progs/demos/texobj.c

   1
   2 /*
   3  * Example of using the 1.1 texture object functions.
   4  * Also, this demo utilizes Mesa's fast texture map path.
   5  *
   6  * Brian Paul   June 1996   This file is in the public domain.
   7  */
   8
   9 #include <assert.h>
  10 #include <math.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include "GL/glut.h"
  15
  16 static GLuint Window = 0;
  17
  18 static GLuint TexObj[2];
  19 static GLfloat Angle = 0.0f;
  20 static GLboolean UseObj = GL_FALSE;
  21
  22
  23 #if defined(GL_VERSION_1_1) || defined(GL_VERSION_1_2)
  24 #  define TEXTURE_OBJECT 1
  25 #elif defined(GL_EXT_texture_object)
  26 #  define TEXTURE_OBJECT 1
  27 #  define glBindTexture(A,B)     glBindTextureEXT(A,B)
  28 #  define glGenTextures(A,B)     glGenTexturesEXT(A,B)
  29 #  define glDeleteTextures(A,B)  glDeleteTexturesEXT(A,B)
  30 #endif
  31
  32
  33
  34
  35 static void draw( void )
  36 {
  37    glClear( GL_COLOR_BUFFER_BIT );
  38
  39    glColor3f( 1.0, 1.0, 1.0 );
  40
  41    /* draw first polygon */
  42    glPushMatrix();
  43    glTranslatef( -1.0, 0.0, 0.0 );
  44    glRotatef( Angle, 0.0, 0.0, 1.0 );
  45    if (UseObj) {
  46 #ifdef TEXTURE_OBJECT
  47       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
  48 #endif
  49    }
  50    else {
  51       glCallList( TexObj[0] );
  52    }
  53    glBegin( GL_POLYGON );
  54    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  55    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  56    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  57    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  58    glEnd();
  59    glPopMatrix();
  60
  61    /* draw second polygon */
  62    glPushMatrix();
  63    glTranslatef( 1.0, 0.0, 0.0 );
  64    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
  65    if (UseObj) {
  66 #ifdef TEXTURE_OBJECT
  67       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
  68 #endif
  69    }
  70    else {
  71       glCallList( TexObj[1] );
  72    }
  73    glBegin( GL_POLYGON );
  74    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  75    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  76    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  77    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  78    glEnd();
  79    glPopMatrix();
  80
  81    glutSwapBuffers();
  82 }
  83
  84
  85
  86 static void idle( void )
  87 {
  88    static double t0 = -1.;
  89    double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
  90    if (t0 < 0.0)
  91       t0 = t;
  92    dt = t - t0;
  93    t0 = t;
  94    Angle += 120.0*dt;
  95    glutPostRedisplay();
  96 }
  97
  98
  99
 100 /* change view Angle, exit upon ESC */
 101 static void key(unsigned char k, int x, int y)
 102 {
 103    (void) x;
 104    (void) y;
 105    switch (k) {
 106       case 27:
 107 #ifdef TEXTURE_OBJECT
 108          glDeleteTextures( 2, TexObj );
 109 #endif
 110          glutDestroyWindow(Window);
 111          exit(0);
 112    }
 113 }
 114
 115
 116
 117 /* new window size or exposure */
 118 static void reshape( int width, int height )
 119 {
 120    glViewport(0, 0, (GLint)width, (GLint)height);
 121    glMatrixMode(GL_PROJECTION);
 122    glLoadIdentity();
 123    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 124    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 125    glMatrixMode(GL_MODELVIEW);
 126    glLoadIdentity();
 127    glTranslatef( 0.0, 0.0, -8.0 );
 128 }
 129
 130
 131 static void init( void )
 132 {
 133    static int width=8, height=8;
 134    static GLubyte tex1[] = {
 135      0, 0, 0, 0, 0, 0, 0, 0,
 136      0, 0, 0, 0, 1, 0, 0, 0,
 137      0, 0, 0, 1, 1, 0, 0, 0,
 138      0, 0, 0, 0, 1, 0, 0, 0,
 139      0, 0, 0, 0, 1, 0, 0, 0,
 140      0, 0, 0, 0, 1, 0, 0, 0,
 141      0, 0, 0, 1, 1, 1, 0, 0,
 142      0, 0, 0, 0, 0, 0, 0, 0 };
 143
 144    static GLubyte tex2[] = {
 145      0, 0, 0, 0, 0, 0, 0, 0,
 146      0, 0, 0, 2, 2, 0, 0, 0,
 147      0, 0, 2, 0, 0, 2, 0, 0,
 148      0, 0, 0, 0, 0, 2, 0, 0,
 149      0, 0, 0, 0, 2, 0, 0, 0,
 150      0, 0, 0, 2, 0, 0, 0, 0,
 151      0, 0, 2, 2, 2, 2, 0, 0,
 152      0, 0, 0, 0, 0, 0, 0, 0 };
 153
 154    GLubyte tex[64][3];
 155    GLint i, j;
 156
 157
 158    glDisable( GL_DITHER );
 159
 160    /* Setup texturing */
 161    glEnable( GL_TEXTURE_2D );
 162    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 163    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
 164
 165
 166    /* generate texture object IDs */
 167    if (UseObj) {
 168 #ifdef TEXTURE_OBJECT
 169       glGenTextures( 2, TexObj );
 170 #endif
 171    }
 172    else {
 173       TexObj[0] = glGenLists(2);
 174       TexObj[1] = TexObj[0]+1;
 175    }
 176
 177    /* setup first texture object */
 178    if (UseObj) {
 179 #ifdef TEXTURE_OBJECT
 180       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
 181       assert(glIsTexture(TexObj[0]));
 182 #endif
 183    }
 184    else {
 185       glNewList( TexObj[0], GL_COMPILE );
 186    }
 187    /* red on white */
 188    for (i=0;i<height;i++) {
 189       for (j=0;j<width;j++) {
 190          int p = i*width+j;
 191          if (tex1[(height-i-1)*width+j]) {
 192             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
 193          }
 194          else {
 195             tex[p][0] = 255;   tex[p][1] = 255;   tex[p][2] = 255;
 196          }
 197       }
 198    }
 199
 200    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 201                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 202    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 203    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 204    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 205    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 206    if (!UseObj) {
 207       glEndList();
 208    }
 209    /* end of texture object */
 210
 211    /* setup second texture object */
 212    if (UseObj) {
 213 #ifdef TEXTURE_OBJECT
 214       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
 215       assert(glIsTexture(TexObj[1]));
 216 #endif
 217       assert(!glIsTexture(TexObj[1] + 999));
 218    }
 219    else {
 220       glNewList( TexObj[1], GL_COMPILE );
 221    }
 222    /* green on blue */
 223    for (i=0;i<height;i++) {
 224       for (j=0;j<width;j++) {
 225          int p = i*width+j;
 226          if (tex2[(height-i-1)*width+j]) {
 227             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 228          }
 229          else {
 230             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 231          }
 232       }
 233    }
 234    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 235                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 236    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 237    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 238    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 239    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 240    if (!UseObj) {
 241       glEndList();
 242    }
 243    /* end texture object */
 244
 245 }
 246
 247
 248
 249 int main( int argc, char *argv[] )
 250 {
 251    glutInit(&argc, argv);
 252    glutInitWindowPosition(0, 0);
 253    glutInitWindowSize(300, 300);
 254    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 255
 256    Window = glutCreateWindow("Texture Objects");
 257    if (!Window) {
 258       exit(1);
 259    }
 260
 261    /* check that renderer has the GL_EXT_texture_object extension
 262     * or supports OpenGL 1.1
 263     */
 264 #ifdef TEXTURE_OBJECT
 265    {
 266       char *exten = (char *) glGetString( GL_EXTENSIONS );
 267       char *version = (char *) glGetString( GL_VERSION );
 268       if (   strstr( exten, "GL_EXT_texture_object" )
 269           || strncmp( version, "1.1", 3 )==0
 270           || strncmp( version, "1.2", 3 )==0 ) {
 271          UseObj = GL_TRUE;
 272       }
 273    }
 274 #endif
 275
 276    init();
 277
 278    glutReshapeFunc( reshape );
 279    glutKeyboardFunc( key );
 280    glutIdleFunc( idle );
 281    glutDisplayFunc( draw );
 282    glutMainLoop();
 283    return 0;
 284 }