/*###########################################################*/
/* Programmer:  L. Grewe from OpenGL source,  1999          */
/*                                                           */
/* lines.c                                                   */
/* Description:  Opens a Window and draws 3 trees.           */
/*   Each tree is drawn with a call to glCallList()          */
/*	 User can choose projection type desired                 */
/*							                                 */
/* Compile:                                                 */  
/* cc -o trees trees.c -lglut -lGLU -lGL -lXmu -lX11 -lm   */
/* Run:	 trees                   						   */
/*###########################################################*/




#include <windows.h>
#include "gl/GL.h"
#include "gl/Glu.h"
#include "gl/glut.h"
#include <stdlib.h>

#include <stdio.h>
#include <math.h>

/*Function prototypes*/
GLvoid display(GLvoid);
GLvoid myinit(GLvoid);
GLvoid create_display_list(GLvoid);


/*Global Variables*/
GLint TREE = 1;
GLUquadricObj *p,*q; //pointers to quadric objects
GLfloat TREE_TRUNK_RADIUS = 5.0;
GLfloat TREE_TRUNK_HEIGHT = 10.0;
GLfloat TREE_TOP_BOTTOM_RADIUS = 10.0;
GLfloat TREE_TOP_HEIGHT = 15.0;




     void main(int argc, char **argv)  
     {  
       
         glutInit(&argc,argv); /*init.  GLUT window sys.*/  

         /*there will be a single buffered  window displaying RGB */ 
         glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB|GLUT_DEPTH);   

         glutInitWindowSize(500,500);   /*size in pixels  */
         glutInitWindowPosition(0,0);   /* located lower-left of screen */ 

         /*Create the window using the setup from the previous glut calls*/  
         glutCreateWindow("TREE- Display List Example");  /*title=Lines Example*/  

         /*tell system what function will be in charge of displaying*/  
         glutDisplayFunc(display);  


         /*Call another function to further initialize window contents*/  
         myinit();  

		 /*Create List*/
		 create_display_list();

         /*this call causes to go in infinite loop waiting for window i/o */  
         glutMainLoop();  

     }  
       
       

    GLvoid create_display_list(GLvoid)

    {
	glNewList(TREE, GL_COMPILE);
          
		  //Rotate so that cylinder will be along the y axis
		  //and not the standard around the z axis
		   glPushMatrix();
		      glRotatef(-90.0, 1.0,0.0,0.0); //rotate -90deg around x axis
			  /*drawing color brown */
			  glColor3f(0.8,0.5,0.0);  
			 gluCylinder(p, TREE_TRUNK_RADIUS, TREE_TRUNK_RADIUS, TREE_TRUNK_HEIGHT,5,5);
			 //move up (now the new z axis) to draw the tree top
			 glTranslatef(0.0,0.0, TREE_TRUNK_HEIGHT);
			 /*drawing color gree */
			  glColor3f(0.0,1.0,0.0);  
		 	 gluCylinder(q, TREE_TOP_BOTTOM_RADIUS, 0.0, TREE_TOP_HEIGHT,5,5);
           glPopMatrix();

	  
	glEndList();
    }
       
        

     /*#####################################*/  
     /*myinit:  this function does a number of
	  *  initialization routines including:clears 
	  *  the background of the graphics system,
	  *  enables depth buffering and sets up 
	  *  viewing conditions 
	  *  the drawing color to 
      *  red.  Finally, viewing parameters are set.*/
     /*#####################################*/  
     GLvoid myinit(GLvoid)  
     {  char val;
	     
		 /*enable depth buffering*/
		 glEnable(GL_DEPTH_TEST);

          /*white background  */
          glClearColor(1.0,1.0,1.0,0.0);  

         /*drawing color red  */
         glColor3f(1.0,0.0,0.0);  

		 /* Viewport settings....currently same as*/
		 /*  default which is viewport=window*/
		 glViewport(0.0, 0.0, 500.0, 500.0);
		 

         /*Viewing Configuration  */
         glMatrixMode(GL_PROJECTION);  /*says will specify project.  */
         glLoadIdentity();   /*load identity matrix.*/  
		 

         /*position of camera..defines position of viewing volume*/
		 /*currently same as default:*/
		 /* eye at origin lookind down -z axis*/
       	 gluLookAt(0.0,0.0,0.0,  0.0,0.0,-1.0,  0.0, 1.0,0.0);
		        /*center of camera,  looking at point,  up vector*/

		 /*Define Viewing Volume Shape*/
		 printf("Choose option desired\n");
	     printf("1: Orthographic\n");
	     printf("2: Perspective with glPerspective\n");
		 printf("3: Perspective with glFrustum\n");
		 val =  getchar();
		 	
		 if(val == '1')
            glOrtho(-300.0,300.0, -300.0, 300.0, 100.0, 4000.0);  /*specifies Othographic proj*/ 
		 else if(val == '2')
		    gluPerspective(90.0, 1.0, 0.0, 1000.0);
		 else
		    glFrustum(-300.0,300.0,-300.0, 300.0, 200.0, 4000.0); /*at near=0 can't see objects...project to <1 pixel
																    near=50 very small
																	near=100-200 get larger
																	near=250 starting to clip off one of the trees*/

        /*allocate quadric object used in drawing cylinder*/
		 p = gluNewQuadric();
		 gluQuadricDrawStyle(p, GLU_FILL); //draw quadric in fill mode
		 q = gluNewQuadric();
		 gluQuadricDrawStyle(q, GLU_FILL); //draw quadric in fill mode
        
		 
		/*Shift to Model Specification Model  */
        glMatrixMode(GL_MODELVIEW);  
     }  




     /*#####################################*/  
     /*display:  this function draws three trees*/  
     /*#####################################*/  
     GLvoid display(GLvoid)  
     {  

	  /*clear color and depth buffers*/	  
	  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	  /*draw trees*/
      glLoadIdentity();   /*load identity matrix.*/  
	  /*move back to draw first tree*/
	  glTranslatef(0.0,0.0,-300.0); 
	  glCallList(TREE);
	  /*move and draw next tree*/
	  glTranslatef(100.0,100.0,100.0);
	  glCallList(TREE);
	  /*move again and draw last tree*/
	  glTranslatef(-200.0, -200.0, -200.0);
	  glCallList(TREE);
        

      glFlush();  /*not needed but asks to draw ASAP.*/  

     }