DEPTHCUE.C

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
/* 
 *  depthcue.c 
 *  This program draws a wireframe model, which uses  
 *  intensity (brightness) to give clues to distance. 
 *  Fog is used to achieve this effect. 
 */ 
#include "glos.h" 
 
#include <GL/gl.h> 
#include <GL/glu.h> 
#include <GL/glaux.h> 
 
void myinit(void); 
void CALLBACK myReshape(GLsizei w, GLsizei h); 
void CALLBACK display(void); 
 
/*  Initialize linear fog for depth cueing. 
 */ 
void myinit(void) 
{ 
    GLfloat fogColor[4] = {0.0, 0.0, 0.0, 1.0}; 
 
    glEnable(GL_FOG); 
    glFogi (GL_FOG_MODE, GL_LINEAR); 
    glHint (GL_FOG_HINT, GL_NICEST);  /*  per pixel   */ 
    glFogf (GL_FOG_START, 3.0); 
    glFogf (GL_FOG_END, 5.0); 
    glFogfv (GL_FOG_COLOR, fogColor); 
    glClearColor(0.0, 0.0, 0.0, 1.0); 
 
    glDepthFunc(GL_LESS); 
    glEnable(GL_DEPTH_TEST); 
    glShadeModel(GL_FLAT); 
} 
 
/*  display() draws an icosahedron. 
 */ 
void CALLBACK display(void) 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glColor3f (1.0, 1.0, 1.0); 
    auxWireIcosahedron(1.0); 
    glFlush(); 
} 
 
void CALLBACK myReshape(GLsizei w, GLsizei h) 
{ 
    if (!h) return; 
    glViewport(0, 0, w, h); 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 3.0, 5.0); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity (); 
    glTranslatef (0.0, 0.0, -4.0);  /*  move object into view   */ 
} 
 
/*  Main Loop 
 */ 
int main(int argc, char** argv) 
{ 
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16); 
    auxInitPosition (0, 0, 400, 400); 
    auxInitWindow ("Distance Using Fog"); 
    myinit(); 
    auxReshapeFunc (myReshape); 
    auxMainLoop(display); 
    return(0); 
}