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