PDA

View Full Version : Textures with glColorTableExt



zvivered
06-14-2002, 09:53 PM
Hello,

I'm looking for a sample that uses glColorTableExt with glTexImage2D in order to display an image with color palette.
Can someone help ?

06-16-2002, 06:06 AM
This example is from the progs/bucciarelli directory in the GLUT source distribution.



/* paltex.c */

/*
* Paletted texture demo.
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#ifdef _WIN32
#include <windows.h>
#endif
#include <GL/glut.h>

// #define GL_EXT_paletted_texture 1

#if defined(GL_EXT_paletted_texture) &amp;&amp; defined(_WIN32)
void (*glColorTableEXT)(GLenum target, GLenum internalFormat,
GLsizei width, GLenum format, GLenum type, const GLvoid * data);
#endif

static float Rot = 0.0;


static void Idle( void )
{
Rot += 5.0;
glutPostRedisplay();
}


static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT );

glPushMatrix();
glRotatef(Rot, 0, 0, 1);

glBegin(GL_POLYGON);
glTexCoord2f(0, 1); glVertex2f(-1, -1);
glTexCoord2f(1, 1); glVertex2f( 1, -1);
glTexCoord2f(1, 0); glVertex2f( 1, 1);
glTexCoord2f(0, 0); glVertex2f(-1, 1);
glEnd();

glPopMatrix();

glutSwapBuffers();
}


static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
}


/* ARGSUSED1 */
static void Key( unsigned char key, int x, int y )
{
switch (key) {
case 27:
exit(0);
break;
}
glutPostRedisplay();
}


/* ARGSUSED1 */
static void SpecialKey( int key, int x, int y )
{
switch (key) {
case GLUT_KEY_UP:
break;
case GLUT_KEY_DOWN:
break;
case GLUT_KEY_LEFT:
break;
case GLUT_KEY_RIGHT:
break;
}
glutPostRedisplay();
}


static void Init( void )
{
#ifdef GL_EXT_paletted_texture
GLubyte texture[8][8] = { /* PT = Paletted Texture! */
{ 0, 0, 0, 0, 0, 0, 0, 0},
{ 0, 100, 100, 100, 0, 180, 180, 180},
{ 0, 100, 0, 100, 0, 0, 180, 0},
{ 0, 100, 0, 100, 0, 0, 180, 0},
{ 0, 100, 100, 100, 0, 0, 180, 0},
{ 0, 100, 0, 0, 0, 0, 180, 0},
{ 0, 100, 0, 0, 0, 0, 180, 0},
{ 0, 100, 255, 0, 0, 0, 180, 250},
};

GLubyte table[256][4];
int i;

if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
#endif
printf("Sorry, GL_EXT_paletted_texture not supported\n");
exit(0);
#ifdef GL_EXT_paletted_texture
}

/* put some wacky colors into the texture palette */
for (i=0;i<256;i++) {
table[i][0] = i;
table[i][1] = 0;
table[i][2] = 127 + i / 2;
table[i][3] = 255;
}

#if defined(GL_EXT_paletted_texture) &amp;&amp; defined(_WIN32)
glColorTableEXT = (void *) wglGetProcAddress("glColorTableEXT");
if (!glColorTableEXT) {
fprintf(stderr, "wglGetProcAddress could not get glColorTableEXT\n");
exit(1);
}
#endif

glColorTableEXT(GL_TEXTURE_2D, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */

glTexImage2D(GL_TEXTURE_2D, /* target */
0, /* level */
GL_COLOR_INDEX8_EXT, /* internal format */
8, 8, /* width, height */
0, /* border */
GL_COLOR_INDEX, /* texture format */
GL_UNSIGNED_BYTE, /* texture type */
texture); /* teh texture */
#endif

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
}


int main( int argc, char *argv[] )
{
glutInit( &amp;argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 640, 480 );

glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );

glutCreateWindow(argv[0]);

Init();

glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
glutIdleFunc( Idle );

glutMainLoop();
return 0;
}

zvivered
06-16-2002, 10:04 AM
Originally posted by Zico:
This example is from the progs/bucciarelli directory in the GLUT source distribution.



/* paltex.c */

/*
* Paletted texture demo.
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#ifdef _WIN32
#include <windows.h>
#endif
#include <GL/glut.h>

// #define GL_EXT_paletted_texture 1

#if defined(GL_EXT_paletted_texture) &amp;&amp; defined(_WIN32)
void (*glColorTableEXT)(GLenum target, GLenum internalFormat,
GLsizei width, GLenum format, GLenum type, const GLvoid * data);
#endif

static float Rot = 0.0;


static void Idle( void )
{
Rot += 5.0;
glutPostRedisplay();
}


static void Display( void )
{
glClear( GL_COLOR_BUFFER_BIT );

glPushMatrix();
glRotatef(Rot, 0, 0, 1);

glBegin(GL_POLYGON);
glTexCoord2f(0, 1); glVertex2f(-1, -1);
glTexCoord2f(1, 1); glVertex2f( 1, -1);
glTexCoord2f(1, 0); glVertex2f( 1, 1);
glTexCoord2f(0, 0); glVertex2f(-1, 1);
glEnd();

glPopMatrix();

glutSwapBuffers();
}


static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
}


/* ARGSUSED1 */
static void Key( unsigned char key, int x, int y )
{
switch (key) {
case 27:
exit(0);
break;
}
glutPostRedisplay();
}


/* ARGSUSED1 */
static void SpecialKey( int key, int x, int y )
{
switch (key) {
case GLUT_KEY_UP:
break;
case GLUT_KEY_DOWN:
break;
case GLUT_KEY_LEFT:
break;
case GLUT_KEY_RIGHT:
break;
}
glutPostRedisplay();
}


static void Init( void )
{
#ifdef GL_EXT_paletted_texture
GLubyte texture[8][8] = { /* PT = Paletted Texture! */
{ 0, 0, 0, 0, 0, 0, 0, 0},
{ 0, 100, 100, 100, 0, 180, 180, 180},
{ 0, 100, 0, 100, 0, 0, 180, 0},
{ 0, 100, 0, 100, 0, 0, 180, 0},
{ 0, 100, 100, 100, 0, 0, 180, 0},
{ 0, 100, 0, 0, 0, 0, 180, 0},
{ 0, 100, 0, 0, 0, 0, 180, 0},
{ 0, 100, 255, 0, 0, 0, 180, 250},
};

GLubyte table[256][4];
int i;

if (!glutExtensionSupported("GL_EXT_paletted_texture")) {
#endif
printf("Sorry, GL_EXT_paletted_texture not supported\n");
exit(0);
#ifdef GL_EXT_paletted_texture
}

/* put some wacky colors into the texture palette */
for (i=0;i<256;i++) {
table[i][0] = i;
table[i][1] = 0;
table[i][2] = 127 + i / 2;
table[i][3] = 255;
}

#if defined(GL_EXT_paletted_texture) &amp;&amp; defined(_WIN32)
glColorTableEXT = (void *) wglGetProcAddress("glColorTableEXT");
if (!glColorTableEXT) {
fprintf(stderr, "wglGetProcAddress could not get glColorTableEXT\n");
exit(1);
}
#endif

glColorTableEXT(GL_TEXTURE_2D, /* target */
GL_RGBA, /* internal format */
256, /* table size */
GL_RGBA, /* table format */
GL_UNSIGNED_BYTE, /* table type */
table); /* the color table */

glTexImage2D(GL_TEXTURE_2D, /* target */
0, /* level */
GL_COLOR_INDEX8_EXT, /* internal format */
8, 8, /* width, height */
0, /* border */
GL_COLOR_INDEX, /* texture format */
GL_UNSIGNED_BYTE, /* texture type */
texture); /* teh texture */
#endif

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
}


int main( int argc, char *argv[] )
{
glutInit( &amp;argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 640, 480 );

glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );

glutCreateWindow(argv[0]);

Init();

glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
glutIdleFunc( Idle );

glutMainLoop();
return 0;
}


Hello,

Thank you for your help.
Is it possible to change the palette after the image was displayed ? How ?

06-17-2002, 03:40 PM
I do not know. Have you checked the man page? http://techpubs.sgi.com/library/tpl/cgi-...ch=glColorTable (http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=man&fname=/usr/share/catman/g_man/cat3/OpenGL/glcolortable.z&srch=glColorTable)