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    glDepthFunc(GL_EQUAL);
  38    /*   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );*/
  39    glClear( GL_COLOR_BUFFER_BIT );
  40
  41    glColor3f( 1.0, 1.0, 1.0 );
  42
  43    /* draw first polygon */
  44    glPushMatrix();
  45    glTranslatef( -1.0, 0.0, 0.0 );
  46    glRotatef( Angle, 0.0, 0.0, 1.0 );
  47    if (UseObj) {
  48 #ifdef TEXTURE_OBJECT
  49       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
  50 #endif
  51    }
  52    else {
  53       glCallList( TexObj[0] );
  54    }
  55    glBegin( GL_POLYGON );
  56    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  57    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  58    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  59    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  60    glEnd();
  61    glPopMatrix();
  62
  63    /* draw second polygon */
  64    glPushMatrix();
  65    glTranslatef( 1.0, 0.0, 0.0 );
  66    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
  67    if (UseObj) {
  68 #ifdef TEXTURE_OBJECT
  69       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
  70 #endif
  71    }
  72    else {
  73       glCallList( TexObj[1] );
  74    }
  75    glBegin( GL_POLYGON );
  76    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  77    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  78    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  79    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  80    glEnd();
  81    glPopMatrix();
  82
  83    glutSwapBuffers();
  84 }
  85
  86
  87
  88 static void idle( void )
  89 {
  90    Angle += 2.0;
  91    glutPostRedisplay();
  92 }
  93
  94
  95
  96 /* change view Angle, exit upon ESC */
  97 static void key(unsigned char k, int x, int y)
  98 {
  99    (void) x;
 100    (void) y;
 101    switch (k) {
 102       case 27:
 103 #ifdef TEXTURE_OBJECT
 104          glDeleteTextures( 2, TexObj );
 105 #endif
 106          glutDestroyWindow(Window);
 107          exit(0);
 108    }
 109 }
 110
 111
 112
 113 /* new window size or exposure */
 114 static void reshape( int width, int height )
 115 {
 116    glViewport(0, 0, (GLint)width, (GLint)height);
 117    glMatrixMode(GL_PROJECTION);
 118    glLoadIdentity();
 119    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 120    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 121    glMatrixMode(GL_MODELVIEW);
 122    glLoadIdentity();
 123    glTranslatef( 0.0, 0.0, -8.0 );
 124 }
 125
 126
 127 static void init( void )
 128 {
 129    static int width=8, height=8;
 130    static GLubyte tex1[] = {
 131      0, 0, 0, 0, 0, 0, 0, 0,
 132      0, 0, 0, 0, 1, 0, 0, 0,
 133      0, 0, 0, 1, 1, 0, 0, 0,
 134      0, 0, 0, 0, 1, 0, 0, 0,
 135      0, 0, 0, 0, 1, 0, 0, 0,
 136      0, 0, 0, 0, 1, 0, 0, 0,
 137      0, 0, 0, 1, 1, 1, 0, 0,
 138      0, 0, 0, 0, 0, 0, 0, 0 };
 139
 140    static GLubyte tex2[] = {
 141      0, 0, 0, 0, 0, 0, 0, 0,
 142      0, 0, 0, 2, 2, 0, 0, 0,
 143      0, 0, 2, 0, 0, 2, 0, 0,
 144      0, 0, 0, 0, 0, 2, 0, 0,
 145      0, 0, 0, 0, 2, 0, 0, 0,
 146      0, 0, 0, 2, 0, 0, 0, 0,
 147      0, 0, 2, 2, 2, 2, 0, 0,
 148      0, 0, 0, 0, 0, 0, 0, 0 };
 149
 150    GLubyte tex[64][3];
 151    GLint i, j;
 152
 153
 154    glDisable( GL_DITHER );
 155
 156    /* Setup texturing */
 157    glEnable( GL_TEXTURE_2D );
 158    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 159    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
 160
 161
 162    /* generate texture object IDs */
 163    if (UseObj) {
 164 #ifdef TEXTURE_OBJECT
 165       glGenTextures( 2, TexObj );
 166 #endif
 167    }
 168    else {
 169       TexObj[0] = glGenLists(2);
 170       TexObj[1] = TexObj[0]+1;
 171    }
 172
 173    /* setup first texture object */
 174    if (UseObj) {
 175 #ifdef TEXTURE_OBJECT
 176       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
 177       assert(glIsTexture(TexObj[0]));
 178 #endif
 179    }
 180    else {
 181       glNewList( TexObj[0], GL_COMPILE );
 182    }
 183    /* red on white */
 184    for (i=0;i<height;i++) {
 185       for (j=0;j<width;j++) {
 186          int p = i*width+j;
 187          if (tex1[(height-i-1)*width+j]) {
 188             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
 189          }
 190          else {
 191             tex[p][0] = 255;   tex[p][1] = 255;   tex[p][2] = 255;
 192          }
 193       }
 194    }
 195
 196    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 197                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 198    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 199    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 200    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 201    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 202    if (!UseObj) {
 203       glEndList();
 204    }
 205    /* end of texture object */
 206
 207    /* setup second texture object */
 208    if (UseObj) {
 209 #ifdef TEXTURE_OBJECT
 210       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
 211       assert(glIsTexture(TexObj[1]));
 212 #endif
 213       assert(!glIsTexture(TexObj[1] + 999));
 214    }
 215    else {
 216       glNewList( TexObj[1], GL_COMPILE );
 217    }
 218    /* green on blue */
 219    for (i=0;i<height;i++) {
 220       for (j=0;j<width;j++) {
 221          int p = i*width+j;
 222          if (tex2[(height-i-1)*width+j]) {
 223             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 224          }
 225          else {
 226             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 227          }
 228       }
 229    }
 230    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 231                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 232    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 233    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 234    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 235    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 236    if (!UseObj) {
 237       glEndList();
 238    }
 239    /* end texture object */
 240
 241 }
 242
 243
 244
 245 int main( int argc, char *argv[] )
 246 {
 247    glutInit(&argc, argv);
 248    glutInitWindowPosition(0, 0);
 249    glutInitWindowSize(300, 300);
 250    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 251
 252    Window = glutCreateWindow("Texture Objects");
 253    if (!Window) {
 254       exit(1);
 255    }
 256
 257    /* check that renderer has the GL_EXT_texture_object extension
 258     * or supports OpenGL 1.1
 259     */
 260 #ifdef TEXTURE_OBJECT
 261    {
 262       char *exten = (char *) glGetString( GL_EXTENSIONS );
 263       char *version = (char *) glGetString( GL_VERSION );
 264       if (   strstr( exten, "GL_EXT_texture_object" )
 265           || strncmp( version, "1.1", 3 )==0
 266           || strncmp( version, "1.2", 3 )==0 ) {
 267          UseObj = GL_TRUE;
 268       }
 269    }
 270 #endif
 271
 272    init();
 273
 274    glutReshapeFunc( reshape );
 275    glutKeyboardFunc( key );
 276    glutIdleFunc( idle );
 277    glutDisplayFunc( draw );
 278    glutMainLoop();
 279    return 0;
 280 }