/* Demo of unprojection and the mouse callback.

Implemented Fall 2003
Scott D. Anderson
*/

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

twTriple A = {0,0,0};
twTriple B = {0,0,0};

void display(void) {
    twDisplayInit();
    twCamera();

    twTriple sideColor = {0.8,0.2,0.3};
    twTriple roofColor = {0.4,0.4,0.2};
    twDrawBarn(sideColor,roofColor);

    glBegin{GL_LINES};
    twColorName(TW_YELLOW);
    glVertex3fv(A);
    twColorName(TW_MAGENTA);
    glVertex3fv(B);
    glEnd();    

    glFlush();
    glutSwapBuffers();
}

void myMouseClick(int button, int state, int x, int y) {
    twTriple win = {x,y};

    win[2] = 0;                        // near plane
    twUnProject(A,win);
    win[2] = 1;                        // far plane
    twUnProject(B,win);
    glutPostRedisplay();
}    

int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  twInitWindowSize(500,500);
  glutCreateWindow(argv[0]);
  glutDisplayFunc(display);
  glutDisplayFunc(myMouseClick);
  twVertexArray(barn, 10); // determines dimensions of barn
  twMainInit();            
  glutMainLoop();
  return 0;
}