ROUNDWAL.CXX

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
#include "glos.h" 
 
#include <GL/glu.h> 
 
#ifdef X11 
#include <GL/glx.h> 
#endif 
 
#include <math.h> 
 
#ifdef WIN32 
#include "stonehen.h" 
#endif 
 
#include "Roundwal.h" 
 
Roundwall::Roundwall() 
{ 
  height = 2; 
  radius = 20; 
  divisions = 20; 
  sint = cost = NULL; 
} 
 
void Roundwall::draw() 
{ 
  float texx = 0; 
  int i; 
  if (sint == NULL) compute_tables(); 
  glBegin(GL_QUAD_STRIP); 
  for (i = 0; i <= divisions; i++, texx += 1.) { 
    glTexCoord2f(texx, 0); 
    glNormal3f(-cost[i], -sint[i], 0); 
    glVertex3f(radius * cost[i], radius * sint[i], 0); 
    glTexCoord2f(texx, 1); 
    glVertex3f(radius * cost[i], radius * sint[i], height); 
  } 
  glEnd(); 
} 
 
void Roundwall::set_divisions(int d) 
{ 
  if (divisions != d) delete_tables(); 
  divisions = d; 
} 
 
void Roundwall::delete_tables() 
{ 
  delete sint; 
  delete cost; 
  sint = cost = NULL; 
} 
 
void Roundwall::compute_tables() 
{ 
  int i; 
  float t, dt; 
 
  delete_tables(); 
  cost = new float[divisions + 1]; 
  sint = new float[divisions + 1]; 
 
  dt = 2. * M_PI / divisions; 
  for (i = 0, t = 0.; i <= divisions; i++, t += dt) { 
    cost[i] = cos(t); 
    sint[i] = sin(t); 
  } 
}