TEXGEN.C

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
/*  texgen.c 
 *  This program draws a texture mapped teapot with  
 *  automatically generated texture coordinates.  The 
 *  texture is rendered as stripes on the teapot. 
 */ 
#include "glos.h" 
 
#include <GL/gl.h> 
#include <GL/glu.h> 
#include <GL/glaux.h> 
 
void myinit(void); 
void makeStripeImage(void); 
void CALLBACK display(void); 
void CALLBACK myReshape(GLsizei w, GLsizei h); 
 
#define stripeImageWidth 32 
GLubyte stripeImage[3*stripeImageWidth]; 
 
void makeStripeImage(void) 
{ 
    int j; 
     
    for (j = 0; j < stripeImageWidth; j++) { 
        stripeImage[3*j] = (j<=4) ? 255 : 0; 
        stripeImage[3*j+1] = (j>4) ? 255 : 0; 
        stripeImage[3*j+2] = 0; 
    } 
} 
 
/* glTexGen stuff: */ 
 
GLfloat sgenparams[] = {1.0, 1.0, 1.0, 0.0}; 
 
void myinit(void) 
{ 
    glClearColor (0.0, 0.0, 0.0, 0.0); 
 
    makeStripeImage(); 
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); 
    glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); 
    glTexParameterf(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
    glTexImage1D(GL_TEXTURE_1D, 0, 3, stripeImageWidth, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, stripeImage); 
 
    glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR); 
    glTexGenfv(GL_S, GL_OBJECT_PLANE, sgenparams); 
 
    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LESS); 
    glEnable(GL_TEXTURE_GEN_S); 
    glEnable(GL_TEXTURE_1D); 
    glEnable(GL_CULL_FACE); 
    glEnable(GL_LIGHTING); 
    glEnable(GL_LIGHT0); 
    glEnable(GL_AUTO_NORMAL); 
    glEnable(GL_NORMALIZE); 
    glFrontFace(GL_CW); 
    glCullFace(GL_BACK); 
    glMaterialf (GL_FRONT, GL_SHININESS, 64.0); 
} 
 
void CALLBACK display(void) 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glPushMatrix (); 
    glRotatef(45.0, 0.0, 0.0, 1.0); 
    auxSolidTeapot(2.0); 
    glPopMatrix (); 
    glFlush(); 
} 
 
void CALLBACK myReshape(GLsizei w, GLsizei h) 
{ 
    if (!h) return; 
    glViewport(0, 0, w, h); 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    if (w <= h) 
    glOrtho (-3.5, 3.5, -3.5*(GLfloat)h/(GLfloat)w,  
        3.5*(GLfloat)h/(GLfloat)w, -3.5, 3.5); 
    else 
    glOrtho (-3.5*(GLfloat)w/(GLfloat)h,  
        3.5*(GLfloat)w/(GLfloat)h, -3.5, 3.5, -3.5, 3.5); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
} 
 
int main(int argc, char** argv) 
{ 
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16); 
    auxInitPosition (0, 0, 200, 200); 
    auxInitWindow ("Texture Map"); 
    myinit(); 
    auxReshapeFunc (myReshape); 
    auxMainLoop(display); 
    return(0); 
}