/* Demo of the classic barn object, augmented with an animation of the
   peak growing to form a kind of "steeple."

Implemented Fall 2003
Scott D. Anderson
*/

#include <stdio.h>
#include <tw.h>

const int barnWidth =30;
const int barnHeight=40;
const int barnLength=50;

twTriple barn[10] = 
{
  {0,0,0},                                 //left, bottom, front 
  {barnWidth,0,0},                         // right, bottom, front 
  {barnWidth,barnHeight,0},                 // right, top, front 
  {0,barnHeight,0},                         // left, top, front 
  {barnWidth/2.0,barnHeight+barnWidth/2.0,0}, // ridge, front 
  {0,0,-barnLength},                     // left, bottom, back 
  {barnWidth,0,-barnLength},             // right, bottom, back 
  {barnWidth,barnHeight,-barnLength},    //right, top, back 
  {0,barnHeight,-barnLength},            // left, top, back 
  {barnWidth/2.0,barnHeight+barnWidth/2.0,-barnLength},// ridge, back 
};

// Almost every facet is a different color so that we can see them.

void drawBarn(GLfloat steepleHeight) {
    // Use steeple instead of barn[4]
    twTriple steeple = {barnWidth/2.0, steepleHeight, 0};
    twColorName(TW_RED);        // set color to red
    glBegin(GL_POLYGON);        // front 
    {
        glVertex3fv(barn[0]);
        glVertex3fv(barn[1]);
        glVertex3fv(barn[2]);
        glVertex3fv(barn[3]);
    }
    glEnd();
    glBegin(GL_POLYGON);        // front ridge 
    {
        glVertex3fv(barn[3]);
        glVertex3fv(barn[2]);
        glVertex3fv(steeple);
    }
    glEnd();
    twColorName(TW_GREEN);
    glBegin(GL_POLYGON);        // back 
    {
        glVertex3fv(barn[5]);
        glVertex3fv(barn[6]);
        glVertex3fv(barn[7]);
        glVertex3fv(barn[8]);
    }
    glEnd();
    glBegin(GL_POLYGON);         // back ridge 
    {
        glVertex3fv(barn[7]);
        glVertex3fv(barn[8]);
        glVertex3fv(barn[9]);
    }
    glEnd();
    twColorName(TW_PURPLE);
    glBegin(GL_POLYGON);        // left side 
    {
        glVertex3fv(steeple);
        glVertex3fv(barn[3]);
        glVertex3fv(barn[8]);
        glVertex3fv(barn[5]);
    }
    glEnd();
    twColorName(TW_MAROON);
    glBegin(GL_POLYGON);        // right side 
    {
      glVertex3fv(barn[1]);
      glVertex3fv(barn[2]);
      glVertex3fv(barn[7]);
      glVertex3fv(barn[6]);
    }
    glEnd();
    twColorName(TW_OLIVE);
    glBegin(GL_POLYGON);        // left side roof 
    {
      glVertex3fv(barn[3]);
      glVertex3fv(steeple);
      glVertex3fv(barn[9]);
      glVertex3fv(barn[8]);
    }
    glEnd();
    glBegin(GL_POLYGON);        /* right side roof */
    {
      glVertex3fv(barn[2]);
      glVertex3fv(steeple);
      glVertex3fv(barn[9]);
      glVertex3fv(barn[7]);
    }
    glEnd();
}

int FrameNumber=-1;                // no animation, yet

const int WinSize = 500;

void saveFrame() {
    char file[20];
    sprintf(file, "animationLab%03d.ppm", FrameNumber++);
    twSaveFrame(WinSize, WinSize, file, 0);
}

bool SaveFrames = false;

GLfloat steepleheight = barnHeight+barnWidth/2.0;

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

    drawBarn(steepleheight);
    
    if(SaveFrames) saveFrame();
    glFlush();
    glutSwapBuffers();
}

bool Grow = false;

void grow(void) {
    steepleheight += 0.01;
    glutPostRedisplay();
}

void keys(unsigned char k, int x, int y) {
    switch (k) {
    case '1':
        SaveFrames = !SaveFrames;
        if(SaveFrames) FrameNumber = 1;
        break;
    case '2':
        Grow = !Grow;
        if(Grow) 
            glutIdleFunc(grow);
        else 
            glutIdleFunc(NULL);
        break;
    case '3':
        grow();
        break;
    }
}


int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
  twInitWindowSize(WinSize,WinSize);
  glutCreateWindow(argv[0]);
  glutDisplayFunc(display);
  twBoundingBox(0,barnWidth,0,barnHeight*2,-barnLength,0);
  twMainInit();            
  twKeyCallback('1',keys,"toggle saving frames");
  twKeyCallback('2',keys,"toggle animation");
  twKeyCallback('3',keys,"one frame");
  glutMainLoop();
  return 0;
}