285 lines
6.7 KiB
C
285 lines
6.7 KiB
C
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/*
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* Example of using the 1.1 texture object functions.
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* Also, this demo utilizes Mesa's fast texture map path.
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*
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* Brian Paul June 1996 This file is in the public domain.
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*/
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#include <assert.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "GL/glut.h"
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static GLuint Window = 0;
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static GLuint TexObj[2];
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static GLfloat Angle = 0.0f;
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static GLboolean UseObj = GL_FALSE;
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#if defined(GL_VERSION_1_1) || defined(GL_VERSION_1_2)
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# define TEXTURE_OBJECT 1
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#elif defined(GL_EXT_texture_object)
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# define TEXTURE_OBJECT 1
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# define glBindTexture(A,B) glBindTextureEXT(A,B)
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# define glGenTextures(A,B) glGenTexturesEXT(A,B)
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# define glDeleteTextures(A,B) glDeleteTexturesEXT(A,B)
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#endif
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static void draw( void )
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{
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glClear( GL_COLOR_BUFFER_BIT );
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glColor3f( 1.0, 1.0, 1.0 );
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/* draw first polygon */
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glPushMatrix();
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glTranslatef( -1.0, 0.0, 0.0 );
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glRotatef( Angle, 0.0, 0.0, 1.0 );
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if (UseObj) {
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#ifdef TEXTURE_OBJECT
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glBindTexture( GL_TEXTURE_2D, TexObj[0] );
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#endif
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}
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else {
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glCallList( TexObj[0] );
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}
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glBegin( GL_POLYGON );
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glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
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glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
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glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
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glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
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glEnd();
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glPopMatrix();
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/* draw second polygon */
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glPushMatrix();
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glTranslatef( 1.0, 0.0, 0.0 );
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glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
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if (UseObj) {
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#ifdef TEXTURE_OBJECT
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glBindTexture( GL_TEXTURE_2D, TexObj[1] );
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#endif
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}
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else {
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glCallList( TexObj[1] );
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}
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glBegin( GL_POLYGON );
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glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
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glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
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glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
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glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
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glEnd();
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glPopMatrix();
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glutSwapBuffers();
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}
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static void idle( void )
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{
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static double t0 = -1.;
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double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
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if (t0 < 0.0)
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t0 = t;
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dt = t - t0;
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t0 = t;
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Angle += 120.0*dt;
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glutPostRedisplay();
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}
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/* change view Angle, exit upon ESC */
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static void key(unsigned char k, int x, int y)
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{
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(void) x;
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(void) y;
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switch (k) {
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case 27:
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#ifdef TEXTURE_OBJECT
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glDeleteTextures( 2, TexObj );
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#endif
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glutDestroyWindow(Window);
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exit(0);
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}
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}
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/* new window size or exposure */
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static void reshape( int width, int height )
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{
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glViewport(0, 0, (GLint)width, (GLint)height);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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/* glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
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glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef( 0.0, 0.0, -8.0 );
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}
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static void init( void )
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{
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static int width=8, height=8;
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static GLubyte tex1[] = {
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 1, 0, 0, 0,
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0, 0, 0, 1, 1, 0, 0, 0,
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0, 0, 0, 0, 1, 0, 0, 0,
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0, 0, 0, 0, 1, 0, 0, 0,
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0, 0, 0, 0, 1, 0, 0, 0,
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0, 0, 0, 1, 1, 1, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0 };
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static GLubyte tex2[] = {
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 2, 2, 0, 0, 0,
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0, 0, 2, 0, 0, 2, 0, 0,
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0, 0, 0, 0, 0, 2, 0, 0,
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0, 0, 0, 0, 2, 0, 0, 0,
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0, 0, 0, 2, 0, 0, 0, 0,
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0, 0, 2, 2, 2, 2, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0 };
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GLubyte tex[64][3];
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GLint i, j;
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glDisable( GL_DITHER );
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/* Setup texturing */
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glEnable( GL_TEXTURE_2D );
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glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
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glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
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/* generate texture object IDs */
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if (UseObj) {
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#ifdef TEXTURE_OBJECT
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glGenTextures( 2, TexObj );
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#endif
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}
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else {
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TexObj[0] = glGenLists(2);
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TexObj[1] = TexObj[0]+1;
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}
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/* setup first texture object */
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if (UseObj) {
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#ifdef TEXTURE_OBJECT
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glBindTexture( GL_TEXTURE_2D, TexObj[0] );
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assert(glIsTexture(TexObj[0]));
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#endif
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}
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else {
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glNewList( TexObj[0], GL_COMPILE );
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}
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/* red on white */
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for (i=0;i<height;i++) {
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for (j=0;j<width;j++) {
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int p = i*width+j;
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if (tex1[(height-i-1)*width+j]) {
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tex[p][0] = 255; tex[p][1] = 0; tex[p][2] = 0;
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}
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else {
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tex[p][0] = 255; tex[p][1] = 255; tex[p][2] = 255;
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}
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}
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}
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glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
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GL_RGB, GL_UNSIGNED_BYTE, tex );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
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if (!UseObj) {
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glEndList();
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}
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/* end of texture object */
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/* setup second texture object */
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if (UseObj) {
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#ifdef TEXTURE_OBJECT
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glBindTexture( GL_TEXTURE_2D, TexObj[1] );
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assert(glIsTexture(TexObj[1]));
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#endif
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assert(!glIsTexture(TexObj[1] + 999));
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}
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else {
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glNewList( TexObj[1], GL_COMPILE );
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}
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/* green on blue */
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for (i=0;i<height;i++) {
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for (j=0;j<width;j++) {
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int p = i*width+j;
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if (tex2[(height-i-1)*width+j]) {
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tex[p][0] = 0; tex[p][1] = 255; tex[p][2] = 0;
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}
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else {
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tex[p][0] = 0; tex[p][1] = 0; tex[p][2] = 255;
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}
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}
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}
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glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
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GL_RGB, GL_UNSIGNED_BYTE, tex );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
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glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
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if (!UseObj) {
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glEndList();
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}
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/* end texture object */
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}
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int main( int argc, char *argv[] )
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{
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glutInit(&argc, argv);
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(300, 300);
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glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
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Window = glutCreateWindow("Texture Objects");
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if (!Window) {
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exit(1);
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}
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/* check that renderer has the GL_EXT_texture_object extension
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* or supports OpenGL 1.1
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*/
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#ifdef TEXTURE_OBJECT
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{
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char *exten = (char *) glGetString( GL_EXTENSIONS );
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char *version = (char *) glGetString( GL_VERSION );
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if ( strstr( exten, "GL_EXT_texture_object" )
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|| strncmp( version, "1.1", 3 )==0
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|| strncmp( version, "1.2", 3 )==0 ) {
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UseObj = GL_TRUE;
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}
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}
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#endif
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init();
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glutReshapeFunc( reshape );
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glutKeyboardFunc( key );
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glutIdleFunc( idle );
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glutDisplayFunc( draw );
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glutMainLoop();
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return 0;
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}
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