** File: extrude1.c
** Description: Renders a 3D image of x, y, z axes.
** Rev: 1.0
** Created: 29 August 2001
** Last Update: 07 October 2002
** Author: Fran Soddell
** Email: F.Soddell@bendigo.latrobe.edu.au
**/
#include <GL/glut.h>
#include <stdio.h>
#include <math.h>
#define TRUE 1
#define FALSE 0
#define PI 3.14159
/*
** manage 3D
*/
enum {x,y,z};
/*
** manage window
*/
int width =400;
int height=400;
int xPosition=50;
int yPosition=70;
/*
** manage world projection
*/
enum {xLeft,xRight,yBottom,yTop,zNear,zFar};
GLdouble world[]={
-5.0,5.0,-5.0,5.0,0.1,100
};
GLdouble fovy =90.0;
GLdouble aspect =1.0;
int perspective =TRUE;
/*
** manage camera
*/
enum {camera1,camera2};
int camera=camera1;
GLdouble eye[][3]={
{0.5,0.5,2.5},{0.0,1.0,3.0}
};
GLdouble centre[][3]={
{0.0,1.0,0.0},{0.0,0.0,0.0}
};
GLdouble up[]={
0.0,1.0,0.0
};
/*
** manage colour
*/
#define ALPHA 0.0
enum {red,green,blue,
yellow,magenta,cyan,
pink,
white,black,colours};
typedef GLfloat colourType[3];
colourType colour[]={
{1.0,0.0,0.0},{0.0,1.0,0.0},{0.0,0.0,1.0},
{1.0,1.0,0.0},{1.0,0.0,1.0},{0.0,1.0,1.0},
{1.0,0.65,0.65},
{1.0,1.0,1.0},{0.0,0.0,0.0}
};
/*
** model management
*/
typedef GLdouble vertexType[3];
#define NGON_SIZE 8
vertexType nGon[NGON_SIZE];
vertexType duplicate[NGON_SIZE];
double radius=0.25;
GLint extrusionMode=GL_LINE_LOOP;
/*
** ***********************************************************
*/
void renderImage(vertexType * image,
int start, int numVertices,
GLint primitive){
int i;
glBegin(primitive);
for(i=start;i<numVertices;i++)
glVertex3dv(image[i]);
glEnd();
}
void extrude(vertexType * front,vertexType * back,
int numVertices,GLint primitive){
int i,j=0;
for(i=0;i<numVertices;i++){
glBegin(primitive);
glVertex3dv(front[j]);
glVertex3dv(back[j]);
if(i==numVertices-1)
j=0;
else
j++;
glVertex3dv(back[j]);
glVertex3dv(front[j]);
glEnd();
}
}
void renderAxis(double length){
glPushMatrix();
glBegin(GL_LINES);
glVertex3d(0,0,0);
glVertex3d(0,0,length);
glEnd();
glTranslated(0,0,length-0.2);
glutWireCone(0.04,0.2,12,9);
glPopMatrix();
}
void axes(){
glLineWidth(1);
glColor3fv(colour[red]);
/* z-axis */
renderAxis(1.5);
glPushMatrix();
/* y-axis */
glRotated(90,0,1.0,0);
glColor3fv(colour[green]);
renderAxis(1.5);
/* x-axis */
glRotated(-90,1,0,0);
glColor3fv(colour[blue]);
renderAxis(1.5);
glPopMatrix();
}
void setProjection(){
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if(!perspective)
glOrtho(world[xLeft], world[xRight],
world[yBottom],world[yTop],
world[zNear], world[zFar]);
else
gluPerspective(fovy,1,world[zNear],world[zFar]);
}
void setCamera(){
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(eye[camera][x], eye[camera][y],eye[camera][z],
centre[camera][x],centre[camera][y],centre[camera][z],
up[x],up[y],up[z]);
}
void display(){
setCamera();
/*
** Clear window with background colour before (re)rendering.
*/
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
axes();
glPopMatrix();
glColor3fv(colour[magenta]);
renderImage(nGon,0,NGON_SIZE,GL_POLYGON);
glColor3fv(colour[pink]);
renderImage(duplicate,0,NGON_SIZE,GL_POLYGON);
if(extrusionMode==-999){
glColor3fv(colour[black]);
extrude(nGon,duplicate,NGON_SIZE,GL_LINE_LOOP);
glColor3fv(colour[red]);
extrude(nGon,duplicate,NGON_SIZE,GL_POLYGON);
}
else{
if(extrusionMode==GL_POLYGON)
glColor3fv(colour[red]);
else
glColor3fv(colour[black]);
extrude(nGon,duplicate,NGON_SIZE,extrusionMode);
}
glPopMatrix();
glutSwapBuffers();;
}
void keyboard(unsigned char key,int xMouse,int yMouse){
static int depthEnabled=FALSE;
static int cullEnabled=FALSE;
switch(key){
case 27 : exit(0);
case 'p': perspective=!perspective;
setProjection();
break;
case 'f': if(fovy<180) fovy+=0.5;
setProjection();
break;
case 'F': if(fovy>0) fovy-=0.5;
setProjection();
break;
case 'C': if(camera==camera1)
camera=camera2;
else camera=camera1;
break;
case 'd': depthEnabled=!depthEnabled;
if(depthEnabled) glEnable(GL_DEPTH_TEST);
else glDisable(GL_DEPTH_TEST);
break;
case 'c': cullEnabled=!cullEnabled;
if(cullEnabled) glEnable(GL_CULL_FACE);
else glDisable(GL_CULL_FACE);
break;
case 'P': extrusionMode=GL_POLYGON; break;
case 'L': extrusionMode=GL_LINE_LOOP; break;
case 'M': extrusionMode=GL_LINES; break;
case 'N': extrusionMode=-999; break;
}
glutPostRedisplay();
}
void reshapeWindow(int w, int h){
int yOrigin=0, xOrigin=0;
if(w>h){
yOrigin=(h-w)/2;
h=w;
}
else{
xOrigin=(w-h)/2;
w=h;
}
glViewport(xOrigin,yOrigin,(GLsizei)w,(GLsizei)h);
setProjection();
}
void setUpGLUT(int argc,char ** argv){
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DEPTH|GLUT_DOUBLE|GLUT_RGB);
glutInitWindowSize(width,height);
glutInitWindowPosition(xPosition,yPosition);
glutCreateWindow("Extruded nGon");
/*
** Register callbacks.
*/
glutDisplayFunc(display);
glutReshapeFunc(reshapeWindow);
glutKeyboardFunc(keyboard);
}
void initialiseGL(){
glClearColor(1,1,1,ALPHA);
glCullFace(GL_BACK);
}
void computeVertices(GLdouble centreX,GLdouble centreY,
GLdouble radius,GLint numVertices){
int i;
GLdouble angle=2*PI/numVertices;
for(i=0;i<numVertices;i++){
nGon[i][x]=centreX+radius*cos(i*angle);
nGon[i][y]=centreY+radius*sin(i*angle);
}
}
void initialise(){
int i;
computeVertices(0.0,0.0,radius,NGON_SIZE);
for(i=0;i<NGON_SIZE;i++){
duplicate[i][x]=nGon[i][x];
duplicate[i][y]=nGon[i][y];
duplicate[i][z]=nGon[i][z]-1.5;
}
}
int main(int argc,char ** argv){
initialise();
setUpGLUT(argc,argv);
initialiseGL();
/*
* Display window and enter the GLUT event
* processing loop.
*/
glutMainLoop();
return 0;
}
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