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/*
* Copyright (c) 1993-1997, Silicon Graphics, Inc.
* ALL RIGHTS RESERVED
* Permission to use, copy, modify, and distribute this software for
* any purpose and without fee is hereby granted, provided that the above
* copyright notice appear in all copies and that both the copyright notice
* and this permission notice appear in supporting documentation, and that
* the name of Silicon Graphics, Inc. not be used in advertising
* or publicity pertaining to distribution of the software without specific,
* written prior permission.
*
* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
*
* US Government Users Restricted Rights
* Use, duplication, or disclosure by the Government is subject to
* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
* (c)(1)(ii) of the Rights in Technical Data and Computer Software
* clause at DFARS 252.227-7013 and/or in similar or successor
* clauses in the FAR or the DOD or NASA FAR Supplement.
* Unpublished-- rights reserved under the copyright laws of the
* United States. Contractor/manufacturer is Silicon Graphics,
* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
*
* OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
*/
/* texgen.c
* This program draws a texture mapped teapot with
* automatically generated texture coordinates. The
* texture is rendered as stripes on the teapot.
* Initially, the object is drawn with texture coordinates
* based upon the object coordinates of the vertex
* and distance from the plane x = 0. Pressing the 'e'
* key changes the coordinate generation to eye coordinates
* of the vertex. Pressing the 'o' key switches it back
* to the object coordinates. Pressing the 's' key
* changes the plane to a slanted one (x + y + z = 0).
* Pressing the 'x' key switches it back to x = 0.
*/
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#define stripeImageWidth 32
GLubyte stripeImage[4*stripeImageWidth];
#ifdef GL_VERSION_1_1
static GLuint texName;
#endif
static void makeStripeImage(void)
{
int j;
for (j = 0; j < stripeImageWidth; j++) {
stripeImage[4*j] = (GLubyte) ((j<=4) ? 255 : 0);
stripeImage[4*j+1] = (GLubyte) ((j>4) ? 255 : 0);
stripeImage[4*j+2] = (GLubyte) 0;
stripeImage[4*j+3] = (GLubyte) 255;
}
}
/* planes for texture coordinate generation */
static GLfloat xequalzero[] = {1.0, 0.0, 0.0, 0.0};
static GLfloat slanted[] = {1.0, 1.0, 1.0, 0.0};
static GLfloat *currentCoeff;
static GLenum currentPlane;
static GLint currentGenMode;
static void init(void)
{
glClearColor (0.0, 0.0, 0.0, 0.0);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
makeStripeImage();
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
#ifdef GL_VERSION_1_1
glGenTextures(1, &texName);
glBindTexture(GL_TEXTURE_1D, texName);
#endif
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
#ifdef GL_VERSION_1_1
glTexImage1D(GL_TEXTURE_1D, 0, GL_RGBA, stripeImageWidth, 0,
GL_RGBA, GL_UNSIGNED_BYTE, stripeImage);
#else
glTexImage1D(GL_TEXTURE_1D, 0, 4, stripeImageWidth, 0,
GL_RGBA, GL_UNSIGNED_BYTE, stripeImage);
#endif
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
currentCoeff = xequalzero;
currentGenMode = GL_OBJECT_LINEAR;
currentPlane = GL_OBJECT_PLANE;
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
glTexGenfv(GL_S, currentPlane, currentCoeff);
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);
}
static void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix ();
glRotatef(45.0, 0.0, 0.0, 1.0);
#ifdef GL_VERSION_1_1
glBindTexture(GL_TEXTURE_1D, texName);
#endif
glutSolidTeapot(2.0);
glPopMatrix ();
glFlush();
}
static void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) 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();
}
/* ARGSUSED1 */
static void keyboard (unsigned char key, int x, int y)
{
switch (key) {
case 'e':
case 'E':
currentGenMode = GL_EYE_LINEAR;
currentPlane = GL_EYE_PLANE;
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
glTexGenfv(GL_S, currentPlane, currentCoeff);
glutPostRedisplay();
break;
case 'o':
case 'O':
currentGenMode = GL_OBJECT_LINEAR;
currentPlane = GL_OBJECT_PLANE;
glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
glTexGenfv(GL_S, currentPlane, currentCoeff);
glutPostRedisplay();
break;
case 's':
case 'S':
currentCoeff = slanted;
glTexGenfv(GL_S, currentPlane, currentCoeff);
glutPostRedisplay();
break;
case 'x':
case 'X':
currentCoeff = xequalzero;
glTexGenfv(GL_S, currentPlane, currentCoeff);
glutPostRedisplay();
break;
case 27:
exit(0);
break;
default:
break;
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(256, 256);
glutInitWindowPosition(100, 100);
glutCreateWindow (argv[0]);
init ();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0;
}
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