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/* $Id: texobj.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
/*
* Example of using the 1.1 texture object functions.
* Also, this demo utilizes Mesa's fast texture map path.
*
* Brian Paul June 1996 This file is in the public domain.
*/
/*
* $Log: texobj.c,v $
* Revision 1.1 1999/08/19 00:55:40 jtg
* Initial revision
*
* Revision 3.1 1999/03/28 18:24:37 brianp
* minor clean-up
*
* Revision 3.0 1998/02/14 18:42:29 brianp
* initial rev
*
*/
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "GL/glut.h"
static GLuint Window = 0;
static GLuint TexObj[2];
static GLfloat Angle = 0.0f;
static GLboolean HaveTexObj = GL_FALSE;
#if defined(GL_VERSION_1_1)
# define TEXTURE_OBJECT 1
#elif defined(GL_EXT_texture_object)
# define TEXTURE_OBJECT 1
# define glBindTexture(A,B) glBindTextureEXT(A,B)
# define glGenTextures(A,B) glGenTexturesEXT(A,B)
# define glDeleteTextures(A,B) glDeleteTexturesEXT(A,B)
#endif
static void draw( void )
{
glDepthFunc(GL_EQUAL);
/* glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );*/
glClear( GL_COLOR_BUFFER_BIT );
glColor3f( 1.0, 1.0, 1.0 );
/* draw first polygon */
glPushMatrix();
glTranslatef( -1.0, 0.0, 0.0 );
glRotatef( Angle, 0.0, 0.0, 1.0 );
if (HaveTexObj) {
#ifdef TEXTURE_OBJECT
glBindTexture( GL_TEXTURE_2D, TexObj[0] );
#endif
}
else {
glCallList( TexObj[0] );
}
glBegin( GL_POLYGON );
glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
glEnd();
glPopMatrix();
/* draw second polygon */
glPushMatrix();
glTranslatef( 1.0, 0.0, 0.0 );
glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
if (HaveTexObj) {
#ifdef TEXTURE_OBJECT
glBindTexture( GL_TEXTURE_2D, TexObj[1] );
#endif
}
else {
glCallList( TexObj[0] );
}
glBegin( GL_POLYGON );
glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
glEnd();
glPopMatrix();
glutSwapBuffers();
}
static void idle( void )
{
Angle += 2.0;
glutPostRedisplay();
}
/* change view Angle, exit upon ESC */
static void key(unsigned char k, int x, int y)
{
(void) x;
(void) y;
switch (k) {
case 27:
#ifdef TEXTURE_OBJECT
glDeleteTextures( 2, TexObj );
#endif
glutDestroyWindow(Window);
exit(0);
}
}
/* new window size or exposure */
static void reshape( int width, int height )
{
glViewport(0, 0, (GLint)width, (GLint)height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
/* glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef( 0.0, 0.0, -8.0 );
}
static void init( void )
{
static int width=8, height=8;
static GLubyte tex1[] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 0, 1, 1, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 0, 0, 1, 0, 0, 0,
0, 0, 0, 1, 1, 1, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0 };
static GLubyte tex2[] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 2, 2, 0, 0, 0,
0, 0, 2, 0, 0, 2, 0, 0,
0, 0, 0, 0, 0, 2, 0, 0,
0, 0, 0, 0, 2, 0, 0, 0,
0, 0, 0, 2, 0, 0, 0, 0,
0, 0, 2, 2, 2, 2, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0 };
GLubyte tex[64][3];
GLint i, j;
glDisable( GL_DITHER );
/* Setup texturing */
glEnable( GL_TEXTURE_2D );
glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
/* generate texture object IDs */
if (HaveTexObj) {
#ifdef TEXTURE_OBJECT
glGenTextures( 2, TexObj );
#endif
}
else {
TexObj[0] = glGenLists(2);
TexObj[1] = TexObj[0]+1;
}
/* setup first texture object */
if (HaveTexObj) {
#ifdef TEXTURE_OBJECT
glBindTexture( GL_TEXTURE_2D, TexObj[0] );
#endif
}
else {
glNewList( TexObj[0], GL_COMPILE );
}
/* red on white */
for (i=0;i<height;i++) {
for (j=0;j<width;j++) {
int p = i*width+j;
if (tex1[(height-i-1)*width+j]) {
tex[p][0] = 255; tex[p][1] = 0; tex[p][2] = 0;
}
else {
tex[p][0] = 255; tex[p][1] = 255; tex[p][2] = 255;
}
}
}
glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
GL_RGB, GL_UNSIGNED_BYTE, tex );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
if (!HaveTexObj) {
glEndList();
}
/* end of texture object */
/* setup second texture object */
if (HaveTexObj) {
#ifdef TEXTURE_OBJECT
glBindTexture( GL_TEXTURE_2D, TexObj[1] );
#endif
}
else {
glNewList( TexObj[1], GL_COMPILE );
}
/* green on blue */
for (i=0;i<height;i++) {
for (j=0;j<width;j++) {
int p = i*width+j;
if (tex2[(height-i-1)*width+j]) {
tex[p][0] = 0; tex[p][1] = 255; tex[p][2] = 0;
}
else {
tex[p][0] = 0; tex[p][1] = 0; tex[p][2] = 255;
}
}
}
glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
GL_RGB, GL_UNSIGNED_BYTE, tex );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
if (!HaveTexObj) {
glEndList();
}
/* end texture object */
}
int main( int argc, char *argv[] )
{
glutInitWindowPosition(0, 0);
glutInitWindowSize(300, 300);
glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
Window = glutCreateWindow("Texture Objects");
if (!Window) {
exit(1);
}
/* check that renderer has the GL_EXT_texture_object extension
* or supports OpenGL 1.1
*/
#ifdef TEXTURE_OBJECT
{
char *exten = (char *) glGetString( GL_EXTENSIONS );
char *version = (char *) glGetString( GL_VERSION );
if ( strstr( exten, "GL_EXT_texture_object" )
|| strncmp( version, "1.1", 3 )==0 ) {
HaveTexObj = GL_TRUE;
}
}
#endif
init();
glutReshapeFunc( reshape );
glutKeyboardFunc( key );
glutIdleFunc( idle );
glutDisplayFunc( draw );
glutMainLoop();
return 0;
}
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