progs/trivial/draw2arrays.c

   1 /* Basic VBO */
   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 GLfloat pos[][3] =
  12    { {  0.9, -0.9, 0.0 },
  13      {  0.9,  0.9, 0.0 },
  14      { -0.9,  0.9, 0.0 },
  15      { -0.9, -0.9, 0.0 } };
  16
  17 GLubyte color[][4] =
  18 { { 0x00, 0x00, 0xff, 0x00 },
  19   { 0x00, 0xff, 0x00, 0x00 },
  20   { 0xff, 0x00, 0x00, 0x00 },
  21   { 0xff, 0xff, 0xff, 0x00 } };
  22
  23 static void Init( void )
  24 {
  25    GLint errno;
  26    GLuint prognum;
  27
  28    static const char *prog1 =
  29       "!!ARBvp1.0\n"
  30       "MOV  result.color, vertex.color;\n"
  31       "MOV  result.position, vertex.position;\n"
  32       "END\n";
  33
  34    glGenProgramsARB(1, &prognum);
  35    glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
  36    glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
  37                       strlen(prog1), (const GLubyte *) prog1);
  38
  39    assert(glIsProgramARB(prognum));
  40    errno = glGetError();
  41    printf("glGetError = %d\n", errno);
  42    if (errno != GL_NO_ERROR)
  43    {
  44       GLint errorpos;
  45
  46       glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
  47       printf("errorpos: %d\n", errorpos);
  48       printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
  49    }
  50
  51
  52    glEnableClientState( GL_VERTEX_ARRAY );
  53    glEnableClientState( GL_COLOR_ARRAY );
  54
  55    glVertexPointer( 3, GL_FLOAT, sizeof(pos[0]), pos );
  56    glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof(color[0]), color );
  57
  58 }
  59
  60
  61
  62 static void Display( void )
  63 {
  64    glClearColor(0.3, 0.3, 0.3, 1);
  65    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  66
  67    glEnable(GL_VERTEX_PROGRAM_ARB);
  68
  69 //   glDrawArrays( GL_TRIANGLES, 0, 3 );
  70    glDrawArrays( GL_TRIANGLES, 1, 3 );
  71
  72    glFlush();
  73 }
  74
  75
  76 static void Reshape( int width, int height )
  77 {
  78    glViewport( 0, 0, width, height );
  79    glMatrixMode( GL_PROJECTION );
  80    glLoadIdentity();
  81    glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  82    glMatrixMode( GL_MODELVIEW );
  83    glLoadIdentity();
  84    /*glTranslatef( 0.0, 0.0, -15.0 );*/
  85 }
  86
  87
  88 static void Key( unsigned char key, int x, int y )
  89 {
  90    (void) x;
  91    (void) y;
  92    switch (key) {
  93       case 27:
  94          exit(0);
  95          break;
  96    }
  97    glutPostRedisplay();
  98 }
  99
 100
 101
 102
 103 int main( int argc, char *argv[] )
 104 {
 105    glutInit( &argc, argv );
 106    glutInitWindowPosition( 0, 0 );
 107    glutInitWindowSize( 250, 250 );
 108    glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
 109    glutCreateWindow(argv[0]);
 110    glewInit();
 111    glutReshapeFunc( Reshape );
 112    glutKeyboardFunc( Key );
 113    glutDisplayFunc( Display );
 114    Init();
 115    glutMainLoop();
 116    return 0;
 117 }