOOTH);
    drawABC();
    glPushMatrix();
    glTranslatef(1,0,0);
    drawCAB();
    glPopMatrix();

    glFlush();
    glutSwapBuffers();
}

int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  twInitWindowSize(800,500);
  glutCreateWindow(argv[0]);
  glutDisplayFunc(display);
  twBoundingBox(0,2,0,1,-1,1);
  twMainInit();            
  glutMainLoop();
  return 0;
}