progs/demos/texobj.c

   1 /* $Id: texobj.c,v 1.5 2000/07/19 23:57:24 brianp 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 #include <math.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include "GL/glut.h"
  14
  15 static GLuint Window = 0;
  16
  17 static GLuint TexObj[2];
  18 static GLfloat Angle = 0.0f;
  19 static GLboolean UseObj = GL_FALSE;
  20
  21
  22 #if defined(GL_VERSION_1_1) || defined(GL_VERSION_1_2)
  23 #  define TEXTURE_OBJECT 1
  24 #elif defined(GL_EXT_texture_object)
  25 #  define TEXTURE_OBJECT 1
  26 #  define glBindTexture(A,B)     glBindTextureEXT(A,B)
  27 #  define glGenTextures(A,B)     glGenTexturesEXT(A,B)
  28 #  define glDeleteTextures(A,B)  glDeleteTexturesEXT(A,B)
  29 #endif
  30
  31
  32
  33
  34 static void draw( void )
  35 {
  36    glDepthFunc(GL_EQUAL);
  37    /*   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );*/
  38    glClear( GL_COLOR_BUFFER_BIT );
  39
  40    glColor3f( 1.0, 1.0, 1.0 );
  41
  42    /* draw first polygon */
  43    glPushMatrix();
  44    glTranslatef( -1.0, 0.0, 0.0 );
  45    glRotatef( Angle, 0.0, 0.0, 1.0 );
  46    if (UseObj) {
  47 #ifdef TEXTURE_OBJECT
  48       glBindTexture( GL_TEXTURE_2D, TexObj[0] );
  49 #endif
  50    }
  51    else {
  52       glCallList( TexObj[0] );
  53    }
  54    glBegin( GL_POLYGON );
  55    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  56    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  57    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  58    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  59    glEnd();
  60    glPopMatrix();
  61
  62    /* draw second polygon */
  63    glPushMatrix();
  64    glTranslatef( 1.0, 0.0, 0.0 );
  65    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
  66    if (UseObj) {
  67 #ifdef TEXTURE_OBJECT
  68       glBindTexture( GL_TEXTURE_2D, TexObj[1] );
  69 #endif
  70    }
  71    else {
  72       glCallList( TexObj[1] );
  73    }
  74    glBegin( GL_POLYGON );
  75    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
  76    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
  77    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
  78    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
  79    glEnd();
  80    glPopMatrix();
  81
  82    glutSwapBuffers();
  83 }
  84
  85
  86
  87 static void idle( void )
  88 {
  89    Angle += 2.0;
  90    glutPostRedisplay();
  91 }
  92
  93
  94
  95 /* change view Angle, exit upon ESC */
  96 static void key(unsigned char k, int x, int y)
  97 {
  98    (void) x;
  99    (void) y;
 100    switch (k) {
 101       case 27:
 102 #ifdef TEXTURE_OBJECT
 103          glDeleteTextures( 2, TexObj );
 104 #endif
 105          glutDestroyWindow(Window);
 106          exit(0);
 107    }
 108 }
 109
 110
 111
 112 /* new window size or exposure */
 113 static void reshape( int width, int height )
 114 {
 115    glViewport(0, 0, (GLint)width, (GLint)height);
 116    glMatrixMode(GL_PROJECTION);
 117    glLoadIdentity();
 118    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 119    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 120    glMatrixMode(GL_MODELVIEW);
 121    glLoadIdentity();
 122    glTranslatef( 0.0, 0.0, -8.0 );
 123 }
 124
 125
 126 static void init( void )
 127 {
 128    static int width=8, height=8;
 129    static GLubyte tex1[] = {
 130      0, 0, 0, 0, 0, 0, 0, 0,
 131      0, 0, 0, 0, 1, 0, 0, 0,
 132      0, 0, 0, 1, 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, 0, 1, 0, 0, 0,
 136      0, 0, 0, 1, 1, 1, 0, 0,
 137      0, 0, 0, 0, 0, 0, 0, 0 };
 138
 139    static GLubyte tex2[] = {
 140      0, 0, 0, 0, 0, 0, 0, 0,
 141      0, 0, 0, 2, 2, 0, 0, 0,
 142      0, 0, 2, 0, 0, 2, 0, 0,
 143      0, 0, 0, 0, 0, 2, 0, 0,
 144      0, 0, 0, 0, 2, 0, 0, 0,
 145      0, 0, 0, 2, 0, 0, 0, 0,
 146      0, 0, 2, 2, 2, 2, 0, 0,
 147      0, 0, 0, 0, 0, 0, 0, 0 };
 148
 149    GLubyte tex[64][3];
 150    GLint i, j;
 151
 152
 153    glDisable( GL_DITHER );
 154
 155    /* Setup texturing */
 156    glEnable( GL_TEXTURE_2D );
 157    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 158    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST );
 159
 160
 161    /* generate texture object IDs */
 162    if (UseObj) {
 163 #ifdef TEXTURE_OBJECT
 164       glGenTextures( 2, TexObj );
 165 #endif
 166    }
 167    else {
 168       TexObj[0] = glGenLists(2);
 169       TexObj[1] = TexObj[0]+1;
 170    }
 171
 172    /* setup first texture object */
 173    if (UseObj) {
 174 #ifdef TEXTURE_OBJECT
 175       glBindTexture( GL_TEXTURE_2D, 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 #endif
 210    }
 211    else {
 212       glNewList( TexObj[1], GL_COMPILE );
 213    }
 214    /* green on blue */
 215    for (i=0;i<height;i++) {
 216       for (j=0;j<width;j++) {
 217          int p = i*width+j;
 218          if (tex2[(height-i-1)*width+j]) {
 219             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 220          }
 221          else {
 222             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 223          }
 224       }
 225    }
 226    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 227                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 228    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 229    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 230    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 231    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 232    if (!UseObj) {
 233       glEndList();
 234    }
 235    /* end texture object */
 236
 237 }
 238
 239
 240
 241 int main( int argc, char *argv[] )
 242 {
 243    glutInit(&argc, argv);
 244    glutInitWindowPosition(0, 0);
 245    glutInitWindowSize(300, 300);
 246    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 247
 248    Window = glutCreateWindow("Texture Objects");
 249    if (!Window) {
 250       exit(1);
 251    }
 252
 253    /* check that renderer has the GL_EXT_texture_object extension
 254     * or supports OpenGL 1.1
 255     */
 256 #ifdef TEXTURE_OBJECT
 257    {
 258       char *exten = (char *) glGetString( GL_EXTENSIONS );
 259       char *version = (char *) glGetString( GL_VERSION );
 260       if (   strstr( exten, "GL_EXT_texture_object" )
 261           || strncmp( version, "1.1", 3 )==0
 262           || strncmp( version, "1.2", 3 )==0 ) {
 263          UseObj = GL_TRUE;
 264       }
 265    }
 266 #endif
 267
 268    init();
 269
 270    glutReshapeFunc( reshape );
 271    glutKeyboardFunc( key );
 272    glutIdleFunc( idle );
 273    glutDisplayFunc( draw );
 274    glutMainLoop();
 275    return 0;
 276 }