progs/demos/texobj.c

   1 /* $Id: texobj.c,v 1.1 1999/08/19 00:55:40 jtg Exp $ */
   2
   3 /*
   4  * Example of using the 1.1 texture object functions.
   5  * Also, this demo utilizes Mesa's fast texture map path.
   6  *
   7  * Brian Paul   June 1996   This file is in the public domain.
   8  */
   9
  10
  11 /*
  12  * $Log: texobj.c,v $
  13  * Revision 1.1  1999/08/19 00:55:40  jtg
  14  * Initial revision
  15  *
  16  * Revision 3.1  1999/03/28 18:24:37  brianp
  17  * minor clean-up
  18  *
  19  * Revision 3.0  1998/02/14 18:42:29  brianp
  20  * initial rev
  21  *
  22  */
  23
  24
  25 #include <math.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include "GL/glut.h"
  29
  30 static GLuint Window = 0;
  31
  32 static GLuint TexObj[2];
  33 static GLfloat Angle = 0.0f;
  34 static GLboolean HaveTexObj = GL_FALSE;
  35
  36
  37 #if defined(GL_VERSION_1_1)
  38 #  define TEXTURE_OBJECT 1
  39 #elif defined(GL_EXT_texture_object)
  40 #  define TEXTURE_OBJECT 1
  41 #  define glBindTexture(A,B)     glBindTextureEXT(A,B)
  42 #  define glGenTextures(A,B)     glGenTexturesEXT(A,B)
  43 #  define glDeleteTextures(A,B)  glDeleteTexturesEXT(A,B)
  44 #endif
  45
  46
  47
  48
  49 static void draw( void )
  50 {
  51    glDepthFunc(GL_EQUAL);
  52    /*   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );*/
  53    glClear( GL_COLOR_BUFFER_BIT );
  54
  55    glColor3f( 1.0, 1.0, 1.0 );
  56
  57    /* draw first polygon */
  58    glPushMatrix();
  59    glTranslatef( -1.0, 0.0, 0.0 );
  60    glRotatef( Angle, 0.0, 0.0, 1.0 );
  61    if (HaveTexObj) {
  62 #ifdef TEXTURE_OBJECT
  63       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
  64 #endif
  65    }
  66    else {
  67       glCallList( TexObj[0] );
  68    }
  69    glBegin( GL_POLYGON );
  70    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  71    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  72    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  73    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  74    glEnd();
  75    glPopMatrix();
  76
  77    /* draw second polygon */
  78    glPushMatrix();
  79    glTranslatef( 1.0, 0.0, 0.0 );
  80    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
  81    if (HaveTexObj) {
  82 #ifdef TEXTURE_OBJECT
  83       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
  84 #endif
  85    }
  86    else {
  87       glCallList( TexObj[0] );
  88    }
  89    glBegin( GL_POLYGON );
  90    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  91    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  92    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  93    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  94    glEnd();
  95    glPopMatrix();
  96
  97    glutSwapBuffers();
  98 }
  99
 100
 101
 102 static void idle( void )
 103 {
 104    Angle += 2.0;
 105    glutPostRedisplay();
 106 }
 107
 108
 109
 110 /* change view Angle, exit upon ESC */
 111 static void key(unsigned char k, int x, int y)
 112 {
 113    (void) x;
 114    (void) y;
 115    switch (k) {
 116       case 27:
 117 #ifdef TEXTURE_OBJECT
 118          glDeleteTextures( 2, TexObj );
 119 #endif
 120          glutDestroyWindow(Window);
 121          exit(0);
 122    }
 123 }
 124
 125
 126
 127 /* new window size or exposure */
 128 static void reshape( int width, int height )
 129 {
 130    glViewport(0, 0, (GLint)width, (GLint)height);
 131    glMatrixMode(GL_PROJECTION);
 132    glLoadIdentity();
 133    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 134    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 135    glMatrixMode(GL_MODELVIEW);
 136    glLoadIdentity();
 137    glTranslatef( 0.0, 0.0, -8.0 );
 138 }
 139
 140
 141 static void init( void )
 142 {
 143    static int width=8, height=8;
 144    static GLubyte tex1[] = {
 145      0, 0, 0, 0, 0, 0, 0, 0,
 146      0, 0, 0, 0, 1, 0, 0, 0,
 147      0, 0, 0, 1, 1, 0, 0, 0,
 148      0, 0, 0, 0, 1, 0, 0, 0,
 149      0, 0, 0, 0, 1, 0, 0, 0,
 150      0, 0, 0, 0, 1, 0, 0, 0,
 151      0, 0, 0, 1, 1, 1, 0, 0,
 152      0, 0, 0, 0, 0, 0, 0, 0 };
 153
 154    static GLubyte tex2[] = {
 155      0, 0, 0, 0, 0, 0, 0, 0,
 156      0, 0, 0, 2, 2, 0, 0, 0,
 157      0, 0, 2, 0, 0, 2, 0, 0,
 158      0, 0, 0, 0, 0, 2, 0, 0,
 159      0, 0, 0, 0, 2, 0, 0, 0,
 160      0, 0, 0, 2, 0, 0, 0, 0,
 161      0, 0, 2, 2, 2, 2, 0, 0,
 162      0, 0, 0, 0, 0, 0, 0, 0 };
 163
 164    GLubyte tex[64][3];
 165    GLint i, j;
 166
 167
 168    glDisable( GL_DITHER );
 169
 170    /* Setup texturing */
 171    glEnable( GL_TEXTURE_2D );
 172    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 173    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
 174
 175
 176    /* generate texture object IDs */
 177    if (HaveTexObj) {
 178 #ifdef TEXTURE_OBJECT
 179       glGenTextures( 2, TexObj );
 180 #endif
 181    }
 182    else {
 183       TexObj[0] = glGenLists(2);
 184       TexObj[1] = TexObj[0]+1;
 185    }
 186
 187    /* setup first texture object */
 188    if (HaveTexObj) {
 189 #ifdef TEXTURE_OBJECT
 190       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
 191 #endif
 192    }
 193    else {
 194       glNewList( TexObj[0], GL_COMPILE );
 195    }
 196    /* red on white */
 197    for (i=0;i<height;i++) {
 198       for (j=0;j<width;j++) {
 199          int p = i*width+j;
 200          if (tex1[(height-i-1)*width+j]) {
 201             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
 202          }
 203          else {
 204             tex[p][0] = 255;   tex[p][1] = 255;   tex[p][2] = 255;
 205          }
 206       }
 207    }
 208
 209    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 210                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 211    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 212    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 213    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 214    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 215    if (!HaveTexObj) {
 216       glEndList();
 217    }
 218    /* end of texture object */
 219
 220    /* setup second texture object */
 221    if (HaveTexObj) {
 222 #ifdef TEXTURE_OBJECT
 223       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
 224 #endif
 225    }
 226    else {
 227       glNewList( TexObj[1], GL_COMPILE );
 228    }
 229    /* green on blue */
 230    for (i=0;i<height;i++) {
 231       for (j=0;j<width;j++) {
 232          int p = i*width+j;
 233          if (tex2[(height-i-1)*width+j]) {
 234             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 235          }
 236          else {
 237             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 238          }
 239       }
 240    }
 241    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 242                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 243    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 244    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 245    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 246    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 247    if (!HaveTexObj) {
 248       glEndList();
 249    }
 250    /* end texture object */
 251
 252 }
 253
 254
 255
 256 int main( int argc, char *argv[] )
 257 {
 258    glutInitWindowPosition(0, 0);
 259    glutInitWindowSize(300, 300);
 260    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 261
 262    Window = glutCreateWindow("Texture Objects");
 263    if (!Window) {
 264       exit(1);
 265    }
 266
 267    /* check that renderer has the GL_EXT_texture_object extension
 268     * or supports OpenGL 1.1
 269     */
 270 #ifdef TEXTURE_OBJECT
 271    {
 272       char *exten = (char *) glGetString( GL_EXTENSIONS );
 273       char *version = (char *) glGetString( GL_VERSION );
 274       if (   strstr( exten, "GL_EXT_texture_object" )
 275           || strncmp( version, "1.1", 3 )==0 ) {
 276          HaveTexObj = GL_TRUE;
 277       }
 278    }
 279 #endif
 280
 281    init();
 282
 283    glutReshapeFunc( reshape );
 284    glutKeyboardFunc( key );
 285    glutIdleFunc( idle );
 286    glutDisplayFunc( draw );
 287    glutMainLoop();
 288    return 0;
 289 }