src/tests/stencilwrap.c

   1 /* Test GL_EXT_stencil_wrap extension.
   2  * This is by no means complete, just a quick check.
   3  *
   4  * Brian Paul  30 October 2002
   5  */
   6
   7 #include <assert.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <math.h>
  11 #include <GL/glew.h>
  12 #include "glut_wrap.h"
  13
  14 GLboolean wrapping;
  15
  16 static void RunTest(void)
  17 {
  18    const GLenum prim = GL_QUAD_STRIP;
  19    GLubyte val;
  20    int bits, max, i;
  21    int expected;
  22    GLboolean failed;
  23
  24    glGetIntegerv(GL_STENCIL_BITS, &bits);
  25    max = (1 << bits) - 1;
  26
  27
  28    glEnable(GL_STENCIL_TEST);
  29    glStencilFunc(GL_ALWAYS, 0, ~0);
  30
  31    /* test GL_KEEP */
  32    glClearStencil(max);
  33    glClear(GL_STENCIL_BUFFER_BIT);
  34    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
  35    failed = GL_FALSE;
  36    printf("Testing GL_KEEP...\n");
  37    expected = max;
  38    glBegin(prim);
  39    glVertex2f(0, 0);
  40    glVertex2f(10, 0);
  41    glVertex2f(0, 10);
  42    glVertex2f(10, 10);
  43    glEnd();
  44    glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
  45    if (val != expected) {
  46       printf("Failed GL_KEEP test(got %u, expected %u)\n", val, expected);
  47       failed = GL_TRUE;
  48    }
  49    else
  50       printf("OK!\n");
  51
  52    /* test GL_ZERO */
  53    glClearStencil(max);
  54    glClear(GL_STENCIL_BUFFER_BIT);
  55    glStencilOp(GL_KEEP, GL_KEEP, GL_ZERO);
  56    failed = GL_FALSE;
  57    printf("Testing GL_ZERO...\n");
  58    expected = 0;
  59    glBegin(prim);
  60    glVertex2f(0, 0);
  61    glVertex2f(10, 0);
  62    glVertex2f(0, 10);
  63    glVertex2f(10, 10);
  64    glEnd();
  65    glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
  66    if (val != expected) {
  67       printf("Failed GL_ZERO test(got %u, expected %u)\n", val, expected);
  68       failed = GL_TRUE;
  69    }
  70    else
  71       printf("OK!\n");
  72
  73    /* test GL_REPLACE */
  74    glClearStencil(max);
  75    glClear(GL_STENCIL_BUFFER_BIT);
  76    glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
  77    failed = GL_FALSE;
  78    printf("Testing GL_REPLACE...\n");
  79    expected = 0;
  80    glBegin(prim);
  81    glVertex2f(0, 0);
  82    glVertex2f(10, 0);
  83    glVertex2f(0, 10);
  84    glVertex2f(10, 10);
  85    glEnd();
  86    glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
  87    if (val != expected) {
  88       printf("Failed GL_REPLACE test(got %u, expected %u)\n", val, expected);
  89       failed = GL_TRUE;
  90    }
  91    else
  92       printf("OK!\n");
  93
  94    /* test GL_INCR (saturation) */
  95    glClearStencil(0);
  96    glClear(GL_STENCIL_BUFFER_BIT);
  97    glStencilOp(GL_KEEP, GL_KEEP, GL_INCR);
  98    failed = GL_FALSE;
  99    printf("Testing GL_INCR...\n");
 100    for (i = 1; i < max+10; i++) {
 101       expected = (i > max) ? max : i;
 102       glBegin(prim);
 103       glVertex2f(0, 0);      glVertex2f(10, 0);
 104       glVertex2f(0, 10);      glVertex2f(10, 10);
 105       glEnd();
 106
 107       glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
 108       if (val != expected) {
 109          printf( "Failed GL_INCR test on iteration #%u "
 110                  "(got %u, expected %u)\n", i, val, expected );
 111          failed = GL_TRUE;
 112       }
 113    }
 114    if ( !failed )
 115       printf("OK!\n");
 116
 117    /* test GL_DECR (saturation) */
 118    glClearStencil(max);
 119    glClear(GL_STENCIL_BUFFER_BIT);
 120    glStencilOp(GL_KEEP, GL_KEEP, GL_DECR);
 121    failed = GL_FALSE;
 122    printf("Testing GL_DECR...\n");
 123    for (i = max-1; i > -10; i--) {
 124       expected = (i < 0) ? 0 : i;
 125       glBegin(prim);
 126       glVertex2f(0, 0);      glVertex2f(10, 0);
 127       glVertex2f(0, 10);      glVertex2f(10, 10);
 128       glEnd();
 129       glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
 130       if (val != expected) {
 131          printf( "Failed GL_DECR test on iteration #%u "
 132                  "(got %u, expected %u)\n", max - i, val, expected );
 133          failed = GL_TRUE;
 134       }
 135    }
 136    if ( !failed )
 137       printf("OK!\n");
 138
 139    /* test GL_INVERT */
 140    glClearStencil(0);
 141    glClear(GL_STENCIL_BUFFER_BIT);
 142    glStencilOp(GL_KEEP, GL_KEEP, GL_INVERT);
 143    failed = GL_FALSE;
 144    printf("Testing GL_INVERT...\n");
 145    expected = max;
 146    glBegin(prim);
 147    glVertex2f(0, 0);
 148    glVertex2f(10, 0);
 149    glVertex2f(0, 10);
 150    glVertex2f(10, 10);
 151    glEnd();
 152    glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
 153    if (val != expected) {
 154       printf("Failed GL_INVERT test(got %u, expected %u)\n", val, expected);
 155       failed = GL_TRUE;
 156    }
 157    else
 158       printf("OK!\n");
 159
 160    if(wrapping)
 161    {
 162       /* test GL_INCR_WRAP_EXT (wrap around) */
 163       glClearStencil(0);
 164       glClear(GL_STENCIL_BUFFER_BIT);
 165       glStencilOp(GL_KEEP, GL_KEEP, GL_INCR_WRAP_EXT);
 166       failed = GL_FALSE;
 167       printf("Testing GL_INCR_WRAP_EXT...\n");
 168       for (i = 1; i < max+10; i++) {
 169          expected = i % (max + 1);
 170          glBegin(prim);
 171          glVertex2f(0, 0);      glVertex2f(10, 0);
 172          glVertex2f(0, 10);      glVertex2f(10, 10);
 173          glEnd();
 174          glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
 175          if (val != expected) {
 176             printf( "Failed GL_INCR_WRAP test on iteration #%u "
 177                  "(got %u, expected %u)\n", i, val, expected );
 178             failed = GL_TRUE;
 179          }
 180       }
 181       if ( !failed )
 182          printf("OK!\n");
 183
 184       /* test GL_DECR_WRAP_EXT (wrap-around) */
 185       glClearStencil(max);
 186       glClear(GL_STENCIL_BUFFER_BIT);
 187       glStencilOp(GL_KEEP, GL_KEEP, GL_DECR_WRAP_EXT);
 188       failed = GL_FALSE;
 189       printf("Testing GL_DECR_WRAP_EXT...\n");
 190       for (i = max-1; i > -10; i--) {
 191          expected = (i < 0) ? max + i + 1: i;
 192          glBegin(prim);
 193          glVertex2f(0, 0);      glVertex2f(10, 0);
 194          glVertex2f(0, 10);      glVertex2f(10, 10);
 195          glEnd();
 196          glReadPixels(0, 0, 1, 1, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, &val);
 197          if (val != expected) {
 198             printf( "Failed GL_DECR_WRAP test on iteration #%u "
 199                "(got %u, expected %u)\n", max - i, val, expected );
 200             failed = GL_TRUE;
 201          }
 202       }
 203       if ( !failed )
 204          printf("OK!\n");
 205    }
 206
 207    glDisable(GL_STENCIL_TEST);
 208 }
 209
 210
 211 static void Display( void )
 212 {
 213    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 214
 215    RunTest();
 216
 217    glutSwapBuffers();
 218 }
 219
 220
 221 static void Reshape( int width, int height )
 222 {
 223    glViewport( 0, 0, width, height );
 224    glMatrixMode( GL_PROJECTION );
 225    glLoadIdentity();
 226    glOrtho(0, width, 0, height, -1, 1);
 227    glMatrixMode( GL_MODELVIEW );
 228    glLoadIdentity();
 229 }
 230
 231
 232 static void Key( unsigned char key, int x, int y )
 233 {
 234    (void) x;
 235    (void) y;
 236    switch (key) {
 237       case 27:
 238          exit(0);
 239          break;
 240    }
 241    glutPostRedisplay();
 242 }
 243
 244
 245 static void Init( void )
 246 {
 247    const char * ver_str;
 248    float        version;
 249
 250    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 251    printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
 252
 253
 254    /* Check for both the extension string and GL version 1.4 on the
 255     * outside chance that some vendor exports version 1.4 but doesn't
 256     * export the extension string.  The stencil-wrap modes are a required
 257     * part of GL 1.4.
 258     */
 259
 260    ver_str = (char *) glGetString( GL_VERSION );
 261    version = (ver_str == NULL) ? 1.0 : atof( ver_str );
 262
 263    wrapping = (glutExtensionSupported("GL_EXT_stencil_wrap") || (version >= 1.4));
 264    if (!wrapping)
 265       printf("GL_EXT_stencil_wrap not supported. Only testing the rest.\n");
 266 }
 267
 268
 269 int main( int argc, char *argv[] )
 270 {
 271    glutInit( &argc, argv );
 272    glutInitWindowPosition( 0, 0 );
 273    glutInitWindowSize( 400, 400 );
 274    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_STENCIL );
 275    glutCreateWindow(argv[0]);
 276    glewInit();
 277    glutReshapeFunc( Reshape );
 278    glutKeyboardFunc( Key );
 279    glutDisplayFunc( Display );
 280    Init();
 281    glutMainLoop();
 282    return 0;
 283 }