progs/trivial/vp-array-hf.c

   1 /* Test glGenProgramsNV(), glIsProgramNV(), glLoadProgramNV() */
   2
   3 #include <assert.h>
   4 #include <string.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <math.h>
   8 #include <GL/glew.h>
   9 #include <GL/glut.h>
  10
  11 typedef union { GLfloat f; GLint i; } fi_type;
  12 /**
  13  * Convert a 4-byte float to a 2-byte half float.
  14  * Based on code from:
  15  * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
  16  */
  17 static GLhalf
  18 _mesa_float_to_half(GLfloat val)
  19 {
  20
  21    const fi_type fi = {val};
  22    const int flt_m = fi.i & 0x7fffff;
  23    const int flt_e = (fi.i >> 23) & 0xff;
  24    const int flt_s = (fi.i >> 31) & 0x1;
  25    int s, e, m = 0;
  26    GLhalf result;
  27
  28    /* sign bit */
  29    s = flt_s;
  30
  31    /* handle special cases */
  32    if ((flt_e == 0) && (flt_m == 0)) {
  33       /* zero */
  34       /* m = 0; - already set */
  35       e = 0;
  36    }
  37    else if ((flt_e == 0) && (flt_m != 0)) {
  38       /* denorm -- denorm float maps to 0 half */
  39       /* m = 0; - already set */
  40       e = 0;
  41    }
  42    else if ((flt_e == 0xff) && (flt_m == 0)) {
  43       /* infinity */
  44       /* m = 0; - already set */
  45       e = 31;
  46    }
  47    else if ((flt_e == 0xff) && (flt_m != 0)) {
  48       /* NaN */
  49       m = 1;
  50       e = 31;
  51    }
  52    else {
  53       /* regular number */
  54       const int new_exp = flt_e - 127;
  55       if (new_exp < -24) {
  56          /* this maps to 0 */
  57          /* m = 0; - already set */
  58          e = 0;
  59       }
  60       else if (new_exp < -14) {
  61          /* this maps to a denorm */
  62          unsigned int exp_val = (unsigned int) (-14 - new_exp); /* 2^-exp_val*/
  63          e = 0;
  64          switch (exp_val) {
  65             case 0:
  66                /* m = 0; - already set */
  67                break;
  68             case 1: m = 512 + (flt_m >> 14); break;
  69             case 2: m = 256 + (flt_m >> 15); break;
  70             case 3: m = 128 + (flt_m >> 16); break;
  71             case 4: m = 64 + (flt_m >> 17); break;
  72             case 5: m = 32 + (flt_m >> 18); break;
  73             case 6: m = 16 + (flt_m >> 19); break;
  74             case 7: m = 8 + (flt_m >> 20); break;
  75             case 8: m = 4 + (flt_m >> 21); break;
  76             case 9: m = 2 + (flt_m >> 22); break;
  77             case 10: m = 1; break;
  78          }
  79       }
  80       else if (new_exp > 15) {
  81          /* map this value to infinity */
  82          /* m = 0; - already set */
  83          e = 31;
  84       }
  85       else {
  86          /* regular */
  87          e = new_exp + 15;
  88          m = flt_m >> 13;
  89       }
  90    }
  91
  92    result = (s << 15) | (e << 10) | m;
  93    return result;
  94 }
  95
  96
  97 GLfloat verts[][4] = {
  98    {  0.9, -0.9, 0.0, 1.0 },
  99    {  0.9,  0.9, 0.0, 1.0 },
 100    { -0.9,  0.9, 0.0, 1.0 },
 101    { -0.9, -0.9, 0.0, 1.0 },
 102 };
 103
 104 GLhalf hverts[16];
 105
 106 GLubyte color[][4] = {
 107    { 0x00, 0x00, 0xff, 0x00 },
 108    { 0x00, 0xff, 0x00, 0x00 },
 109    { 0xff, 0x00, 0x00, 0x00 },
 110    { 0xff, 0xff, 0xff, 0x00 },
 111 };
 112
 113 GLuint indices[] = { 0, 1, 2, 3 };
 114
 115 static void Init( void )
 116 {
 117    GLint errno;
 118    GLuint prognum;
 119    GLuint i, j;
 120
 121    static const char *prog1 =
 122       "!!ARBvp1.0\n"
 123       "MOV  result.color, vertex.color;\n"
 124       "MOV  result.position, vertex.position;\n"
 125       "END\n";
 126
 127    if (!glutExtensionSupported("GL_ARB_half_float_vertex")) {
 128       printf("GL_ARB_half_float_vertex not found!\n");
 129       exit(0);
 130    }
 131
 132    glGenProgramsARB(1, &prognum);
 133    glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
 134    glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
 135                       strlen(prog1), (const GLubyte *) prog1);
 136
 137    assert(glIsProgramARB(prognum));
 138    errno = glGetError();
 139    printf("glGetError = %d\n", errno);
 140    if (errno != GL_NO_ERROR)
 141    {
 142       GLint errorpos;
 143
 144       glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
 145       printf("errorpos: %d\n", errorpos);
 146       printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
 147    }
 148
 149    for (i = 0; i < 4; i++)
 150       for (j = 0; j < 4; j++)
 151          hverts[i * 4 + j] = _mesa_float_to_half(verts[i][j]);
 152
 153    glEnableClientState( GL_VERTEX_ARRAY );
 154    glEnableClientState( GL_COLOR_ARRAY );
 155    glVertexPointer( 4, GL_HALF_FLOAT, 8, hverts );
 156    glColorPointer( 4, GL_UNSIGNED_BYTE, 0, color );
 157
 158 }
 159
 160
 161
 162 static void Display( void )
 163 {
 164    glClearColor(0.3, 0.3, 0.3, 1);
 165    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 166
 167    glEnable(GL_VERTEX_PROGRAM_NV);
 168    glDrawElements( GL_TRIANGLES, 3, GL_UNSIGNED_INT, indices );
 169
 170    glFlush();
 171 }
 172
 173
 174 static void Reshape( int width, int height )
 175 {
 176    glViewport( 0, 0, width, height );
 177    glMatrixMode( GL_PROJECTION );
 178    glLoadIdentity();
 179    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
 180    glMatrixMode( GL_MODELVIEW );
 181    glLoadIdentity();
 182    /*glTranslatef( 0.0, 0.0, -15.0 );*/
 183 }
 184
 185
 186 static void Key( unsigned char key, int x, int y )
 187 {
 188    (void) x;
 189    (void) y;
 190    switch (key) {
 191       case 27:
 192          exit(0);
 193          break;
 194    }
 195    glutPostRedisplay();
 196 }
 197
 198
 199
 200
 201 int main( int argc, char *argv[] )
 202 {
 203    glutInit( &argc, argv );
 204    glutInitWindowPosition( 0, 0 );
 205    glutInitWindowSize( 250, 250 );
 206    glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
 207    glutCreateWindow(argv[0]);
 208    glewInit();
 209    glutReshapeFunc( Reshape );
 210    glutKeyboardFunc( Key );
 211    glutDisplayFunc( Display );
 212    Init();
 213    glutMainLoop();
 214    return 0;
 215 }